SecProbe.io

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April
8, 2026

     Re:
    Oruka Therapeutics, Inc.
 Acceleration Request for Registration Statement
    on Form S-3
 Registration File No. 333-294852

Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Attention: Tyler Howes

Dear Mr. Howes,

In accordance with Rule
461 under the Securities Act of 1933, as amended, we hereby request acceleration of the effective date of the Registration Statement
on Form S-3 (File No. 333-294852) (the “Registration Statement”) of Oruka Therapeutics, Inc. We respectfully request that
the Registration Statement be declared effective as of 4:00 P.M. Eastern Time on April 10, 2026, or as soon as practicable thereafter.

Once the Registration
Statement has been declared effective, please orally confirm that event with our counsel, Davis Polk & Wardwell LLP, by calling Alan
F. Denenberg at (650) 752-2004 or Beth LeBow at (650) 752-2079.

Thank you for your assistance
in this matter.

    Very truly yours,

    Oruka
                    Therapeutics, Inc.

    By:
    /s/
    Paul Quinlan

    Name:
    Paul Quinlan

    Title:
    General Counsel and Corporate Secretary

<DOCUMENT>
<TYPE>TEXT-EXTRACT
<SEQUENCE>2
<FILENAME>filename2.txt
<TEXT>
 April 7, 2026

Lawrence Klein
Chief Executive Officer
Oruka Therapeutics, Inc.
855 Oak Grove Avenue, Suite 100
Menlo Park, CA 94025

 Re: Oruka Therapeutics, Inc.
 Registration Statement on Form S-3
 Filed April 2, 2026
 File No. 333-294852
Dear Lawrence Klein:

 This is to advise you that we have not reviewed and will not review your
registration
statement.

 Please refer to Rules 460 and 461 regarding requests for acceleration.
We remind you
that the company and its management are responsible for the accuracy and
adequacy of their
disclosures, notwithstanding any review, comments, action or absence of action
by the staff.

 Please contact Tyler Howes at 202-551-3370 with any questions.

 Sincerely,

 Division of
Corporation Finance
 Office of Life
Sciences
cc: Alan Denenberg, Esq.
</TEXT>
</DOCUMENT>

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November 22, 2024

VIA EDGAR AND EMAIL

United States Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, DC 20549

    Attn:
     Jessica Dickerson

    Re:
    Oruka Therapeutics, Inc.

Registration Statement on Form S-1

Filed November 14, 2024

File No. 333-283212

To Whom it May Concern:

Pursuant to Rules 460 and 461 promulgated under
the Securities Act of 1933, as amended (the “Act”), Oruka Therapeutics, Inc., a Delaware corporation (the “Company”),
hereby respectfully requests that the effective time of the above referenced Registration Statement on Form S-1 filed by the Company be
accelerated to 4:15 p.m., Eastern Time, on November 26, 2024 or as soon thereafter as practicable, unless we or our outside counsel, Gibson,
Dunn & Crutcher LLP, request by telephone that such Registration Statement be declared effective at some other time. In making this
acceleration request, the Company acknowledges that it is aware of its obligations under the Act.

Once the Registration Statement is effective,
please orally confirm the event with our counsel, Gibson, Dunn & Crutcher LLP by calling Branden Berns at (415) 393-4631.

    Very truly yours,

    ORUKA THERAPEUTICS, INC.

    By:
    /s/ Paul Quinlan

    Name:
    Paul Quinlan

    Title:
    General Counsel

    cc:

    Arjun Agarwal, Oruka Therapeutics, Inc.

    Diana Kwon, Oruka Therapeutics, Inc.

    Ryan A. Murr, Gibson, Dunn & Crutcher LLP

    Branden C. Berns, Gibson, Dunn & Crutcher LLP

November 22, 2024
Lawrence Klein
Chief Executive Officer
Oruka Therapeutics, Inc.
855 Oak Grove Avenue
Suite 100
Menlo Park, CA 94025
Re:Oruka Therapeutics, Inc.
Registration Statement on Form S-1
Filed November 14, 2024
File No. 333-283212
Dear Lawrence Klein:
            This is to advise you that we have not reviewed and will not review your registration
statement.
            Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you
that the company and its management are responsible for the accuracy and adequacy of their
disclosures, notwithstanding any review, comments, action or absence of action by the staff.
            Please contact Jessica Dickerson at 202-551-8013 with any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:Branden Berns, Esq.

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ARCA biopharma, Inc.

10170 Church Ranch Way, Suite 100

Westminster, CO 80021

July 23, 2024

VIA EDGAR

United States Securities and Exchange Commission

Division of Corporation Finance

Office of Life Sciences

100 F. Street, N.E.

Washington, D.C. 20549

Attention: Ibolya Ignat, Daniel Gordon, Tamika Shepard and Joshua Gorsky

 Re: ARCA biopharma,
                                            Inc.

    Registration Statement on Form S-4

    File No. 333- 279387

    Acceleration Request

Ladies and Gentlemen:

Pursuant to Rule 461 of the Securities Act
of 1933, as amended, ARCA biopharma, Inc., a Delaware corporation (the “Issuer”), hereby respectfully requests
that the effectiveness of the above captioned registration statement be accelerated so that it becomes effective at 4:00 p.m., Eastern
Time, on July 24, 2024, or as soon thereafter as practicable, or at such later time as the Issuer may orally request via telephone call
to the staff of the Securities and Exchange Commission. The Issuer hereby authorizes each of Brent Fassett, Ethan Lutske, Ross Tanaka
or Savir Punia of Wilson Sonsini Goodrich & Rosati, Professional Corporation, counsel to the Issuer, to make such request on
its behalf.

Please contact Brent Fassett of Wilson Sonsini
Goodrich & Rosati, Professional Corporation, at (303) 256-5901 with any questions you may have concerning this request. In addition,
please provide a copy of the Commission’s order declaring the registration statement effective to Mr. Fassett via email at bfassett@wsgr.com
and via mail at Wilson Sonsini Goodrich & Rosati, Professional Corporation, 1155 Canyon Boulevard, Suite 400, Boulder, Colorado 80302.

    Sincerely,

    ARCA BIOPHARMA, INC.

    By:
    /s/ C. Jeffrey Dekker

    Name: C. Jeffrey Dekker

Title: Chief Financial Officer

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    Wilson
Sonsini Goodrich & Rosati

Professional Corporation

    1881
    9th Street

    Boulder,
Colorado 80302-5148

    o:
    303.256.5900

    f: 866.974.7329

    July 22, 2024

Via
EDGAR

United
States Securities and Exchange Commission

Division
of Corporation Finance

Office
of Life Sciences

100
F Street, N.E.

Washington,
D.C. 20549-3628

Attention:
Ibolya Ignat, Daniel Gordon, Tamika Sheppard and Joshua Gorsky

 Re: ARCA
biopharma, Inc.

Amendment
No. 2 Registration Statement on Form S-4

Filed
July 9, 2024

File
No. 333-279387

Ladies
and Gentlemen,

On
behalf of ARCA biopharma, Inc. (the “Company”), we are submitting this letter to the Securities and Exchange Commission
(the “SEC”) via EDGAR in response to the comment letter from the staff of the SEC (the “Staff”),
dated July 16, 2024 (the “Comment Letter”), pertaining to the Company’s above-referenced Registration Statement
on Form S-4/A (the “First Amended Registration Statement”). In connection with such responses, the Company is concurrently
filing Amendment No. 3 to the Second Amended Registration Statement (the “Third Amended Registration Statement”).

For
your convenience, the Staff’s comments are summarized in this letter, and each comment is followed by the applicable responses
on behalf of the Company. Unless otherwise indicated, page references in the responses correspond to the page numbers in the Second Amended
Registration Statement. Capitalized terms used in this letter but otherwise not defined herein shall have the meanings set forth in the
Second Amended Registration Statement.

Amendment
No. 2 to Registration Statement on Form S-4

Opinion
of Lucid, ARCA’s Financial Advisor, to ARCA’s Board of Director, page 112

 1. We
                                            note your disclosure that Lucid, in connection with its opinion, "[r]eviewed and analyzed
                                            certain internal financial analyses, including . . . projections as to cost and expenses
                                            . . . and other information concerning Oruka prepared by Oruka[.]" Please disclose these
                                            financial projections and discuss the material assumptions and limitations underlying the
                                            financial projections or, alternatively, please explain why such disclosures are not required
                                            pursuant to Item 4(b) of Form S-4 and Item 1015(b)(6) of Regulation MA.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that the requested disclosure was previously included
on pages 113 and 264 of the Third Amended Registration Statement. The Company respectfully directs the staff to the language set forth
on pages 113 and 264, which is as follows:

Further,
as ARCA’s board of directors was aware, Oruka’s management did not provide Lucid with, and Lucid did not otherwise have access
to, financial forecasts regarding Oruka’s businesses, other than certain cash burn projections, and, accordingly, Lucid did not
perform either a discounted cash flow analysis or any multiples-based analyses with respect to Oruka.

austin
     beijing
     boston
     BOULDER
     brussels
     hong kong
     london
      los angeles
     new york
     palo alto
     SALT LAKE CITY
     san diego
     san francisco
      seattle
     shanghai
     washington, dc
     wilmington, de

Securities
and Exchange Commission

July
22, 2024

Page
2

In
response to the Staff’s comment, the Company has revised the above disclosure on page 113 of the Third Amended Registration Statement
to clarify that the expected net proceeds from the Merger and the Oruka pre-closing financing, together with Oruka’s existing cash
and sales of additional convertible notes under the Purchase Agreement, will enable Oruka to fund its operating expenses through 2027.

*****

Please
contact the undersigned at (303) 256-5901 or via email at bfassett@wsgr.com if you have any questions with respect to the foregoing.

  Very truly yours,

  /s/ Brent D. Fassett

  Brent D. Fassett

  Wilson Sonsini Goodrich & Rosati P.C.

cc: Thomas
                                            A Keuer, ARCA biopharma, Inc.

C.
Jeffrey Dekker, ARCA biopharma, Inc.

Ethan
Lutske, Wilson Sonsini Goodrich & Rosati P.C.

Ross
Tanaka, Wilson Sonsini Goodrich & Rosati P.C.

