The Big Beast: GSK joins the fray

"Ofatumumab is a completely humanised monoclonal antibody that depletes B-cells by binding to CD20 on their surface. You will have noted that this is not a unique strategy and ofatumumab follows on the results of rituximab and ocrelizumab. In other words
ofatumumab is a me-to drug. Big Pharma like to play it safe; there is little chance of ofatumumab not being effective in MS. In this study ofatumumab suppressed MRI activity by >99%. These results is one of the best results to date in the MS space. The bad news is that at sometime during this study the small Danish biotech, Genmab, who was developing this product decided to partner with GSK. GSK for strategic reasons took the decision that a subcutaneous route would be a better option for this drug and had to repeat the phase 2 development programme. The simple switch from intravenous to a subcutaneous formulation will delay the development of ofatumumab by about 4-5 years. This is a great pity for MSers. Why so long? GSK were simply too slow out of the blocks in getting the repeat phase 2 study designed and done. one of the more nimble smaller competitors would have done this in 18-24 months. Despite the delay ofatumumab offers MSers in the future another very highly-active drug with a side effect profile that looks very promising."

"I predict that the class of monoclonal antibodies that deplete B-cells (anti-CD20 and anti-CD19) will be the real game-changers in the field; they come with very high-efficacy and have a relatively good safety profile. There are, however, several unanswered questions around their use in MS. (1) How should they be used; as maintenance therapies or as induction therapies. A maintenance therapy requires the drug to be given continuously and indefinitely. In comparision, an induction therapy require a treatment period of say 2 years and then a watch and see approach with re-treatment given if MS disease activity reemerges. No prizes for guessing what class of drug Pharma want. The distinction between maintenance and induction is not trivial and affects pricing and reimbursement. In short it gives Pharma executives a big headache. (2) How safe is long-term B cell depletion? Can you survive without any circulating B cells for 30 or 40 years? I suspect you can as there are a large number of hereditary disorders, which affect B cells. We simply treat these patients with immunoglobulin or antibody replacement therapy. (3) Do anti-CD20s work in non-relapsing progressive MS? The Roche ocrelizumab PPMS trial will address this question. (4) How do B cell depleters work? Are they working via an anti-EBV mechanism? As you know EBV resides in B-cells and B-cell depleting agents are very good at suppressing EBV viral loads. In fact Rituximab, which is very effective in MS, is the only licensed anti-EBV drug on the market; it has a license for EBV-associated post-transplant lymphoproliferative disease. (5) Do other drugs and strategies that transiently deplete B cells working in the same way, for example mitoxantrone, cyclophosphamide, alemtuzumab, cladribine, bone marrow transplant, etc.? I love it when science results in more questions be asked than it answers; innovation feeds innovation."

"Let's celebrate these results. Well done to the investigators and MSers for participating in this trial. And thank you Genmab and GSK; it is good to have another kid on the block."
SOURCE 

Safety and efficacy of ofatumumab in relapsing-remitting multiple sclerosis: A phase 2 study. Neurology. 2014 Jan 22.
OBJECTIVES: We present the first study to explore safety and efficacy of the human CD20 monoclonal antibody ofatumumab in relapsing-remittingmultiple sclerosis (RRMS).

CONCLUSIONS: Ofatumumab (up to 700 mg) given 2 weeks apart was not associated with any unexpected safety concerns and was well tolerated in patients with RRMS. MRI data suggest a clinically meaningful effect of ofatumumab for all doses studied. Results warrant further exploration of ofatumumab in RRMS.
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