GSK's Dovato Matches Gilead's HIV Juggernaut Biktarvy with Less Weight Gain in Spanish Trial

At the forefront of HIV treatment, Gilead Sciences' flagship drug, Biktarvy, has become a benchmark for other new drugs to follow. A recent head-to-head study, called PASO DOBLE, revealed that GlaxoSmithKline's (GSK) two-drug treatment Dovato maintained comparable efficacy against the virus as Gilead's three-drug treatment.

The Phase 4 study was conducted at 30 research centers in Spain and involved 553 patients who had successfully suppressed HIV. The study found that patients who switched to either Dovato or Biktarvy maintained viral suppression after 48 weeks, reaching the intended target. Specific data showed that 2.2 percent of 277 patients treated with Dovato had levels of viral RNA back up to 50 copies/ml or more in their blood, compared to just 0.7 percent of 276 patients treated with Biktarvy. This 1.4-percentage-point difference meets the pre-set non-inferiority standard of 4%.

In an important secondary endpoint, the Biktarvy group had significantly more weight gain than the Dovato group. Over 48 weeks, the mean weight change in the Biktarvy group was 1.81 kg compared to 0.89 kg in the Dovato group. The proportion of patients with more than 5% weight gain was 29.9% in the Biktarvy group and 20% in the Dovato group, showing a significant difference. This trend was particularly pronounced in patients switching from tenofovir disoproxil fumarate (TDF) regimen.

"This is an important finding because treatment-related weight gain is a concern for many people living with HIV," Harmony Garges, chief medical officer of ViiV Healthcare at GSK, said in the statement.

Weight gain is a known side effect of certain HIV drugs, including integrase inhibitors used in Dovato and Biktarvy. The use of TAF also causes weight gain, and this dual mechanism may lead to more significant weight gain.

Lead researcher Dr Esteban Martinez added: "Current HIV treatment regimens are very effective at suppressing the virus, so we need to study the effects of these therapies outside the virus, such as weight gain."

Martinez emphasized that as the effectiveness of HIV drugs improves, the focus of the development of next-generation drugs is shifting to characteristics such as reducing side effects or reducing the frequency of administration. Dovato is GSK's first step in this direction and aims to reduce long-term toxicity by reducing drug ingredients to two.

The key competition between GSK and Gilead is now focused on the development of long-acting therapies based on two-drug formulations. GSK's bimonthly injection Cabenuva has won some acceptance, but the company acknowledges that longer dosing intervals are needed to have a greater impact. Gilead has a slight edge in this area, launching Sunlenca, a biannual drug, and is actively developing complete therapies based on capsid protein inhibitors.