Craigavon-based pharmaceutical firm Galen has begun to sell its flagship menopausal treatment, Femring, in the US.

The launch, which is expected to generate annual revenues of about $50 million (€42.2 million) for Galen from 2007 onwards, comes three months after Femring was officially approved by US regulator, the Food and Drug Administration (FDA).

It is the first product that Galen has developed and successfully brought through the FDA regulatory approval process and its commercial launch represents an important milestone for the company.

Analysts say further FDA approvals are likely to follow. Mr Roger Boissonneault, Galen chief executive officer, said yesterday that Galen was "committed to being a partner for women at all stages of life".

Femring, a vaginal oestrogen product designed to treat menopausal symptoms, will be supported by a national advertising campaign in the US over coming months.

The US market for menopausal products is worth more than $1 billion each year, in part because of the high incidence of hysterectomies among American women.

It is estimated that as many as 52 million women will be of menopausal age or over in the US in the next decade.

Galen claims that Femring is particularly well positioned to take advantage of this market because it treats both hot flushes and vaginal symptoms simultaneously.

However, as the product's launch comes slightly behind schedule, it is unlikely to make a material impact on Galen's revenues for this year.

Shares in Galen closed at €8.09 in Dublin last night, up 11 cents on the day.

In London, they dropped 6p to close at £5.64 sterling.