SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* BVF PARTNERS L P/IL (Last) (First) (Middle) 44 MONTGOMERY ST. 40TH FL (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Calithera Biosciences, Inc. [ CALA ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 05/21/2020
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, $0.0001 par value(1)	05/21/2020		S		1,027,016	D	$6	3,712,340	D(2)
Common Stock, $0.0001 par value(1)	05/21/2020		S		1,064,332	D	$6	2,766,561	D(3)
Common Stock, $0.0001 par value(1)	05/21/2020		S		192,250	D	$6	480,432	D(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* BVF PARTNERS L P/IL (Last) (First) (Middle) 44 MONTGOMERY ST. 40TH FL (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* BIOTECHNOLOGY VALUE FUND L P (Last) (First) (Middle) 44 MONTGOMERY STREET 40TH FL (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* BIOTECHNOLOGY VALUE FUND II LP (Last) (First) (Middle) 44 MONTGOMERY STREET 40TH FL (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* Biotechnology Value Trading Fund OS LP (Last) (First) (Middle) P.O. BOX 309 UGLAND HOUSE (Street) GRAND CAYMAN E9 KY1-1104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* BVF Partners OS Ltd. (Last) (First) (Middle) P.O. BOX 309 UGLAND HOUSE (Street) GRAND CAYMAN E9 KY1-1104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses

1. Name and Address of Reporting Person* BVF INC/IL (Last) (First) (Middle) 44 MONTGOMERY STREET 40TH FL (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* LAMPERT MARK N (Last) (First) (Middle) 44 MONTGOMERY STREET 40TH FL (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. This Form 4 is filed jointly by Biotechnology Value Fund, L.P. ("BVF"), Biotechnology Value Fund II, L.P. ("BVF2"), Biotechnology Value Trading Fund OS LP ("Trading Fund OS"), BVF Partners OS Ltd. ("Partners OS"), BVF Partners L.P. ("Partners"), BVF Inc. and Mark N. Lampert (collectively, the "Reporting Persons"). Following the transactions reported herein, for the purposes of Section 16, the Reporting Persons ceased to beneficially own 10% or more of the outstanding shares of Common Stock of the Issuer. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein.

2. Securities owned directly by BVF. As the general partner of BVF, Partners may be deemed to beneficially own the securities owned directly by BVF. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF.

3. Securities owned directly by BVF2. As the general partner of BVF2, Partners may be deemed to beneficially own the securities owned directly by BVF2. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF2. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF2.

4. Securities owned directly by Trading Fund OS. As the general partner of Trading Fund OS, Partners OS may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment manager of Trading Fund OS and the sole member of Partners OS, Partners may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by Trading Fund OS. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by Trading Fund OS.

	BVF Partners L.P., By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President	05/26/2020
	Biotechnology Value Fund, L.P., By: BVF Partners L.P., its investment manager, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President	05/26/2020
	Biotechnology Value Fund II, L.P., By: BVF Partners L.P., its investment manager, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President	05/26/2020
	BVF Partners OS Ltd., By: BVF Partners L.P., its sole member, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President	05/26/2020
	Biotechnology Value Trading Fund OS LP, By: BVF Partners L.P., its investment manager, BVF Inc., its general partner, By: /s/ Mark N. Lampert, President	05/26/2020
	BVF Inc., By: /s/ Mark N. Lampert, President	05/26/2020
	/s/ Mark N. Lampert	05/26/2020
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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