	UNITED STATES
	SECURITIES AND EXCHANGE COMMISSION
	Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. )*

Catalyst Biosciences, Inc.

(Name of Issuer)

Common Stock, $0.001 par value

(Title of Class of Securities)

14888D109

(CUSIP Number)

January 19, 2018

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

o	Rule 13d-1(b)
x	Rule 13d-1(c)
o	Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 14888D109						Page 2 of 13

	1.	Name of Reporting Persons Venrock Healthcare Capital Partners II, L.P.

	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)		x(1)
		(b)		o

	3.	SEC Use Only

	4.	Citizenship or Place of Organization Delaware

Number of Shares Beneficially Owned by Each Reporting Person With:			5.		Sole Voting Power 0

			6.		Shared Voting Power 340,676(2)

			7.		Sole Dispositive Power 0

			8.		Shared Dispositive Power 340,676(2)

	9.	Aggregate Amount Beneficially Owned by Each Reporting Person 340,676(2)

	10.	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o

	11.	Percent of Class Represented by Amount in Row (9) 5.4%(3)

	12.	Type of Reporting Person (See Instructions) PN

(1) Venrock Healthcare Capital Partners II, L.P. (“VHCP II”), VHCP Co-Investment Holdings II, LLC (“VHCP Co II”), VHCP Management II, LLC, Bong Koh and Nimish Shah are members of a group for the purposes of this Schedule 13G.

(2) Consists of (i) 242,404 shares of common stock held by VHCP II and (ii) 98,272 shares of common stock held by VHCP Co II.

(3) This percentage is calculated based upon 6,366,604 shares of common stock outstanding as of January 19, 2018, as set forth in Issuer’s Registration Statement on Form S-3 filed with the Securities and Exchange Commission on January 22, 2018.

CUSIP No. 14888D109						Page 3 of 13

	1.	Name of Reporting Persons VHCP Co-Investment Holdings II, LLC

	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)		x(1)
		(b)		o

	3.	SEC Use Only

	4.	Citizenship or Place of Organization Delaware

Number of Shares Beneficially Owned by Each Reporting Person With:			5.		Sole Voting Power 0

			6.		Shared Voting Power 340,676(2)

			7.		Sole Dispositive Power 0

			8.		Shared Dispositive Power 340,676(2)

	9.	Aggregate Amount Beneficially Owned by Each Reporting Person 340,676(2)

	10.	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o

	11.	Percent of Class Represented by Amount in Row (9) 5.4%(3)

	12.	Type of Reporting Person (See Instructions) OO

(2) Consists of (i) 242,404 shares of common stock held by VHCP II and (ii) 98,272 shares of common stock held by VHCP Co II.

CUSIP No. 14888D109						Page 4 of 13

	1.	Name of Reporting Persons VHCP Management II, LLC

	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)		x(1)
		(b)		o

	3.	SEC Use Only

	4.	Citizenship or Place of Organization Delaware

Number of Shares Beneficially Owned by Each Reporting Person With:			5.		Sole Voting Power 0

			6.		Shared Voting Power 340,676(2)

			7.		Sole Dispositive Power 0

			8.		Shared Dispositive Power 340,676(2)

	9.	Aggregate Amount Beneficially Owned by Each Reporting Person 340,676(2)

	10.	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o

	11.	Percent of Class Represented by Amount in Row (9) 5.4%(3)

	12.	Type of Reporting Person (See Instructions) OO

(2) Consists of (i) 242,404 shares of common stock held by VHCP II and (ii) 98,272 shares of common stock held by VHCP Co II.

CUSIP No. 14888D109						Page 5 of 13

	1.	Name of Reporting Persons Koh, Bong

	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)		x(1)
		(b)		o

	3.	SEC Use Only

	4.	Citizenship or Place of Organization United States

Number of Shares Beneficially Owned by Each Reporting Person With:			5.		Sole Voting Power 0

			6.		Shared Voting Power 340,676(2)

			7.		Sole Dispositive Power 0

			8.		Shared Dispositive Power 340,676(2)

	9.	Aggregate Amount Beneficially Owned by Each Reporting Person 340,676(2)

	10.	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o

	11.	Percent of Class Represented by Amount in Row (9) 5.4%(3)

	12.	Type of Reporting Person (See Instructions) IN

(2) Consists of (i) 242,404 shares of common stock held by VHCP II and (ii) 98,272 shares of common stock held by VHCP Co II.

CUSIP No. 14888D109						Page 6 of 13

	1.	Name of Reporting Persons Shah, Nimish

	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)		x(1)
		(b)		o

	3.	SEC Use Only

	4.	Citizenship or Place of Organization United States

Number of Shares Beneficially Owned by Each Reporting Person With:			5.		Sole Voting Power 0

			6.		Shared Voting Power 340,676(2)

			7.		Sole Dispositive Power 0

			8.		Shared Dispositive Power 340,676(2)

	9.	Aggregate Amount Beneficially Owned by Each Reporting Person 340,676(2)

	10.	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o

	11.	Percent of Class Represented by Amount in Row (9) 5.4%(3)

	12.	Type of Reporting Person (See Instructions) IN

(2) Consists of (i) 242,404 shares of common stock held by VHCP II and (ii) 98,272 shares of common stock held by VHCP Co II.

