GSK's ViiV looks to future of injectable HIV treatment as long-acting PrEP decision looms

GlaxoSmithKline GSK House in Brentford, UK
A PrEP version of cabotegravir is up for an FDA decision in January. (GlaxoSmithKline)

The future of ViiV Healthcare's HIV business is injectable.

By 2026, the majority-GlaxoSmithKline-owned joint venture expects long-acting regimens to generate around £2 billion ($2.65 billion) in sales. And by 2031, it estimates that 90% of its business will be in that same long-acting market, executives said Monday on a call with investors. 

ViiV expects injectables to steal significant market share from oral treatments, such as Gilead’s Biktarvy, which currently dominate the HIV field. In the prevention arena, the company is awaiting an FDA ruling on its long-acting cabotegravir, with the decision expected to come in January.

Overall, ViiV aims to weather the loss of exclusivity of dolutegravir—the key component in Dovato—in the latter half of the decade “through the changing mix of our portfolio and the success of our pipeline,” ViiV CEO Deborah Waterhouse said on the call.  

ViiV forecasts continued growth for its long-acting injectables in the second half of the decade, with cabotegravir slated to supplant dolutegravir as the company’s “foundational” medicine, Waterhouse said.

In PrEP, where Gilead currently dominates, GSK’s opportunity remains “unrealized,” SVB Leerink analysts wrote in a note to clients Tuesday. Some of the chief uncertainties hanging over the business include patient and doctor willingness to commit to injectables, realistic duration of treatment and market size, the analysts noted.

But demand is “high” in the U.S. for a long-acting injectable PrEP drug like cabotegravir, Waterhouse said.  

“The stigma around PrEP use and the perceived hassle of daily dosing are currently top drivers of discontinuation of PrEP,” she added.

RELATED: GSK's Cabenuva scores thumbs up from England's NICE, giving HIV patients a new long-acting treatment option

ViiV’s portfolio is ultimately “a show-me story,” SVB Leerink said. The company will need to play up cabotegravir’s more convenient dosing and schedule, as well as achieve broad payer coverage and “better penetration for PrEP,” the analysts said.

Fewer than 25% of Americans who could benefit are taking PrEP, Waterhouse said. Despite that fact, the U.S. PrEP market is “strong and viable”—and worth some £1.5 billion ($2 billion), in GSK’s estimation. The company expects the U.S. PrEP market to grow to £4 billion to £5 billion ($5.3 billion to $6.6 billion) by 2030.

Looking at the bigger picture, GSK estimates the overall HIV treatment and prevention market is worth some £26 billion ($34.4 billion), Waterhouse said.

Cabenuva, which GSK says is the world’s “first and only” long-acting injectable HIV treatment, snagged FDA approval in January. The drug is also approved in Europe under the name Vocabria/Rekambys.

RELATED: GlaxoSmithKline's long-acting HIV drug nabs FDA priority review as a preventative option

Since then, the long-acting treatment has launched in 11 markets, with ten more market launches planned for 2022, Waterhouse said. The drug has achieved more than 80% payer coverage in the U.S., she added.

As for the £2 billion ViiV expects its long-acting cabotegravir franchise to generate, the company didn’t say how much would come from treatment and how much from prevention. SVB Leerink analysts said that by 2026, they expect PrEP “is likely to still be a smaller portion of revenue,” but that PrEP penetration is likely to increase with the introduction of ultra-long-acting and self-administered injectables, which could roll out later this decade.

Cabotegravir’s star is rising in PrEP. Optimism around the preventative version of the drug hinges on two late-stage trials of men who have sex with men, transgender women and cisgender women. Both studies were stopped early by independent data safety monitoring boards after cabotegravir trumped Gilead’s daily pill Truvada in both men and women.

A PrEP launch for cabotegravir could challenge the reigning HIV king, Gilead, and its oral PrEP drugs Truvada and Descovy. Truvada, for its part, lost U.S. exclusivity last year, making the potential launch of a cabotegravir prevention option even more of a threat.