SecProbe.io

May 30, 2013

Via E -mail
Ramesh Kumar, Ph.D.
President and Chief Executive Officer
Onconova Therapeutics, Inc.
375 Pheasant Run
Newtown, PA 18940

Re: Onconova Therapeutics, Inc.
Confidential Draft Registration Statement on Form S -1
Submitted May 3, 2013
CIK No. 0001130598

Dear Dr. Kumar:

We have reviewed your confidential draft registration statement and have the following
comments. In some of our comments, we may ask you to provide us with infor mation so we may
better understand your disclosure.

Please respond to this letter by providing the requested infor mation and either
submitting an a mended confidential draft re gistration state ment or publicly  filing your
registration s tatement on EDGAR.  If you do  not believe our comments apply to your facts
and circu mstances or do not believe an  amendment is a ppropriate, please tell us why in your
response.

After revie wing the infor mation you provide  in response to these com ments and your
amended confidential draft registration state ment or filed registration state ment, we may have
additio nal co mments.

General

1. Please sub mit all outstanding exhibits as soon as prac ticable.  We may have further
comments upon exa mination of these exhibits.

2. Please provide us proofs of all graphic, visual or photographic information you will
provide in the printed prospectus prior to its use, for example in a preliminary prospectus.
Please note that we may have comments regarding this material.

Ramesh Kumar , Ph.D.
Onconova Therapeutics, Inc.
May 30 , 2013
Page 2

 3. Please supplementally provide us with copies of all written communications, as defined
in Rule 405 under the Securities Act, that you, or anyone authorized to do so on your
behalf, present to potential investors in reliance on Section 5(d) of the Securities A ct,
whether or not they retain copies of the communications. Similarly, please
supplementally provide us with any research reports about you that are published or
distributed in reliance upon Section 2(a)(3) of the Securities Act of 1933 added by
Section 1 05(a) of the Jumpstart Our Business Startups Act by any broker or dealer that is
participating or will participate in your offering.

4. We will deliver comments to your confidential treatment request under separate cover.

5. Please  update  your filing to include unaudited interim financial  statements and related
financial schedules for the quarterly periods ended March 31, 2013 and 2012  as required
by Rule 3-12 of Regulation S -X.

6. Please provide the information required (including Exhibit 16) u nder Regulation S -K
Item 304 and Item 11(i) of Form S -1 regarding the change in accountants for year 2012.

Risk Factors
“Our product candidates may cause undesirable side effects…,” page 16

7. Please expand the discussion in this risk factor to disclose th e extent to which you have
observed undesirable side effects in your trials, including any safety or toxicity issues,
and the impact, if any, on the prospects for obtaining marketing approval of your product
candidates.  We note, for example, your disclosu re on pages 85 -88 detailing certain drug -
related adverse events occurring in your rigosertib trials.

Special Note Regarding Forward -Looking Statements and Industry Data, page 46

8. Please note that it is not appropriate to state or imply that you do not ha ve liability for the
statements in your registration statement. Your  statement s at the bottom of page 47 that
you have not independently verified  market and industry data obtained from third -party
sources or your own internal company research could  imply t hat you are not taking
liability for the statistical and other industry and market data included in your registration
statement. In order to eliminate any inference that you are not liable for all of the
information in your registration statement, please delete these statements or include a
statement s pecifically accepting liability for these statements.

Use of Proceeds, page 48

9. We note your statement that you have not yet determined the amount of proceeds to be
spent on any of the areas listed in the second paragraph of this section, such as research
and development and clinical trial expenditures.  However, if the company has sp ecific
purposes in mind for the use of proceeds, Item 504 of Regulation S -K requires disclosure

Ramesh Kumar , Ph.D.
Onconova Therapeutics, Inc.
May 30 , 2013
Page 3

 of the approximate amount intended to be used for each such purpose.  This is required
even if, as you note in your prospectus, management will have broad discr etion in
allocating the proceeds and that the ultimate use of proceeds will depend on several
contingencies and is subject to change.

Management’s Discussion and Analysis of
Financial Condition and Results of Operations
Financial Overview, page 57

10. We note your disclosure of “research funding” for 2011 and 2012 in the table on page 57.
Please clarify the amount of research funding attributable to payments from LLS.

