VIVUS, Inc. announced data on TA-1790, its oral phosphodiesterase type 5 (PDE5) inhibitor for the treatment of erectile dysfunction (ED). The Phase 2 head-to-head at-home study comparing the onset of action between TA-1790 and Pfizer's Viagra (sildenafil) showed comparable results. With each product, subjects had erections sufficient to achieve vaginal penetration on approximately 80 per cent of attempts. These successful attempts occurred, on average, within 20 minutes after dosing.

This double blind, randomized, crossover study in the home setting provides additional data to complement the earlier trial in the clinical setting (the in-clinic RigiScan efficacy trial results announced June 2003). The efficacy demonstrated by TA-1790 in this at-home trial continues to support the rapid absorption and onset of action seen in the earlier in-clinic trial; however, it did not out-perform Viagra as it did in the in-clinic study.

"TA-1790's onset of action was consistently strong in both the at-home and in-clinic studies," said John Dietrich, vice president of R&D for VIVUS. "These data and our belief in the overall safety profile of TA-1790 support our plans to continue the TA-1790 clinical development programme. The Phase 2 dose ranging clinical trial and routine safety studies evaluating the interaction of TA-1790 with various drugs are expected to demonstrate the differentiating characteristics between TA-1790 and other PDE5 inhibitors on the market. These studies will be initiated in first half of 2004."

VIVUS plans to present full peer-reviewed data results from this Phase 2 at-home study at the Western Sectional meeting of the American Urological Association (AUA) in August 2004.

"The clinical development of TA-1790 is a high priority for VIVUS," said Leland Wilson, VIVUS' CEO. "We remain excited about the potential of the product to fill additional needs in the growing ED market."

In March 2001, VIVUS announced it had licensed TA-1790 from Tanabe Seiyaku Co., Ltd., Japan-based pharmaceutical company. The compound is a fast-acting, highly-selective PDE5 inhibitor for the treatment of erectile dysfunction.