Vertex Pharmaceuticals Inc. (VRTX:US) said U.S. regulators placed a partial clinical hold on its trial of a drug for hepatitis C after three patients receiving a high dose of the medicine showed signs of potential liver toxicity. The shares sank the most in eight months.
The Food and Drug Administration hold is on a study in the U.S. using a dose of 200 milligrams of the drug VX-135, the Cambridge, Massachusetts-based company said yesterday in a statement. The trial, in the second of three phases generally required for approval, is continuing in the 100-milligram dose.
Vertex is competing with drugmakers including Gilead Sciences Inc. (GILD:US), AbbVie Inc. (ABBV:US) and Bristol-Myers Squibb Co. (BMY:US) to develop an oral hepatitis C treatment that doesn’t involve injections of interferon, which can cause flu-like symptoms. The hepatitis C virus, which attacks the liver and can lead to liver cancer, affects about 150 million people worldwide.
“Developing safe and effective medicines for patients is our goal,” Robert Kauffman, Vertex chief medical officer, said in the statement. “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 U.S.”
Vertex dropped 7.9 percent to $80.71 at 4 p.m. New York time for its biggest decline since November. The shares are up 93 percent this year.