Savir
S. Punia, Wilson Sonsini Goodrich & Rosati P.C.

Ryan
A. Murr, Gibson, Dunn & Crutcher LLP

Branden
C. Berns, Gibson, Dunn & Crutcher LLP

July 16, 2024
Thomas A. Keuer
President and Chief Operating Officer
ARCA biopharma, Inc.
10170 Church Ranch Way, Suite 100
Westminster, CO 80021
Re:ARCA biopharma, Inc.
Amendment No. 2 to Registration Statement on Form S-4
Filed July 9, 2024
File No. 333-279387
Dear Thomas A. Keuer:
            We have reviewed your amended registration statement and have the following comment.
            Please respond to this letter by amending your registration statement and providing the
requested information. If you do not believe the comment applies to your facts and circumstances
or do not believe an amendment is appropriate, please tell us why in your response.
            After reviewing any amendment to your registration statement and the information you
provide in response to this letter, we may have additional comments. Unless we note otherwise,
any references to prior comments are to comments in our July 3, 2024 letter.
Amendment No. 2 to Registration Statement on Form S-4
Opinion of Lucid, ARCA's Financial Advisor, to ARCA's Board of Directors, page 112
1.We note your disclosure that Lucid, in connection with its opinion, "[r]eviewed and
analyzed certain internal financial analyses, including . . . projections as to cost and
expenses . . . and other information concerning Oruka prepared by Oruka[.]" Please
disclose these financial projections and discuss the material assumptions and limitations
underlying the financial projections or, alternatively, please explain why such disclosures
are not required pursuant to Item 4(b) of Form S-4 and Item 1015(b)(6) of Regulation M-
A.

July 16, 2024
Page 2
            Please contact Jenn Do at 202-551-3743 or Daniel Gordon at 202-551-3486 if you have
questions regarding comments on the financial statements and related matters. Please contact
Tamika Sheppard at 202-551-8346 or Joshua Gorsky at 202-551-7836 with any other questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:Brent D. Fassett

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    Wilson Sonsini Goodrich & Rosati

    Professional Corporation

    1881 9th Street

    Suite 110

    Boulder, CO 80302

    o: 303.256.5900

    f: 866.974.7329

July 9, 2024

Via EDGAR

United States Securities and Exchange Commission

Division of Corporation Finance

Office of Life Sciences

100 F Street, N.E.

Washington, D.C. 20549-3628

Attention: Ibolya Ignat, Daniel Gordon, Tamika Sheppard and Joshua
Gorsky

 Re: ARCA biopharma, Inc.

Registration Statement on Form S-4

Filed June 18, 2024

File No. 333-279387

Ladies and Gentlemen,

On behalf of ARCA biopharma, Inc. (the “Company”),
we are submitting this letter to the Securities and Exchange Commission (the “SEC”) via EDGAR in response to the comment
letter from the staff of the SEC (the “Staff”), dated July 3, 2024 (the “Comment Letter”), pertaining
to the Company’s above-referenced Registration Statement on Form S-4/A (the “First Amended Registration Statement”).
In connection with such responses, the Company is concurrently filing Amendment No. 2 to the First Amended Registration Statement (the
“Second Amended Registration Statement”).

For your convenience, the Staff’s comments
are summarized in this letter, and each comment is followed by the applicable responses on behalf of the Company. Unless otherwise indicated,
page references in the responses correspond to the page numbers in the Second Amended Registration Statement. Capitalized terms used in
this letter but otherwise not defined herein shall have the meanings set forth in the Second Amended Registration Statement.

Amendment No. 1 to Registration Statement
on Form S-4

Oruka’s Pipeline, page 214

 1. We note your response to prior comment 11 and your revised disclosure on page 214. We note that the
pipeline table does not provide an indication for ORKA-003 or “Combinations.” Given the status of development and limited disclosure
regarding the programs for ORKA-003 and “Combinations,” it does not appear appropriate to highlight these programs in your pipeline
table. If these programs are material to your business to warrant inclusion in your pipeline table, please expand your disclosure in your
Business section to provide a more fulsome discussion of these programs, including descriptions of preclinical studies or other development
activities conducted. Alternatively, please remove these programs from the pipeline table or advise.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the pipeline table on page 214
of the Second Amended Registration Statement to remove the programs from the pipeline table in response to the Staff’s comment.

austin  beijing  boston
BOULDER  brussels  hong kong  london  los angeles  new york  palo alto

SALT LAKE CITY  san diego  san francisco  seattle  shanghai  washington, dc  wilmington, de

Securities and Exchange Commission

July 9, 2024

Page 2

 2. Please revise your pipeline table to include columns of equal width for each of Phase 1,
Phase 2 and Phase 3 of clinical testing.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the pipeline table on page 214
of the Second Amended Registration Statement in response to the Staff’s comment.

*****

Please contact the undersigned at (303) 256-5901
or via email at bfassett@wsgr.com if you have any questions with respect to the foregoing.

    Very truly yours,

    /s/ Brent D. Fassett

    Brent D. Fassett

    Wilson Sonsini Goodrich & Rosati P.C.

cc: Thomas A Keuer, ARCA biopharma, Inc.

C. Jeffrey Dekker, ARCA
biopharma, Inc.

Ethan Lutske, Wilson Sonsini
Goodrich & Rosati P.C.

Ross Tanaka, Wilson Sonsini
Goodrich & Rosati P.C.

Savir S. Punia, Wilson
Sonsini Goodrich & Rosati P.C.

Ryan A. Murr, Gibson, Dunn
& Crutcher LLP

Branden C. Berns, Gibson,
Dunn & Crutcher LLP

July 3, 2024
Thomas A. Keuer
President and Chief Operating Officer
ARCA biopharma, Inc.
10170 Church Ranch Way, Suite 100
Westminster, CO 80021
Re:ARCA biopharma, Inc.
Amendment No. 1 to Registration Statement on Form S-4
Filed June 18, 2024
File No. 333-279387
Dear Thomas A. Keuer:
            We have reviewed your amended registration statement and have the following
comments.
            Please respond to this letter by amending your registration statement and providing the
requested information. If you do not believe a comment applies to your facts and circumstances
or do not believe an amendment is appropriate, please tell us why in your response.
            After reviewing any amendment to your registration statement and the information you
provide in response to this letter, we may have additional comments. Unless we note otherwise,
any references to prior comments are to comments in our June 11, 2024 letter.
Amendment No. 1 to Registration Statement on Form S-4
Oruka's Pipeline, page 214
1.We note your response to prior comment 11 and your revised disclosure on page 214. We
note that the pipeline table does not provide an indication for ORKA-003 or
"Combinations." Given the status of development and limited disclosure regarding the
programs for ORKA-003 and "Combinations," it does not appear appropriate to highlight
these programs in your pipeline table. If these programs are material to your business to
warrant inclusion in your pipeline table, please expand your disclosure in your Business
section to provide a more fulsome discussion of these programs, including descriptions of
preclinical studies or other development activities conducted. Alternatively, please
remove these programs from the pipeline table or advise.
2.Please revise your pipeline table to include columns of equal width for each of Phase 1,
Phase 2 and Phase 3 of clinical testing.

July 3, 2024
Page 2
            Please contact Jenn Do at 202-551-3743 or Kevin Kuhar at 202-551-3662 if you have
questions regarding comments on the financial statements and related matters. Please contact
Tamika Sheppard at 202-551-8346 or Joshua Gorsky at 202-551-7836 with any other questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:Brent D. Fassett

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  Wilson Sonsini Goodrich & Rosati

Professional Corporation

650 Page Mill Road

Palo Alto, California 94304-1050

o: 650.493.9300

f: 866.974.7329

Via EDGAR

United States Securities and Exchange Commission

Division of Corporation Finance

Office of Life Sciences

100 F Street, N.E.

Washington, D.C. 20549-3628

Attention: Ibolya Ignat, Daniel Gordon, Tamika Sheppard and Joshua
Gorsky

 Re: ARCA biopharma, Inc.

Registration Statement on Form S-4

Filed May 14, 2024

File No. 333-279387

Ladies and Gentlemen,

On behalf of ARCA biopharma, Inc. (the “Company”),
we are submitting this letter to the Securities and Exchange Commission (the “SEC”) via EDGAR in response to the comment
letter from the staff of the SEC (the “Staff”), dated June 11, 2024 (the “Comment Letter”), pertaining
to the Company’s above-referenced Registration Statement on Form S-4 (the “Registration Statement”). In connection
with such responses, the Company is concurrently filing Amendment No. 1 to the Registration Statement (the “Amended Registration
Statement”).

For your convenience, the Staff’s comments
are summarized in this letter, and each comment is followed by the applicable responses on behalf of the Company. Unless otherwise indicated,
page references in the responses correspond to the page numbers in the Amended Registration Statement. Capitalized terms used in this
letter but otherwise not defined herein shall have the meanings set forth in the Amended Registration Statement.

Registration Statement on Form S-4

Cover Page

1. Please clarify your disclosure to state, if true, that upon the completion of the proposed merger,
the combined company will be a “controlled company” under the Nasdaq listing rules. To the extent necessary, please also add
a risk factor discussing the risks to shareholders related to owning shares in a controlled company.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on the Cover
Page of the Amended Registration Statement in response to the Staff’s comment to state that the Company will not be a “controlled
company” under the Nasdaq listing rules.

2. We note your disclosure that ARCA “intends to file an initial listing application for the combined
company with Nasdaq.” Please revise your disclosure here to clarify whether the Merger is contingent upon the approval of your Nasdaq
listing application.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on the Cover
Page and on page 13 of the Amended Registration Statement in response to the Staff’s comment to state that the listing approval
for ARCA biopharma, Inc.’s securities on the Nasdaq is a closing condition of the merger.

austin      beijing      boston      BOULDER      brussels      hong kong      london      los angeles      new york      palo alto

SALT LAKE CITY      san diego      san francisco      seattle      shanghai      washington, dc      wilmington, de

Securities and Exchange Commission

June 18, 2024

Page 2

Risk Factors

Risks Related to the Merger

ARCA’s expected disposal of its
historical assets and operations in connection with its proposed Merger…, page 15

3. We note your disclosure here that “ARCA has two remaining ongoing development programs, and it
will dispose of (or is in the process of disposing of) its legacy technology and intellectual property.” Please clarify here and
elsewhere as appropriate whether ARCA expects to dispose of its historical assets regardless of whether the stockholders approve the Merger.
Additionally, please clarify here and elsewhere as appropriate whether the “legacy technology and intellectual property” that
ARCA is in the process of disposing of includes the development programs for Gencaro and rNAPc2.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on pages 18
and 198 of the Amended Registration Statement in response to the Staff’s comment.

