0000950123-04-005343 424B3 1 20040429 REGENERON PHARMACEUTICALS INC 0000872589 2834 133444607 NY 1231 424B3 33 333-74464 04761819 777 OLD SAW MILL RIVER RD TARRYTOWN NY 10591-6707 9143477000 424B3 1 y96793b3e424b3.htm PROSPECTUS SUPPLEMENT NO. 9