ASH Preview: Zevalin

As I said I my last post, when I do previews like this for the ASH meeting, I'm not trying to be comprehensive. If something seems important, I'll look at it. (You'll see a few of those coming up.) But if something seems interesting t me personally, I'll look at that, too.

This is one of those "interesting to me personally" previews. It's for session #1825 "Real-world outcomes of Y90-ibritumomab tiuxetan (Zevalin) in low-grade B-cell non-Hodgkin lymphoma: A single-institution experience."

Zevalin is a type of RadioImmunoTherapy, or RIT. You don't see much about RIT anymore, at least not in the U.S., and there's a reason for that. RIT treatments were created to solve a problem with blood cancers in using radiation. Radiation can be an effective treatment, particularly for cancers with solid tumors. A beam of radiation can be aimed directly at a tumor. But that's not the case with blood cancers -- the cells are always moving around in the bloodstream, so it is literally a moving target. RIT works by taking a monoclonal antibody (something like Rituxan), which targets a protein on a cancer cell (CD20 is the target for both Rituxan and Zevalin). It also includes a small bit of radiation. So when the RIT finds a CD20 target, it attaches itself to the cancer cell, putting the little bit of radiation onto the cancer cell and killing it. And even better, at least in theory, because the radiation is aimed at a very specific target, there is less chance of it affecting healthy cells, so there should be fewer severe side effects. 

Zevalin was approved by the FDA for Relapsed and Refractory Follicular Lymphoma in 2002, and another RIT called Bexxar was approved right around the same time. I was diagnosed in 2008, so there were lots of follow-up studies being conducted and reported on in those first few years after I was diagnosed. And it was all very exciting to me. I remember the first article from a medical journal that I really got excited about was a report of R-CHOP and Zevalin, where Zevalin was used a salvage therapy (that is, it was given after R-CHOP to kind of clean up any leftover cancer cells). The idea of using three different treatment types -- a monoclonal antibody, traditional chemotherapy, and an RIT -- that work on the cancer cells in different ways, just made so much sense to me. 

So Zevalin has been on my mind for almost as long as I have been an FL patient. And those early studies showed that it was very effective. I remember communicating with two or three folks who had been in trials for Zevalin, and who had been in remission for years.

So why do we hear so little about it now?

Well, at least in the U.S., it's for a couple of reasons, but the biggest was a ruling by the FDA about how Zevalin had to be administered. Because it involves some radiation, the FDA ruled that it could only be administered by a Radiation Oncologist, someone with about 400 hours of specialized training. So while Rituxan or CHOP can be administered right in the treatment room at an oncologist's office, they would need to send you to a specialist if they thought RIT was the best option. And even in 2008, there were already a number of other options for FL treatment, so there wasn't much reason to send a patient to another specialist, or to do 400 hours of specialized training themselves. 

Soon after that ruling, the maker of Bexxar pulled the treatment from the market.But Zevalin has stuck around.  I have no idea how often it is used these days, but as far as I know, it's still available. Interestingly, a few years ago, there was another attempt at getting an RIT approved. It was called Betalutin, and it was pulled after a phase 2 trial. I kind of predicted that was going to happen when I first started reading about it.  

So what is this particular ASH presentation about?

Well, it looks at "real world" outcomes for people who received Zevalin -- patients who were not in a clinical trial. Some of those folks were followed for 22 years, from the time Zevalin was approved by the FDA.

A total of 122 patients with B Cell Non-Hodgkin's Lymphoma (most of them had FL) from one cancer center were followed. 72 of them had received one previous treatment, 43 used it as a salvage therapy after chemo, and 6 used it as a first treatment. The median age was 64 years old. 

The Overall Response Rate was just under 78%, which is pretty great for an FL treatment -- 70.8% ORR for the R/R patients, 88.4% for the salvage patients, and 100% for the first treatment patients.

The media Overall Survival was just under 10 years for the whole group. (Remember, Overall Survival measures dying from any cause, not just something Lymphoma-related, and "median" means that half of the group lived less than the median number, but half lived more than the number.) The median OS was 6.5 years for the R/R group, 15.2 years for the salvage group, and 8.4 years for the first line group. The median time to next treatment was 7.4 years, and 18 patients developed a secondary cancer.  

In their conclusion, the researchers say that Zevalin still has a place in the treatment options for certain patients. That's probably true, especially considering it is about the same cost (maybe even a little cheaper) than something like Rituxan. But I also think it's very unlikely that it's going to suddenly get popular, given all of the other treatment options we have now.

It's always interesting to look back and think about what might have been. I certainly don't have any regrets about being treated with Rituxan instead of something else. But I also can't help but wonder what the path for other FL patients would have been if Zevalin had become more popular. It's not a perfect treatment, by any means, but it might have helped a lot more people than it was able to.

More ASH previews soon.