(Reuters) - Canada's Cardiome Pharma Corp said it will cut about 85 percent of its workforce after its partner Merck & Co stopped the development of an oral version of their drug to treat irregular heart rhythm.

The two companies were earlier developing an oral version of vernakalant, a drug to treat chronic atrial fibrillation -- a heart rhythm disorder that can lead to stroke and heart failure.

Merck pulled out in March, citing the regulatory environment and the anticipated development timeline.

Cardiome, which develops drugs for diseases of the heart and circulatory system, said it expects up to $5.0 million in restructuring charges over the rest of the year.

Merck will, however, continue to support the intravenous version of vernakalant, marketed in the European Union and Latin America as Brinavess.

Another Canadian drug development company QLT Inc, which has been going through a shake-up after activist investors gained control of its board, cut 68 percent of its workforce and said its chief executive resigned.

Cardiome shares were down 1 percent at 44.5 Canadian cents in early trade on Monday on the Toronto Stock Exchange.