Tuesday, April 30, 2013

Zevalin and Follicular Lymphoma

The Journal of Clinical Oncology published an article earlier this month on the effectiveness of Zevalin. The article is called, quite simply, "90Yttrium-Ibritumomab Tiuxetan Consolidation of First Remission in Advanced-Stage Follicular Non-Hodgkin Lymphoma: Updated Results After a Median Follow-Up of 7.3 Years From the International, Randomized, Phase III First-Line Indolent Trial." 

I'll translate: "Using Zevalin as an immediate follow-up to successful first treatment for Follicular Lymphoma Patients: We've been doing this for over 7 years and it's working, blah blah blah."

Some background, first, because I haven't really discussed Zevalin recently, and I apparently have a bunch of new readers.

Zevalin, along with Bexxar, are known as RadioImmunoTherapy treatments (RIT). RIT is a pretty successful way of battling Follicular Lymphoma. It basically uses Rituxan, which seeks out the CD20 antibody on FL cells and attaches itself to them. but what makes Zevalin (and Bexxar) different is that they add a tiny bit of radiation to each molecule of Rituxan. Traditional radiation doesn't usually work in FL, because the cells are traveling through the blood stream. Since Rituxan seeks out individual FL cells, it can deposit that bit of radiation on the cell. Healthy cells are more likely to be spared.

Early studies of Zevalin were extremely positive: very effective, with fewer of the side effects of traditional radiation (since it's targeted). The FDA approved it as a consolidation therapy -- basically, something that could be used immediately after another treatment to make sure all the FL cells got killed off. There was a lot of talk a few years ago, after the FDA approval, that a three-way treatment strategy might be the way to attack Follicular Lymphoma: a chemo/Rituxan cocktail, with a Zevalin chaser. Chemo, Rituxan, and Zevalin work in three different ways, so maybe that approach will finally be the thing that fools the FL cells?

There's been less talk of that lately, as traditional chemo seems to be dying off as a future focus. And Zevalin never really got the traction it should have gotten, given how successful it was in early trials. There are a few reasons for this, and they have nothing to do with its actual effectiveness. Zevalin can't be administered in an oncologist's office; it has to be done by a special team of nuclear medicine specialists, given that it is radioactive. Plus, there's some kind of Medicare-reimbursement issue that I don't fully understand that discourages doctors from using it. So, basically, there are monetary and political issues that keep it from being used, even though Zevalin is an effective treatment.

And the JOC study does confirm that Zevalin is effective. This article is actually one of the few long-term studies Zevalin. It looked at 409 patients with advanced Follicular Lymphoma who had a full- or partial-response to their first treatment. Half were given no treatment, and half were given Zevalin as a follow-up. The patients who got Zevalin fared much better. After 7.3 years, 41% of those patients had not had any additional growth in their cancer. Only 22% of the non-Zevalin patients had similar results.

If you don't want to wade through the original article, Cure Today has a nice summary.

I like to think that results like this will spark more of an interest in Zevalin, though I get less optimistic about it as time goes on. Which is a shame, because the idea that we are treating with such a different mechanism than other treatments is really attractive. Maybe, as combinations of newer treatments are being tried out, someone will decide to return to Zevalin as a consolidation treatment, and we'll see some great things happen.

In the meantime, it remains another arrow in the quiver, and we can never have too many of them.

1 comment:

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