Merck & Co and Schering-Plough have decided to withdraw a New Drug Application for a combination tablet of the firms’ big-selling Claritin and Singulair, and are terminating their eight-year respiratory joint venture.

It is not an overly-surprising decision, coming as it does a couple of months after the two companies received a not-approvable letter from the US Food and Drug Administration for a proposed fixed combination of S-P’s Claritin (loratadine) and Merck’s Singulair (montelukast) for the treatment of allergic rhinitis symptoms in patients who want relief from nasal congestion. The respiratory JV was set up in 2000 specifically to develop and sell the combination pill.

As a result of the the plug being pulled on the JV, S-P expects to receive $105 million from Merck, to be recognised over the remaining three quarters of 2008. The companies also noted that the actions had no impact on their cholesterol joint venture, through which they market the controversial drug Vytorin, a combination of Zetia (ezetimibe) and Zocor (simvastatin).

Promising Phase III telcagepant data
Meantime, Merck has presented late-stage data on its investigational migraine treatment telcagepant which shows that the drug significantly improved relief of migraine pain and symptoms two hours after dosing compared to placebo. Also, the efficacy results for telcagepant 300mg were similar to the highest recommended dose of AstraZeneca’s blockbuster Zomig (zolmitriptan) and resulted in a lower incidence of adverse events.

The data comes from a Phase III 1,380-patient study, was presented at the American Headache Society annual meeting in Boston. Merck noted that telcagepant, an oral calcitonin gene-related peptide receptor antagonist, has since been reformulated into a solid tablet (rather than a liquid-fill capsule) and is being evaluated in ongoing trials and a filing with the FDA is scheduled for 2009.