#CMSC17 – Cladribine Reduced Annual MS Relapse Rate by 55% to 57%, Trials Show

Cladribine tablets reduced relapsing multiple sclerosis patients’ annual relapse rate by 55 to 57 percent, depending on the dose, according to clinical trials.

EMD Serono, a unit of Cladribine’s developer, Merck, presented the trial results at the 31st annual meeting of the Consortium of Multiple Sclerosis Centers in New Orleans, May 24-27. The presentation was titled “Benefits of Cladribine Tablets in patients with multiple sclerosis free from clinical and radiological indicators of disease activity in the CLARITY Extension study.”

Information presented at the conference adds “to the body of research evaluating the efficacy and safety of Cladribine Tablets as a potential treatment option for patients with relapsing MS,” Joseph Leveque, EMD Serono’s chief medical officer, said in a press release. “Our ongoing research underscores the company’s commitment to developing new therapeutic options for patients with MS.”

The Phase 3 CLARITY trial (NCT00213135) and the CLARITY Extension study (NCT00641537) investigated Cladribine’s safety and effectiveness in relapsing remitting MS (RRMS) patients. Researchers analyzed the change in participants’ annual relapse rate, whether treatment could increase the number of relapse-free patients, and whether it could reduce the progression of disability associated with MS.

Patients on a higher dose of Cladribine had a 55 percent reduction in their annual relapse rate and patients on a lower dose a 57 percent reduction after 96 weeks, compared with patients who received a placebo.

The tablets also significantly increased the number of patients who did not develop new brain lesions. The figures were 73 percent of all patients on the lower Cladribine dose and nearly 90 percent on the higher dose, compared with a placebo.

“We compared the results from two two-year studies to further understand the duration of efficacy of Cladribine Tablets,” said Kottil Rammohan, one of the trial researchers. “It’s important that we saw similar results replicated in the CLARITY EXTENSION trial, which further supports the overall efficacy profile of Cladribine Tablets. Rates of clinical and MRI disease activity-free status were consistent with Cladribine Tablets across all subsets of MS patients for the duration in both trials.”

Researchers also evaluated Cladribine in the ORACLE-MS trial (NCT00725985). Patients who received Cladribine after their first demyelinating event significantly reduced the risk of their condition progressing to a definite MS diagnosis, compared with those on a placebo. MS is associated with deterioration of the brain’s protective myelin nerve coating, so a first demyelinating event marks the first symptoms arising from that deterioration.

In all of the Cladribine clinical trials, the most common side effect was lymphopenia, an abnormal reduction in the number of white blood cells called lymphocytes.

Cladribine is an oral small molecule that selectively targets immune lymphocytes. The white blood cells are believed to play a central role in mechanisms underlying MS.