Research and Development Expenses, page 62

11. You state on page 59 that research and d evelopment activities are central to your business
model and that you plan to increase your research and development expenses for the
foreseeable future. While you state that you do not currently utilize a formal time
allocation system to capture expenses on a project -by-project basis, please expand your
disclosure to provide the following:
 The costs you do track by project for each period presented and to date and a
reconciliation of the total of these project costs to the total expenses presented on
your statement of operations and comprehensive loss.  In this regard, it appears,
for example, that you may track external cost by project as you are able to
quantify on page 70 that $8.4 million of the increase in research and development
expenses in 2012 as  compared to 2011 relates to clinical trials expenses for
rigosertib.
 Explain why management does not maintain and evaluate all research and
development costs by project.  Explain how you use functional area expenditures
to evaluate and prioritize your R&D  activities.
 Explain how you monitor development progress for individual projects.
 Absent costs by project, please provide other quantitative or qualitative disclosure
that indicates the amount of the company’s resources being used on the project
such as b y stage of development (i.e. discovery, pre -clinical, clinical phase I,
clinical II and phase III) and/or other meaningful breakout.

Stock -Based Compensation, page 63

12. We have the following comments regarding your disclosure and accounting for stock -
based compensation:
 Since you have not disclosed an estimated offering price we are deferring a final
evaluation of stock compensation and other costs recognized until the estimated
offering price is specified.  We may have further comments in this r egard when
the amendment containing that information is filed.

Ramesh Kumar , Ph.D.
Onconova Therapeutics, Inc.
May 30 , 2013
Page 4

  In the first paragraph of your discussion about the fair value of stock option grants
from January 1, 2011 to February 1, 2012 you indicate that you utilized an
assumed annual volatility rate  of 64.0% based on historical share price trading
data for a group of 10 companies you considered comparable to yours.  Please tell
us the name of these 10 companies and explain to us why you deemed them to be
comparable to you.  In your response, for each  of these companies tell us the
following information at your valuation date:
o annual revenues;
o annual product revenues;
o net income/loss;
o assets;
o equity;
o number of products in development and their stages of development; and
o number of marketed products
 Please provide in your filing containing the IPO price range, a discussion of each
significant factor contributing to the difference between the fair value as of the
date of each grant and the estimated IPO price range. Please reconcile and explain
the differ ences between the mid -point of your estimated offering price range and
the fair values included in your analysis.

Operating and Capital Expenditure Requirements, page 73

13. To the extent practicable, please quantify the estimated costs mentioned in this sec tion
that you will incur as a result of being a public company.

Business, page 81
Our Product Candidates, page 79

14. Please disclose in this section whether there is an effective investigational new drug
application (IND) for each of the following:
 Rigose rtib for treatment of higher risk MDS in intravenous formulation
 Rigosertib for treatment of lower risk MDS in oral formulation
 Rigosertib for treatment of head and neck cancer
 Rigosertib for treatment of pancreatic cancer
 ON 013105 for treatment of lymphoma
 Recilisib for treatment of ARS

In each case, if an IND has been filed for the compound and corresponding treatment
indicated, please disclose the identity of the filer and the date of filing.  If an IND has not
been filed, please explain why.

Ramesh Kumar , Ph.D.
Onconova Therapeutics, Inc.
May 30 , 2013
Page 5

 Treating Myelodysplastic Syndromes, page 81

15. Please explain how the mechanism of action for hypomethylating drugs differs from
rigosertib.  Specifically, please clarify why rigosertib does not pose the same risk of
patient failure and drug resistance as  azacitidine or decitabine, the current standard of
care for higher risk MDS patients.

Phase 1/2 Trial Results of Rigosertib in Patients with Myelodysplastic Syndromes, page 83

16. Please clarify the reason why a follow -up bone marrow biopsy was only availa ble for 30
of the 39 patients treated in these clinical trials.  Please also disclose whether you expect
any similar difficulties in obtaining follow -up biopsies in the ONTIME trial.  If so,
explain what effect, if any, this could have on the evaluation of  trial results and the
support of efficacy claims for rigosertib.

Collaborations, page 90

17. Please clarify in this section whether your $10.2 million in government funding for
recilisib was part of a formal agreement with the Department of Defense.  If s o, please
describe the material terms of that agreement and the parties’ respective obligations in
this section and file the agreement as an exhibit to the registration statement.

The Leukemia and Lymphoma Society

18. Please explain more specifically what “advancing the clinical development of rigosertib”
means under the terms of the LLS agreement, as well as the process for determining that
the company has failed to fulfill this obligation.