CUSIP No. 14888D109

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Introductory Note: This Schedule 13G is filed on behalf of Venrock Healthcare Capital Partners II, L.P., a limited partnership organized under the laws of the State of Delaware (“VHCP II”), VHCP Co-Investment Holdings II, LLC, a limited liability company organized under the laws of the State of Delaware (“VHCP Co II”), VHCP Management II, LLC, a limited liability company organized under the laws of the State of Delaware (“VHCP Management II” and collectively with VHCP II and VHCP Co II, the “Venrock Entities”), Bong Koh (“Koh”) and Nimish Shah (“Shah”) in respect of shares of common stock of Catalyst Biosciences, Inc.

Item 1.

(a)		Name of Issuer

		Catalyst Biosciences, Inc.

(b)		Address of Issuer’s Principal Executive Offices

		260 Littlefield Avenue
		South San Francisco, CA 94080

Item 2.

(a)		Name of Person Filing

		Venrock Healthcare Capital Partners II, L.P.
		VHCP Co-Investment Holdings II, LLC
		VHCP Management II, LLC
		Bong Koh
		Nimish Shah

(b)

Address of Principal Business Office or, if none, Residence

New York Office:	Palo Alto Office:	Boston Office:

530 Fifth Avenue	3340 Hillview Avenue	34 Farnsworth Street
22nd Floor	Palo Alto, CA 94304	3rd Floor
New York, NY 10036		Boston, MA 02210

(c)		Citizenship

		Each of the Venrock Entities was organized in Delaware. Koh and Shah are both United States citizens.

(d)		Title of Class of Securities

		Common Stock, $0.001 par value per share

(e)		CUSIP Number

		14888D109

Item 3. If this statement is filed pursuant to §§240.13d-1(b), or 240.13d-2(b) or (c), check whether the person filing is a:

Not applicable

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Item 4. Ownership

(a)

Amount Beneficially Owned as of January 19, 2018:

Venrock Healthcare Capital Partners II, L.P.	340,676	(1)
VHCP Co-Investment Holdings II, LLC	340,676	(1)
VHCP Management II, LLC	340,676	(1)
Bong Koh	340,676	(1)
Nimish Shah	340,676	(1)

(b)

Percent of Class as of January 19, 2018:

Venrock Healthcare Capital Partners II, L.P.	5.4	%(2)
VHCP Co-Investment Holdings II, LLC	5.4	%(2)
VHCP Management II, LLC	5.4	%(2)
Bong Koh	5.4	%(2)
Nimish Shah	5.4	%(2)

(c)

Number of shares as to which the person has, as of January 19, 2018:

(i)

Sole power to vote or to direct the vote

Venrock Healthcare Capital Partners II, L.P.		0
VHCP Co-Investment Holdings II, LLC		0
VHCP Management II, LLC		0
Bong Koh		0
Nimish Shah		0

(ii)

Shared power to vote or to direct the vote

Venrock Healthcare Capital Partners II, L.P.	340,676	(1)
VHCP Co-Investment Holdings II, LLC	340,676	(1)
VHCP Management II, LLC	340,676	(1)
Bong Koh	340,676	(1)
Nimish Shah	340,676	(1)

(iii)

Sole power to dispose or to direct the disposition of

Venrock Healthcare Capital Partners II, L.P.		0
VHCP Co-Investment Holdings II, LLC		0
VHCP Management II, LLC		0
Bong Koh		0
Nimish Shah		0

CUSIP No. 14888D109

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(iv)

Shared power to dispose or to direct the disposition of

Venrock Healthcare Capital Partners II, L.P.	340,676	(1)
VHCP Co-Investment Holdings II, LLC	340,676	(1)
VHCP Management II, LLC	340,676	(1)
Bong Koh	340,676	(1)
Nimish Shah	340,676	(1)

(1) These shares are owned directly as follows: (i) 242,404 shares of common stock held by VHCP II and (ii) 98,272 shares of common stock held by VHCP Co II. VHCP Management II is the general partner of VHCP II and the manager of VHCP Co II. Messrs. Koh and Shah are the managing members of VHCP Management II.

(2) This percentage is calculated based upon 6,366,604 shares of common stock outstanding as of January 19, 2018, as set forth in Issuer’s Registration Statement on Form S-3 filed with the Securities and Exchange Commission on January 22, 2018.

Item 5. Ownership of Five Percent or Less of a Class

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following o.

Item 6. Ownership of More than Five Percent on Behalf of Another Person

Not Applicable

Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person.

