GlaxoSmithKline and Pfizer joint venture firm ViiV Healthcare has commenced a Phase III trial programme to assess the safety and efficacy of dolutegravir (Tivicay) and rilpivirine (Edurant) as maintenance therapy for adult patients with HIV.

The Phase III programme includes two replicate studies, SWORD-1 (NCT02429791) and SWORD-2 (NCT02422797).

The studies will assess 48 week viral suppression with a two drug regimen combining an integrase inhibitor (dolutegravir) and a non-nucleoside reverse transcriptase inhibitor (rilpivirine) in patients with HIV who have already achieved viral suppression with a three drug regimen.

ViiV Healthcare chief scientific and medical officer Dr John Pottage said: "We are able to attain initial viral suppression with a standard three drug regimen and the question is whether we can maintain viral suppression with two drugs instead of three."

The programme will assess the efficacy, safety, and tolerability of switching to dolutegravir plus rilpivirine from current INI-,NNRTI-, or PI-based antiretroviral regimen in HIV-1-infected adults who are virologically suppressed.

SWORD-1 and SWORD-2 are replicate 148-week, randomised, open-label and non-inferiority studies to evaluate the antiviral activity and safety of a two-drug regimen of DTG + RPV compared with current antiretroviral therapy.

The company plans to enrol up to 500 patients in each study across 13 countries, which will include patients from groups underrepresented in HIV clinical studies, such as women and people over 50 years of age.

According to the company, the primary endpoint is proportion of patients with plasma HIV-1 RNA less than 50 copies per millilitre (c/mL) at week 48 and secondary endpoints comprise evaluation of the development of viral resistance, measurements of safety and tolerability, and changes in renal, bone and cardiovascular biomarkers.

In June 2014, ViiV Healthcare partnered with Janssen Sciences Ireland UC to evaluate the potential of combining dolutegravir and rilpivirine in a single-tablet, in a bid to expand the treatment options for HIV patients.

Image: Scanning electron micrograph of HIV-1 budding (in green) from cultured lymphocyte. Photo: courtesy of C. Goldsmith.