June 27, 2014

Merck Serono will not proceed with FDA approval of oral cladribine

Merck Serono has decided not to pursue approval of its oral therapy cladribine (Movectro) for the treatment of relapsing forms of multiple sclerosis. In March 2011, the U.S. Food and Drug Administration requested additional analyses or new studies on cladribine from Merck Serono before they proceeded with the new drug application. Merck Serono announced that ongoing clinical trials of cladribine would not address the FDA’s requirements for approval. Details of these requirements have not been made public. Merck Serono plans to complete the current clinical trials and patient registry that are underway, and results will be published.

Cladribine was initially granted fast-track status by the FDA in 2006, but the FDA refused to file the company's new drug application in 2009 due to potential safety concerns. During clinical trials, lymphocytopenia (reduction of white blood cells), herpes zoster infections and neoplasms (abnormal masses of tissue - including malignant growths) were more common in cladribine than placebo recipients. Other adverse events reported were headaches and cold symptoms. 
Cladribine is believed to work by interfering with the activity of white blood cells in the central nervous system, thereby interrupting the immune attacks that cause the unpredictable symptoms of MS. Injectable cladribine is used to treat hairy cell leukemia. Studies of oral cladribine funded by Merck Serono include:

  • The ONWARD study, an investigation of the safety and effectiveness of adding high or low doses of oral cladribine to Rebif® (interferon beta-1a, EMD Serono Inc. and Pfizer.   
  • The ORACLE MS study, designed to evaluate the safety and effectiveness of oral cladribine in people who have experienced a neurological episode that puts them at risk for developing MS.

  • The CLARITY study, designed to evaluate the safety and effectiveness of oral cladribine versus placebo in people with relapsing-remitting MS.

Several other oral therapies are currently in Phase III studies. The MS Society of Canada will provide updates on the following therapies as information becomes available:

BG-12 (dimethyl fumarate) vs. glatiramer acetate (Copaxone®)
CONFIRM study, to compare the safety and effectiveness of BG-12 to glatiramer acetate in relapsing-remitting MS.  

Cannabis extract (dronabinol)  
CUPID study, to determine ability of dronabinol to prevent disease progression in primary progressive and secondary progressive MS.

Fingolimod (Gilenya™, Novartis)
INFORMS study, to test safety and effectiveness of this drug in primary progressive MS.

Laquinimod vs. interferon beta-1a (Avonex®) vs placebo
BRAVO study, to assess the compound in relapsing-remitting MS.

Teriflunomide (HMR1726)
TOPIC study, to assess the compound  in clinically isolated syndrome (CIS) and TOWER study for relapsing-remitting MS. TENERE study compares it to Rebif.

With information from the National MS Society (USA)