X0508 4 2026-03-05 0001658551 Amylyx Pharmaceuticals, Inc. AMLX 0001326969 Bedrosian Camille L C/O AMYLYX PHARMACEUTICALS, INC. 55 CAMBRIDGE PARKWAY, SUITE 6W CAMBRIDGE MA 02142 false true false false Chief Medical Officer false Common Stock 2026-03-05 4 A false 95990 0 A 265285 D Stock Option (Right to Buy) 14.10 2026-03-05 4 A false 143985 0 A 2036-03-05 Common Stock 143985 143985 D The reported transaction involves the Reporting Person's receipt of a restricted stock unit ("RSU") award. The RSUs shall vest in 4 equal annual installments, with the first installment vesting on March 1, 2027, subject to the Reporting Person's continued service to the Issuer through each such vesting date. 25% of the shares subject to the option shall vest and become exercisable on March 1, 2027, and the remaining shares shall vest monthly over the remaining 36 months, subject to the Reporting Person's continuous service to the Issuer through each such vesting date. /s/ Joshua B. Cohen, as Attorney in Fact 2026-03-09