Risks Related to Oruka’s Reliance
on Third Parties

Oruka currently relies, and plans to rely
in the future, on third parties…, page 72

4. Please revise your disclosure to explain that the current U.S. House of Representatives version
of the BIOSECURE Act identifies WuXi Biologics as a biotechnology company of concern. Additionally, please revise your disclosure to clarify whether
WuXi Biologics (Hong Kong) Limited is a subsidiary or affiliate of WuXi Biologics.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on page 73 of
the Amended Registration Statement in response to the Staff’s comment.

The Merger

Background of the Merger, page 96

5. We note your disclosure that in June of 2022, the Special Committee determined to abandon a non-binding
proposal for a reverse merger styled transaction due to the counterparty’s “early stage of development and substantial cash needs.”
Please revise your disclosure here to provide further details about that counterparty’s stage of development.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on page 98 of
the Amended Registration Statement in response to the Staff’s comment.

Securities and Exchange Commission

June 18, 2024

Page 3

6. We note your disclosure that it was the view of the Special Committee “that the $6,000,000 enterprise
value ascribed to ARCA was within the range of values ascribed in other recent reverse merger transactions . . . .” Please provide
further details about the range of values that the Special Committee examined in this regard, including, but not limited to, the low-end
and high-end of those values. Additionally, please provide further details about the companies that were involved in the other recent
reverse merger transactions that the Special Committee reviewed.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on pages 102,
115, 116, 118, 119 and 120 of the Amended Registration Statement in response to the Staff’s comment.

Material U.S. Federal Income Tax Consequences
of the Merger, page 125

7. We note your disclosure that the parties “intend” for the Merger to qualify as a reorganization
within the meaning of Section 368(a) of the Internal Revenue Code. Please revise to make clear whether the parties expect the Merger to
be tax-free to U.S. holders. If you are able to conclude that the Merger is likely to be tax-free to U.S. holders, please file a
tax opinion supporting such a conclusion. If there is uncertainty regarding the tax treatment of the Merger, counsel’s opinion
should discuss the degree of uncertainty. For further guidance see Staff Legal Bulletin No. 19 and Item 601(b)(8) of Regulation S-K.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that, in accordance with Section III of Staff Legal
Bulletin No. 19, the Company will file a pre-effective amendment that includes opinions of counsel from the Company and Oruka covering
the material tax consequences of the merger as Exhibit 8.1 and Exhibit 8.2 to the Registration Statement and will revise the applicable
disclosures in the Registration Statement accordingly.

ARCA’s Business

Overview, page 196

8. We note your disclosure on page 18 that ARCA plans to dispose of its historical assets and operations
in connection with the proposed Merger. Please revise your disclosure in this section and elsewhere as appropriate to explain how and
when the disposal of such assets and operations is expected to take place.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on pages 18 and 198 of
the Amended Registration Statement in response to the Staff’s comment.

Securities and Exchange Commission

June 18, 2024

Page 4

ORKA-001, page 212

9. We note your disclosure that “[b]ased on recent precedent for PsO, Oruka anticipates that the
entire development program from first-in-human to biologics license application [] filing could take as little as six to seven years based
on the averages for recently approved medicines.” Please revise your disclosure here to note that Oruka has no control over the length
of time needed for FDA review.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on page 215 of
the Amended Registration Statement in response to the Staff’s comment.

Oruka’s Business

Overview, page 212

10. We note your disclosure on page 73 that Oruka currently relies on foreign CROs and CMOs, “including
WuXi Biologics (Hong Kong) Limited [  ] and will likely continue to rely on foreign CROs and CMOs in the future.” Please revise your
disclosure in this section to disclose the nature of the business that Oruka conducts with WuXi Biologics (Hong Kong) Limited.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on page 73 of
the Amended Registration Statement in response to the Staff’s comment.

Oruka’s Pipeline, page 212

11. Please revise your disclosure to explain what is meant by the term “Combinations” as it appears
in the pipeline table.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on page 214 of
the Amended Registration Statement in response to the Staff’s comment.

Clinical Development Plans, page 223

12. Please clarify whether Oruka has submitted an IND with the FDA for Phase 1 clinical trials involving either ORKA-001 or ORKA-002.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on pages 225
and 226 of the Amended Registration Statement in response to the Staff’s comment.

Securities and Exchange Commission

June 18, 2024

Page 5

Management Following the Merger

Non-Employee Directors, page 272

13. Please revise your disclosure here with respect to Ms. Ball to specifically identify the experience,
qualifications, attributes or skills that led to the conclusion that Ms. Ball should serve as a director. Refer to Item 401(e) of Regulation
S-K.

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on pages 274 and 275 of
the Amended Registration Statement in response to the Staff’s comment.

Unaudited Pro Forma Condensed Combined
Financial Information

Notes to Unaudited Pro Forma Condensed
Combined Financial Information

Accounting for the Merger, page 289

14. Please provide us an analysis concerning whether ARCA will become a shell company as
defined in Rule 12b-2 of the Exchange Act prior to the closing of the Merger.  Explain the plans for ARCA’s two remaining
ongoing development programs. Revise your disclosures as necessary to support the reverse recapitalization accounting planned for
the Merger.

Response: Rule 12b-2 of the
Exchange Act defines a shell company as “a registrant … that has: (1) No or nominal operations; and (2) Either: (i) No or
nominal assets; (ii) Assets consisting solely of cash and cash equivalents; or (iii) Assets consisting of any amount of cash and cash
equivalents and nominal other assets. The test for a shell company is conjunctive; that is, it must satisfy both prongs of the definition
in order to qualify as a shell company.

With respect to prong (1), the Company
during the three months ended March 31, 2024 had ongoing operations as reflected in its quarterly spend of $2.4 million, a portion of
which related to research and development expenses. As such, the Company has more than nominal operations. With respect to prong (2),
the Company has two remaining ongoing development programs, Gencaro and rNAPc2, including technology and intellectual property related
to such programs. As such, the Company has more than nominal other assets. In the absence of the Merger, the Company would not consider
itself a shell company and, accordingly, prior to the consummation of the Merger, the Company will not consider itself a shell company.

In January of 2024, the SEC published
an adopting release with respect to Special Purpose Acquisition Companies, Shell Companies, and Projections (the “Release”).
In footnote 943 of the Release, the SEC

clarified what it has stated to have
been its longstanding position that “the requirements applicable to reporting shell company business combinations adopted herein
will apply to any company that sells or otherwise disposes of its historical assets or operations in connection with or as part of a plan
to combine with a non-shell private company in order to convert the private company into a public one. This is true regardless of whether
such sale or disposal of the legacy assets or operations occurs prior to or after the consummation of the business combination.”
As reflected, in the Amended Registration Statement, the Company expects to dispose of its legacy technology and intellectual property,
including those related to Gencaro and rNAPc2, upon the consummation of the Merger. Any such disposal of legacy technology and intellectual
property will be contingent upon obtaining stockholder approval for the Merger. Accordingly, the Company acknowledges that in accordance
with the SEC’s position articulated in the Release, the Company will become a shell company upon consummation of the Merger.

Securities and Exchange Commission

June 18, 2024

Page 6

With
respect to the reverse recapitalization accounting treatment that is reflected in the Unaudited Pro Forma Condensed Combined Financial
Information, the Company is considered in the Merger to be the accounting acquirer. According to section 12100 of the SEC’s Financial
Reporting Manual, “[t]he Staff considers a public shell reverse acquisition to be a capital transaction in substance, rather than
a business combination. That is, the transaction is a reverse recapitalization, equivalent to the issuance of stock by the private company
for the net monetary assets of the shell corporation accompanied by a recapitalization. The accounting is similar to that resulting from
a reverse acquisition, except that no goodwill or other intangible assets should be recorded.” Given the Company’s conclusion
above that the Company will become a shell company upon consummation of the Merger, we respectfully note our view that the accounting
treatment that is reflected in the Unaudited Pro Forma Condensed Combined Financial Information is accurate as written.

Adjustments to Unaudited Pro Forma Condensed
Combined Balance Sheet as of March 31, 2024, page 290

15. Please revise your disclosure in this note to more clearly explain how you arrived to the amounts
presented for adjustment 5(c.) For example, it is not clear from your narrative whether the $249.8 million adjustment to
cash is net of transaction costs of $20.0 million given that the transaction costs appear to have been accounted
for on a separate line through adjustment 5(d.) Consider disaggregating the $249.8 million adjustments recorded to cash and to APIC
similar to the table presented for adjustment 5(j.)

Response:
The Company respectfully acknowledges the Staff’s comment and advises the Staff that it has revised the disclosure on page 292 of
the Amended Registration Statement in response to the Staff’s comment.

Comparison of Rights of Holders of ARCA
Capital Stock and Oruka Capital Stock, page 299

16. We note your disclosure here, as well as in your risk factor on page 84 that the combined company will
provide for the federal district courts of the United States of America to be the exclusive forum for the resolution of any complaint
asserting a cause of action against the combin

United States securities and exchange commission logo
June 11, 2024
Thomas A. Keuer
President and Chief Operating Officer
ARCA biopharma, Inc.
10170 Church Ranch Way, Suite 100
Westminster, CO 80021
Re:ARCA biopharma, Inc.
Registration Statement on Form S-4
Filed May 14, 2024
File No. 333-279387
Dear Thomas A. Keuer:
            We have reviewed your registration statement and have the following comments.
            Please respond to this letter by amending your registration statement and providing the
requested information. If you do not believe a comment applies to your facts and circumstances
or do not believe an amendment is appropriate, please tell us why in your response.
            After reviewing any amendment to your registration statement and the information you
provide in response to this letter, we may have additional comments.
Registration Statement on Form S-4
Cover Page
1.Please clarify your disclosure to state, if true, that upon the completion of the proposed
merger, the combined company will be a "controlled company" under the Nasdaq listing
rules. To the extent necessary, please also add a risk factor discussing the risks to
shareholders related to owning shares in a controlled company.
2.We note your disclosure that ARCA "intends to file an initial listing application for the
combined company with Nasdaq." Please revise your disclosure here to clarify whether
the Merger is contingent upon the approval of your Nasdaq listing application.

