For the second time this year, Otsuka has sued the FDA for loss of patent protection for its schizophrenia drug Abilify — this time to reverse the agency’s approval of Alkermes’ Aristada.

Otsuka argues the FDA denied the brandmaker’s right to three years of exclusivity for its next-generation Abilify Maintena (aripiprazole) when it approved Aristada (aripiprazole lauroxil).

Alkermes has already launched Aristada in the U.S.

The FDA denied an Otsuka petition on Oct. 5, saying Aristada’s approval can’t be blocked by exclusivity applicable to Abilify Maintena because it contains a different active molecule. Otsuka maintains that it is the same molecule.

The Japanese drugmaker argues that the FDA committed “regulatory sleight of hand” in determining that Abilify Maintena and Aristada are different for purposes of exclusivity, but letting Aristada rely upon Otsuka’s aripiprazole safety and effectiveness data.

In May, Otsuka lost a lawsuit claiming the FDA knowingly removed its monopoly protection by extending Abilify’s pediatric indication for Tourette syndrome to adults, which the company had not sought. That decision cleared the way for the U.S. launch of Abilify knock-offs by Hetero Labs, Teva, Alembic Pharmaceuticals and Torrent Pharmaceuticals.

Otsuka Pharmaceutical v. Burwell et al.was filed in U.S. District Court for the District of Columbia. The FDA does not comment on pending litigation. Otsuka and Alkermes could not be reached for comment by press time. — Jonathon Shacat