Updated results of a clinical trial on Betalutin, a RadioImmunoTherapy (RIT) treatment, were published yesterday in the journal Blood Advances: "Phase 1/2a study of 177Lu-lilotomab satetraxetan in relapsed/refractory indolent non-Hodgkin lymphoma." The results look good, though the treatment has some complications to overcome.
I have found RadioImmunoTherapy fascinating for a long time, probably because the RIT treatment Zevalin got an extended approval from the FDA around the time I started paying attention these things, in 2009. Around that time, I had met (online) a few Follicular Lymphoma patients who had benefited from it (and are still benefiting).
RIT works by combining the best of radiation and targeted therapies. Regular radiation that is used on solid tumors just can't work on a blood cancer. The beam of radiation that goes after, say, a lung cancer tumor cannot hit a blood cancer cell. They just don't stop moving long enough to be hit by a beam of radiation.
To solve this problem, RIT takes a bit of radiation and attaches it to a monoclonal antibody (something like Rituxan). Because the antibody seeks out specific blood cancer cells (those that have the CD20 protein on their surface), the RIT antibody can bring that little bit of radiation directly to the blood cancer cell. It is less likely to affect healthy cells that way, while still giving the patient the benefits of radiation.
Betalutin is a little bit different from Zevalin (or Bexxar, another RIT treatment for FL that is no longer available). The big difference is that Betalutin targets the CD37 protein, while Zevalin targeted CD20.
The article gives updated results of a phase 1/phase 2 clinical trial. It involves 74 patients with Relapsed/Refractory indolent lymphomas, including 57 with Follicular Lymphoma. Patients were given Rituxan and Lilitomab (a monoclonal antibody that targets CD37), and then the Betalutin. (RIT is given in just one dose.)
Results were positive: The Overall Response Rate was 65%, with 30% Complete Response. For the FL patients, the ORR was 65%. For FL patients who had already received two or more treatments, the ORR was 70%, with a CR rate of 24%. The overall median duration of response was 13.6 months, and for those with a CR, 30 months.
Side effects were manageable, with the blood count issues that are common in lymphoma treatments.
Overall, pretty good results. Certainly not a potential cure, but, as the researchers point out, for R/R patients who need an effective treatment, but who may have physical issues that would make some more aggressive treatments too difficult.
It's a fairly small study (naturally, since it's phase 1/phase 2), but there seems to be enough good news to justify a larger study. (And given the reports I see from the manufacturer of Betalutin, they seem pretty committed to going through trials and getting it approved.)
The potential problems for Betalutin (at least in the United States) don't come from the treatment itself, but from the regulations for how the treatment can be given. Only doctors with a specific type of training can administer the treatment, so unlike Rituxan or chemo, a regular old oncologist can't give this treatment. It has to be given by someone with special training, and it's not the kind of thing that most oncologists would go through. The reason for this is because the treatment involves radioactivity, which could be dangerous if not handed correctly. Lymphomation created a survey a few years ago asking the FDA to reconsider this regulation, though it doesn't seem to have had any effect.
As I said, I have been fascinated by RIT for almost as long as I have been a Follicular Lymphoma patient. I've spoken to some folks who had very good long-term results from RIT. It was only a few months ago that a very positive study of long-term effectiveness of Zevalin was published. search this blog for "Zevalin" or "RadioImmunoTherapy" and you'll see a lot of good stuff.
But it's a matter of getting that good stuff to the people who can benefit from it.
As I said, the makers of Betalutin seem pretty committed to getting this treatment approved. So maybe they'll do some of the work necessary to make it easier to administer, at least in the U.S.
I look forward to more good results from future trials.
The more (options)- the merrier :).
ReplyDeleteIt appears that Betalutin is somewhat inferior to Zevalin - median PFS 1.2 year vs 2.5 years. It takes many years to prove anything with follicular lymphoma, and Betalutin data might change after, say, 5-year follow-up.