X0306 4 2020-06-04 0 0001680581 Fulcrum Therapeutics, Inc. FULC 0001778713 Cadavid Diego C/O FULCRUM THERAPEUTICS, INC. 26 LANDSDOWNE STREET CAMBRIDGE MA 02139 0 1 0 0 SVP Clinical Development Common Stock 2020-06-04 4 M 0 226 4.83 A 67011 D Common Stock 2020-06-04 4 S 0 226 20.0498 D 66785 D Common Stock 2020-06-05 4 M 0 451 4.83 A 67236 D Common Stock 2020-06-05 4 S 0 451 20.1791 D 66785 D Stock Option (right to buy) 4.83 2020-06-04 4 M 0 226 0.00 D 2028-07-10 Common Stock 226 14588 D Stock Option (right to buy) 4.83 2020-06-05 4 M 0 451 0.00 D 2028-07-10 Common Stock 451 14137 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 19, 2019. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.01 to $20.10, inclusive. The reporting person undertakes to provide to Fulcrum Therapeutics, Inc., any security holder of Fulcrum Therapeutics, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.04 to $20.31, inclusive. The reporting person undertakes to provide to Fulcrum Therapeutics, Inc., any security holder of Fulcrum Therapeutics, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (3) to this Form 4. The shares underlying the option are scheduled to vest in equal quarterly installments from July 16, 2018 through July 15, 2022. /s/ Peter Thomson, as attorney-in-fact for Diego Cadavid 2020-06-08