The Food and Drug Administration will not approve the investigational multiple sclerosis drug cladribine unless its manufacturer, EMD Serono Inc., "provides an improved understanding of the safety risks and the overall benefit-risk profile either through additional analyses or by additional studies," the company announced March 2.
The FDA issued a complete response letter to the company, saying that the oral drug cannot be approved with the application in its current form, although the agency said that cladribine’s effectiveness in treating relapsing remitting MS had been proved in its phase III trial, CLARITY (Cladribine Tablets Treating MS Orally).
In addition to further analyses of the CLARITY trial, EMD Serono has two ongoing trials with cladribine: an open-label extension of CLARITY and ORACLE MS (Oral Cladribine in Early MS) that it hopes to use to use to address the FDA’s questions.
In 2010, the European Medicines Agency declined to approve cladribine, although Russia and Australia approved the drug.
Cladribine is an antineoplastic agent that has been approved for the treatment of active hairy cell leukemia. It selectively induces apoptosis of lymphocytes while having relatively transient effects on other immune cells.
EMD Serono is the U.S. subsidiary of Merck.