The early results are in for a Phase 3 clinical trial testing Alkermes’ schizophrenia drug, and the company’s drug worked just as well as a medication already used to treat the psychiatric condition. But so far, it hasn’t distinguished itself on the side effect profile.
Weight gain is a common side effect of psychiatric medications, including the generic schizophrenia drug olanzapine that was given to participants in a control arm of the trial. The Alkermes (NASDAQ: ALKS) drug ALKS 3831 combines olanzapine with a second compound called samidorphan. By putting the two compounds together in a single pill, the company, based in Dublin, Ireland and Waltham, MA, hopes to bring patients the benefits of the schizophrenia medication without the weight gain. But according to the initial results Alkermes reported from the first of two Phase 3 studies, patients treated with its drug did gain weight.
In a conference call to discuss the early clinical trial results, Elliot Ehrich, Alkermes’ executive vice president for research and development, said that this first Phase 3 trial was designed to test the drug’s efficacy. The patients who received the Alkermes drug and those who were given olanzapine gained weight at similar rates. But with a study lasting just four-weeks, the time frame was too short for researchers to draw any definitive conclusions about weight gain, he said. Ehrich added that the company is moving ahead with a Phase 1 metabolic study of ALKS 3831 as well as an additional long-term study that will assess weight gain in patients.
Alkermes CEO Richard Pops pointed to results from an earlier Phase 2 study of the drug that enrolled 300 patients. In that trial, patients gained weight but the rate of weight gain started to level off after 21 days. If samidorphan does limit the weight gain that comes with psychiatric medications, it might take more time for that effect to show up in clinical trial participants, he said.
The results released Thursday are from a Phase 3 study that enrolled 403 patients who were showing paranoid delusions, aggressiveness, and other signs of schizophrenia. Patients were randomized to receive either ALKS 3831 or a placebo. The study also included a third group of patients given olanzapine.
The good news for Alkermes is that patients treated with its drug showed improvement in schizophrenia symptoms. The main goal of the trial was showing a statistically significant reduction in scores on a medical assessment that is used to evaluate patients who have schizophrenia. Alkermes says its drug met that goal, as did olanzapine. The study also met a secondary goal of improving patient scores on another scale used to assess the severity of schizophrenia symptoms.
Besides weight gain, the most common side effects observed in patients who received the Alkermes drug or olanzapine were drowsiness and dry mouth.
Alkermes plans to present full results from the clinical trial at a future medical meeting. A second Phase 3 study, which will test ALKS 3831 in patients for six months, is ongoing. The company expects to report data from that trial next year.