POWER OF ATTORNEY


       The undersigned as a Section 16 reporting person of Catalyst Biosciences,
Inc. (the "Company"), hereby constitutes and appoints each of Nassim Usman,
Clinton J. Musil, Faisal Shawwa and Seline Miller, signing singly, as the
undersigned's true and lawful attorney-in-fact to:

1) execute for and on behalf of the undersigned, in the undersigned's capacity
as an officer of the Company, Forms 3, 4, and 5 in accordance with Section 16(a)
of the Securities Exchange Act of 1934 and the rules thereunder;

2) do and perform any and all acts for and on behalf of the undersigned which
may be necessary or desirable to complete and execute any such Form 3, 4, or 5,
complete and execute any amendment or amendments thereto, and timely file such
form with the U.S. Securities and Exchange Commission and any securities
exchange or similar authority; and

3) take any other action of any type whatsoever in connection with the foregoing
which, in the opinion of such attorney-in-fact, may be of benefit to, in the
best interest of, or legally required by, the undersigned, it being understood
that the documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

   The undersigned hereby grants to the attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted.  The undersigned also ratifies hereby any action previously taken by
the attorney-in-fact that would have been authorized by this power of attorney
if it has been in effect at the time such action was taken.  The undersigned
acknowledges that the foregoing attorney-in-fact, in serving in such capacity at
the request of the undersigned, is not assuming, nor is the Company assuming,
any of the undersigned's responsibilities to comply with Section 16 of the
Securities Exchange Act of 1934, as amended.

   This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorney-in-fact.

   IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of 7/17/2021.


/s/ Errol De Souza
Name:  Errol B. De Souza