ViiV Healthcare, a global specialist HIV company established in November 2009 by GlaxoSmithKline (GSK) and Pfizer, announced 24-week data from the phase IIIb/IV STRIIVING study, an open-label study evaluating the efficacy, safety and tolerability of switching from an antiretroviral therapy (ART) to the once-daily, fixed-dose dolutegravir-based regimen, Triumeq (abacavir/dolutegravir/lamivudine) in virologically suppressed adults with HIV-1 (n=274).

The study included (n=277) adults who remained on their existing ART to 24 weeks. STRIIVING met its primary endpoint, demonstrating that viral suppression was non-inferior for patients switching to abacavir/dolutegravir/lamivudine (HIV RNA <50 copies/ml in intention to treat efficacy (ITTe, primary endpoint; n=551): 85 per cent vs. 88 per cent [adjusted difference -3.4 per cent; 95 per cent CI: -9.1, 2.3], per protocol (PP; n=435): 93 per cent vs. 93 per cent [adjusted difference -0.3 per cent; 95 per cent CI: -4.9, 4.4]). No patients had protocol defined virologic failure (confirmed plasma HIV-1 RNA =400 copies/ml) and therefore no patients were evaluated for treatment-emergent resistance in either arm (ITTe).

Furthermore, statistically, the treatment satisfaction score improved significantly more for those patients switching to once-daily (abacavir/dolutegravir/lamivudine) from their established regimen, as assessed by the HIV treatment satisfaction questionnaire (adjusted difference 2.4, 95 per cent CI: 1.3, 3.5; p<0.001).

“For clinicians, choosing among antiretroviral therapies now involves balancing efficacy with factors such as tolerability, dosing, ability to use with other medications, and resistance profile. These data support the use of once-daily abacavir/dolutegravir/lamivudine as a treatment option in the switch setting for appropriate patients,” said John Pottage, MD, chief scientific and medical officer, ViiV Healthcare.

The STRIIVING study recruited patients switching from a broad range of protease inhibitor (PI; n=234), integrase strand transfer inhibitor (INSTI; n=146) and non-nucleoside reverse transcriptase inhibitor (NNRTI; n=171)-based regimens, with the aim of reflecting a common clinical situation.

Patients switching to abacavir/dolutegravir/lamivudine reported more adverse events (AEs) leading to withdrawal compared with those who continued on their established regimen (ITTe: 4 per cent vs. 0 per cent). The majority of these AEs were Grade I & 2.1 The most common AEs (= 5 per cent) reported in patients switched to the abacavir/dolutegravir/lamivudine arm included cough (5 per cent), diarrhoea (7 per cent), fatigue (7 per cent), headache (5 per cent), nausea (10 per cent) and upper respiratory tract infection (7 per cent).1The AE profile observed with abacavir/dolutegravir/lamivudine in the study is in line with previous studies with dolutegravir-based regimens.

The most commonly reported (=2 per cent) adverse reactions of at least moderate intensity in treatment-naïve adult subjects receiving Triumeq were insomnia (3 per cent), headache (2 per cent), and fatigue (2 per cent).

Triumeq is a once-daily dolutegravir-based regimen, containing the integrase strand transfer inhibitor (INSTI) dolutegravir and the nucleoside reverse transcriptase inhibitors (NRTIs) abacavir and lamivudine.

Two essential steps in the HIV life cycle are replication – when the virus turns its RNA copy into DNA – and integration – the moment when viral DNA becomes part of the host cell’s DNA. These processes require two enzymes called reverse transcriptase and integrase. NRTIs and INSTIs interfere with the action of the two enzymes to prevent the virus from replicating. This decrease in replication will lead to less virus being available to cause subsequent infection of uninfected cells.