Weeks after Gilead Sciences Inc. got hit with a $200 million verdict in March for infringing Merck & Co.’s patents on a Hepatitis C medication, Fish & Richardson litigators turned the game around for their client.

Lead trial attorneys Juanita Brooks and Jonathan Singer, San Diego partners at the firm, which represented Gilead, ­persuaded U.S. District Judge Beth Labson Freeman to toss the ­verdict due to Merck’s “unclean hands.”