Firms race to find a Viagra for women

A GLOBAL race to develop the first effective treatment for sexual problems in women is under way, with a bonanza in prospect for the winner. Since the worldwide success of Viagra, the male impotence drug, multinational drug companies are vying to develop a treatment that will prove as appealing to women.

More than a dozen compounds are being examined, at least half of which are already being tested in trials. Some of them are existing drugs licensed for other conditions which are now being investigated as treatments for "female sexual dysfunction".

Dr David Delvin, a specialist in sexual problems who runs clinics in London and Cambridge, said: "I have had a lot of requests from women to try Viagra but have said no, because it is not licensed for women. Quite obviously when someone produces a drug that increases the female libido there will be a colossal market."

Sex problems in women are more complex than in men. But more women are affected - an estimated four in 10 compared with one in 10 impotent men.

Drugs being researched fall into two main categories - those that improve arousal by increasing the blood flow to the genitals, which involves similar physiological mechanisms in both sexes, and those that increase sexual desire, many of which are based on the male sex hormone testosterone.

Testosterone, described as the "fuel of love", is a key to desire in both sexes, although levels are much lower in women and fall after the menopause. Giving testosterone supplements carries the risk of causing hirsutism (growth of a beard) and heart problems, and companies have sought ways of combating these effects by combining testosterone with the female hormone oestrogen.

A report published last year on the potential market for treatments for female sexual dysfunction said that two million women entered the menopause every year in the US, and the current generation was more sexually demanding than any previous one.

The report, by FT Pharmaceuticals, identified seven drugs that were either being tested or awaiting tests in the US. Several more, from companies including Eli Lilley and Abbott Pharmaceuticals, have since joined the race.

Estratest, a combined testosterone-oestrogen hormone preparation, is one of the first drugs shown to have an effect on the desire centres in the brain. It is licensed in the US for the treatment of menopausal symptoms, but not sexual difficulties. However, a small study of 20 post-menopausal women with low sexual desire found all those who were treated with the drug reported a return of libido.

Dr John Peter, chief executive of Solvay Pharmaceuticals in the UK, said: "I would think there is a substantial potential market. We have been putting a huge effort into Estratest in the US and we are now engaged in a large-scale programme to make it a modern, scientifically supported product."

Pfizer, the manufacturer of Viagra, has completed a trial of the male impotence treatment on 500 women in 19 countries in Europe and North America and the results are expected in the autumn. Andy Burrows, Pfizer's spokesman, said: "We will be looking for any hint of efficacy, but it won't give us the information to go to the regulatory authorities. The female situation is more complex than the male, and has a larger psychological component. In blokes it is more of a hydraulics problem, and it is measurable."

`Female Sexual Dysfunction', published by FT Pharmaceuticals, is available from 149 Tottenham Court Road, London W1P 9LL, price pounds 295

Drugs For Women With Sexual Problems

Drug Chemical name Disorder Company Development stage

Viagra Sildenafil Arousal Pfizer In trials

Vasomax Phentolamine Arousal Zonagen In trials

No name Apomorphine Arousal Pentech In trials

No name Apomorphine Arousal Harvard Scientific In trials

FemProx Alprostadil Arousal NexMed In trials

Estratest Testosterone/ Desire Solvay In trials oestrogen

Livial Tibolone Desire Organon Licensed in UK for treatment of `decreased libido')

Testosterone - Desire TheraTech with In trials skin patch Proctor & Gamble