 FirstName LastNameThomas A. Keuer
 Comapany NameARCA biopharma, Inc.
 June 11, 2024 Page 2
 FirstName LastName
Thomas A. Keuer
ARCA biopharma, Inc.
June 11, 2024
Page 2
Risk Factors
Risks Related to the Merger
ARCA's expected disposal of its historical assets and operations in connection with its proposed
Merger . . . , page 15
3.We note your disclosure here that "ARCA has two remaining ongoing development
programs, and it will dispose of (or is in the process of disposing of) its legacy technology
and intellectual property." Please clarify here and elsewhere as appropriate whether
ARCA expects to dispose of its historical assets regardless of whether the stockholders
approve the Merger. Additionally, please clarify here and elsewhere as
appropriate whether the "legacy technology and intellectual property" that ARCA is in the
process of disposing of includes the development programs for Gencaro and rNAPc2.
Risks Related to Oruka's Reliance on Third Parties
Oruka currently relies, and plans to rely in the future, on third parties . . . , page 72
4.Please revise your disclosure to explain that the current U.S. House of Representatives
version of the BIOSECURE Act identifies WuXi Biologics as a biotechnology company
of concern. Additionally, please revise your disclosure to clarify whether WuXi Biologics
(Hong Kong) Limited is a subsidiary or affiliate of WuXi Biologics.
The Merger
Background of the Merger, page 96
5.We note your disclosure that in June of 2022, the Special Committee determined to
abandon a non-binding proposal for a reverse merger styled transaction due to the
counterparty's "early stage of development and substantial cash needs." Please revise your
disclosure here to provide further details about that counterparty's stage of development.
6.We note your disclosure that it was the view of the Special Committee "that the
$6,000,000 enterprise value ascribed to ARCA was within the range of values ascribed in
other recent reverse merger transactions . . . ." Please provide further details about the
range of values that the Special Committee examined in this regard, including, but not
limited to, the low-end and high-end of those values. Additionally, please provide further
details about the companies that were involved in the other recent reverse merger
transactions that the Special Committee reviewed.
Material U.S. Federal Income Tax Consequences of the Merger, page 125
7.We note your disclosure that the parties "intend" for the Merger to qualify as a
reorganization within the meaning of Section 368(a) of the Internal Revenue Code. Please
revise to make clear whether the parties expect the Merger to be tax-free to U.S. holders.
If you are able to conclude that the Merger is likely to be tax-free to U.S. holders, please
file a tax opinion supporting such a conclusion. If there is uncertainty regarding the tax
treatment of the Merger, counsel’s opinion should discuss the degree of uncertainty. For

 FirstName LastNameThomas A. Keuer
 Comapany NameARCA biopharma, Inc.
 June 11, 2024 Page 3
 FirstName LastName
Thomas A. Keuer
ARCA biopharma, Inc.
June 11, 2024
Page 3
further guidance see Staff Legal Bulletin No. 19 and Item 601(b)(8) of Regulation S-K.
ARCA's Business
Overview, page 196
8.We note your disclosure on page 18 that ARCA plans to dispose of its historical assets
and operations in connection with the proposed Merger. Please revise your disclosure in
this section and elsewhere as appropriate to explain how and when the disposal of such
assets and operations is expected to take place.
ORKA-001, page 212
9.We note your disclosure that "[b]ased on recent precedent for PsO, Oruka anticipates that
the entire development program from first-in-human to biologics license application []
filing could take as little as six to seven years based on the averages for recently approved
medicines." Please revise your disclosure here to note that Oruka has no control over the
length of time needed for FDA review.
Oruka's Business
Overview, page 212
10.We note your disclosure on page 73 that Oruka currently relies on foreign CROs and
CMOs, "including WuXi Biologics (Hong Kong) Limited [] and will likely continue to
rely on foreign CROs and CMOs in the future." Please revise your disclosure in this
section to disclose the nature of the business that Oruka conducts with WuXi Biologics
(Hong Kong) Limited.
Oruka's Pipeline, page 212
11.Please revise your disclosure to explain what is meant by the term "Combinations" as it
appears in the pipeline table.
Clinical Development Plans, page 223
12.Please clarify whether Oruka has submitted an IND with the FDA for Phase 1 clinical
trials involving either ORKA-001 or ORKA-002.
Management Following the Merger
Non-Employee Directors, page 272
13.Please revise your disclosure here with respect to Ms. Ball to specifically identify the
experience, qualifications, attributes or skills that led to the conclusion that Ms. Ball
should serve as a director. Refer to Item 401(e) of Regulation S-K.

 FirstName LastNameThomas A. Keuer
 Comapany NameARCA biopharma, Inc.
 June 11, 2024 Page 4
 FirstName LastName
Thomas A. Keuer
ARCA biopharma, Inc.
June 11, 2024
Page 4
Unaudited Pro Forma Condensed Combined Financial Information
Notes to Unaudited Pro Forma Condensed Combined Financial Information
Accounting for the Merger, page 289
14.Please provide us an analysis concerning whether ARCA will become a shell company as
defined in Rule 12b-2 of the Exchange Act prior to the closing of the Merger.  Explain the
plans for ARCA's two remaining ongoing development programs. Revise your disclosures
as necessary to support the reverse recapitalization accounting planned for the Merger.
5. Adjustments to Unaudited Pro Forma Condensed Combined Balance Sheet as of March 31,
2024, page 290
15.Please revise your disclosure in this note to more clearly explain how you arrived to the
amounts presented for adjustment 5(c.) For example, it is not clear from your narrative
whether the $249.8 million adjustment to cash is net of transaction costs of $20.0 million
given that the transaction costs appear to have been accounted for on a separate line
through adjustment 5(d.) Consider disaggregating the $249.8 million adjustments recorded
to cash and to APIC similar to the table presented for adjustment 5(j.)
Comparison of Rights of Holders of ARCA Capital Stock and Oruka Capital Stock, page 299
16.We note your disclosure here, as well as in your risk factor on page 84 that the combined
company will provide for the federal district courts of the United States of America to be
the exclusive forum for the resolution of any complaint asserting a cause of action against
the combined company or any of its directors, officers, employees, or agents and arising
under the Securities Act. Please disclose that there is uncertainty as to whether a court
would enforce such a provision. Please also state that investors cannot waive compliance
with the federal securities laws and the rules and regulations thereunder. In that regard, we
note that Section 22 of the Securities Act creates concurrent jurisdiction for federal and
state courts over all suits brought to enforce any duty or liability created by the Securities
Act or the rules and regulations thereunder. Additionally, please revise to note that this
provision may also make it more costly for a shareholder to bring a claim against you.
Principal Stockholders of ARCA, page 309
17.For the table here, as well as the table on page 312, please identify in footnotes all natural
persons who have voting and/or investment power over the shares held by named entities.

 FirstName LastNameThomas A. Keuer
 Comapany NameARCA biopharma, Inc.
 June 11, 2024 Page 5
 FirstName LastName
Thomas A. Keuer
ARCA biopharma, Inc.
June 11, 2024
Page 5
            We remind you that the company and its management are responsible for the accuracy
and adequacy of their disclosures, notwithstanding any review, comments, action or absence of
action by the staff.
            Refer to Rules 460 and 461 regarding requests for acceleration. Please allow adequate
time for us to review any amendment prior to the requested effective date of the registration
statement.
            Please contact Ibolya Ignat at 202-551-3636 or Daniel Gordon at 202-551-3486 if you
have questions regarding comments on the financial statements and related matters. Please
contact Tamika Sheppard at 202-551-8346 or Joshua Gorsky at 202-551-7836 with any other
questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Brent D. Fassett

CORRESP
1
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CORRESP

 ARCA biopharma, Inc.

10170 Church Ranch Way, Suite 100

Westminster, Colorado 80021

 (720) 940-2200

 March 26, 2021

VIA EDGAR

 United States
Securities and Exchange Commission

 Division of Corporation Finance

100 F Street, N.E.

 Washington, D.C. 20549

Attn:    Ms. Westbrook

Re:    ARCA biopharma, Inc.

  Registration Statement on Form S-3

  File No. 333-254585

Acceleration Request

Requested Date:

Tuesday, March 30, 2021

Requested Time:

4:00 p.m. Eastern Time

 Ladies and Gentlemen:

 Pursuant
to Rule 461 under the Securities Act of 1933, as amended, ARCA biopharma, Inc. hereby requests that the Securities and Exchange Commission take appropriate action to cause the above-referenced Registration Statement on Form S-3 to become effective at 4:00 p.m. Eastern Time on Tuesday, March 30, 2021, or as soon thereafter as is practicable.

If you have any questions regarding this request, please contact Brent D. Fassett of Cooley LLP at (720) 566 4025 or Ryan Lewis of Cooley
LLP at (720) 576-1913.

Sincerely,

ARCA BIOPHARMA, INC.

By:

 /s/ Brian Selby

Brian Selby

Vice President, Finance

United States securities and exchange commission logo
March 26, 2021
Michael Bristow
President and Chief Executive Officer
ARCA biopharma, Inc.
10170 Church Ranch Way, Suite 100
Westminster, CO 80021
Re:ARCA biopharma, Inc.
Registration Statement on Form S-3
Filed March 22, 2021
File No. 333-254585
Dear Dr. Bristow:
            This is to advise you that we have not reviewed and will not review your registration
statement.
            Please refer to Rules 460 and 461 regarding requests for acceleration.  We remind you
that the company and its management are responsible for the accuracy and adequacy of their
disclosures, notwithstanding any review, comments, action or absence of action by the staff.
            Please contact Christine Westbrook at 202-551-5019 with any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Brent D. Fassett, Esq.