Intellectual Property, page  93

19. We note your research agreement with Mount Sinai School of Medicine.  Please disclose
all material terms of that agreement in this section, including which, if any, of your
products and patents  are implicated under this research agreement.  Please als o file this
agreement as an exhibit to the registration statement.

20. Please disclose whether you license or own the composition -of-matter patent and the
method of treatment patent for rigosertib.

Manufacturing, page 96

21. Please identify the material ter ms of your manufacturing and supply agreements.  Please
file these agreements as exhibits to the registration statement as well.  Alternat ively, if
you do not believe any of these agreements is material , please advise us as to the basis of
your conclusions .

Ramesh Kumar , Ph.D.
Onconova Therapeutics, Inc.
May 30 , 2013
Page 6

Management, pages 113 -115

22. We note your discussion of consulting agreements with certain members of your clinical
advisory and scientific advisory boards “covering their respective financial
arrangements.”  Please describe payments and other material  terms of these agreements
and file them as exhibits to the registration statement.  If you do not believe these
agreements are material, please advise us as to the basis of your conclusions.

Shares El igible for Future Sale, page 144

23. Once available, please file the form of lock -up agreement as an exhibit to your
registration statement.

Consolidated Financial Statements
Notes to Consolidated Financial Statements
Report of Independent Registered Public Accounting Firm, page F -3

24. Please tell us if May 2, 2013 is the original signature date for EisnerAmper LLP’s audit
of your financial statements for the year ended December 31, 2011.  If not, tell us the
original signature date and the reason(s) it changed.  Tell us if any of the adjustments
referred to on pages 68 -69 related to and were recorded in year 2011 as a restatement of
those financial statements.

15. License and Collaboration Agreements
Baxter Agreement, page F -34

25. In 2012, you recognized $42.4 million in revenue relating to the Baxter agreem ent.
Please address the following and reference for us any authoritative literature you relied
upon to support your position:
 Please elaborate on your assertion that the license has standalone value to Baxter.
In your response, tell us how Baxter can exp loit the license without the additional
development services that you are obligated to perform.  Tell us:
o whether and how Baxter or any other party can perform these
development services given your expertise with your intellectual property;
o whether Baxter has the rights and full access to past and future intellectual
information in order to obtain regulatory approval of rigosertib in Europe;
o whether Baxter is performing any development activities related to
rigosertib; and
o how the fact that you will own all  marketing approvals and regulatory
filings pursuant to section 6.1 of your agreement with Baxter filed as
Exhibit 10.1 to your draft submission impacts Baxter’s ability to exploit
the license.

Ramesh Kumar , Ph.D.
Onconova Therapeutics, Inc.
May 30 , 2013
Page 7

  Please tell us why it is appropriate to recognize the revenue allocated to the
research and development services deliverable through March 31, 2014 when it
appears that you are obligated to file all regulatory submissions in Europe and it
appears unlikely that you will be in a position to have these submissions filed  and
approved by then.
 Please tell us why you do not believe your participation on the joint committee as
disclosed in the third paragraph on page F -36 is a deliverable under your Baxter
agreement.  In your response, please tell us:
o the composition of the committee;
o the term of the committee;
o your obligation to participate;
o what happens if you do not participate; and
o the dispute resolution provisions.

26. Please revise your filing to disclose each individual potential future milestone you could
receive and it s related contingent consideration as required by ASC 605 -28-50-2b.

Index to Exhibits, page II -7

27. Please file your joint venture agreement with GVK Biosciences as an exhibit to your
registration statement.

If you intend to respond to these comments with an amended draft registration statement,
please submit it and any associated correspondence in accordance with the guidance we provide
in the Division’s October 11, 2012 announcement on the SEC website at
http://www.sec.gov/divisions/corpfin/cfannounc ements/drsfilingprocedures101512.htm.

Please keep in mind that we may publicly post filing review correspondence in
accordance with our December 1, 2011 policy
(http://www.sec.gov/divisions/corpfin/cfannouncements/edgarcorrespondence.htm). If you
intend t o use Rule 83 (17 CFR 200.83) to request confidential treatment of information in the
correspondence you submit on EDGAR, please properly mark that information in each of your
confidential submissions to us so we do not repeat or refer to that information in our comment
letters to you.

Ramesh Kumar , Ph.D.
Onconova Therapeutics, Inc.
May 30 , 2013
Page 8

 You may contact Jim Peklenk at (202) 551 -3661  or Mark Brunhofer at ( 202) 551 -3638  if
you have questions regarding comments on the financial statements and related matters.