X0306 4 2020-11-09 0 0001649904 RHYTHM PHARMACEUTICALS, INC. RYTM 0001801372 Chien Jennifer 222 BERKELEY STREET, 12TH FLOOR BOSTON MA 02116 0 1 0 0 EVP, Head of North America Stock Option (Right to Buy) 24.29 2020-11-09 4 A 0 100000 0 A 2030-11-08 Common Stock 100000 100000 D The stock options were granted on November 9, 2020. 25% of the shares subject to the option will vest and become exercisable on November 9, 2021 and the remaining 75% of the shares subject to the option shall vest and become exercisable in 12 substantially equal installments upon the Reporting Person's completion of each three full months of successive service to the Issuer thereafter. /s/ Hunter Smith, attorney-in-fact for Jennifer Chien 2020-11-10