X0306 4 2020-09-29 0001374690 Larimar Therapeutics, Inc. LRMR 0001215242 LEFF JONATHAN S C/O LARIMAR THERAPEUTICS, INC. THREE BALA PLAZA EAST, SUITE 506 BALA CYNWYD PA 19004 1 0 0 0 Stock Option (right to buy) 11.9 2020-09-29 4 A 0 16600 0 A 2030-07-16 Common Stock 16600 16600 D The Reporting Person, a partner in Deerfield Management Company, L.P., has no pecuniary interest in the securities reported herein and disclaims beneficial ownership of such securities. The Reporting Person holds the option for the benefit, and at the direction, of Deerfield Management Company, L.P. The Option was granted on July 16, 2020 subject to stockholder approval, which was obtained at the Company's special meeting of stockholders on September 29, 2020. The vesting commencement date for the option is July 16, 2020, and the option vests in equal monthly installments over 36 months, subject to the Reporting Person's continued service with the Issuer through each applicable vesting date. /s/ Jennifer Johansson, Attorney-in-fact 2020-09-30