Shares of Alkermes PLC soared 21% in premarket trade Monday, after the biopharmaceutical company said the Food and Drug Administration accepted for review the company's new drug application (NDA) for its treatment of major depressive disorder (MDD). The acceptance comes after the FDA had initially issued a "refusal to file" letter for the MDD treatment, ALKS 5461, on March 30. The stock had plunged 22% on April 2, when the news of the letter was released. Alkermes said the rescission of the refusal letter followed "productive interactions" with the FDA, in which it "clarified" certain aspects of the NDA submission, without any additional data or analyses submitted. Alkermes's stock had tumbled 22.3% year to date through Friday, while the SPDR S&P Biotech ETF had gained 5.6% and the S&P 500 had slipped 0.7%.