Bristol-Myers Squibb Co. and Pfizer Inc. are fighting to keep a slew of consumer lawsuits involving their blockbuster drug Eliquis in Delaware federal court, arguing June 16 that the cases should be considered as a part of multidistrict litigation in New York.

A group of 30 individual plaintiffs, however, say the cases should be remanded to Delaware Superior Court, where they were filed—and quickly removed—last month.