GSK upbeat on new HIV drug test results

GlaxoSmithKline announced on Tuesday that its majority-owned specialist HIV company ViiV Healthcare, which was established with Pfizer and Shionogi as shareholders, had released detailed study results from one of its phase III programme.

The FTSE 100 drugmaker said the specific programme was evaluating the safety and efficacy of switching virologically suppressed patients from a three- or four-drug antiretroviral regimen to a two-drug regimen of dolutegravir from ViiV Healthcare and rilpivirine from Janssen Sciences Ireland UC.

Headline results were announced in December 2016 and detailed study results were being presented at the annual Conference on Retroviruses and Opportunistic Infections in Seattle.

GSK reiterated that the use of dolutegravir and rilpivirine as a two-drug regimen for HIV-1 maintenance therapy remained investigational and was not approved anywhere in the world.

“The dolutegravir and rilpivirine regimen achieved non-inferior viral suppression at 48 weeks compared with a three- or four-drug regimen in both pooled and individual analyses of the SWORD 1 and SWORD 2 studies,” GSK said in a statement.

“Virologic suppression rates were similar between treatment arms.

“The median duration of antiretroviral treatment was just over four years at the time of entry into the studies.”

GSK said the most commonly reported adverse events in the dolutegravir and rilpivirine arm were nasopharyngitis, headache, diarrhoea and upper respiratory tract infection.

For the CAR arm, the most commonly reported adverse events were nasopharyngitis, upper respiratory tract infection, back pain, headache and diarrhoea.

The studies were ongoing for 148 weeks.

“The results from these studies may change our understanding of how HIV can be managed,” said ViiV Healthcare chief scientific and medical officer John C Pottage, Jr.

“For more than 20 years we thought that three or more drugs were required to maintain virologic suppression, but the SWORD studies provide compelling data that suppression may be maintained with a two drug regimen of dolutegravir and rilpivirine.

“These data mark an exciting first step towards making two drug regimens a reality in HIV treatment.”

Dr Pottage said the company was planning regulatory submissions for the two-drug regimen as a single tablet this year.

GSK said the programme was comprised of two studies with over 1000 patients who previously achieved viral suppression on a three- or four-drug, or protease inhibitor antiretroviral regimen.

The patients were randomised to either stay on their three- or four-drug regimen or switch to a dolutegravir and rilpivirine regimen.

Virologic failure rates were less than 1% in the dolutegravir and rilpivirine arm and 1% in the three- or four- antiretroviral-drug arm, and no INSTI resistance-associated mutations were reported.

The overall rate of serious adverse events was comparable between treatment groups, GSK claimed, with 27 adverse events for dolutegravir + rilpivirine and 21 for CAR.

“As would be expected when switching from a stable regimen to a new regimen, more adverse events were reported and led to withdrawal from the study in the dolutegravir and rilpivirine arm (at 21) compared to the CAR arm (at 3),” GSK said.