Bipolar drug – conflicting result
Budapest – Hungary’s largest drugmaker Gedeon Richter Ltd. and US partner Forest Laboratory said that a Phase II clinical trial of their orally active drug cariprazine (RGH-188) for bipolar depression produced no “statistically significant” result compared with placebo treatment. The companies tested two dosages of their once-daily D3/D2 dopamine receptor partial agonist/antagonist in 234 adult patients with bipolar I or II depression without psychotic features in a two-arm study with a low dose (0.25-0.75 mg/day) and high-dose group (1.5- 3.0 mg/day).
While no effect was observed after 8 weeks of treatment in the low-dose group, the development partners announced at the end of August that “there was evidence of a clinically relevant treatment effect in the high-dose arm.” Gedeon Richter and Forest Laboratories are now expected to conduct an additional Phase II dose-response trial to examine a wider range of doses.
Cariprazine is currently being tested in several Phase III trials for schizophrenia and bipolar mania. The drug acts as a D3/D2 antagonist/partial agonist, depending on actual dopaminergic tone, and preferentially binds to D3 receptors.