The maker of Mosunetuzumab, the bispecific, released news this week that their phase III clinical trial for Mosunetuzumab and Lenalidomide seems to be an improvement over R-Squared. I think I have received about 20 different notifications from Google Alerts about it. That's a decent indication that this is a big deal.
As you probably know, Mosunetuzumab is the first bispecific to be approved for treating Follicular Lymphoma. Bispecifics work because they have two parts. One targets a protein on the surface of the cancer cell (CD20) and the other targets a protein on an immune cell (CD3). By attaching to both, it brings the immune cell next to the cancer cell and allows the immune cell to eliminate it.
The phase III clinical trial is called CELESTIMO. It's a two-arm randomized study, meaning the 400 or so patients in the trial are randomly given one of two treatments. So ne group received Mosunetuzumab + Lenalidomide, and the other received R-Squared (Rituxan + Lenalidomide, also known as Revlimid, which gives you the two Rs).
[I want to make a prediction here. Mosunetuzumab is also known as Lunsumio. This combination is going to end up being known as L-squared -- Lunsumio + Lenalidomide. If you're comparing it to R-Squared, this just seems inevitable. I'm all for it. I just wish this blogging program did a better job with superscripts so I wouldn't have to type out :Squared" all the time.]
The results of the CELESTIMO trial are very positive. The manufacturer says the Mosunetuzumab combination resulted in a higher PFS (Progression Free Survival) than the R-Squared, meaning it took longer for patients' disease to become get worse. The manufacturer also said there were no new side effects from combination, only those that were already known about from Mosunetuzumab and Lenalidomide separately.
The manufacturer didn't release any data to back all of this up. They said they will do that either at an upcoming medical conference or in a publication.
[Prediction #2: They'll release the results at ASH and it's going to be one of the major sessions, big enough to be held in the ballroom of the hotel. And then it will be published in the journal Blood just a few days later.]
It's a big deal, given R-Squared's history. The combination was approved in the U.S. in 2019, and it was seen as a major step forward. It was the first non-chemotherapy treatment that was shown to be as effective as traditional chemotherapy like R-CHOP or Bendamustine. Chemotherapy still has a place in FL treatment, but newer treatments are more targeted, doing less damage to healthy cells. (To be clear -- one big takeaway when R-Squared was approved was that it had different side effects than chemotherapy. Not better or worse, but different.)
So if a second non-chemotherapy treatment exists that better than both chemo and R-Squared, then that's a very big deal. We won't really know just how big a deal until the manufacturer releases the data that shows us how effective and how safe it really is.
It's also a big deal given all of the excitement that we saw over the summer from the EHA conference over a presentation on Epcoritamab and R-Squared. Epcoritamab is the second bispecific to be approved for FL, and it has been used in combination with several other treatments in different trials. I suspect the manufacturer of Mosunetuzumab released this news without any data because they wanted to remind people that Mosunetuzumab is still around and there is plenty to be excited about for their bispecific as well.
I'll keep an eye on this one. I'm pretty confident we'll get the data at ASH in a few months (though I'm also notoriously not good at predicting things.)
More soon. I have to get a few more posts in while I can still use both arms.