A new drug to prevent HIV could hit markets very soon.

The results of the world’s biggest ever HIV prevention studies revealed the drug, Descovy, was as good as Truvada when it came to preventing HIV.

Truvada and generic versions of it are used around the world as pre-exposure prophylaxis (PrEP). For two years, pharmaceutical giant Gilead has conducted the DISCOVER trial. The trial measured the efficacy of Descovy as a potential new PrEP drug.

The study conducted across 50 sites in the United States, enrolled 5,387 cis men who have sex with men (MSM) and trans women at risk of acquiring HIV through sex.

Gilead which has held the patent for Truvada in many parts of the world – and still holds it in the US – released the trial results last week.

Mike Elliott, Gilead’s vice president of medical affairs in Europe, the Middle East and Africa said the results were ‘quite exciting’.

‘The study backs almost exactly what we expected,’ he told Gay Star News.

Truvada vs Descovy

The DISCOVER trial found Descovy was a efficacious as Truvada in preventing HIV.

During the trial, seven people receiving a once-daily dose of Descovy acquired sexually transmitted HIV. That’s compared to 15 given Truvada during the trial.

That meant Descovy met the pre-established criteria for non-inferiority to Truvada.

Better for people with kidney problems

‘It didn’t get to that superiority (over Truvada) but showed very good efficacy and numerically fewer transmissions than Truvada,’ Elliott said.

‘And then there are those important measures on renal and bone.’

The DISCOVER trial revealed Descovy had ‘improved renal and bone safety’ compared to Truvada.

That discovery was welcomed by, Matthew Hodson executive director of NAM / aidsmap.

‘It’s really good news that there is a formulation for PrEP for people that have kidney problems,’ he said.

‘The number of people who are going to benefit are quite low, it’s maybe better for older people, over the age of 40 and is more likely to be recommended for people who have pre-existing kidney problems.’

How much will it cost?

Dr Will Nutland is the co-founder of PrEPster, a programme that seeks to ‘educate and agitate’ for PrEP access in England. In 2016, PrEPster expressed concern about the DISCOVER trial.

He also agreed that Descovy is unlikely to be used by a lot of people. But it was a ‘further option for oral PrEP that might offer an alternative for people with serious kidney issues’.

‘The current formulation of PrEP (TDF/FTC) works incredibly well, with very few sides effects for the vast majority of people. TDF/FTC was the formulation of PrEP used in all other major international PrEP trials and is the formulation used in the England IMPACT Trial and by NHS Scotland,’ he said.

‘Given current patent issues on Descovy – and its relative high cost compared with current formulations of oral PrEP – its unlikely to be widely used in the near future.

‘The generic versions of TDF/FTC PrEP (Gilead’s patented version is Truvada) are cheap, widely available and have VERY few side effects and are expected to be the main drug of choice for oral PrEP into the foreseeable future. Current available versions of PrEP work very well.’

Gilead said it did not know what the market cost of Descovy would be. But Elliot denied its readiness for market coincided with the end of the US patent for Truvada.

‘Once we developed (the formulation for Descovy) we moved it rapidly through for treatment,’ Elliot said.

‘So it was not related on that patent expiry date, it was related on when we made the discovery and how quickly we could move through development.

‘So i don’t think anyone would say we moved it slowly through development. From having the molecules and starting the study has been fairly quick.’

Gilead’s Descovy patent expires in 2022 in the United States and in 2021 in the European Union.

What comes next?

Gilead plans to file Descovy with regulators in the US as a new PrEP treatment following the DISCOVER results.

‘Then we’ll do the normal process of then talking to regulators, governments around the world and the community about how we proceed to make it available around the world,’ Elliot said.

‘We’ve only just got the data, we’re moving thoughtfully but in response to what we hear from the community.’

In terms of what impact Descovy might have in the UK, British HIV Association chair, Chloe Orkin said it might not be so huge.

‘The DISCOVER trial showed once again just how effective PrEP is in reducing new infections of HIV,’ she said.

‘PrEP using FTC/TAF was compared to PrEP using FTC/TDF (Truvada) and both drugs were equally effective (non-inferior) .

‘Given the very similar outcomes it is probably unlikely to change the way PrEP is commissioned in the UK.’

Matthew Hodson said while the DISCOVER results were exciting, there were many more PrEP developments in the ‘pipeline’.

‘We’re not at the end of the road in developments in PrEP,’ he said.

‘There is more stuff in the pipeline, including injectable and implantable PrEP, where adherence will be less of an issue.’