X0306 4 2020-06-05 0 0001649904 RHYTHM PHARMACEUTICALS, INC. RYTM 0001473930 Foley Todd C/O MPM ASSET MANAGEMENT 450 KENDALL STREET CAMBRIDGE MA 02142 1 0 0 0 Common Stock 2020-06-05 4 S 0 1896 20.00 D 2024893 I See Footnote The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. The shares were sold as follows: 1,825 by MPM BioVentures V, L.P. ("BV V") and 71 by MPM Asset Management Investors BV5 LLC ("AM BV5"). MPM BioVentures V GP LLC and MPM BioVentures V LLC ("BV LLC") are the direct and indirect general partners of BV V and BV LLC is the manager of AM BV5. Ansbert Gadicke, Luke Evnin and Todd Foley are the members of BV LLC. The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein. Shares are held as follows: 1,949,171 by BV V and 75,722 by AM BV5. The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein. /s/ Todd Foley 2020-06-05