CORRESP
1
filename1.htm

CORRESP

 Via Edgar

May 18, 2020

 United States Securities and Exchange Commission

 Division of Corporation Finance

 Office of Life Sciences

 100 F Street, N.E.

 Washington, D.C. 20549

Attn: Paul Fischer

RE:

 ARCA biopharma, Inc. (the “Registrant”)

Registration Statement on Form S-3

 Filed May 7,
2020

 File No. 333-238067

 Acceleration Request

         Requested Date:        May 20,
2020

         Requested Time:       4:00 P.M. Eastern
Time

 Ladies and Gentlemen:

In accordance with Rule 461 under the Securities Act of 1933, as amended, the Registrant hereby requests that the Securities and Exchange
Commission take appropriate action to cause the above-referenced Registration Statement on Form S-3 (the “Registration Statement”) to become effective on May 20, 2020, at 4:00 p.m., Eastern Time, or as soon thereafter as is
practicable, or at such later time as the Registrant may orally request via telephone call to the staff of the Division of Corporation Finance. The Registrant hereby authorizes each of Brent Fassett, Nathan Jeffries and Kurtis Zinger of Cooley LLP,
counsel to the Registrant, to make such request on its behalf.

 Once the Registration Statement has been declared effective, please orally
confirm that event with Brent Fassett of Cooley LLP at (720) 566-4025, or in his absence either Judy Lai of Cooley LLP at (720) 566-4039 or Kurtis Zinger of Cooley LLP at (702) 566-4057.

Very truly yours,

/s/ Brian L. Selby

 Brian L. Selby

 Vice President,
Finance

cc:

 Brent Fassett, Cooley LLP

 Judy Lai, Cooley
LLP

 Kurtis Zinger, Cooley LLP

United States securities and exchange commission logo
May 14, 2020
Michael Bristow, M.D.
President
ARCA biopharma, Inc.
11080 Circle Point Road, Suite 140
Westminster, CO 80020
Re:ARCA biopharma, Inc.
Registration Statement on Form S-3
Filed May 7, 2020
File No. 333-238067
Dear Dr. Bristow:
            This is to advise you that we have not reviewed and will not review your registration
statement.
            Please refer to Rules 460 and 461 regarding requests for acceleration.  We remind you
that the company and its management are responsible for the accuracy and adequacy of their
disclosures, notwithstanding any review, comments, action or absence of action by the staff.
            Please contact Paul Fischer at 202-551-3415 with any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Brent Fassett, Esq.

CORRESP
1
filename1.htm

Acceleration Request

 May 10, 2017

VIA EDGAR

 U.S. Securities and
Exchange Commission

 Division of Corporation Finance

 100 F
Street, N.E.

 Washington, D.C. 20549

Attn:

Dorrie Yale

Re:

ARCA biopharma, Inc.

 Registration Statement on Form S-3

 File No. 333-217459

 Acceleration Request

             Requested
Date:                Friday, May 12, 2017

             Requested
Time:               4:00 P.M. Eastern Daylight Time

 Ladies and Gentlemen:

 In
accordance with Rule 461 under the Securities Act of 1933, as amended, the undersigned registrant (the “Registrant”) hereby requests that the Securities and Exchange Commission (the “Commission”) take
appropriate action to cause the above-referenced Registration Statement on Form S-3 (File No. 333-217459) (the “Registration Statement”) to become effective on May 12, 2017, at 4:00 p.m., Eastern Daylight Time, or
as soon thereafter as is practicable, or at such later time as the Registrant may orally request via telephone call to the staff (the “Staff”).

Once the Registration Statement has been declared effective, please orally confirm that event with Brent Fassett of Cooley LLP, counsel to the Registrant, at
(720) 566-4025, or in his absence, Nathan Jeffries at (720) 566-4104.

 [Signature page follows]

 Very truly yours,

ARCA BIOPHARMA, INC.

By:

/s/ Brian L. Selby

 Brian L. Selby

 Vice President,
Finance

 cc: Brent Fassett, Cooley LLP

CORRESP
1
filename1.htm

CORRESP

 May 10, 2017

VIA EDGAR

 U.S. Securities
and Exchange Commission

 Division of Corporation Finance

 100
F Street, N.E.

 Washington, D.C. 20549

 Attn:

Dorrie Yale

 Re:

 ARCA biopharma, Inc.

 Registration
Statement on Form S-3

 File No. 333-217459

 Ladies and Gentlemen:

Reference is made to our letter, filed as correspondence with the U.S. Securities and Exchange Commission via EDGAR on May 8, 2017, in which
we requested the acceleration of the effective date of the above-referenced Registration Statement on Form S-3 (File No. 333-217459) to Wednesday, May 10, 2017, at 4:00 p.m., Eastern Daylight Time, in accordance with Rule 461 under the Securities
Act of 1933, as amended. We are no longer requesting that such Registration Statement be declared effective at this time and we hereby formally withdraw our request for acceleration of the effective date thereof.

 Very truly yours,

ARCA biopharma, Inc.

By:

/s/ Brian L. Selby

 Brian L. Selby

 Vice President,
Finance

 cc: Brent Fassett, Cooley LLP

CORRESP
1
filename1.htm

Acceleration Request

 May 8, 2017

VIA EDGAR

 U.S. Securities and
Exchange Commission

 Division of Corporation Finance

 100 F
Street, N.E.

 Washington, D.C. 20549

Attn:
Dorrie Yale

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-3

File No. 333-217459

Acceleration Request

Requested Date:

Wednesday, May 10, 2017

Requested Time:

4:00 P.M. Eastern Daylight Time

 Ladies and Gentlemen:

 In
accordance with Rule 461 under the Securities Act of 1933, as amended, the undersigned registrant (the “Registrant”) hereby requests that the Securities and Exchange Commission (the “Commission”) take appropriate
action to cause the above-referenced Registration Statement on Form S-3 (File No. 333-217459) (the “Registration Statement”) to become effective on May 10, 2017, at 4:00 p.m., Eastern Daylight Time, or as soon thereafter
as is practicable, or at such later time as the Registrant may orally request via telephone call to the staff (the “Staff”).

 Once the
Registration Statement has been declared effective, please orally confirm that event with Brent Fassett of Cooley LLP, counsel to the Registrant, at (720) 566-4025, or in his absence, Nathan Jeffries at (720) 566-4104.

[Signature page follows]

Very truly yours,

ARCA BIOPHARMA, INC.

By:

/s/ Brian L. Selby

  Brian L. Selby

  Vice President, Finance

cc:
Brent Fassett, Cooley LLP

May 5, 2017
Michael Bristow
President and Chief Executive Officer
ARCA biopharma, Inc.
11080 CirclePoint Road, Suite 140
Westminster, CO 80020
ARCA biopharma, Inc.
Registration Statement on Form S-3
Filed April 25, 2017
File No. 333-217459Re:
Dear Dr. Bristow :
        This is to advise you that we have not reviewed and will not review your registration
statement.
        Please refer to Rules 460 and 461 regarding requests for acceleration.  We remind you
that the company and its management are responsible for the accuracy and adequacy of their
disclosures, notwithstanding any review, comments, action or absence of action by the staff.
        Please contact Dorrie Yale at 202-551-8776 with any questions.
Division of Corporation Finance
Office of Healthcare & Insurance
cc: Brent D. Fassett

CORRESP
1
filename1.htm

CORRESP

 July 16, 2015

VIA EDGAR

 United States
Securities and Exchange Commission

 Division of Corporation Finance

100 F Street, N.E.

 Washington, D.C. 20549

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-3

Filed: July 7, 2015

File No. 333-205533

 Ladies and Gentlemen:

ARCA biopharma, Inc. (the “Company”) hereby requests that the Securities and Exchange Commission (the
“Commission”) take appropriate action to cause the above-referenced filing to become effective at 4:00 p.m. Eastern Time on Monday, July 20, 2015, or as soon thereafter as is practicable.

The Company hereby acknowledges that:

•

should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from taking any action with respect to the filing;

•

the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from its full responsibility for the adequacy and accuracy of the
disclosure in the filing; and

•

the Company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

 Sincerely,

ARCA BIOPHARMA, INC.

By:

 /s/ Brian L. Selby

Brian L. Selby

Vice President, Finance

cc:
Jeffrey P. Riedler, Assistant Director, SEC

Christina De Rosa, Esq., SEC

Brent D. Fassett, Esq., Cooley LLP

July 15, 2015

Via E -mail
Michael R. Bristow
President and Chief Executive Officer
ARCA biopharma, Inc.
11080 CirclePoint Road, Suite 140
Westminster, CO 80020

Re: ARCA biopharma, Inc.
 Registration Statement on Form S-3
Filed  July 7, 2015
  File No.  333-205533

Dear Mr. Bristow :

This is to advise you that we have not  reviewed and will not review your registration
statement .

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes the information the Securities Act of 193 3 and
all applicable Securities  Act rules require.   Since the company and its management are  in
possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

In the event you request acceleration of the effective date of the pending regist ration
statement , please provide  a written statement from the company acknowledging that:

 should the Commission or the staff, acting pursuant to delegated authority, declare the
filing effective, it does not foreclose the Commission from taking any action wit h respect
to the filing;

 the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in th e filing; and

 the company may not assert staff comments and the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal
securities laws of the United States.

Please refer to Rules 460 and 461 regarding requests for  acceleration .  We will consider a
written request for acceleration of the effective date of the registration statement as confirmation

Michael R. Bristow
ARCA biopharma, Inc.
July 15, 2015
Page 2

 of the fact that those requesting acceleration are aware of their respective responsibilities under
the Securities Act of 1933 and the Securities Exchange Act of 1934 as they relate to the proposed
public offering of the registered securities .

Please  contact Christina De Rosa at (202) 551 -3577 or me  at (202) 551 -3715  with any
questions.

Sincerely,

 /s/ Daniel Greenspan for

 Jeffrey P. Riedler
Assistant Director

cc: Via E -mail
            Brent D. Fassett
            Cooley LLP
            380 Interlocken Crescent, Suite 900
            Broomfield, Colorado 80021

CORRESP
1
filename1.htm

CORRESP

 May 2, 2014

 VIA EDGAR

 United States
Securities and Exchange Commission

 Division of Corporation Finance

100 F Street, N.E.

 Washington, DC 20549

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-3

Filed: April 4, 2014

File No. 333-195054

 Ladies and Gentlemen:

ARCA biopharma, Inc. (the “Company”) hereby requests that the Securities and Exchange Commission (the
“Commission”) take appropriate action to cause the above-referenced filing to become effective at 4:00 p.m. Eastern Time on Tuesday, May 6, 2014, or as soon thereafter as is practicable.

