Tuesday, July 16, 2013

Follicular Lymphoma: GA101

The journal Blood has published the results of a phase 2 clinical trial involing GA101 (also known as Obinutuzumab) and chemotherapy. Results were very positive -- enough to consider Obinutuzumab as a possible alternative to Rituxan (?).

Obinutuzumab is similar to Rituxan, in that they are both monclonal antibodies that target the CD20 molecule on B cells. There have a been a whole bunch of monoclonal antibodies developed since Rituxan, though none really seems to do a better job. Obinutuzumab is different for two reasons: first it is fully humanized. That is, unlike Rituxan, which was developed from mouse cells, Obinutuzumab was developed from human cells. There is some speculation that this difference means fewer allergic reactions.

More importantly, Obinutuzumab is glycoengineered. Glycoengineering is a process whereby certain sugars on the antibody molecule are changed to the molecule attaches to its target more easily. Combine those two qualities -- better attachment and fewer side effects -- and you just might have an improvement on Rituxan.

The results from this clinical trial aren't going to determine whether we have a Rituxan replacement.

But it does point to the effectiveness of Obinutuzumabin combination with CHOP.

The trial involved combining Obinutuzumab with either CHOP or FC (Fludarabine and Cyclophosphamide), The important results are 1) there were no significant side effects (though there were more with FC than with CHOP), and 2) it's a pretty effective combination: 96% of patients receiving the CHOP combo had a response, and 93% of FC patients received a response.

Pretty darn good.

It's a phase 2 trial, so its goal is to prove that a phase 3 trial is worth conducting -- one with more participants, to show that the results can hold.

And this one trial won't really solve much, given all of that. I still contend, as I've said several times recently, that chemo is probably on its way out (though it won't disappear completely as an option -- it will diminish in use). So these results are great, but they're not the long-term solution we're looking for.

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