In the wake of a $120 million verdict against it in California for refusing to cover experimental cancer treatments, Aetna U.S. Healthcare Inc. has filed suit in U.S. District Court in Philadelphia demanding that six other insurers help cover the judgment under negligence and excess insurance policies purchased by Aetna.

The suit, which seeks more than $75 million in coverage, was filed by attorneys Jerome R. Richter, Ann B. Laupheimer and Daniel H. Wheeler of Blank Rome Comisky & McCauley on behalf of Blue Bell, Pa.-based Aetna U.S. Healthcare Inc. and Aetna Services Inc. of Hartford, Conn.