Initial Statement of Beneficial Ownership (3)

FORM 3	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0104 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * ORBIMED ADVISORS LLC	2. Date of Event Requiring Statement (MM/DD/YYYY) 7/24/2017	3. Issuer Name and Ticker or Trading Symbol ALPINE IMMUNE SCIENCES, INC. [ALPN]
(Last)        (First)        (Middle) 601 LEXINGTON AVENUE, 54TH FLOOR	4. Relationship of Reporting Person(s) to Issuer (Check all applicable) __ X __ Director                            _____ 10% Owner _____ Officer (give title below)          _____ Other (specify below)
(Street) NEW YORK, NY 10022-4629        (City)              (State)              (Zip)	5. If Amendment, Date Original Filed (MM/DD/YYYY)	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 Beneficially Owned
1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 4)	2. Date Exercisable and Expiration Date (MM/DD/YYYY)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks: Peter Thompson ("Thompson") serves on the Issuer's Board as a representative of OrbiMed Private Investments VI, LP ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the sole general partner of OPI VI, and OrbiMed Advisors LLC ("Advisors"), a registered adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of GP VI. Samuel D. Isaly ("Isaly"), a natural person, is the managing member of, and holder of a controlling interest in, Advisors. By virtue of such relationships, GP VI, Advisors and Isaly may be deemed to have voting and investment power with respect to the Issuer's securities held by OPI VI and as a result may be deemed to have beneficial ownership over such securities. Thompson is an employee of Advisors.

No securities are beneficially owned.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
ORBIMED ADVISORS LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK, NY 10022-4629	X
OrbiMed Capital GP VI LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK, NY 10022	X
ISALY SAMUEL D 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK, NY 0022	X

Signatures
/s/ Samuel D. Isaly		7/26/2017
** 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 5(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).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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