WHITEHOUSE STATION, N.J. (AP) — Merck said Thursday it received U.S. approval for an extended-release version of its diabetes drug Janumet designed to be taken once a day, instead of twice a day.

The FDA approved Janumet XR to help patients with type 2 diabetes control their blood sugar levels, in combination with diet and exercise, the company said in a statement. Janumet is a combination pill that includes sitagliptin, the primary ingredient in the company’s drug Januvia, with an older diabetes drug, metformin.

The newly approved Janumet XR contains an extended-release version of metformin.

The FDA approved the new drug based on chemical studies that showed the combination pill was comparable to taking Januvia and extended release metformin separately.

Merck reported combined sales of $1.3 billion for Januvia and Janumet last year, according to its most recent earnings report. The company does not break out sales of Janumet.

Shares of Merck fell 17 cents to close at $38.46. Also Thursday, the drugmaker predicted little growth in the coming year as its top-selling drug, the asthma and allergy treatment Singular, loses patent protection and faces competition from cheaper generic copies.