RHYTHM PHARMACEUTICALS, INC. — Director's Dealing 2017

Oct 10, 2017

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: RHYTHM PHARMACEUTICALS, INC. (RYTM)
CIK: 0001649904
Period of Report: 2017-10-10

Reporting Person: ORBIMED ADVISORS LLC (10% Owner)
Reporting Person: OrbiMed Capital GP V LLC (10% Owner)
Reporting Person: ISALY SAMUEL D (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2017-10-10	Common Stock	C	2546295	—	Acquired	2546295	Indirect
2017-10-10	Common Stock	P	355000	$17.00	Acquired	2901295	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2017-10-10	Series A Convertible Preferred Stock	$	C	2546295	Disposed		Common Stock (2546295)	Indirect

Footnotes

F1: In connection with the closing of the Issuer's initial public offering, each share of the Issuer's series A convertible preferred stock (the "Series A Preferred") converted into the Issuer's common stock on a 9.17-for-one basis without payment or consideration. The Series A Preferred had no expiration date.

F2: The reportable securities are held of record by OrbiMed Private Investments V, LP ("OPI V"). OrbiMed Capital GP V LLC ("GP V") is the sole general partner of OPI V and OrbiMed Advisors LLC ("Advisors"), a registered adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of GP V. 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 V, Advisors and Isaly may be deemed to have voting and investment power with respect to the securities held by OPI V and as a result, may be deemed to have beneficial ownership over such shares.

F3: This report on Form 4 is jointly filed by GP V, Advisors and Isaly. Each of OPI V, GP V, Advisors and Isaly disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

F4: Reflects the number of shares of Series A Preferred held by the Reporting Person on an as-converted to common stock basis.