The Company hereby acknowledges that:

•

should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from taking any action with respect to the filing;

•

the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from its full responsibility for the adequacy and accuracy of the
disclosure in the filing; and

•

the Company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

 Sincerely,

ARCA BIOPHARMA, INC.

By:

/s/ Patrick M. Wheeler

 Patrick M. Wheeler

 Chief Financial
Officer

cc:
Jeffrey Riedler, Assistant Director, SEC

Christina De Rosa, SEC

Brent Fassett, Esq., Cooley LLP

John Bernard, Esq., Cooley LLP

April 14, 2014

Via E -mail
Dr. Michael Bristow
President and Chief Executive Officer
ARCA biopharma, Inc.
11080 CirclePoint Road, Suite 140
Westminster, Colorado 80020

Re: ARCA biopharma, Inc.
Registration Statement on Form S-3
Filed  April 4, 2014
  File No.  333-195054

Dear Dr. Bristow :

We have limited our review of your  regist ration statement to the issue  we hav e addressed
in our comment .

Please respond to this letter by amending your registration statement and providing the
requested information .  Where  you do not believe our comment applies  to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.

After revi ewing any amendment to your registration statement and the information you
provide in response to this comment , we may have  additional comments.

1. We are currently processing your  pending request for confidential treatment.   Please be
advised that we will  not be in a position to declare this registration statement effective
until we resolve all issues concerning the confidential treatment request.

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes the information the Securities Act of 193 3 and
all applicable Securities  Act rules require.   Since the company and its management are in
possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

Dr. Michael Bristow
ARCA biopharma, Inc.
April 14, 2014
Page 2

 Notwithstanding our comment , in the event you request accel eration of the effective date
of the pending registration statement please provide a written statement from the company
acknowledging that:

 should the Commission or the staff, acting pursuant to delegated authority, declare the
filing effective, it does n ot foreclose the Commission from taking any action with respect
to the filing;

 the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

 the company  may not assert staff comments and the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal
securities laws of the United States.

Please refer to Rules 460 and 461 regarding requests for  acceleration .  We will consider a
written request for acceleration of the effective date of the registration statement as confirmation
of the fact that those requesting acceleration are aware of their respective responsibilities under
the Securities Act of 1933 and the Securities Exchange Act of 1934 as they relate to the proposed
public offering of the securities specified in the above registration statement.  Please allow
adequate time  for us to review any amendment prior to the requested effective date of  the
registration statement.

Please contact Christina De Rosa  at (202) 551 -3577  or me at (202) 551 -3715  with any
other questions.

Sincerely,

 /s/ Daniel  Greenspan  for

Jeffrey P. Riedler
Assistant Director
cc: Via E -mail
 Brent D. Fassett
 Cooley LLP
 380 Interlocken  Crescent, Suite 900
 Broomfield, CO 80021

CORRESP
1
filename1.htm

CORRESP

 May 24, 2013

 VIA EDGAR

 United States Securities and Exchange Commission

 Division of Corporation Finance

 100
F Street, N.E.

 Washington, DC 20549

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-1

Filed: March 25, 2013

File No. 333-187508

 Ladies and
Gentlemen:

 ARCA biopharma, Inc. (the “Company”) hereby requests that the Securities and Exchange Commission (the
“Commission”) take appropriate action to cause the above-referenced filing to become effective at 4:00 p.m. Eastern Time on Wednesday, May 29, 2013, or as soon thereafter as is practicable.

The Company hereby acknowledges that:

•

 should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from
taking any action with respect to the filing;

•

 the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from
its full responsibility for the adequacy and accuracy of the disclosure in the filing; and

•

 the Company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person
under the federal securities laws of the United States.

 Sincerely,

ARCA BIOPHARMA, INC.

By:

    /s/ Patrick M. Wheeler

Patrick M. Wheeler

Chief Financial Officer

cc:

Jeffrey Riedler, Assistant Director, SEC

Austin Stephenson, Esq., SEC

Daniel Greenspan, Esq., SEC

Brent D. Fassett, Esq., Cooley LLP

CORRESP
1
filename1.htm

CORRESP

 May 23, 2013

 VIA EDGAR

 United States Securities and Exchange Commission

 Division of Corporation Finance

 100
F Street, N.E.

 Washington, DC 20549

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-1

 Filed: March 25, 2013

 File No. 333-187508

Ladies and Gentlemen:

 Effective immediately, the undersigned withdraw the request for acceleration sent to your office via EDGAR on May 16, 2013, which requested that the Commission take appropriate action
to cause the above-referenced Registration Statement to become effective at 4:00 p.m. Eastern Time on May 20, 2013 or as soon thereafter as practicable. The undersigned anticipate filing an additional acceleration request in the near future.

 Sincerely,

 ARCA
BIOPHARMA, INC.

By:

 /s/ Patrick M. Wheeler

Patrick M. Wheeler

Chief Financial Officer

cc:
Jeffrey Riedler, Assistant Director, SEC

 Austin Stephenson, Esq., SEC

 Daniel Greenspan, Esq., SEC

Brent D. Fassett, Esq., Cooley LLP

CORRESP
1
filename1.htm

CORRESP

 May 16, 2013

 VIA EDGAR

 United States Securities and Exchange Commission

 Division of Corporation Finance

 100
F Street, N.E.

 Washington, DC 20549

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-1

Filed: March 25, 2013

File No. 333-187508

 Ladies and
Gentlemen:

 ARCA biopharma, Inc. (the “Company”) hereby requests that the Securities and Exchange Commission (the
“Commission”) take appropriate action to cause the above-referenced filing to become effective at 4:00 p.m. Eastern Time on Monday, May 20, 2013, or as soon thereafter as is practicable.

The Company hereby acknowledges that:

•

 should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from
taking any action with respect to the filing;

•

 the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from
its full responsibility for the adequacy and accuracy of the disclosure in the filing; and

•

 the Company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person
under the federal securities laws of the United States.

 Sincerely,

 ARCA BIOPHARMA, INC.

By:

    /s/ Patrick M. Wheeler

Patrick M. Wheeler

Chief Financial Officer

cc:

Jeffrey Riedler, Assistant Director, SEC

Austin Stephenson, Esq., SEC

Daniel Greenspan, Esq., SEC

Brent D. Fassett, Esq., Cooley LLP

CORRESP
1
filename1.htm

CORRESP

 Brent D. Fassett

 T: +1 720 566
4025

 fassettbd@cooley.com

VIA EDGAR AND FEDEX

 April 4, 2013

 Securities and Exchange Commission

 Division of Corporation Finance

100 F Street, N.E.

 Washington, D.C. 20549-3628

Attn:
Jeffrey P. Riedler

Austin Stephenson

Daniel Greenspan

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-1

Filed March 25, 2013

File No. 333-187508

 Dear Mr. Riedler:

 On behalf of our client, ARCA biopharma, Inc. (the “Company”), we submit this letter in response to comments received
from the staff (the “Staff”) of the Securities and Exchange Commission by letter dated April 2, 2013 (the “Comment Letter”) with respect to the Registration Statement. The numbering of the
paragraphs below corresponds to the numbering in the Comment Letter, the text of which we have incorporated into this response letter for convenience. Except where otherwise indicated, page references in the text of the responses below correspond to
the page numbers in Amendment No. 1 to the Registration Statement (“Amendment No. 1”), being submitted concurrently with this letter.

 Staff Comments and Company Responses

 Executive Compensation, page 38

1.
We note your inclusion of a summary compensation table in this section pursuant to Item 402(n) of Regulation S-K. Please provide the additional disclosure in
this section that is required under Item 402(o)-(r), as well as any other information required under Item 402 that is applicable to your company.

 Response: The Company acknowledges the Staff’s comment and has provided the additional disclosure on pages 38 - 43 of Amendment No. 1 as requested.

Incorporation of Certain Information by Reference, page 51

2.
Please revise to incorporate by reference all Form 8-Ks filed since the fiscal year ended December 31, 2012 as required by General Instruction VII and
Item 12 of Form S-1. We refer you to Question 113.05 of the Securities Act Forms Compliance and Disclosure Interpretations.

 380
INTERLOCKEN CRESCENT, SUITE 900, BROOMFIELD, CO 80021-8023 T: (720) 566-4000 F: (720) 566-4099 WWW.COOLEY.COM

 Securities and Exchange Commission

 April 4, 2013

 Page Two

 Response: The Company acknowledges the Staff’s comment and has provided the references to
all Form 8-Ks filed since the fiscal year ended December 31, 2012 on page 56 of Amendment No. 1 as requested.

 Undertakings, page
II-6

3.
Please revise your disclosure to include all applicable undertakings required under Item 512(a) and 512(h) of Regulation S-K.

Response: The Company acknowledges the Staff’s comment and has provided all applicable undertakings on page II-6 of Amendment No. 1 as
requested.

 **********

 380
INTERLOCKEN CRESCENT, SUITE 900, BROOMFIELD, CO 80021-8023 T: (720) 566-4000 F: (720) 566-4099 WWW.COOLEY.COM

 Securities and Exchange Commission

 April 4, 2013

 Page Three

 The Company respectfully requests the Staff’s assistance in completing the review of the
Registration Statement and Amendment No. 1 as soon as possible. Please advise us if we can provide any further information or assistance to facilitate your review. Please direct any further comments or questions regarding the Registration
Letter or this response letter to me at (720) 566-4025 or Diana M. Devot at (720) 566-4239.

