X0508 4 2025-02-12 0 0001649904 RHYTHM PHARMACEUTICALS, INC. RYTM 0001801372 Lee Jennifer Kayden C/O RHYTHM PHARMACEUTICALS, INC. 222 BERKELEY STREET, 12TH FLOOR BOSTON MA 02116 0 1 0 0 EVP, Head of North America 1 Common Stock 2025-02-12 4 S 0 600 56.39 D 4813 D Common Stock 2025-02-12 4 S 0 10 56.41 D 4803 D Common Stock 2025-02-12 4 S 0 1205 56.39 D 3598 D Common Stock 2025-02-13 4 S 0 1205 58 D 2393 D The sales reported in the Form 4 was effected pursuant to a Rule 10b5-1 instruction adopted prior to February 27, 2023 solely with the intent to cover withholding taxes in connection with the vesting of certain previously reported restricted stock units. The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 8, 2024. /s/ Stephen Vander Stoep, Attorney-in-Fact for Jennifer Kayden Lee 2025-02-14