Gilead has been hit with a clinical hold from the FDA for five tests of its experimental HIV combination treatment amid safety concerns.
In a statement released Tuesday, June 10, the California Big Pharma said trials of GS-1720, an investigational integrase strand transfer inhibitor, and/or GS-4182, an investigational capsid inhibitor, had been put on a full FDA hold.
The drugs had been in two phase 2/3 tests known as WONDERS-1 and WONDERS-2, as well as three earlier phase 1 studies.
The more advanced tests, starting with WONDERS-1, are looking at the safety and efficacy of GS-1720 and GS-4182 against Gilead’s approved once-a-day HIV pill Biktarvy in virologically suppressed people with the virus.
In WONDERS-2, Gilead was testing the combo therapy versus Biktarvy in HIV patients who hadn’t had treatment.
The hold comes after “the identification of a safety signal of decreases in CD4+T-cell (CD4) and absolute lymphocyte counts in a subset of participants receiving the combination of GS-1720 and GS-4182,” Gilead said in its statement.
This can signal immune system compromise and a potential worsening of the disease.
“We intend to investigate and pursue the potential of both agents and are committed to working with regulatory authorities to resolve the issues underlying the clinical hold,” the company said in the release.
No timeline was given for any potential resumption of the trials.
Gilead stressed that this hold does not impact its clinical work on its other long-acting oral and injectable investigational HIV treatment combinations.
Shares in the pharma were down around 2% to $110.71 by mid-morning Tuesday.