Merck KGaA Shoots Its Hobbled Horse, Oral Cladribine

Merck KGaA (the US subsidiary of which is Merck Serono) announced yesterday that it will cease late-stage development of oral cladribine for the treatment of multiple sclerosis. The company cites the FDA's safety (probably cancer-related) concerns about the drug. In addition, Merck KGaA will pull oral cladribine from markets in Russia and Australia, where the compound has been available under the ridiculous trade name Movectro.

Merck KGaA implies in a press release that its decision to kill oral cladribine has something to do with forthcoming safety data (or lack thereof) from continuing trials of the drug—namely, the extension phase of the CLARITY trial, the ORACLE MS study, and/or the ONWARD study. In March, the FDA issued a complete response letter, indicating that it would not approve oral cladribine on the basis of the drug's safety profile; but Merck KGaA put an exceptionally rosy spin on the news...which it has evidently now rescinded.

Oral cladribine was, at one time, in a nail-biting horse race for FDA approval with fingolimod (Gilenya), Novartis's orally administered challenger. Fingolimod was approved by the FDA for the treatment of relapsing-remitting MS in September of last year and is expected to take a sizable chunk of the market* from other disease-modifying drugs, like frontrunners interferon beta (eg, Avonex; Biogen Idec) and glatiramer acetate (Copaxone; Teva).

* Despite its staggering cost.