SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* Ipsen, S.A. (Last) (First) (Middle) 65 QUAI GEORGES GORSE (Street) BOULOGNE-BILLANCOURT I0 92100 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 10/04/2017	3. Issuer Name and Ticker or Trading Symbol RHYTHM PHARMACEUTICALS, INC. [ RYTM ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person 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)
Common Stock	599,330	I	The owner of record of the securities is Sutrepa SAS. Sutrepa SAS is controlled by Ipsen SA

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: 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
Series A-1 Junior Convertible Preferred Stock	(1)	(1)	Common stock	45,831	(1)	I	The owner of record of the securities is Sutrepa SAS. Sutrepa SAS is controlled by Ipsen SA
Series A Convertible Preferred Stock	(2)	(2)	Common Stock	167,938	(2)	I	The owner of record of the securities is Sutrepa SAS. Sutrepa SAS is controlled by Ipsen SA

Explanation of Responses:

1. At any time at the holder's election or upon the closing of the Issuer's initial public offering (the "IPO"), each share of the Issuer's series A-1 junior convertible preferred stock (the "Series A-1 Junior Preferred") is convertible into shares of the Issuer's common stock on a 9.17-for-one basis without payment or consideration. The Series A-1 Junior Preferred has no expiration date.

2. At any time at the holder's election or upon the closing of the Issuer's initial public offering (the "IPO"), each share of the Issuer's series A convertible preferred stock (the "Series A Preferred") is convertible into shares of the Issuer's common stock on a 9.17-for-one basis without payment or consideration. The Series A Preferred has no expiration date.

	David Meek, CEO of IPSEN SA	10/04/2017
	** 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).
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