ImClone used Lonza as back up until their own manufacturing facility (think the BB50 plant) was approved…
Erbitux is the correct answer (credit to jbog). The FDA rejected the CMC section of ImClone’s initial Erbitux BLA to produce at the in-house BB36 plant*, and hence the original commercial production came from Lonza (#msg-2363542, #msg-2362817). BB50, the newer of ImClone’s two manufacturing facilities, did not come online until much later.