Gilead’s Descovy gets FDA panel OK for PrEP, but not for women

Gilead’s Descovy got a green light from an FDA advisory committee for HIV pre-exposure prophylaxis (PrEP) yesterday – but as expected its use in women was a point of contention.

Descovy (emtricitabine/tenofovir alafenamide) breezed through a vote on whether it was safe and effective for men who have sex with men and transgender women – with 16 in favour to two against – but the panel was split on approval in cisgender women, voting 10 to 8 against including them on the label.

The panel said it was concerned by a lack of data on cisgender women at risk of being infected with HIV by a partner in Gilead’s clinical trials programme for Descovy, echoing the view expressed in the FDA briefing document published ahead of the meeting.

Analysts at Jefferies suggest cisgender women account for around 7% of PrEP prescriptions in the US.

The advisory committee acknowledged the FDA’s position that there isn’t enough pharmacokinetic data to demonstrate Descovy reaches high enough concentrations in the vagina and cervix to provide protection against HIV.

Gilead wants Descovy to replace its older drug Truvada (emtricitabine/tenofovir disoproxil fumarate) as the go-to drug for PrEP, a standing that has driven growth in the latter drug’s to around $3 billion last year.

Two-thirds of its turnover in the US is thought to come from PrEP but that lucrative franchise is facing the threat of generic competition as the patents on Truvada’s active ingredients start to fall.  

In the first half of the year revenues of the drug fell by around $100 million to $1.32 billion, mainly because of competition outside the US where it only has patent protection until September.

According to Gilead, Descovy achieves intracellular drug concentration levels above the estimated protective threshold more quickly than Truvada and those levels persist longer than with the older drug. It also says the new product has a cleaner safety profile.

The panel said Gilead doesn’t yet have convincing data to show the new drug is anything other than non-inferior to Truvada, which should be sufficient to support approval, but may count against Gilead’s efforts to position Descovy as a replacement for Truvada once low-cost generics become available.

“We appreciate the advisory committee’s thoughtful review and discussion of the data,” commented Diana Brainard, Gilead’s head of HIV and emerging viruses.

“Descovy represents a potential new therapeutic option for people at risk of sexually acquired HIV-1 infection,” she added. “If approved for a PrEP indication, Descovy could play a meaningful role in the federal initiative to address the nation’s HIV epidemic.”

The AIDS Healthcare Foundation has challenged Gilead to charge just $1 per pill for Descovy for PrEP use, pointing to the “billions of dollars Gilead has already made on its roster of HIV/AIDS medications.”

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