Regulators agreed that suvorexant had been show effective in doses above 10 milligrams, but said does of 30 milligrams or higher had proven dangerous in clinical trials. The government indicated that it will not allow Merck to sell the drug in pills containing more than a 10 milligram dosage, the Wall Street Journal notes.
The rejection means that Merck will have to re-file for approval. That could mean the drug won’t hit the market for months.
A Merck executive noted that new new clinical trials will be needed for 10 milligram pills, but that testing would be required to produce the lower-dosage pills.
In February, Merck’s shares tumbled after the company said it would delay efforts to seek FDA approval for its osteoporosis drug, odanacatib.
Despite the news, shares of Merck rose fractionally in Monday morning trading.