Not Applicable

Item 8. Identification and Classification of Members of the Group

Not Applicable

Item 9. Notice of Dissolution of a Group

Not Applicable

CUSIP No. 14888D109

Page 10 of 13

Item 10. Certification

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: January 29, 2018

Venrock Healthcare Capital Partners II, L.P.			VHCP Co-Investment Holdings II, LLC

By:	VHCP Management II, LLC,		By:	VHCP Management II, LLC,
	its General Partner			its Manager

By:	/s/ David L. Stepp		By:	/s/ David L. Stepp
	Name:	David L. Stepp		Name:	David L. Stepp
	Title:	Authorized Signatory		Title:	Authorized Signatory

VHCP Management II, LLC

By:	/s/ David L. Stepp
	Name:	David L. Stepp
	Title:	Authorized Signatory

/s/ David L. Stepp, as attorney-in-fact
Bong Koh

/s/ David L. Stepp, as attorney-in-fact
Nimish Shah

EXHIBITS

A:		Joint Filing Agreement

B:		Power of Attorney for Bong Koh

C:		Power of Attorney for Nimish Shah

CUSIP No. 14888D109

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EXHIBIT A

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Common Stock of Catalyst Biosciences, Inc. and further agree that this agreement be included as an exhibit to such filing. Each party to the agreement expressly authorizes each other party to file on its behalf any and all amendments to such statement. Each party to this agreement agrees that this joint filing agreement may be signed in counterparts.

In evidence whereof, the undersigned have caused this Agreement to be executed on their behalf this 29th day of January, 2018.

Venrock Healthcare Capital Partners II, L.P.			VHCP Co-Investment Holdings II, LLC

By:	VHCP Management II, LLC,		By:	VHCP Management II, LLC,
	its General Partner			its Manager

By:	/s/ David L. Stepp		By:	/s/ David L. Stepp
	Name:	David L. Stepp		Name:	David L. Stepp
	Title:	Authorized Signatory		Title:	Authorized Signatory

VHCP Management II, LLC

By:	/s/ David L. Stepp
	Name:	David L. Stepp
	Title:	Authorized Signatory

/s/ David L. Stepp, as attorney-in-fact
Bong Koh

/s/ David L. Stepp, as attorney-in-fact
Nimish Shah

CUSIP No. 14888D109

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EXHIBIT B

POWER OF ATTORNEY FOR BONG KOH

KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and appoints each of Lisa Harris, Sherman G. Souther, Jr. and David L. Stepp, signing individually, the undersigned’s true and lawful attorney-in fact and agent to:

(i) prepare, execute and file, for and on behalf of the undersigned, any and all documents and filings that are required or advisable to be made with the United States Securities and Exchange Commission, any stock exchange or similar authority, under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations promulgated thereunder, including without limitation (a) any Joint Filing Agreement under Rule 13d-1(k) of the Exchange Act (or any successor provision thereunder), Schedule 13D and Schedule 13G (or any successor schedules or forms adopted under the Exchange Act) and any amendments thereto in accordance with Section 13 of the Exchange Act and the rules thereunder, and (b) Forms 3, 4 and 5 and any amendments thereto in accordance with Section 16(a) of the Exchange Act and the rules thereunder; and

(ii) take any other action of any nature whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit, 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 such 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 acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming, nor is Venrock assuming, any of the undersigned’s responsibilities to comply with the Exchange Act, including without limitation Sections 13 and 16 of the Exchange Act.

This Power of Attorney shall remain in full force and effect until the earliest to occur of (a) the undersigned is no longer required to file any form or document with respect to the undersigned’s holdings of and transactions in securities issued by a company, (b) revocation by the undersigned in a signed writing delivered to the foregoing attorney-in-fact or (c) until such attorney-in-fact shall no longer be employed by Venrock.

IN WITNESS WHEREOF, the undersigned has cause this Power of Attorney to be executed as of this 26th day of January, 2015.

	/s/ Bong Koh
	Bong Koh

CUSIP No. 14888D109

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EXHIBIT C

POWER OF ATTORNEY FOR NIMISH SHAH

KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and appoints each of David L. Stepp, Sherman G. Souther and Lisa D. Harris, signing individually, the undersigned’s true and lawful attorney-in fact and agent to:

(i) prepare execute and file, for and on behalf of the undersigned, any and all documents and filings that are required or advisable to be made with the United States Securities and Exchange Commission, any stock exchange or similar authority, under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations promulgated thereunder, including without limitation (a) any Joint Filing Agreement under Rule 13d-1(k) of the Exchange Act (or any successor provision thereunder), Schedule 13D and Schedule 13G (or any successor schedules or forms adopted under the Exchange Act ) and any amendments thereto in accordance with Section 13 of the Exchange Act and the rules thereunder, and (b) Forms 3, 4 and 5 and any amendments thereto in accordance with Section 16(a) of the Exchange Act and the rules thereunder; and

The undersigned hereby grants to such 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 acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of undersigned, is not assuming, nor is Venrock assuming, any of the undersigned’s responsibilities to comply with the Exchange Act, including without limitation Sections 13 and 16 of the Exchange Act.

This power of Attorney shall remain in full force and effect until the earliest to occur of (a) the undersigned is no longer required to file any form or document with respect to the undersigned’s holdings of and transactions in securities issued by a company, (b) revocation by the undersigned in a signed writing delivered to the foregoing attorney-in-fact, or (c) until such attorney-in-fact shall no longer be employed by VR Management, LLC (or its successor).

IN WITNESS WHEREOF, the undersigned has cause this Power of Attorney to be executed as of this 13th day of February, 2017.

/s/ Nimish Shah