BioSante Pharmaceuticals, Inc. (NASDAQ: BPAX), today announced completion of enrollment in its ongoing LibiGel (testosterone gel) Phase III cardiovascular and breast cancer safety study. LibiGel is in development for the treatment of female sexual dysfunction (FSD), specifically, hypoactive sexual desire disorder (HSDD) in menopausal women, for which there is no FDA-approved product.
“LibiGel remains the only product in the world in Phase III clinical development for the treatment of HSDD”
BioSante has been informed by the LibiGel safety study independent Executive Committee regarding the outcome of the sample size analysis that determines the number of subjects to be enrolled in the LibiGel Phase III safety study. The FDA-agreed sample size analysis indicates that enrollment should stop, based on meeting a minimum 90 percent predictive probability of success of the safety study to show the safety of LibiGel at the primary data analysis. As per the protocol, the safety study will continue for 12 months of therapy from the last subject enrolled before the primary analysis will be conducted by BioSante, which will provide the data for BioSante's new drug application (NDA) submission anticipated to be made in 2012. The study will continue for five years.
BioSante reported that the independent Data Monitoring Committee (DMC) reviewed unblinded data in over 3,250 women enrolled and over 3,450 women-years of exposure in its LibiGel Phase III cardiovascular and breast cancer safety study including 22 adjudicated cardiovascular (CV) events. To date, the cardiovascular event rate is lower than anticipated at approximately 0.58 percent. There have been nine breast cancers reported; also a lower than anticipated rate of approximately 0.24 percent.
Although enrollment is complete, the Phase III LibiGel safety study will continue as per the FDA-agreed protocol, without modification, after the sixth unblinded review of study safety data by the DMC, during which no safety issues were identified to BioSante. BioSante remains blinded as to which events fall into the LibiGel arm or the placebo arm of the study.
"Formal completion of enrollment in the LibiGel safety study is based on the third sample size re-estimation analysis, and the first time that BioSante has been informed that the analysis indicates that enrollment should stop. We are very encouraged that after six reviews of all unblinded safety data, no safety issues have been raised to us by the independent DMC," stated Michael Snabes, M.D., Ph.D., senior vice president of medical affairs for BioSante. "The LibiGel safety study will continue as per protocol and the DMC will continue to take its periodic unblinded looks at all safety data. BioSante will remain blinded until the primary data analysis which, as per protocol, will occur after the last subject enrolled has been in the study for 12 months of therapy."
The sample size analysis was conducted, by the DMC's unblinded statistician, based on 3,307 subjects enrolled at the time of the analysis and on 22 adjudicated CV events. Since the analysis, an additional 250 subjects have been enrolled. The sample size analysis requires BioSante to stop enrollment of subjects when there is at least a 90% chance of meeting one or both of the following criteria one year after enrollment is completed: the ratio of the rate of CV events on LibiGel compared to placebo has an upper bound of the 97.2% confidence interval ≤ 2, or the 97.2% confidence interval for the risk difference is ≤ 1% (and less than twice the observed CV events in the LibiGel group vs. placebo group).
Subjects have been enrolled in this study for an average of 12.8 months. More than 1,500 subjects have been enrolled in the study for more than a year and over 700 subjects for more than two years. The periodic reviews by the DMC are based on the DMC's protocol-defined mandate in accordance with FDA Guidance on study oversight. BioSante's objective is to submit the LibiGel NDA by the end of 2012.
"LibiGel remains the only product in the world in Phase III clinical development for the treatment of HSDD," said Stephen M. Simes, BioSante's president & CEO. "The ability to stop enrollment as per the sample size analysis that indicates a 90 percent predictive probability of success is very encouraging for the outcome of our LibiGel Phase III clinical development program. With this most recent development, we continue to believe that LibiGel will be the first product approved by the FDA to treat HSDD, also referred to as FSD, in menopausal women."
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