Complex sentence: Eli Lilly, Parke-Davis, Wyeth, Pitman-Moore, and Cutter--had difficulties in completely inactivating the polio virus, and three companies other than Cutter were sued but the cases were settled out of court.
Split into simpler sentences: Eli Lilly, Parke-Davis, Wyeth, Pitman-Moore, and Cutter--had difficulty completely inactivating the polio virus. Three companies other than Cutter were sued, but the cases settled out of court.