By Caroline Copley
ZURICH (Reuters) - An experimental Roche drug designed to treat the "negative symptoms" of schizophrenia failed to meet its main goal in two late-stage studies, dealing a blow to the Swiss drugmaker's research hopes in the risky area of brain science.
Results of two Phase III trials found bitopertin in combination with antipsychotic therapy did not significantly reduce negative symptoms after 24 weeks of treatment compared with placebo. A third late-stage study is ongoing.
Roughly 26 million people are affected by schizophrenia worldwide, but current treatment options for the disorder's negative symptoms - which include social withdrawal, lack of motivation and reduced emotional reactivity - are limited.
"These results are disappointing for people with negative symptoms because more effective treatments are needed for these debilitating effects of schizophrenia," said Sandra Horning, Roche's chief medical officer and global head of product development.
The data are also a blow for Roche, which has upped its investment in neuroscience in recent years as it looks to branch out beyond its core cancer expertise. It is currently running late-stage studies in Alzheimer's disease, multiple sclerosis and schizophrenia.
Many large pharmaceutical companies including Merck, Novartis and AstraZeneca have cut back on research in the area as new drugs prove hard to find.
The success rate for brain drugs in Phase III is poor, averaging around 50 percent against 50-80 percent for other disease areas.
Kepler Cheuvreux analyst Fabian Wenner said the results showed Roche was taking more time to succeed in new fields outside of oncology, which he said would be critical to secure sustainable growth in the long term.
In recent years Roche has scrapped drugs to treat diabetes and boost levels of "good" high-density cholesterol.
While a successful treatment for schizophrenia's negative symptoms could have notched up more than a billion dollars a year in sales, many analysts had modest expectations for bitopertin.
Current consensus forecasts point to annual sales of $407 million by 2017, according to Thomson Reuters Cortellis.
Roche is conducting three additional Phase III studies investigating bitopertin for sub-optimally controlled symptoms, such as hallucinations and delusions.
The drugmaker said it would await the data from its remaining studies before deciding on the next steps for the drug.
(Reporting by Caroline Copley; Editing by Mark Potter)