[Form 4] RHYTHM PHARMACEUTICALS, INC. Insider Trading Activity

Rhea-AI Filing Summary

Rhythm Pharmaceuticals (RYTM) reported insider activity by its Chief Technical Officer. On 10/16/2025, the officer exercised stock options for 2,093 shares at $27.35 and 12,344 shares at $30.66, then sold 2,693 shares at a weighted average $110.9482, 8,332 shares at $112.0554, and 3,412 shares at $112.81. The trades were made under a Rule 10b5-1 plan adopted on August 8, 2024. Following the transactions, the officer reported 8,509 shares beneficially owned directly. Option holdings reported after the exercises were 14,657 (at $27.35) and 10,469 (at $30.66).

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Shulman Joseph

(Last) (First) (Middle)

C/O RHYTHM PHARMACEUTICALS, INC.

222 BERKELEY STREET, 12TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
RHYTHM PHARMACEUTICALS, INC. [ RYTM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Technical Officer

3. Date of Earliest Transaction (Month/Day/Year)
10/16/2025

4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/16/2025		M		2,093	A	$27.35	10,602	D
Common Stock	10/16/2025		M		12,344	A	$30.66	22,946	D
Common Stock	10/16/2025		S(1)		2,693	D	$110.9482(2)	20,253	D
Common Stock	10/16/2025		S(1)		8,332	D	$112.0554(3)	11,921	D
Common Stock	10/16/2025		S(1)		3,412	D	$112.81(4)	8,509	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options (Right to Buy)	$27.35	10/16/2025		M			2,093	(5)	01/31/2033	Common Stock	2,093	$0	14,657	D
Stock Options (Right to Buy)	$30.66	10/16/2025		M			12,344	(6)	02/10/2031	Common Stock	12,344	$0	10,469	D

Explanation of Responses:

1. The sale reported in this Form 4 was effected pursuant to Rule 10b5-1 instruction adopted on August 8, 2024.

2. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $110.23 to $111.00 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

3. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $111.50 to $112.48 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

4. The price reported in Column 4 is a weighted average price. The securities were sold in multiple transactions at prices ranging from $112.51 to $113.14 per common stock. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

5. The stock options were granted on February 1, 2023. The options vest and become exercisable in 16 substantially equal installments upon the Reporting Person's completion of each three full months of successive service to the Issuer following the grant date.

6. The stock option is fully vested.

	/s/ Stephen Vander Stoep, attorney-in-fact for Joseph Shulman	10/20/2025
	** 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 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

What did RYTM's CTO report on Form 4?

The CTO exercised options for 2,093 shares at $27.35 and 12,344 shares at $30.66, then sold 2,693, 8,332, and 3,412 shares at weighted average prices around $111–$113 on 10/16/2025.

Were the RYTM insider trades under a Rule 10b5-1 plan?

Yes. The filing states the sales were effected pursuant to a Rule 10b5-1 plan adopted on August 8, 2024.

How many RYTM shares does the insider hold after the transactions?

Following the reported transactions, the insider reported 8,509 shares beneficially owned directly.

What prices were the RYTM shares sold at?

Weighted average prices: $110.9482 (range $110.23–$111.00), $112.0554 (range $111.50–$112.48), and $112.81 (range $112.51–$113.14).

What RYTM options remain held after the exercises?

Reported post-transaction option holdings were 14,657 (exercise price $27.35, expiring 01/31/2033) and 10,469 (exercise price $30.66, expiring 02/10/2031).

What is the insider's role at RYTM?

The reporting person is an Officer, serving as Chief Technical Officer.