New York, Dec 22: Propecia, Merck & Co Inc's newly approved once-a-day pill for male pattern hair loss, should become a surefire success as the most effective drug to restore lost hair and slow continuing loss of hair, Wall Street analysts said.

But analysts had widely divergent levels of enthusiasm for the drug, which won marketing approval on Monday from the US Food and Drug Administration, with some arguing it will easily achieve ``blockbuster'' status and others seeing only respectable annual sales of $300 million to $500 million.

David Maris of Aros Securities said Propecia was ``by far the best currently available therapy'' and likely to achieve $1 billion in annual sales within five years because of pent-up demand for more effective treatment among 33 million American men suffering from hair loss.

Maris said the only real competition for Propecia will be Pharmacia & Upjohn Inc's Rogaine, a topical drug launched in 1988 but introduced over the counter in 1996, after continuing lackluster annual prescription sales of about $100 million.

Pharmacia & Upjohn saw Rogaine revenues jump to $162 million last year as the product became available in drug stores and supermarkets, despite data showing it caused ``moderate to dense'' hair regrowth in only 26 per cent of men who used it for four months.

An extra-strength Rogaine formulation, recently approved by the US Food and Drug Administration and now available over the counter, helped the same percentage of people, but worked better than conventional strength Rogaine within only two months.

Merck said studies showed Propecia increased hair growth in 66 per cent of 1,879 men aged 18 to 41 with mild to moderate hair loss on the vertex (top of the head) and anterior mid-scalp (front of the scalp except the temples and widow's peak area).Also, it said only 17 per cent of men treated with Propecia for two years showed hair loss, in contrast to 72 per cent of people who took placebos, or dummy pills, in the clinical trials.

Schroder and Co analyst Jami Rubin forecast Propecia would have annual sales of $300 million to $500 million within four years.

``That's not a big number, not a blockbuster. Most investors are not looking for billion dollar sales.''

She added many analysts had expected Rogaine to have annual sales of $1 billion when it was launched, only to be sorely disappointed. That experience has dampened expectations for all hair-growth products, she added. A principal financial securities analyst, Eugene Melnitchenko, was also expecting Propecia sales of $300 million to $500 million.

``Rogaine discouraged a lot of people from using these kinds of products, so Merck will have do a strong job of convincing people their's is more effective,'' Melnitchenko said.

Merck spokesman Christopher Allman confirmed Merck had signed up advertising company Young & Rubicam for a direct-to- consumer campaign to tell the Propecia story, but he declined to give specifics.

Not to be caught napping, Pharmacia & Upjohn spokesman JeffPalmer said his company had earmarked $80 million to advertise Rogaine products in 1998.Merck said women were not allowed to use Propecia, which works by preventing conversion of the male hormone testosterone to a related chemical, because if taken by pregnant women it could cause abnormalities in a male baby's sex organs.

It added that a small number of men using the drug, less than two per cent, reported sexual problems such as reduced desire and difficulty achieving erections.

``But if you stop using the drug, the sexual dysfunction problems go away,'' said Rodman & Renshaw analyst Mario Corso, who predicted Propecia sales of $950 million in 2001.

Rogaine's most common side effect is itchy dry scalp.Merck said the average retail cost of Propecia will be $45 to $49 per month, with a 10 per cent rebate for patients buying a three-month ``ProPak'' supply.

Copyright © 1997 Indian Express Newspapers (Bombay) Ltd.