The phase III clinical trials comparing the investigational drug alemtuzumab (Lemtrada) to Rebif in patients with relapsing-remitting multiple sclerosis (RRMS) showed that 78 per cent of patients treated with alemtuzumab remained relapse-free for two years, providing statistically significant improvement over interferon beta-1a (78 per cent vs 59 per cent at two years, p<0.0001) and meeting this secondary endpoint. Sanofi and its subsidiary Genzyme announced this  new results from the CARE-MS I trial on Saturday.

The CARE-MS I results were presented on Saturday at the 5th Joint Triennial Congress of the European and Americas Committees for Treatment and Research in Multiple Sclerosis. Genzyme is developing alemtuzumab for relapsing MS in collaboration with Bayer HealthCare.

As previously reported, treatment with alemtuzumab resulted in a 55 percent reduction in relapse rate compared to interferon beta-1a over two years of study (p<0.0001), satisfying this co-primary endpoint and meeting the predefined protocol criteria for declaring the study a success. At the two-year time point, very few alemtuzumab patients (8 per cent) experienced a sustained increase, or worsening, in disability as measured by the Expanded Disability Status Scale (EDSS) (vs 11 per cent of patients in the interferon beta-1a group). However, the difference between groups for this co-primary endpoint were not statistically significant (p=0.22) and there was no difference in the mean EDSS score between groups.

The CARE-MS I trial compared treatment with alemtuzumab (12 mg/day by IV administration for 5-days, with a second 3-day IV administration one year later), to treatment with subcutaneous interferon beta-1a (44 mcg administered by injection three times per week) in 581 patients with relapsing-remitting MS who had received no previous treatment to suppress MS, except for steroids.

“CARE-MS I confirms that, in a head-to-head comparison with Rebif, disease activity is significantly reduced in patients with early relapsing-remitting multiple sclerosis treated with alemtuzumab, over the first two years of observation,” said Professor Alastair Compston, Chair of the Steering Committee overseeing the conduct of the study and head of the Department of Clinical Neurosciences at the University of Cambridge, United Kingdom. “These data support the robust efficacy profile and potential that alemtuzumab offers for patients with relapsing-remitting multiple sclerosis requiring a more effective option than currently available therapies.”

“Lemtrada’s robust effects over and above those of Rebif on relapses and a variety of clinical and imaging endpoints reinforces its potential as an effective treatment option for MS patients,” said David Meeker, MD, chief operating officer, Genzyme. “We look forward to the results of CARE-MS II, our second phase III study, later this year to extend these results by confirming Lemtrada’s effects in patients with continued disease activity while receiving another MS treatment.”

Common adverse events associated with alemtuzumab in the CARE-MS I study included infusion-associated reactions which were generally mild to moderate. Additionally, the incidence of infections was increased, the most common infections involving the upper respiratory and urinary tract and oral herpes. Infections were predominantly mild to moderate in severity and none were life-threatening or fatal.

Another phase III clinical trial, CARE-MS II, is currently underway, evaluating alemtuzumab against interferon beta-1a in relapsing-remitting MS patients who have relapsed while on therapy. Top-line results from that trial are expected to be available in the fourth quarter of 2011.

The company expects to file for US and EU approval of alemtuzumab in relapsing MS in the first quarter of 2012, and alemtuzumab has been granted Fast Track designation by the US Food and Drug Administration (US FDA). Since it is not yet approved for the treatment of MS, alemtuzumab must not be used in MS patients outside of a formal, regulated clinical trial setting in which appropriate patient monitoring measures are in place.

Genzyme has the worldwide rights to alemtuzumab and has primary responsibility for the development and commercialization of alemtuzumab in MS. Bayer HealthCare has been co-developing alemtuzumab in MS with Genzyme. Bayer HealthCare retains an option to co-promote alemtuzumab in MS and upon regulatory approval and commercialization would receive contingent payments based on sales revenue.