United States securities and exchange commission logo

                            September 16, 2020

       Norbert Bischofberger, Ph.D.
       President and Chief Executive Officer
       Kronos Bio, Inc.
       1300 So. El Camino Real, Suite 300
       San Mateo, CA 94402

                                                        Re: Kronos Bio, Inc.
                                                            Amendment No. 1 to
Draft Registration Statement on Form S-1
                                                            Submitted September
3, 2020
                                                            CIK No. 0001741830

       Dear Dr. Bischofberger:

             We have reviewed your amended draft 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 providing the requested
information and either submitting
       an amended draft registration statement or publicly filing your
registration statement on
       EDGAR. 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

             After reviewing the information you provide in response to these
comments and your
       amended draft registration statement or filed registration statement, we
may have additional

       Amendment No. 1 to Draft Registration Statement on Form S-1 submitted
September 3, 2020

       Overview , page 1

   1.                                                   We note your disclosure
on page 4 that you anticipate making your first IND submission
                                                        from among the
discovery programs in 2022. We also note that the milestones column in
                                                        the discovery program
table indicates an IND submission in 2022 and appears to apply to
                                                        all programs. Please
revise your disclosure to clarify whether a IND submission is
                                                        expected for each
discovery program in 2022 or revise the table accordingly. Additionally,
                                                        we note that the MYC
discovery program does not include a specific indication. Please
                                                        explain why such
discovery program is sufficiently material to include in the table or
                                                        remove the program.
 Norbert Bischofberger, Ph.D.
Kronos Bio,LastNameNorbert   Bischofberger, Ph.D.
Comapany 16,
September  NameKronos
               2020     Bio, Inc.
Page 2     16, 2020 Page 2
FirstName LastName
2.       Please remove the timeline associated with the initiation of the Phase
2/3 program for KB-
         0742 from the anticipated milestones column in your pipeline table, as
it appears to be
         premature and speculative, or explain why such disclosure is
3.       We not your disclosure that you are currently planning to initiate a
single-arm Phase 1/ 2
         clinical trial in 2021 for ENTO in subjects with relapsed or
refractory FLT3 mutated
         AML. However, your pipeline table suggests that you have already
completed a Phase 1
         clinical trial. Please shorten the second arrow for ENTO as
appropriate to illustrate the
         product candidate's current status.
4.       We note your disclosure that your End of Phase 2 meeting with the FDA
and similar
         discussions with European regulatory agencies are not expected to
occur until the first half
         of 2021 and that following and subject to such discussions you plan to
proceed to a
         registrational Phase 2/3 trial. Please revise your disclosure
throughout the prospectus to
         make it clear that you have not yet discussed with the FDA the
potential of your Phase 2/3
         clinical trial to serve as a registrational trial. For example, please
include such disclosure
         on page 1 where you first discuss your plans to initiate a
registrational Phase 2/3 clinical
         trial in 2021.
SYK Program: ENTO and LANRA, page 2

5.       Please revise your disclosure to include the actual results observed
in the retrospective
         analysis, including with respect to CR rates and overall survival.
Please also indicate the
         number of subjects analyzed. In an appropriate location in your
prospectus, please also
         explain how you determined which subjects had high HOX/MEIS mRNA
expression and
         which subjects had low HOX/MEIS mRNA expression.
Prior Development of ENTO, page 119

6.       We note your response to prior comment 9 and your revised disclosure
that five subjects
         reported serious AEs assessed by the investigator as related to ENTO.
To the extent there
         was a serious AE that the investigator could not determine was
unrelated to treatment,
         please clearly disclose the event and the number of affected patients.
Therapeutic Rationale and Clinical Data in HOX/MEIS-High AML, page 120

7.       We note your disclosure that retrospective biomarker analysis of Arm A
explored the
         hypothesis that patients with high HOX/MEIS mRNA are more likely to
benefit from the
         addition of ENTO to IC. We also note your discussion of CR rates in
the genetic subsets
         associated with high HOX/MEIS expression (NPM1 and MLL-r) compared to
         with neither mutation. Please clarify whether an analysis was
conducted comparing CR
         rates in patients with these genetic subsets receiving combined ENTO
and IC therapy to
         CR rates in patients with these genetic subsets of patients receiving
IC alone or whether
         there are historical CR rates in these genetic subsets for IC therapy
 Norbert Bischofberger, Ph.D.
Kronos Bio,LastNameNorbert   Bischofberger, Ph.D.
Comapany 16,
September  NameKronos
               2020     Bio, Inc.
Page 3     16, 2020 Page 3
FirstName LastName
       You may contact Sasha Parikh at 202-551-3627 or Julie Sherman at
202-551-3640 if you
have questions regarding comments on the financial statements and related
matters. Please
contact Deanna Virginio at 202-551-4530 or Tim Buchmiller at 202-551-3635 with
any other


                                                        Division of Corporation
                                                        Office of Life Sciences
cc:      Charles J. Bair, Esq.