United States securities and exchange commission logo

                               June 23, 2021

       Rachel Haurwitz, Ph.D.
       President and Chief Executive Officer
       Caribou Biosciences, Inc.
       2929 7th Street, Suite 105
       Berkeley, California 94710

                                                        Re: Caribou
Biosciences, Inc.
                                                            Amendment No. 1 to
Draft Registration Statement on Form S-1
                                                            Submitted June 11,
                                                            CIK No. 0001619856

       Dear Dr. Haurwitz:

             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

       Draft Registration Statement on Form S-1 - Amendment No. 1

       Prospectus Summary
       Overview, page 1

   1.                                                   Please revise your
pipeline table so that the Phase 2 and Phase 3 trials are graphically
                                                        depicted in two
different columns, or tell us the basis for your belief that you will be able
                                                        to conduct Phase 2/3
trials for all your product candidates. While we note your revised
                                                        disclosure in response
to our prior comment 1 below the pipeline table that "Phase 3 may
                                                        not be required if
Phase 2 is registrational," we believe it is overly speculative to depict
                                                        these two columns as
being part of the same clinical trial at this stage. To this point, we
                                                        note your disclosure on
page 30 that "the general approach for FDA approval of a new
 Rachel Haurwitz, Ph.D.
Caribou Biosciences, Inc.
June 23, 2021
Page 2
      biologic is for the sponsor to provide dispositive data from at least two
adequate and well-
      controlled clinical trials of the relevant biologic in the applicable
patient population."
Strategic Agreements, page 149

2.    We note your response to our prior comment 10 and re-issue the comment as
it relates to
      the AbbVie Agreement. Please revise the description of the upper range of
the royalty
      payments to a range within ten percentage points (for example, between
twenty and thirty
Financial Statements
Note 2. Summary of Significant Accounting Policies
Revenues, page F-9

3.    Your expanded disclosures indicate that certain of the your license
agreements have, for
      accounting purposes, two performance obligations: a license and a
material right for
      annual license renewal agreements. Please better describe the nature and
accounting for
      these agreements, including whether the licenses granted represent a
right to use or a right
      to access; the factors considered in concluding that these two
performance obligations
      were individually distinct; the expected contract term with all
reasonably likely renewal
      periods; and how you determined the transaction price and allocated
revenues to each
      performance obligation. Clarify whether or not the annual maintenance
fees referenced
      on pages F-23 and F-52 related to these agreements and if so, how. Please
reference the
      technical guidance upon which you relied.
       You may contact Franklin Wyman at 202-551-3660 or Jeanne Baker at
202-551-3691 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Dillon Hagius at 202-551-7967 or Irene Paik at 202-551-6553 with any
other questions.

FirstName LastNameRachel Haurwitz, Ph.D.
                                                            Division of
Corporation Finance
Comapany NameCaribou Biosciences, Inc.
                                                            Office of Life
June 23, 2021 Page 2
cc:       Ashok Mukhey
FirstName LastName