Researchers reported that a two-drug combination of ViiV Healthcare's integrase inhibitor dolutegravir (Tivicay) with its NRTI lamivudine (Epivir) produced a sustained reduction in viral loads to less than 50 copies in 18 out of 20 people. Most regimens contain at least three drugs from two different classes in order to effectively control HIV.
However, the small PADDLE study looked at giving just two drugs (dolutegravir, lamivudine) from two classes to 20 people who were new to treatment. If effective, this regimen would reduce a person's long-term exposure to three or more drugs and could possibly reduce costs and perhaps long-term side effects.
Great care was taken to ensure participant safety: average CD4 count was about 500; no one had hepatitis B (which lamivudine alone is insufficient to treat); and all had lower viral loads averaging ~24,000 at screening. Viral load tests were taken very frequently within the first four weeks and nearly monthly afterwards to identify possible early failure.
After 48 weeks, 18 of the 20 people reached viral loads <50 copies, though viral levels greatly decreased within the first few weeks. One of the remaining two had virus rebound to ~250 copies but then regained control before week 48. No mutations were found. The 20th person died from suicide.
This pilot gives way to additional study that will include people with higher viral loads and lower CD4 counts. ViiV announced two large Phase III studies of this combination to start soon.
P Cahn, et. al. Dolutegravir-lamivudine as initial therapy in HIV-infected, ARV naive patients: 48 week results of the PADDLE trial. 2016 International AIDS Conference, Durban, South Africa. Abstract FRAB0104LB.