Shares in the USA's BioSante Pharmaceuticals have gone through the floor on disappointing late-stage data for its female sexual dysfunction treatment LibiGel.

The company published top-line results from two Phase III studies of LibiGel (testosterone gel) for hypoactive sexual desire disorder (HSDD) in postmenopausal women, which show that the trials did not meet the co-primary or secondary endpoints. Although there were no statistical differences in the endpoints for the studies, which involved nearly 1,200 women, BioSante said that all results "were in the appropriate directions".

Specifically, in the BLOOM-1 study, women treated with LibiGel showed an increase of 1.47 days with a satisfying sexual event compared to baseline, while those receiving placebo gel showed an increase of 1.26 days. In BLOOM 1, there was an increase in the total number of satisfying sexual events of 3.87 from baseline (+83%) in the LibiGel group compared to 3.52 (+65%) for placebo. In BLOOM-2, women using  LibiGel showed an increase of 1.0 day with a satisfying sexual event compared to 1.28 days with placebo gel showed an increase of 1.28 days.

BioSante chief executive Stephen Simes said "we obviously are very disappointed" as "we have been committed to LibiGel for many years". He added that the firm will "continue to analyse the efficacy trial data fully and determine plans for our next steps" but investors seem to have decided already - shares in Biosante slumped 78% to less than $0.50 in after-hours trading.

The data represents another failure in the quest to find treatments for HSDD. In October 2010, Boehringer Ingelheim decided to discontinue flibanserin, an oral drug originally developed as an antidepressant and described in some circles as 'female Viagra', after advisors to the US Food and Drug Administration had expressed concerns on safety and efficacy.

In September last year, Warner Chilcott withdraw its application to extend the treatment scope of its female sexual dysfunction patch Intrinsa (testosterone) in Europe. The latter was approved in July 2006 for the treatment of HSDD in women who have had their uterus and both ovaries removed, and Warner acquired the product through its £3.1 billion purchase of Procter & Gamble’s pharma unit in 2009.