Repligen Corporation completes patient enrollment in RG2417 Phase 2b clinical trial

Repligen Corporation (Nasdaq: RGEN) reported today that it has completed enrollment of patients in its Phase 2b clinical trial of RG2417, an oral formulation of uridine, in patients with bipolar depression.  This study is a double-blind, placebo-controlled trial designed to assess the efficacy of 8 weeks of treatment with RG2417 or a placebo on the symptoms of bipolar depression as measured by the Montgomery-Asberg Depression Rating Scale (MADRS).  The study enrolled 175 patients at 29 clinical sites within the United States, and we expect to report top-line results in the first quarter of 2011.

The primary objective of this study is to assess the safety and efficacy of RG2417 on the symptoms of bipolar depression by demonstrating a greater improvement in the MADRS score of the patients receiving RG2417 when compared to placebo over the 8-week treatment period.  Patients were initially screened for a score of bipolar depression symptoms of greater than 20 on the MADRS and subsequently confirmed to meet the criteria for bipolar depression using an alternate diagnostic tool to ensure that patients have the appropriate diagnosis for inclusion in the study.  Evaluations for symptoms of depression are conducted at baseline and then weekly using the MADRS, a standardized, rater-administered scale, which has been used for numerous drug trials in bipolar disorder.  In addition to the MADRS ratings, patients conduct a weekly self-assessment of their symptoms, which is used to cross check the fidelity of the MADRS raters.  Additional secondary and exploratory objectives include improvements in the Clinical Global Impression Scale, difference in the end of study MADRS scores, and a lack of increase in mania as measured by the Young's Mania Rating Scale.

The average baseline MADRS of the 175 patients recruited into this study was 31.3 compared to 30.4 in the Phase 2a study and there has been a high degree of fidelity between the MADRS scores determined by the raters and the patient's self-assessment of depression symptoms during the 8-week treatment period.  To date, there have been no serious adverse events determined to be related to RG2417, which continues to support an advantageous tolerability and safety profile for the drug.

"We are very pleased to have completed the patient enrollment phase of this study," stated Walter C. Herlihy, President and Chief Executive Officer of Repligen Corporation.  "We believe that this study has been adequately powered to detect a potential benefit of treatment with RG2417 consistent with our Phase 2a results."

This study was designed to confirm and extend the results of a Phase 2a study in which 6 weeks of treatment with RG2417 improved the symptoms of bipolar depression when compared to placebo as measured by the MADRS.  The positive effect of treatment with RG2417 in the Phase 2a study was primarily observed in patients with a significant history of disease as determined by the number of episodes of mania and depression experienced during their lifetime.  The Phase 2a results demonstrated that RG2417 was safe and well tolerated.

Bipolar disorder, also known as manic depression, is an illness marked by extreme changes in mood, thought, energy and behavior in which a person's mood can alternate between the "poles" of mania and depression.  Bipolar disorder is a chronic illness associated with substantial morbidity and mortality, ranking worldwide behind unipolar depression and alcohol abuse among psychiatric illnesses for related disabilities and overall economic burden of illness.  The lifetime financial burden of bipolar disorder in the United States is about $600,000 per patient, depending on resistance to treatment and persistence of symptoms.  Although several therapies are approved for the treatment of bipolar disorder, many individuals are unable to tolerate the treatment-related side effects, and incomplete clinical response, relapse and recurrence remain common clinical problems.  There are more than five million adults worldwide with bipolar disorder, an area of high unmet medical need due to the ineffectiveness and significant side effects of current therapies.