Merck & Co. said Monday it will file for U.S. marketing approval of its experimental insomnia drug suvorexant in 2012.

Merck said late-stage studies of the effectiveness of the drug are complete and said it will seek approval from the Food and Drug Administration. Suvorexant is designed to treat insomnia without causing sleepiness the following morning.

The company has said it plans to file for approval of suvorexant and four other key drug candidates in 2012 and 2013.

Shares of Merck slipped 11 cents to $38.26 in afternoon trading Monday.

(Copyright 2012 by The Associated Press.  All Rights Reserved.)