By Saumya Joseph

(Reuters) – Amag Pharmaceuticals Inc’s treatment to boost sexual desire in premenopausal women will be offered at $899 and is the only injectable drug on the market for hypoactive sexual desire disorder (HSDD).

The therapy, Vyleesi, was approved in June and will be available in September through the company’s specialty pharmacy distribution network that would deliver the treatment to patients’ homes.

Women will be able to buy a pack of four injectors of which one needs to be administered at least 45 minutes before anticipated sexual activity, the company said on Tuesday. It will compete with Sprout Pharmaceuticals’ Addyi, a once-daily pill.

Both treatments aim to help women with HSDD, which affects about six million American women.

But unlike Viagra for men, which increases blood flow to the male sexual organ, Vyleesi – chemically known as bremelanotide – activates pathways in the brain involved in sexual desire.

“It’s not a one size fits all solution … There is no ideal desire,” Dr. Julie Krop, Amag’s chief medical officer, told Reuters.

“It’s about trying to relieve the distress of individuals who are suffering because their desire is not at the level that it needs to be for them,” Krop said.

Addyi has a list price of more than $400 for a pack of 30 tablets, or about half of what it was just a year earlier, Sprout said. A pack of four Vyleesi autoinjectors will amount to six to eight weeks supply on average, according to Amag.

But the list price is not necessarily what patients actually pay for a drug. “Out-of-pocket” costs vary based on the duration of the treatment and individual healthcare plans.

Sprout said out-of-pocket costs for patients on Addyi are nothing for the first eight weeks and $25 per month thereafter if they have insurance coverage or $99 per month for the uninsured.

Amag will initially offer the first pack of auto-injectors for free and subsequent prescription refills will cost no more than $99.

Addyi was approved under intense pressure from advocacy groups despite a review by FDA scientists that deemed the drug minimally effective and possibly unsafe. The therapy was acquired by Bausch Health Cos Inc, then known as Valeant Pharmaceuticals, but sold back to the former owners after two years of dismal sales.

The FDA has recommended patients to not take more than one dose of Vyleesi within 24 hours or more than eight doses per month and does not place any restriction on the use of alcohol as in the case of Addyi.

Vyleesi was developed by Palatin Technologies Inc and Amag holds exclusive North American sales rights.

Palatin shares were up 11% at 86 cents, while Amag shares were up 3% at $9.17.

(Reporting by Saumya Sibi Joseph in Bengaluru; Editing by Sriraj Kalluvila, Bernard Orr)