Bristol-Myers Squibb said it withdrew its U.S. marketing application for an oral drug combination to treat hepatitis C, citing a “rapidly evolving” treatment landscape in the country.

The drugmaker’s shares fell nearly 2 percent in early trading.

Bristol-Myers is racing against Merck & Co and AbbVie to try and cut the treatment time by half and avoid side effects from older standard drugs interferon and ribavirin.

Interferon and ribavirin treat hepatitis C (HCV) in about 24 weeks, but their side effects have led to thousands of patients putting off the treatment to wait for new drugs.

Bristol-Myers’ two-drug combination treatment, in a late-stage study in April, showed that it could cure HCV infections in 12 weeks in 82 percent of patients who were unable to tolerate interferon and ribavirin.

The company also has a three-drug combination that, based on earlier studies, is expected to cure more people in the same 12 weeks, an efficacy rate that would compete favorably with that of rival treatments.

A U.S. marketing application for this three-drug combination is expected early next year.

The drugmaker’s now-shelved two-drug combination was approved in July for use in Japan.

Bristol-Myers said on Tuesday it would continue to pursue a U.S. marketing approval for daclatasvir, one component of the two-drug combination.

The company said it plans to submit additional data on daclatasvir from an ongoing program to the U.S. Food and Drug Administration.

Bristol-Myers’ shares were down 1.9 percent to $50.13. Through Monday’s close, the stock had gained 3.7 percent since the company reported late-stage results from the two-drug combination on April 10.

###

(Reuters)