FDA places partial hold on phase 2 HCV drug study

The FDA has called for a partial hold on a phase 2 US study of a hepatitis C medication, according to a press release.

Vertex Pharmaceuticals will cease assessment of a 200-mg dose of VX-135, a nucleotide analog HCV polymerase inhibitor, after elevated liver enzymes were observed among patients receiving a 400-mg dose of the drug, along with ribavirin, in a phase 2 European study. The company will continue to evaluate a 100-mg dose with ribavirin in its 12-week US study.

According to the release, 100-mg and 200-mg doses administered with ribavirin in the company’s 12-week European study were well tolerated, with no incidence of serious adverse events or cardiac or liver safety concerns. Vertex, with Bristol Myers Squibb, also recently initiated a phase 2 study in New Zealand in which VX-135 is administered with NS5A replication complex inhibitor daclatasvir. In the initial phase, 20 patients with HCV genotype 1 will receive 100 mg or 200 mg VX-135 for 12 weeks, with planned expansion to include patients with genotypes 1 and 3.

In the US study, 10 patients with HCV genotype 1 have received 10 or more weeks of therapy, with results from the 100-mg recipients anticipated within the year. As per a request from the FDA, the company will submit further preclinical, pharmacokinetic and clinical data from ongoing studies of VX-135 during the fourth quarter.

“Developing safe and effective medicines for patients is our goal,” Robert Kauffman, MD, PhD, senior vice president and chief medical officer at the company, said in the release. “We are committed to continuing to work closely with the FDA to provide the data needed to support evaluation of a 200-mg dose of VX-135 in the US.”