DUBLIN ( TheStreet) -- First thing I did after reading Alkermes' ( ALKS) announcement about positive results from a mid-stage study of its depression drug ALKS 5461 was to make sure the company didn't enroll patients in India. Investors know from past, painful experience -- Targacept ( TRGT) (ouch!) -- that depression drug studies run in India can't be trusted. Whew... Alkermes conducted the study in the good ol' US of A. That's re-assuring. Alkermes intends to move ALKS 5461, an once-daily pill that modulates opioid receptors in the brain, into pivotal phase III depression studies based on the results of the phase II study announced Wednesday. Alkermes shares were up 9% to $27.80 in Wednesday trading. The phase II study enrolled 142 patients diagnosed with major depression that was not well controlled with current medications. The patients were randomized to receive ALKS 5461 or a placebo as an add-on therapy to their existing anti-depression medication. After four weeks of treatment, ALKS 5461 significantly reduced depression symptoms compared to placebo using standard clinical measures, including the Hamilton Depression Rating Scale. The drug was well tolerated. Detailed data from the study will be presented at a medical meeting in May, Alkermes said. "The improvements in depressive symptoms observed in patients treated with ALKS 5461 in this study were clinically meaningful and among the most robust I have seen in a phase 2 study for depression in the past two decades," said Dr. Maurizio Fava, Director of the Depression Clinical and Research Program at Massachusetts General Hospital and an investigator in the study, in a statement. Of course, investors have heard such exclamations about phase II depression drug studies before, only to be shattered when the benefits evaporated in larger, phase III studies. Still, expectations for ALKS 5461 were relatively low because there was so little prior clinical data on the drug to examine. Unlike Targacept and its failed depression drug, Alkermes conducted its phase II study of ALKS 5461 at U.S. centers and with centralized raters to eliminate as much potential biased reporting of data as possible. "Alkermes' pipeline is often overlooked by investors, and we've been saying that 2013 could begin to change this sentiment," said Cory Kasimov in a note to clients. Alkermes is also conducting a phase III study of ALKS 9070, a once-monthly version of the blockbuster schizophrenia drug Abilify, with results expected in the second half of the year. ALKS 9070 trails a competing long-acting version of Abilify from Otsuka that was recently approved for use in the U.S. Both ALKS 9070 and ALKS 5461 are essential elements in Alkermes' strategy to develop and market its own internally developed drugs and diversify revenue growth beyond royalties collected on its drug-delivery technology platform. -- Reported by Adam Feuerstein in Boston. Follow Adam Feuerstein on Twitter.