RIT for FL: Betalutin

I've been talking about Betalutin for a few months now -- since the ASH conference, I think -- so I suppose it's time I wrote about it, huh?

It's especially timely since we've seen good news with RadioIummnoTherapy (RIT) in the last couple of months, too, with research showing that it is effective and safe.

Just as a reminder -- RIT is a type of radiation therapy. Conventional radiation therapy is effective on some types of solid tumors. Not so much on most blood cancers, where the cancer cells are floating around to much to shoot at them with a beam of radiation. RIT solves that problem -- it attaches a tiny bit of radiation to an antibody (something like Rituxan) that seeks out and attaches itself to a protein on the cancer cell (Rituxan attaches to CD20). The result is, ideally, the benefits of radiation without the side effects, since the radiation doesn't travel too far beyond the cancer cell.

Betalutin is, of course, another type of RIT.

There have already been a couple of other RIT treatments approved in the U.S. -- Zevalin, which is still around, and Bexxar, which is no longer being made. (Why? More on that below.)

Betalutin in a little different from other RIT treatments. It stays in the body a little bit longer, so it can kill off more cells, and the radiation it releases doesn't travel as far, so it should spare more healthy cells nearby. Most importantly, Betalutin targets CD37, rather than CD20. So for patients who are refractory to Rituxan (that is, it has stopped working for them), Betalutin could be a more effective option.

Someone sent me a link for a really nice video explaining how Betalutin works. Watch it here.

Researchers presented data for Betalutin at ASH in December. In the phase I/II trial, 61 patients were given straight Lilotomab (the monoclonal antibody that targets CD37), and then Betalutin (Lilotomab plus the bits of radiation). The study has 4 different arms, with patients receiving different doses to test which one works best (this is common in early trials). One arm seems particularly effective for Follicualr Lymphoma patients, with 81% of the 21 FL patients showing a Response, 28% of them showing a Complete Response. (You can look at the ASH abstract link for more details of the study, including safety issues, which were pretty good.)

Updated data were presented at the ASH meeting (you can see some of the numbers here).

As always, there are a couple of things worth mentioning.

First, this is an early trial. Approval in the U.S. would not happen for a while, assuming a phase III trial goes as well. Given that the makers of Betalutin are targeting patients who are refractory to Rituxan, it seems like they have a good target population that needs treatments. But it will be a while before this is available.

Second, and maybe more important, is that RIT faces some barriers in the U.S. The rules for handling radioactive treatments are strict -- it cuts down on the number of doctors who can administer it. It's a big reason why Bexxar could never get a grip, and why Zevalin is so under-used, despite its effectiveness. The video I linked above does mention that Betalutin comes in a ready-to-use formulation. I don't know if that makes it easier to administer, or if those same limitations will apply.

(You might remember Lymphomation made an effort to advocate for lymphoma patients by getting Congress to change those rules. It's never too late to get in touch with members of Congress to educate them about our disease and its treatments.)

So, bottom line is, in my opinion, Betalutin could end up being an effective treatment option for FL patients who are refractory to Rituxan. And you know I'm always in favor of having more options for us. This could be especially true for patients in Europe and other parts of the world where there is more enthusiasm for RIT.

As for the U.S., it's going to be a tougher road, but not a completely closed one. Just bumpier.