AMAG bags FDA okay for second ‘female Viagra’ drug

AMAG Pharma has won US approval for a new drug to treat decreased libido in premenopausal that will compete with a Sprout Pharma’s Addyi.

The new therapy – Vyleesi (bremelanotide) – is a first-in-class melanocortin 4 receptor agonist originally developed by Palatin Technologies and is the second drug to be approved by the FDA after Addyi (flibanserin) for hypoactive sexual desire disorder (HSDD) that causes distress.

Addyi proved to be a controversial product when it was approved in 2015, with critics accusing the US regulator of giving into lobbying and giving the green light to a drug that had shown modest activity in trials and had serious safety issues if taken with alcohol.

That didn’t stop blockbuster sales projections for Addyi, which encouraged Valeant (now Bausch Health) to license the drug in a $1 billion deal. As it turned out, the product has been a commercial flop with sales estimated at around $10 million a year, hamstrung by a black box warning over the alcohol issue and a hefty price of $800 per month, and Valeant handed back rights to Sprout in 2017.

AMAG, which has licensed North American rights to Vyleesi from Palatin in a $465 million deal in 2017, is hoping Vyleesi will achieve the success that has eluded Addyi, particularly as it doesn’t have the alcohol safety issue.  It does however have some restrictions on use in women with cardiovascular disease as it seems to cause transient increases in blood pressure in some people.

The company says HSDD is an under-estimated disorder that affects around one in 10 pre-menopausal women, equivalent to millions of women in the US, and has shown consistency across endpoints in clinical trials that eluded Addyi.

Analysts at Ladenburg Thalman said recently that there are 4-6 million women in the US with HSDD, who mostly “suffer…in silence”, and say that despite the controversy over HSDD they believe the condition is both “real and debilitating.”

Vyleesi’s subcutaneous injection route of administration could be a drag on sales given that Addyi is dosed orally, but they expect that will not be a barrier for women motivated to seek treatment – although acknowledge that could be a small population unless AMAG’s awareness-raising drive delivers.

They expect “some wind at the back of Vyleesi as media and talk shows are likely to spread some attention on HSDD and Vyleesi,” while AMAG “has shown early signs of success in its online HSDD awareness campaign, which we believe will be essential to Vyleesi’s adoption.”

The market for male erectile dysfunction products was tiny until the approval of Viagra, largely because earlier treatment relied on direct injection of prostaglandins into the vasculature of the penis or surgical implants.

AMAG and Palatin think HSDD just needs the right product to be available, and that Vyleesi fulfils that role. While Addyi is more helpful with relieving the distress than restoring desire, Vyleesi appears to benefit both elements of the disorder, and only has to be taken ‘on-demand’ rather than continually.

Ladenburg Thalman expect Vyleesi to reach $300 million in sales by 2021 and $732 million by 2030, based on an estimated price of around $400 per month, or $100 per shot.

Palatin meanwhile is due to pick up $60 million from AMAG on US approval, with royalties of $30 million and $95 million at those time points if their sales predictions are correct.