Race for rivals to Viagra

NOW THAT Pfizer's Viagra pill has established itself as the first- line treatment for impotence, the race is on for other companies to find a treatment for the one-third of impotence patients who don't respond to Viagra or can't take it.

"For people who fail with Viagra, there is a real battle for second- line therapy," said Steve Lisi, a drugs industry analyst with Mehta Partners. The issue is set to dominate the American Urology Association's annual conference, which starts here next week. "This is a hot topic," he said. "It's going to take up most of the AUA meeting."

Schering-Plough last year joined the game by acquiring the rights to market Zonagen's Vasomax pill if it wins Food and Drug Administration (FDA) approval. Abbott Laboratories and Japan's Takeda Chemical Industries are preparing to file for approval to market their apomorphine pill treatment for male erectile dysfunction. Less convenient remedies like Vivus's Muse and Pharmacia and UpJohn's Caverject are already on the market.

Viagra-mania will overshadow the topics that usually dominate AUA conferences, such as prostate cancer, incontinence and an enlarged prostate condition known as BPH.

The market for impotence treatments took off last month when Pfizer introduced Viagra as the first pill treatment for

impotence. Reports of the drug's effectiveness have led 1 million men to seek Viagra prescriptions.

The drug does not suit all patients, however, as it should not be taken with nitrates - common drugs that dilate arteries in patients with chest pain. That combination can lead to severely lowered blood pressure, a heart attack or death. The FDA last week said at least six people had died while taking Viagra, though it was not clear whether the deaths were linked to the drug's use.

The FDA said it still considers Viagra safe and effective, while investors said they did not think reports of the deaths would hurt the drug's long- term sales. Analysts estimate that Viagra sales will reach $2bn (pounds 1.2bn) next year, more than 12 times the combined $158m of sales reported by Muse and Caverject.

Rival companies are counting on the interest generated by Viagra to encourage more men to seek treatment for impotence and increasing sales for other remedies, especially to men whose heart medication makes it risky to use Viagra.

"When you've got a really big drug, people who never would have gone to doctors start to do so," said Jerry Castellini, a Loomis Sayles fund manager.

Impotence is a problem for as estimated 30 million men in the US, including more than one-third of 40-year-olds and two-thirds of 70-year-olds.

Physicians attending the AUA conference will be able to review the results of late-stage clinical trials of two new pills for impotence, TAP Holdings's apomorphine and Zonagen's Vasomax. The studies will be part of the companies' applications for FDA approval.

Vasomax will be marketed by Schering-Plough, one of the world's leading drug makers. Apomorphine's developer TAP is owned by two other pharmaceutical giants , Abbott Laboratories of Illinois and Takeda Chemical Industries of Japan.

Vasomax has had a troubled genesis. Eight groups of shareholders have filed lawsuits against Zonagen, frustrated by delays in filing for FDA approval. But Zonagen shares have nearly doubled this year after the Houston-based company signed Schering-Plough as its marketing partner.

Zonagen plans to file a new drug application with the FDA by the end of next month. TAP expects to seek approval by the middle of next year.

Non-invasive treatments like Viagra, Zonagen, apomorphine and topical creams will one day be able to treat 80 per cent of impotence sufferers, estimates Ira Sharlip, member of the AUA's impotence guidelines committee. That leaves the rest of the market to treatments such as Vivus's Muse, the top-selling impotence product before Viagra, and Pharmacia & Upjohn's Caverject injection.

Mr Sharlip described these drugs' users as "men who have already come out and said to their primary care physicians that they have this problem and want to be treated. The 20 per cent of people Viagra doesn't work for are going to say: 'What are my alternatives?'"

Vivus is developing an improved version of Muse, its technique that uses a pellet inserted in the urethra. The urology meeting will hear the results of clinical trials of that product, which seeks to boost the effectiveness of Muse by adding an alpha blocker to the pellet. Muse had sales of $108m last year, more than double the $47m rung up by Caverject, according to IMS Health.

There will also be discussion on whether these medications can be used to treat sexual dysfunction in women. "If Viagra and other products are effective and safe for treating female dysfunction, you at least double the market," said Mr Sharlip. It could take several more years to show whether the drugs are effective and safe for women.

Copyright: IOS & Bloomberg