More Success for RIT for Follicular Lymphoma

There has been a lot of stuff written lately about RadioImmunoTherapy -- at least, more than I would have expected, given how difficult it is in the U.S. to get RIT. We no longer have Bexxar as an option, and Zevalin is hanging on despite being very underused, given its successes.

In January, I wrote about the great long-term results that RIT was showing in one study. Then, in March, I wrote about some data for the newer RIT called Betalutin. There's at least one abstract for RIT research in Follicular Lymphoma that's being presented at ASCO this year (more on that soon).

And a few weeks ago, Hematological Oncology published "Management of Newly Diagnosed High‐Risk and Intermediate‐Risk Follicular Lymphoma with ⁹⁰Y Ibritumomab Tiuxetan in a Phase II Study."

In this phase II trial, 33 patients with high-risk or intermediate-risk FL were given R-CHOP , followed by Zevalin, and then 2 years of Rituxan Maintenance. (The abstract that I link to doesn't describe what "intermediate-risk and high-risk FL means, but the clinical trial details do. They used FLIPI scores of 2-5. I won't get into what FLIPI is here,Three months post radio‐immunotherapy, 28/33 (85%) patients had achieved complete response including 6 patients who had only a partial response to chemo‐immunotherapy and converted to complete response after radio‐immunotherapy. The 5‐year progression‐free survival for intermediate and high risk was 79% and 58%, respectively. but I'll send you to Lymphomation.org if you want to learn more.)

The results: Intermediate-risk patients had a 5 year Overall Survival of 88%, and high-risk was 85%. Pretty good results.

The 5 year Progression-Free Survival was 79% for Intermediate and 58% for high.

Three months after RIT, 85% of the patients (28 of 33) had a Complete Response, including 6 who had only had a Partial response after the R-CHOP.

Again, all pretty good.

Naturally, there were side effects, as one would expect from so much treatment. Most were manageable, though there were some harsher ones, including thrombocytopenia (low platelet levels) and neutropenia (low white blood cell levels), and one patient developed Myelodysplastic Syndrome, which cayuses abnormal blood cells.

Still, the reserachers believe the approach deserves further study (perhaps a phase III trial).

Of course, the usual precautions apply here -- it's a phase II trial, with only 33 patients, which is a very small number.

It's also kind of an older trial, begun in 2011. The upside of that is, we're getting some important long-term results. The downside is, FLIPI seems a little less sophisticated than some other ways of measuring high-risk. It would be interesting to see how this treatment would work on EFS24 patients -- in the last couple of years, it has been widely recognized that patients whose disease gets worse within 24 months after they receive Immunochemotherapy (something like R-CHOP or R-B). FLIPI is fine, but it doesn't seem as accurate as EFS24 in labeling high-risk patients. For example, I have a FLIPI score of 2, Intermediate, and I would have qualified for this study, but my disease is very different from someone with EFS24.

All of that said, this is just more evidence that RIT has a place in the treatment options for Follicular Lymphoma. It's not easy to administer (though regulations in the U.S. could make it easier), it is effective in the long-term, and it is reasonably safe.

Let's hope changes are made in the U.S. that make it more available, and that it remains available to the rest of the world.