RHYTHM PHARMACEUTICALS, INC. — Director's Dealing 2017

Oct 4, 2017

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: RHYTHM PHARMACEUTICALS, INC. (RYTM)
CIK: 0001649904
Period of Report: 2017-10-04

Reporting Person: Flynn James E (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Mgmt L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: DEERFIELD MANAGEMENT CO (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Special Situations Fund, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Mgmt III, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Private Design Fund III, L.P. (10% Owner, Possible Member of 10% Group)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Series A Preferred Stock	$		Common Stock (291005)		Indirect
Series A Preferred Stock	$		Common Stock (291005)		Indirect

Footnotes

F1: Each share of Series A Preferred Stock is convertible into 0.1090513 shares of the Issuer's common stock upon the closing of the Issuer's initial public offering (on an adjusted basis, after giving effect to the 1-for-9.17 reverse stock split effected by the Issuer in connection with its initial public offering). Shares of Series A Preferred Stock will automatically convert into shares of the Issuer's common stock upon the closing of the Issuer's initial public offering of common stock.

F2: This Form 3 is being filed by the undersigned as well as the entities listed on the Joint filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt III, L.P. is the general partner of Deerfield Private Design Fund III, L.P. ("Fund III"). Deerfield Mgmt, L.P. is the general partner of Deerfield Special Situations Fund, L.P. (collectively with Fund III, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt III, L.P., Deerfield Mgmt, L.P. and Deerfield Management Company, L.P. In accordance with Instruction 5 (b)(iv) to Form 3, the entire amount of the Issuer's securities held by the Funds is reported herein.

F3: For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.