SC 13G

NAMES OF REPORTING PERSONS

Perceptive Advisors LLC

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)

(a) ☐ (b) ☒

SEC USE ONLY

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. )*

Rhythm Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

76243J105

(CUSIP Number)

September 30, 2024

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐

Rule 13d-1(b)

☒

Rule 13d-1(c)

☐

Rule 13d-1(d)

*	The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 76243J105


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 5,435,210
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 5,435,210

CUSIP No. 76243J105


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 5,435,210
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 5,435,210

CUSIP No. 76243J105


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 3,976,880
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 3,976,880

CUSIP No. 76243J105


NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 1,458,330
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 1,458,330

Item 1(a).

Name of Issuer:

Rhythm Pharmaceuticals, Inc. (the “Issuer”)

Item 1(b).

Address of Issuer’s Principal Executive Offices:

222 Berkely Street, 12^th Floor

Boston, MA 02116

Item 2(a).

Names of Persons Filing:

The names of the persons filing this report (collectively, the “Reporting Persons”) are:

Perceptive Advisors LLC (“Perceptive Advisors”)

Joseph Edelman (“Mr. Edelman”)

Perceptive Life Sciences Master Fund, Ltd. (the “Master Fund”)

Perceptive Discovery ID LP (“Discovery ID”)

Item 2(b).

Address of Principal Business Office or, if None, Residence:

The address of the principal business office of each of the Reporting Persons is:

51 Astor Place, 10th Floor

New York, NY 10003

Item 2(c).

Citizenship:

Perceptive Advisors is a Delaware limited liability company

Mr. Edelman is a United States citizen

The Master Fund is a Cayman Islands corporation

Discovery ID is a Delaware limited liability company

Item 2(d).

Title of Class of Securities:

Common stock, $0.001 par value per share (“Common Stock”)

Item 2(e).

CUSIP Number:

76243J105

Item 3.

If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

Not applicable.

Item 4.

Ownership.

The information required by this item with respect to each Reporting Person is set forth in Rows 5 through 9 and 11 of the cover page to this Schedule 13G. The ownership percentages reported are based on an aggregate of 61,457,069 shares of Common Stock outstanding as of November 3, 2024, as reported by the Issuer in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 6, 2024, and give effect to the conversion of 90,000 shares of the Issuer’s Series A Convertible Preferred Stock, par value $0.001 per share (the “Series A Convertible Preferred Stock”) held by the Reporting Persons at the current Conversion Rate of 20.8333 shares of Common Stock to be issued upon the conversion of each $1,000 of liquidation preference.

The Master Fund directly holds 3,560,214 shares of Common Stock. Master Fund holds Series A Convertible Preferred Stock convertible into 416,666 shares of Common Stock. Discovery ID holds Series A Convertible Preferred Stock convertible into 1,458,330 shares of Common Stock. Perceptive Advisors serves as the investment manager to the Master Fund and may be deemed to beneficially own shares held by the Master Fund. Mr. Edelman is the managing member of Perceptive Advisors and may be deemed to beneficially own the shares held by the Master Fund.

Item 5.

Ownership of Five Percent or Less of a Class.

If this statement is being filed to report the fact that as of the date hereof the Reporting Persons have ceased to be the beneficial owner of more than five percent of the class of securities, check the following ☐.

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

Not applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not applicable.

Item 8.

Identification and Classification of Members of the Group.

Not applicable.

Item 9.

Notice of Dissolution of Group.

Not applicable.

Item 10.

Certification.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.


Date:		November 14, 2024

PERCEPTIVE ADVISORS LLC

By:		/s/ Joseph Edelman
		Name: Joseph Edelman
		Title: Managing Member

/s/ Joseph Edelman
JOSEPH EDELMAN

PERCEPTIVE LIFE SCIENCES MASTER FUND, LTD.

By:		Perceptive Advisors LLC

By:		/s/ Joseph Edelman
		Name: Joseph Edelman
		Title: Managing Member

PERCEPTIVE DISCOVERY FUND LP

By:		Perceptive Discovery GP, LLC, its general partner

By:		/s/ Joseph Edelman
		Name: Joseph Edelman
		Title: Managing Member