REGN1979: Bispecific for Follicular Lymphoma

Following up on a comment from William, who linked to an article about the Bispecific REGN1979. Lymphoma News Today reported on the results of a Phase I trial for REGN1979, with very positive outcomes for patients with Follicular Lymphoma.

(I'm going to be shameless for a second, and remind everyone that I write a monthly column for Lymphoma News Today called "Things That Give Me Hope." I might as well make my editors happy and see if I can't increase our readership a little bit.)

Anyway, REGN1979 is a Bispecific, a fairly new type of treatment. The "Bi" in "Bispecific" usually means "two." In this case, it means the Bispecific attracts and attaches to two different proteins. It's kind of like a double-sided Rituxan. As you probably know, Rituxan works by finding the CD20 protein on a B cell and attaching itself to it. REGN1979, as a Bispecific, does just that -- it finds the CD20 on a cancerous B cell. But then it also finds the CD3 protein on an immune cell -- the cells that kill invaders in the blood. By connecting a cancer cell to an immune cell, the Bispecific can bring them together and let the immune cell do its thing.

This study was actually presented at the ASH conference last December. The results then were excellent, with all 7 Follicular Lymphoma patients getting a response (5 Complete and 2 Partial). The Lymphoma News Today article reports on updated results that were presented at the European Hematology Association conference last month. Results are still excellent, though with a few more patients, they are not quite as high: 13 of 14 patients (91%) had a response, with 10 of 14 (71%) getting a Complete Response.

The side effects were "manageable," and included (83% of patients), cytokine release syndrome (57%), chills (54%), and infections (49%), as well as the blood count and nerve issues that are common in FL treatments. Four patients had to drop the trial because of the side effects they experienced, and more had their disease progress. Also, 27 patients dropped the trial due to disease progression and several patients enrolled in the trial died (though this seems to have come from issues unrelated to the treatment itself, but because they already had advanced disease or other health issues, which is not uncommon in phase 1 trials).

I'm interested in Bispecifics (there are a few of them out there in trials) because my oncologist thought I would be a good candidate for a trial for this treatment. I'm sure William was interested in REGN1979 because the article points out that two of the patients who had a response were also former CAR-T patients. As I have been writing about lately, CAR-T works very well for some patients, but not alll of them. So it's great to see that a Bispecific could work for them.

It will be interesting to see how REGN1979 and other Bispecifics work in the longer term, and if a phase 2 trial would show different results, especially in terms of side effects. A significant number of patients had to drop out of this phase 1 trial. But phase 1 trials often include patients who have disease that has progressed a lot, and are willing to try things. That can throw off the results (whoch is why they don't include the entire group, including the drop-outs).

As I said, I'm very interested in this type of treatment. I'm hoping I won't need any treatment for a while, but I'd like to see some updated results at some point in the future.