ViiV builds case for switching to its two-drug HIV combinations

ViiV Healthcare says it has data that shows people with HIV can safely switch from Gilead's three-drug therapies to one of its two-drug alternatives, without any loss of efficacy.

48-week data from the phase 3 TANGO study indicates that Dovato (dolutegravir/lamivudine) was just as effective as triple therapies that included Gilead’s tenofovir alafenamide fumarate (TAF) at suppressing HIV, without evidence of any drug resistance.

ViiV – which is majority owned by GlaxoSmithKline – has a lot riding on being able to encourage switching of HIV-positive people to its two-drug therapies, which include Dovato for newly-diagnosed patients and Juluca (dolutegravir/rilpivirine) for second-line treatment.

The TANGO study is intended to show that people with HIV can reduce the number of medicines in their HIV treatment regimen, potentially reducing the risk of side effects and drug interactions, while still maintaining viral suppression.

ViiV needs to convince patients, prescribers and payers that there is a real benefit to that approach if it is to challenge drugs like Gilead’s three-drug Biktarvy (bictegravir/emtricitabine/TAF) product, which has grown quickly since its launch last year and is already hitting a $1bn-plus annual sales rate.

In particular, it needs to establish that there is no risk that using two rather than three drugs can increase the risk of resistance developing, particular in real-world settings were people may miss a dose. That is a concern which some suggest has been behind the relatively slow take-up of Juluca since its launch.

The 48-week data are a big step forward in that regard, but analysts think that sales of GSK’s drug will only start to gather momentum after there is more on-market experience with the drug.

In the meantime, Gilead looks set to continue to dominate the market with its three-drug therapies, currently holding a 73% market share according to IQVIA data. For comparison, Biktarvy brought in $739m in sales in the first quarter of the year, compared to $70m for Juluca in the second-line setting.

ViiV has said it thinks the treatment-naïve population will be the key battleground, however, and with Dovato it has a two-drug option to offer the approximately 25,000 new HIV patients diagnosed in Europe every year.

Injectable option

Meanwhile, ViiV also had an update this week on another drug candidate that it hopes could wrest market share from Gilead.

It has now started a new clinical trial of a two-drug combination of cabotegravir and rilpivirine that it thinks could be given as a single depot injection just once a month – freeing patients from having to take daily tablets and reducing the risk of skipped doses that could encourage resistance.

The CUSTOMIZE trial will try to find the most practical and efficient ways to implement a monthly injectable treatment regimen if approved, including how to address the increased frequency of clinic visits. ViiV already has data showing that the Janssen-partnered duo works and has submitted it for approval, with an FDA verdict due before the end of the year.

With daily oral antiretroviral therapies, physicians see their patients once or twice per year, but with an injectable they would have to be seen by a healthcare provider every month, pointed out Richard Elion, director of clinical research at the Washington Health Institute.

“Although some people living with HIV may prefer once monthly visits to their provider, this would be a paradigm shift in the treatment of HIV, and providers may encounter challenges delivering a smooth service,” he added.