RHYTHM PHARMACEUTICALS, INC. — Director's Dealing 2017

Oct 6, 2017

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: RHYTHM PHARMACEUTICALS, INC. (RYTM)
CIK: 0001649904
Period of Report: 2017-10-05

Reporting Person: BAKER BROS. ADVISORS LP (Former 10% owner)
Reporting Person: Baker Bros. Advisors (GP) LLC (Former 10% owner)
Reporting Person: BAKER FELIX (Former 10% owner)
Reporting Person: BAKER JULIAN (Former 10% owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2017-10-05	Common Stock	C	82969	—	Acquired	82969	Indirect
2017-10-05	Common Stock	C	1081051	—	Acquired	1081051	Indirect
2017-10-05	Common Stock	P	87809	$17.00	Acquired	170778	Indirect
2017-10-05	Common Stock	P	797191	$17.00	Acquired	1878242	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2017-10-05	Series A Convertible Prefered	$	C	760829	Disposed		Common Stock (82969)	Indirect
2017-10-05	Series A Convertible Prefered	$	C	9913242	Disposed		Common Stock (1081051)	Indirect

Footnotes

F1: Represents shares of common stock of Rhythm Pharmaceuticals, Inc. (the "Issuer") received upon conversion of shares of the Issuer's Series A Convertible Preferred Stock ("Series A Preferred") which automatically convert into common stock of the Issuer on a 9.17 for 1 basis (the "Conversion Ratio") without consideration upon the closing of the initial public offering of the Issuer ("IPO").

F2: After giving effect to the transactions reported herein, and as a result of their ownership interest in Baker Biotech Capital (GP), LLC, Julian C. Baker and Felix J. Baker may be deemed to have an indirect pecuniary interest in shares of the Issuer's common stock reported in column 5 of Table I directly held by 667, L.P. ("667"), a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F3: After giving effect to the transactions reported herein, and as a result of their ownership interest in Baker Brothers Life Sciences Capital (GP), LLC, Julian C. Baker and Felix J. Baker may be deemed to have an indirect pecuniary interest in shares of the Issuer's common stock reported in column 5 of Table I directly held by Baker Brothers Life Sciences, L.P. ("Life Sciences" and together with 667, the "Funds"), a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4: On October 5, 2017, 667 and Life Sciences purchased 87,809 and 797,191 shares of common stock of the Issuer at a price of $17.00 per share, respectively, pursuant to an IPO.

F5: Effective upon the closing of the Issuer's IPO, the Series A Preferred shares of the Issuer were converted at the Conversion Ratio without consideration into the number of common shares of the Issuer shown in Column 7. The Series A Preferred shares did not have an expiration date and were convertible at any time, at the holder's election, into common shares of the Issuer.

F6: Pursuant to Instruction 4(c)(iii), this response has been left blank.

F7: Baker Bros. Advisors LP (the "Adviser") serves as the Investment Adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are principals of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F8: The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds. Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.