SecProbe.io

Mail Stop 4720

April 12, 2016

Via E -mail
Walter Klemp
Chief Executive Officer
Moleculin Biotech, Inc.
2575 West Bellfort, Suite 333
Houston, Texas 77054

Re: Moleculin Biotech, Inc.
Amendment No. 2 to Registration Statement on Form S -1
Filed March 22, 2016
  File No. 333 -209323

Dear Mr. Klemp :

We have reviewed your amended registration statement  and have the following
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 .  If 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.   Unless we note
otherwise, our references to prior comments are to comments in our March 4, 2016 letter .

Risk Factors
Risks Relating to our Business
“We have completed and will in the future complete related party transactions that were not and
will not be conducted on an arm’s length basis, ” page 12

1. Please clarify your response to prior comment 2 to state whether the related party
transactions you did not conduct on an arm’s length basis  resulted in terms that are
similar to a third party agreement.  If the terms were more favorable to you than they
would have been with a third party, tell us how you accounted for the more favorable
terms.

Walter Klemp
Moleculin Biotech, Inc.
April 12, 2016
Page 2

Business, page 42

2. We note your response to prior comment 9 and the associated revise d disclosure in the
prospectus. On page 42 in the section “Business – Corporate History,” please make the
following revisions and any necessary conforming revisions throughout the prospectus:

 When you refer to Dr. Shepard and the data reported in the Callisto -sponsored
research trials, please reiterate here that Dr. Shepard is also curre ntly your Chief
Medical Officer ;

 Please remove from your discussion the concl usion reported at the 2009 ASCO
presentation that “Nanomolecular Lipos omal Annamycin was effective even in
refractory ALL,” as this statement does not appear in the journal article reporting
the results of the trial and was not subject to peer review , unlike the article .
Moreover, the use of the term “effective” in this instance  does not appear
consistent with the concept of efficacy as applied by the FDA and may confuse
investors;

 If you retain the disc ussion regarding the observed  efficacy signal  and the
definition of efficacy as used in the Phase I/II ALL study, please define the term
“efficacy signal” as used in the journal article  and  make clear that neither the
patient response s observed nor the criteria underlying an “efficacy signal” would
satisfy the FDA’s standards for proof of efficacy ; and

 Disclose  that the study’s conclus ion, as reported in the journal article,  was only
that Annamycin had “encouraging anti -leukemic activity.”

Moleculin, LLC
Statements of Operations, page F -13

3. Please tell us why your research and development expenses decreased from $270,991 at
September 30, 2015 to $12 5,442 at December 31, 2015.

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 o f the
registration statement.

Walter Klemp
Moleculin Biotech, Inc.
April 12, 2016
Page 3

You may contact Keira Nakada at (202) 551 -3659 or Lisa Vanjoske at (202) 551 -3614 if
you have questions regarding comments on the financial statements and related matters.  Please
contact Scot Foley at (202) 551 -3383, Daniel Greenspan at (202 ) 551 -3623 or me at (202) 551 -
3675 with any other questions.

Sincerely,

 /s/ Daniel Greenspan for

 Suzanne Hayes
Assistant Director
Office of Healthcare and Insurance

cc:    Cavas S. Pavri
              Schiff Hardin LLP