144 0001683607 XXXXXXXX LIVE 0000872589 REGENERON PHARMACEUTICALS, INC. 000-19034 777 OLD SAW MILL RIVER ROAD TARRYTOWN NY 10591 9148477000 Bassler Bonnie L Director COMMON RBC CAPITAL MARKETS LLC

250 NICOLLET MALL, SUITE 1700 MINNEAPOLIS MN 55401

1500 1200000.00 103282318 01/07/2026 NASDAQ COMMON 01/07/2026 OPTION EXERCISE ISSUER N 1500 01/07/2026 CHECK N BONNIE BASSLER C/O RBC CAPITAL MARKETS LLC

250 NICOLLET MALL MINNEAPOLIS MN 55401

REGENERON PHARMACEUTICALS INC 11/20/2025 760 570000.00 SOLD PURSUANT TO A RULE 10B5-1 PLAN ESTABLISHED 05/02/25 01/07/2026 05/02/2025 POA / JEFFREY EISCHENS