Clinical hold on Merck HIV trials

Tuesday 14 December 2021

United States

The US Food and Drug Administration has placed clinical holds on six trials of the HIV medicine islatravir after some trial participants showed a decrease in total lymphocyte and CD4+ T cell counts – a sign of weakened immune systems. Developed by Merck & Co Inc, islatravir is being studied for both the treatment and prevention of HIV-1 infection. “With the FDA’s clinical hold, no new studies may be initiated,” the company announced on 13 December.