Forest Laboratories, Inc and Gedeon Richter Plc announced positive top-line results from a phase-IIb clinical trial of the novel, investigational antipsychotic agent cariprazine for the treatment of acute exacerbation of schizophrenia.

For the primary endpoint, the Positive and Negative Syndrome Scale (PANSS), the data showed that patients with schizophrenia treated with cariprazine experienced significant symptom improvement compared to placebo patients within the first week of treatment and at each subsequent time point studied.

Based on this latest schizophrenia data, subject to a complete review of the full results, and the previously announced phase-II results in patients suffering from acute mania associated with bipolar I disorder, the companies intend to initiate phase-3 trials for both indications in early 2010. Cariprazine is currently also undergoing phase-II clinical trials in patients with Bipolar Depressive Disorder and as adjunctive therapy in Major Depressive Disorder.

Discovered by researchers at Gedeon Richter and licensed in the United States and Canada by Forest Laboratories in 2004, cariprazine is an orally active D3/D2 partial agonist with preferential binding to D3 receptors. Additionally, cariprazine has a relatively low potency at other receptor sites, such as 5-HT2C, histamine H1, muscarinic, and adrenergic receptor sites, that have been associated with adverse events in some other drugs in the class.

“Both the latest clinical trial results for cariprazine in patients suffering from schizophrenia and the previous proof of concept results in bipolar mania, confirm our long held belief in this compound. I congratulate the research teams who have persevered in their pursuit to develop cariprazine through sophisticated and sometimes difficult clinical trial programmes,” said Howard Solomon, chairman and chief executive officer of Forest Laboratories. “Our strategy to invest in promising product opportunities that have been discovered by highly creative and innovative partners, around the world, continues to bear fruit and we look forward to advancing the late-stage cariprazine development program.”

Dr Marco Taglietti, president of Forest Research Institute, said, “With positive potentially pivotal trials in both schizophrenia and bipolar mania, we are excited about the opportunity to expedite our phase-III clinical programmes and bring this important therapy to the market as quickly as possible. We have worked closely with Gedeon Richter since the time we licensed cariprazine and we will continue to explore the clinical potential of cariprazine for other conditions, including bipolar depression and as adjunctive therapy in Major Depressive Disorder.”

“We are very encouraged by these results as we believe that cariprazine has the potential to be a valuable new treatment option for people suffering from schizophrenia. These results are considered as a further step towards our commitment conducting original research in the field of CNS disorders, where our team has excellent expertise,” said Erik Bogsch, chief executive officer, Gedeon Richter Plc.

Forest Laboratories is a US-based pharmaceutical company with a long track record of building partnerships and developing and marketing products that make a positive difference in people’s lives.