The glaucoma drug Alphagan P is responsible for about $240 million in annual revenue for the pharmaceutical company Allergan Inc. So it’s no surprise that when Apotex Corp. and Exela Pharmsci Inc. told the Food and Drug Administration that they wanted to make generic versions of the drug, Allergan and its lawyers at Fish & Richardson filed patent infringement suits to stop them.

The result? An Oct. 23 ruling from Delaware federal district court Chief Judge Gregory Sleet that gives Allergan exclusive rights to make the drug until 2022. By our math, that ruling is worth a few billion to Fish’s client.

After an eight-day bench trial last March, Sleet found that the five Allergan patents at issue in the case were valid and enforceable. He also concluded that Allergan had not committed inequitable conduct. The only good news for Apotex and Exela was that he declined to award attorney fees and costs to Allergen.

The Fish & Richardson team was led by Jonathan Singer and included William Marsden and Juanita Brooks. According to Singer, at trial Apotex had Katten Muchin Rosenman and Potter Anderson & Corroon. Exela was represented by Bingham McCutchen. We called Katten and Bingham for comment but didn’t hear back.

This article first appeared on The Am Law Litigation Daily blog on AmericanLawyer.com.