Campath Efficacy in MS Holds Up

The mAb alemtuzumab (Campath; Genzyme/Bayer Healthcare) appears to provide the same kind of robust efficacy in multiple sclerosis as natalizumab (Tysabri; Elan/Biogen Idec). But like natalizumab, alemtuzumab is not without its risks.

Extension data from the ongoing phase 2 trial of alemtuzumab (CAMMS223) in patients with early, relapsing MS were presented last week at the World Congress on Treatment and Research in MS. Impressive efficacy outcomes with the drug in previous reports appear to be sustained at 36 months.

Specifically alemtuzumab significantly reduced the cumulative number of relapses and the time to sustained disability by more than 70%, when compared with interferon beta-1a (Rebif; EMD Serono/Pfizer). The percentage of relapse-free patients was also significantly higher with alemtuzumab (80% vs 50%), and the EDSS score actually dropped by 0.39 points with alemtuzumab treatment. (The EDSS score with interferon beta increased by 0.38 points.)

Adverse events of note are shown.

36-Month Outcome	Alemtuzumab	Interferon Beta-1a
No. patients with grade 3 infections	13	1
No. patients with grade 4/5 infections	0	0
Autoimmune thyroid dysfunction, %	23	3
ITP, %	2.8	0.5

Of acute concern is the rate of ITP with alemtuzumab treatment, an event which may be anticipated by platelet monitoring. Two, industry-supported, phase 3 studies (here and here) of alemtuzumab and interferon beta-1a in relapsing MS are currently recruiting patients. Primary outcome measures are the relapse rate and the time to sustained disability at 2 years. Blood monitoring will be performed monthly.

Alemtuzumab, a humanized anti-CD52 mAb, is FDA approved for the treatment of B-cell CLL. Interferon beta-1a is approved for the treatment of relapsing MS and has been shown (like other available interferon betas) to reduce the relapse rate in MS by approximately one third, when compared with placebo.

CLL = chronic lymphocytic leukemia; EDSS = Expanded Disability Status Scale; ITP = idiopathic thrombocytopenic purpura; mAb = monoclonal antibody. 

Fab fragment of alemtuzumab linked to antigen (yellow) from Wikipedia.

HT: Medscape Medical News