 /s/ Brent D. Fassett

Brent D. Fassett

Partner, Cooley LLP

cc:
Michael Bristow, President and Chief Executive Officer

Patrick M. Wheeler, Chief Financial Officer

Diana M. Devot, Cooley LLP

Amandalee McPherson, KPMG

 380
INTERLOCKEN CRESCENT, SUITE 900, BROOMFIELD, CO 80021-8023 T: (720) 566-4000 F: (720) 566-4099 WWW.COOLEY.COM

April 2 , 2013

Via E -mail
Michael R. Bristow
President and Chief Executive Officer
ARCA biopharma, Inc.
8001 Arista Place, Suite 430
Broomfield, CO 80021

Re: ARCA biopharma, Inc.
  Registration Statement on Form S-1
Filed  March 25, 2013
  File No.  333-187508

Dear Mr. Bristow :

We have limited our review of your registration statement to those issues we have
addressed in our comments.  In  some of our comments, we may ask you to provide us with
information so we may better understand your disclosure.

Please respond to this letter by amending your registration statement and providing the
requested information .  Where you do not believe our comments apply to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.

After reviewing any amendment to your registration statement and the information you
provide in response to these  comments , we may have  additional comments.

Executive Compensation, page 38

1. We note your inclusion of a summary compensation table in this section pursuant to Item
402(n) of Regulation S -K.  Please provide the additional disclosure in this section that is
requi red under Item 402(o) -(r), as well as any other information required under Item 402
that is applicable to your company.

Incorp oration of Certain Information b y Reference, page 51

2. Please revise to incorporate by reference all Form 8 -Ks filed since the fiscal year ended
December 31, 2012 as required by General Instruction VII and Item 12 of Form S -1.  We
refer you to Question 113.05 of the Securities Act Forms Compliance a nd Disclosure
Interpretations.

Michael R. Bristow
ARCA biopharma, Inc.
April 2 , 2013
Page 2

 Undertakings, page II -6

3. Please revise your disclo sure to include all applicable undertakings required under Item
512(a) and 512(h) of Regulation S -K.

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes the informati on the Securities Act of 193 3 and
all applicable Securities  Act rules require.   Since the company and its management are in
possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures th ey have made.

Notwithstanding our comments, in the event you request acceleration of the effective date
of the pending registration statement please provide a written statement from the company
acknowledging that:

 should the Commission or the staff, acting pursuant to delegated authority, declare the
filing effective, it does not foreclose the Commission from taking any action with respect
to the filing;

 the action of the Commission or the staff, acting pursuant t o delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

 the company may not assert staff comments and the declaration of effect iveness as a
defense in any proceeding initiated by the Commission or any person under the federal
securities laws of the United States.

Please refer to Rules 460 and 461 regarding requests for  acceleration .  We will consider a
written request for acceleration of the effective date of the registration statement as confirmation
of the fact that those requesting acceleration are aware of their respective responsibilities under
the Securities Act of 1933 and the Securities Exchange Act of 1934 as they relate to the proposed
public offering of the securities specified in the above registration statement.  Please allow
adequate time  for us to review any amendment prior to the requested effective date of the
registration statement.

Michael R. Bristow
ARCA biopharma, Inc.
April 2 , 2013
Page 3

 Please conta ct Austin Stephenson at (202) 551 -3192 , Daniel Greenspan at (202) 551 -
3623,  or me at (202) 551 -3715 with any  questions.

Sincerely,

 /s/ Daniel  Greenspan  for

 Jeffrey P. Riedler
Assistant Director

cc: Via E -mail
Brent D. Fassett, Esq.
Cooley LLP

CORRESP
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filename1.htm

Correspondence

 January 24, 2012

 VIA ELECTRONIC CORRESPONDENCE AND EDGAR

 United States Securities and Exchange Commission

 Division of Corporate Finance

Mail Stop 6010

 100 F Street, N.E.

Washington, D.C. 20549

Attn:
Jeffrey Riedler

John Krug

RE:
ARCA biopharma, Inc.

Registration Statement on Form S-3 (File No. 333-178984)

 Ladies and Gentlemen:

 The undersigned registrant (the “Company”) hereby requests that
the Securities and Exchange Commission (the “Commission”) take appropriate action to cause the above-referenced Registration Statement on Form S-3 to become effective on January 26, 2012, at 4:00 p.m., Eastern Time, or as soon
thereafter as is practicable.

 In connection with this request, the Company acknowledges that:

•

 should the Commission or the staff of the Commission (the “Staff”), acting pursuant to delegated authority, declare the filing effective, it
does not foreclose the Commission from taking any action with respect to the filing;

•

 the action of the Commission or the Staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from
its full responsibility for the adequacy and accuracy of the disclosure in the filing; and

•

 the Company may not assert Staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person
under the federal securities laws of the United States.

 Very truly yours,

ARCA BIOPHARMA, INC.

 /s/ Patrick M. Wheeler

 Patrick M. Wheeler

Chief Financial Officer

cc:
Brent Fassett, Esq., Cooley LLP

CORRESP
1
filename1.htm

Correspondence

 Brent D. Fassett

 T: +1 720 566 4025

 fassettbd@cooley.com

 January 24, 2012

 Division of Corporation Finance

U.S. Securities & Exchange Commission

100 F Street, NE

 Washington, D.C. 20549

 Attn:

    Jeffrey Riedler

    John Krug

    Daniel Greenspan

 Re:

ARCA biopharma, Inc.

    Amendment No.1 to Registration Statement on Form S-3

    Filed January 12, 2012

    File Nos. 333-178984

 Dear Mr. Riedler, Mr. Krug and Mr. Greenspan:

 On behalf of ARCA biopharma, Inc. (the “Company”), enclosed for electronic filing via EDGAR pursuant to the Securities Act of 1933, as amended, is Amendment No. 1 to the
Company’s Registration Statement on Form S-3 originally filed with the Securities and Exchange Commission (the “Commission”) on January 12, 2012.

 Response to Staff Comments

 This letter includes the responses and supplemental information
requested by the staff of the Commission (the “Staff”) in a letter dated January 19, 2012 to Dr. Michael Bristow from Mr. Jeffrey Riedler. For your convenience, each of the Staff’s comments has been
reprinted in italics below.

 Amendment No. 1 reflects changes made in response to the Staff’s comments, as well as limited updating
with respect to the filing of this amendment and the final prospectus.

 Signature Page

1. Comment: The registration statement should also be signed by the registrant’s controller or principal accounting officer. Any person who
occupies more than one of the specified positions required to sign the registration statement should indicate each capacity in which he signs the registration statement. See Instructions to Signatures to Form S-3.

380 INTERLOCKEN CRESCENT, SUITE 900, BROOMFIELD, CO 80021-8023 T: (720) 566-4000 F: (720) 566-4099 WWW.COOLEY.COM

 Securities and Exchange
Commission

 January 24, 2012

 Page
Two

 Response: The Company has revised the signature page as requested to indicate that
the Company’s principal financial officer is also its principal accounting officer. The Company has obtained manually executed signature pages from such officer in both such capacities prior to the time of this electronic filing.

Please do not hesitate to contact the undersigned at (720) 566-4025 or Bryn Weaver at (720) 566-4252 if we can be of assistance.

 Very truly yours,

COOLEY LLP

 /s/ Brent D. Fassett

 Brent D. Fassett

 Enclosure

 380 INTERLOCKEN CRESCENT, SUITE 900, BROOMFIELD, CO 80021-8023 T: (720) 566-4000 F:
(720) 566-4099 WWW.COOLEY.COM

January 19, 2012
Via E-Mail
Dr. Michael Bristow President and Chief Executive Officer  ARCA biopharma, Inc. 8001 Arista Place, Suite 430 Broomfield, Colorado 80021
Re: ARCA biopharma, Inc.
  Registration Statement on Form S-3
Filed January 12, 2012
  File Nos. 333-178984

Dear Dr. Bristow:
 We have limited our review of your registra tion statement to those issues we have
addressed in our comments.  In some of our comments, we may ask you to provide us with
information so we may better understand your disclosure.
 Please respond to this letter by amending your registration statement and providing the
requested information.  Where you do not beli eve our comments apply to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.
 After reviewing any amendment to your re gistration statement and the information you
provide in response to these comments, we may have additional comments.

Signatures

1. The registration statement should also be signed by the registrant’s controller or principal
accounting officer.  Any person w ho occupies more than one of the specified positions
required to sign the registration statement should indicate each capacity in which he signs
the registration statement.  See Instru ctions to Signatures to Form S-3.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing incl udes the information the Securities Act of 1933 and
all applicable Securities Act rules require.  Since the company and its management are in
possession of all facts relating to a company’s disc losure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

Dr. Michael Bristow ARCA biopharma, Inc. January 19, 2012 Page 2

 Notwithstanding our comments, in the event you request acceleration of  the effective date
of the pending registration statement please pr ovide a written statement from the company
acknowledging that:

 should the Commission or the staff, acting purs uant to delegated authority, declare the
filing effective, it does not foreclose the Co mmission from taking any action with respect
to the filing;

 the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

 the company may not assert staff comments a nd the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.  Please refer to Rules 460 and 461 regarding re quests for acceleration.  We will consider a
written request for acceleration of  the effective date of the regi stration statement as confirmation
of the fact that those reques ting acceleration are aware of thei r respective responsibilities under
the Securities Act of 1933 and the Securities Excha nge Act of 1934 as they relate to the proposed
public offering of the securities specified in th e above registration stat ement.  Please allow
adequate time for us to review any amendment prior to the requested effective date of the
registration statement.

Please contact John Krug, Senior Counsel, at (202) 551-3862, Dan Greenspan, Branch
Chief, at (202) 551-3623 or me at  (202) 551-3715 with any questions.

Sincerely,
  /s/ Jeffrey Riedler     Jeffrey Riedler
Assistant Director
    cc: Brent D. Fassett, Esquire       Bryn P. Weaver, Esquire       Cooley LLP       300 Interlocken Crescent, Suite 900       Broomfield, Colorado 80021

CORRESP
1
filename1.htm

Correspondence

 March 31, 2011

 VIA EDGAR

 United States Securities and Exchange Commission

 Division of Corporation Finance

 100
F Street, N.E.

 Washington, DC 20549

Re:
ARCA biopharma, Inc.

Registration Statement on Form S-3

Filed: March 8, 2011

File No. 333-172686

 Ladies and
Gentlemen:

 ARCA biopharma, Inc. (the “Company”) hereby requests that the Securities and Exchange Commission (the
“Commission”) take appropriate action to cause the above-referenced filing to become effective at 4:00 p.m. Eastern Time on Monday, April 4, 2011, or as soon thereafter as is practicable.

