Viagra has a new rival.
German drug firm Bayer AG says latest tests show up to 85 per cent of men treated with its anti-impotence pill have improved erections - results that match or exceed studies of Viagra, Pfizer's blockbuster.
Earlier trials of Bayer's pill, dubbed vardenafil, showed it improved erections in
up to 80 per cent of men, regardless of age.
Pfizer says Viagra improves erections for up to 82 per cent of men.
The latest tests of the Bayer treatment, announced to the Sexual Medicine Society of North America, involved 736 men with mild to severe impotence.
The lead researcher for the study, Dr Wayne Hellstrome of Tulane University School of Medicine, New Orleans, said the latest tests "show vardenafil consistently achieves positive responses across a broad range of patients with erectile dysfunction, regardless of the cause or severity of the disorder".
Bayer and GlaxoSmithKline, Europe's biggest drugmaker, plan to jointly market their pill worldwide next year, except in Japan. Bayer expects annual sales of the drug to reach $US900 million ($2.15 billion).
Vardenafil would challenge Viagra, which in 1998 was the first pill to treat impotence.
The Bayer drug may also have to compete with another anti-impotence pill called Cialis, developed by Indianapolis drugmaker Eli Lilly and ICOS Corp. They have been waiting for Government approval for the drug since June and could beat vardenafil on to the market.
Viagra, Cialis and vardenafil work by blocking an enzyme called phosphodiesterase 5, and all require sexual stimulation. Trials suggest Cialis and vardenafil act faster and have fewer side-effects than Viagra.
Cialis trials showed it did not cause patients to experience a blue haze in their vision, a temporary side-effect associated with Viagra.
Bayer said patients taking vardenafil had mild to moderate side-effects, including headache, upset stomach and sinusitis.
- REUTERS
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