Leerink analyst Paul Matteis believes "multiple approvability questions" remain after Alkermes this morning presented additional clinical data for ALKS 5461 in treatment resistant depression. The FDA's acceptance of a novel trial design and tweaked clinical endpoint are among the outstanding issues, Matteis tells investors in a research note. Today's data are unlikely to "materially shift the debate in the short term," the analyst adds. Matteis, however, remains "encouraged by the breadth of precedent for FDA flexibility in psychiatry" ahead of an ALKS 5461 new drug application filing in the second half of the year. He reiterates an Outperform rating on Alkermes. The stock in afternoon trading is up 57c to $57.79.