ASH: Another Possible Rituxan Replacement

The ASH Conference is now actually over (it ended Monday), but I still have lots of Follicular Lymphoma news to go through. We're starting to see lots of folks bragging about their presentations, which is great. There was a lot of stuff worth bragging about this year.

It seems like one of the really big winners of this conference was Obinutuzumab, which I wrote about a few weeks ago. It is a potential replacement for Rituxan -- it operates in much the same way, but may be even more effective because of the way it was created. (Of course, the really really big winners are those of us with Follicular Lymphoma....)

Rituxan has been a huge part of why Follicular Lymphoma survival rates have been increasing in the last 20 years or so, and there have been a bunch of attempts to find a monoclonal antibody that can improve on Rituxan. So far, no one has been able to find one. Until now. I don't think Obinutuzumab will replace Rituxan completely (oncologists' habits are hard to break), but it might chip away at its dominance.

Combine that with another presentation from ASH, and we might very well see a lot less Rituxan soon.

Rituxan's patents have expired (in 2013 in Europe and a few months ago in the U.S.). That means generic or biosimilar versions can be sold. Biosimilars are basically copies of the already-used treatment (in this case, Rituxan). If they are developed properly, they will be as effective as the original, with the same kinds of side effects. They will also likely be cheaper, since pharmaceutical companies use a lot of their profits to help recoup their costs for research and marketing of their products. A generic or biosimilar has a head start -- people already know it works as well as Rituxan.

Of course, that assumes that it does work.

The ASH presentation called "A Phase III Efficacy and Safety Study of the Proposed Rituximab Biosimilar GP2013 Versus Rituximab in Patients with Previously Untreated Advanced Follicular Lymphoma" set out to show that a biosimilar can indeed work as well as Rituxan.

The researchers tested a biosimilar called GP2013. The study looked at 629 patients in 26 counties. Half were given the chemotherapy CVP + GP2013, and then 2 years of maintenance with GP2013. The other group was given CVP + Rituxan, plus 2 years of Rituxan maintenance.

The Overall Response Rate for the GP2013 group was 87.1%. For the Rituxan group, it was 87.5%. That's a very small difference -- enough to say that the biosimilar is indeed similar to the original. The researchers also tried to measure median Progression-Free Survival and Overall Survival, but the median had not been reached after 3 years (that is, less than half of the group had progressed or died, so they couldn't measure it).

Both groups also had similar side effects.


There are actually quite a few Rituxan biosimilars being developed. I'm still not willing to say they will replace Rituxan completely, but it's good to know there are some out there. Cost is a factor for everyone, if something can give the same results for a lower price, we all benefit.

The only thing left for GP2013 to do is come up with a better name. They definitely need something snappier -- ideally, with an X or a Z in it. Or more than one. My suggestion? "Rituxisimilex." (If you're reading, dear researchers, you're welcome to use that name. No charge. Just keep doing what you're doing.)