From the August 10 edition of The Journal of Clinical Oncology comes a report from France on dosing for Obinutuzumab (also known as GA101).
Not a hugely ground-breaking report (though it is part of a larger study): 40 Follicular Lymphoma patients were given Obinutuzumab, but in different doses. Half the patients received 400 mg of Obinutuzumab for 8 cycles; the other half received 1600 mg initially, and then 800 for the rest of the cycles. Results were clearly better for the 1600 group: 55% had a response, while only 17% of the 400 group responded.
That 55% doesn't seem all that impressive, but there are further results that make this a little better: 38 of the 40 patients had already had Rituxan, and 22 of them were refractory to Rituxan (meaning Rituxan had pretty much stopped working, which is not uncommon with Rituxan). Of the 10 patients who were refractory and had the 1600 mg, 5 had a response. Of the 12 in the 400 group, only 1 had a response.
I think this is significant. Obinutuzumab might be an option for people who tried Rituxan and had it fail. Both target CD20 on B cells, but apparently work by different mechanisms (so says the head of the study, Dr. Gilles Salles, in another article that reported on these results).
Now, as I was writng this, I couldn't help thinking about another very recent report on a Monoclonal Antibody seen as a rival to Rituxan -- Epratuzumab, which had very similar results to Rituxan, and which I was kind of negative about in a post last week. The two reports (on Epratuzumab and Obinutuzuma) are similar in a way, both offering alternatives to Rituxan, with presumably similar side effects. So why am I a little more excited about this report on Obinutuzumab, which doesn't seem as effective as Rituxan?
Let me clear: I'm not down on Epratuzumab by any means. I think it's a great thing, and another necessary arrow in the quiver. But I really objected to the way the manufacturer was "selling" it in the press release, as something people can try if they don't want chemo. I guess I don't like it's being presented as a choice, as if fear of losing hair is the only factor. It certainly is a factor -- I would never discount the emotional issues that go into choosing a treatment. If that's the only issue, there are other things to try -- including Rituxan. Why offer a choice when time could be spent on something better than what we have?
Obinutuzumab, as it is presented here, is not just a choice other than Rituxan. It's an option for when Rituxan fails. There is, to me, a big difference.
It's hard being a cancer patient. There are people who think having an
indolent lymphoma is good ("If you're going to have one, this is the one
to have," some of us have heard). We have more choices, and often more time
to choose. We're lucky that way. But it has its downsides, too.
The bottom line is, as Follicular Lymphoma patients, we have three possible monoclonal antibodies to choose from -- Rituxan, Epratuzuma, and Obinutuzumab. They do different things, and they'll be appropriate in different situations. With our oncologists' help, we should be able to make the right choice.