The Company hereby acknowledges that:

•

 should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from
taking any action with respect to the filing;

•

 the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the Company from
its full responsibility for the adequacy and accuracy of the disclosure in the filing; and

•

 the Company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person
under the federal securities laws of the United States.

 Sincerely,

ARCA BIOPHARMA, INC.

By:

/s/Patrick M. Wheeler

Patrick M. Wheeler

Chief Financial Officer

cc:

Jeffrey Riedler, Assistant Director, SEC

Brent D. Fassett, Esq., Cooley LLP

March 11, 2011

Dr. Michael Bristow President and Chief Executive Officer ARCA biopharma, Inc. 8001 Arista Place, Suite 200
Broomfield, Colorado 80021

Re: ARCA biopharma, Inc.
  Registration Statement on Form S-3
Filed March 9, 2011
  File No. 333-172686

Dear Dr. Bristow:
 We have limited our review of your registration statement to the filing of Part III
information prior to effectiveness.
 Please respond to this letter by amending your registration statement to include the
required Part III information or filing your definitive proxy statement prior to requesting acceleration of the registration statement.
 After reviewing any amendment to your re gistration statement and the information you
provide in response to this comment, we may have additional comments.
 We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing incl udes the information the Securities Act of 1933 and
all applicable Securities Act rules require.  Since the company and its management are in
possession of all facts relating to a company’s disclosure, they are responsible for the accuracy and adequacy of the disclosures they have made.
Notwithstanding our comment, in the event you request acceleration of the effective date
of the pending registration statement please pr ovide a written statement from the company
acknowledging that:

• should the Commission or the staff, acting purs uant to delegated authority, declare the
filing effective, it does not foreclose the Co mmission from taking any action with respect
to the filing;

• the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

Michael Bristow ARCA biopharma, Inc. March 11, 2011 Page 2

• the company may not assert staff comments a nd the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.  Please refer to Rules 460 and 461 regarding re quests for acceleration.  We will consider a
written request for acceleration of  the effective date of the regi stration statement as confirmation
of the fact that those reques ting acceleration are aware of thei r respective responsibilities under
the Securities Act of 1933 and the Securities Excha nge Act of 1934 as they relate to the proposed
public offering of the securities specified in the above registration stat ement.  Please allow
adequate time for us to review any amendment prior to the requested effective date of the registration statement.
 Please contact Johnny Gharib at (202) 551- 3170 or me at (202) 551-3715 with any
questions.
Sincerely,
       Jeffrey Riedler
Assistant Director
 cc:  Brent D. Fassett, Esq.  Cooley LLP  380 Interlocken Crescent, Suite 900  Broomfield, Colorado 80021

December 22, 2010
 Patrick M. Wheeler Chief Financial Officer ARCA biopharma, Inc. 8001 Arisra Place, Suite 200 Broomfiled, CO  80021
Re: ARCA biopharma, Inc.
 Form 10-K for Fiscal Year Ended December 31, 2009
  Filed March 4, 2010
File No.  000-22873

Dear Mr. Wheeler:
 We have completed our review of your Form 10-K and have no further comments at this
time.           S i n c e r e l y ,             J o e l  P a r k e r          A c c o u n t i n g  B r a n c h  C h i e f

CORRESP
1
filename1.htm

Correspondence Letter

 8001 Arista Place, Suite 200

 Broomfield, CO 80021

 Phone: 720-940-2200, Fax: 720-208-9261

 December 21, 2010

 Jim B.
Rosenberg

 Senior Assistant Chief Accountant

 Division of Corporation Finance

 U.S. Securities and Exchange Commission

450 Fifth Street, N.W.

 Washington, D.C. 20549

Re:
 ARCA biopharma, Inc.

 Form 10-K for Fiscal Year Ended December 31, 2009

 Filed March 4, 2010

 File No. 000-22873

 Dear
Mr. Rosenberg,

 On behalf of ARCA biopharma, Inc. (“ARCA”), this letter responds to the comments of the Staff of the Securities
and Exchange Commission (the “Commission”) set forth in the letter dated December 10, 2010 (“Comment Letter”) relating to the above-referenced Annual Report on Form 10-K. Set forth in italicized print below is the
Staff’s comment, as set forth in the Comment Letter, followed by ARCA’s response.

 Form 10-K for the Fiscal Year Ended
December 31, 2009

 Item 8. Financial Statements and Supplementary Data

Consolidated Statement of Cash Flows, page 66

1.
Please tell us why your statement of cash flows reflects a $20.5 million change in accrued expenses and other liabilities, while the balance sheet appears to
indicate that the change in these accounts is substantially less. Similarly, please also address the change in your accounts payable.

 ARCA’s Response:

 The difference between the change in accrued expenses and other liabilities
reflected on the statement of cash flows compared to the change indicated on the balance sheet is primarily caused by the accrued expenses and other liabilities that ARCA assumed in the merger with Nuvelo, Inc. on January 27, 2009 (the
“Merger”) and the subsequent satisfaction of such liabilities prior to December 31, 2009. As follows, ARCA has supplementally provided a roll-forward of the accrued expenses and other liabilities balances from December 31, 2008
to December 31, 2009.

 1

 ARCA biopharma, Inc.

 File No. 000-22873

(in thousands)

Accrued expenses and other liabilities

 Balances as of December 31, 2008:

 Accrued compensation and employee benefits

$
1,071

 Accrued expenses and other liabilities

1,549

 Subtotal

$
2,620

 Liabilities assumed in the Merger: {a}

 Accrued employee liabilities

3,579

 Other current liabilities

1,406

 Accrued facility exit costs

13,278

 Other liabilities

74

 Unfavorable lease obligation

943

 Subtotal

19,280

 Change in accrued expenses and other liabilities (net of amounts acquired and noncash items), as per the statement of cash
flows:

(20,454
)

 Other roll-forward items, net: {b}

(449
)

 Balances as of December 31, 2009:

 Accrued compensation and employee benefits

241

 Accrued expenses and other liabilities

756

 Total

$
997

{a}
See Note 2, Merger with Nuvelo, Inc. on January 27, 2009, to ARCA’s consolidated financial statements on Form 10-K for the year ended December 31,
2009 for the acquisition consideration allocation as of the date of the Merger.

{b}
Other roll-forward items, net includes, among other items, adjustments to reconcile net loss to net cash used in operating activities and certain noncash transactions.

 2

 ARCA biopharma, Inc.

 File No. 000-22873

 The difference between the change in accounts payable reflected on the statement of cash flows compared
to the change indicated on the balance sheet is primarily caused by the accounts payable that ARCA assumed as a result of the Merger and the subsequent satisfaction of such liabilities prior to December 31, 2009. As follows, ARCA has
supplementally provided a roll-forward of the accounts payable balance from December 31, 2008 to December 31, 2009.

(in thousands)

 Accounts Payable

 Balance as of December 31, 2008

$
804

 Accounts payable assumed in the Merger {a}

2,189

 Change in accounts payable (net of amounts acquired), as per the statement of cash flows

(2,460
)

 Balance as of December 31, 2009

$
533

{a}
See Note 2, Merger with Nuvelo, Inc. on January 27, 2009, to ARCA’s consolidated financial statements on Form 10-K for the year ended December 31,
2009 for the acquisition consideration allocation as of the date of the Merger.

 In connection with responding to the Comment
Letter, we acknowledge that:

•

 ARCA is responsible for the adequacy and accuracy of the disclosure in the filing;

•

 Staff comments or changes to disclosure in response to Staff comments do not foreclose the Commission from taking any action with respect to the
filing; and

•

 ARCA may not assert Staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the
United States.

 We trust this letter is fully responsive to the Comment Letter. Please do not hesitate to contact me if
you have any questions relative to this matter.

Very truly yours,

/s/ Patrick M. Wheeler

 Patrick M. Wheeler,

 Chief
Financial Officer

cc:
      Brent D. Fassett, Cooley LLP

      Michael R. Bristow, President and Chief Executive Officer

      Christopher D. Ozeroff, Senior Vice President and General Counsel

 3

December 10, 2010

Patrick M. Wheeler Chief Financial Officer ARCA biopharma, Inc. 8001 Arisra Place, Suite 200 Broomfiled, CO  80021
Re: ARCA biopharma, Inc.
 Form 10-K for Fiscal Year Ended December 31, 2009
  Filed March 4, 2010
File No.  000-22873

Dear Mr. Wheeler:

We have reviewed your filing and have the fo llowing comment.  In our comment, we ask
you to provide us with information so we may better understa nd your disclosure.
 Please respond to this letter within te n business days by providing the requested
information or by advising us when you will provide the requested response.  If you do not believe the comment applies to your facts a nd circumstances, please tell us why in your
response.  Please furnish us a letter on EDGAR under the form type label CORRESP that keys
your response to our comment.
   After reviewing the information provided, we may raise additional comments and/or
request that you amend your filing.

Item 8. Financial Statements and Supplementary Data

Consolidated Statement of Cash Flows, page 66

1. Please tell us why your statement of cash fl ows reflects a $20.5 million change in accrued
expenses and other liabilities, while the balance sheet appears to  indicate that the change in
these accounts is substantially less.  Sim ilarly, please also addre ss the change in your
accounts payable.
 We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing include s the information the Securities Exchange Act of
1934 and all applicable Exchange Act rules requir e.  Since the company and its management are
in possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.
 In responding to our comments, please provi de a written statement from the company
acknowledging that:

Patrick M. Wheeler
ARCA biopharma, Inc. December 10, 2010 Page 2

• the company is responsible for the adequacy and accuracy of the disclo sure in the filing;
• staff comments or changes to disclosure in response to staff comments do not foreclose
the Commission from taking any action with respect to the filing; and
• the company may not assert staff comments as a defense in any proceeding initiated by
the Commission or any person under the federa l securities laws of  the United States.

You may contact Tabatha Akin s, Staff Accountant (202) 551 -3658 or Mary Mast, Senior
Staff Accountant at (202) 551-3613 if you have any questions regarding the comment.  In this
regard, do not hesitate to c ontact me, at (202) 551-3679.

Sincerely,

Jim B. Rosenberg
Senior Assistant Chief Accountant