ASH Preview: Long-Term Results of RIT

Back to ASH Previews.

The next one I found interesting is "Long-Term Outcome of Patients with Low-Grade Follicular Lymphoma Treated with Yttrium-90 Ibritumomab Tiuxetan: The Mayo Clinic Experience."

Yttrium-90 Ibritumomab Tiuxetan is better known as Zevalin, and it is a type of RadioImmunoTherapy, or RIT.

If you're new to Follicular Lymphoma, you may not eve know about RIT. It's a lot like Rituxan, in that it seeks out and attaches itself to cancerous B Cells (in fact, Zevalin attaches to CD20, the same protein that Rituxan attaches to). But RIT is different -- it has a little bit of radiation attached to it. Standard radiation that if often used on solid tumors just won't work on blood cancer. You can't hit a moving target, like a blood cell, with a beam of radiation. But RIT solves that by tracking down the cancer cells in the blood, attaching to them, and delivering that little bit of radiation right to the cell. Ideally, it cuts down on the typical side effects of radiation because it is targeted to specific cells.  

I'll admit, I'm fascinated by RIT. As a treatment, it hit its peak right about the time I was starting to understand my disease and learn more about it, and I know of a bunch of folks who have had more than 10 years of cancer-free living after RIT.

Unfortunately, it has never been used as much as it should have been used in the United States. Because it involves radiation, it requires extensive, specialized training in order to be administered. When it was first approved, there were also some related issues regarding how doctors were paid for it. Despite how effective it has been, the administrative difficulties have kept it from being used as much as it probably should be used.

Still, there is lots of research being done on RIT, including Zevalin (search this blog and you'll see few stories from 2018 on Zevalin), and a new RIT, Betalutin, was given Fast rack designation by the FDA last year. I'm hoping that if it does get approval in the U.S., they'll find a way to get it into patients.

As for this particular ASH presentation, the researchers looked at the long-term effectiveness of Zevalin in patients at one cancer center (The Mayo Clinic). Patients had low grade FL (grade 1 or 2). Basically, they wanted to see how Zevalin affected Overall Survival and how long patients went before needing another treatment.

Looking back at medical records, they found 137 FL patients had Zevalin between 2003 and 2018.

Median follow up was 10.2 years; median age of patients was 60, and 69% of patients were still alive.

For patients who had Zevalin as their first treatment, there was a 100% Overall Response Rate, and a 93% Complete Response Rate. For patients who had Zevalin as a second or later treatment, the OR was 93%, and the CR was 73%.

Of the 108 patients who a Complete Response, 45% of them still had that response a median of 7 years later. Only 43% of the first-line patients relapsed in that time, while 71% of the second-line patients did.

For the whole group, the median Progression Free Survival (how long it took for the disease to get worse or comeback) was 2.5 years, and the median Time To Next Teatment was 3.6 years. The PFS and TTNT numbers were better for the first-line group than the second line group.

Now the Big Number: media Overall Survival for the whole group was 18 years.  It was also 18 years for the second-line group, and a median hadn't been reached yet for the first-line group (since the median is the exact midpoint of the group, that means not enough people had died yet to measure the median -- a very excellent thing).

None of this very surprising to me, given the excellent long-term results in the people I now who had it years ago.

The researchers conclude that the numbers for Zevalin after almost 20 years are even better than they were when they first started measuring all of this. They recommend using Zevalin in combination with newer treatments as a way of extending their effectiveness.

That certainly seems like good advice. In fact, a recent study looked at patients who had Bendamustine + Rituxan, followed by Zevalin. The B + R had a 97% Overall Response, with a 56% Complete Response. When they followed it with Zevalin, there was again a 97% OR, but the CR went up to 89%.

It's good stuff, that RIT.

It would sure be nice if we could find a way to get it to more people who could be helped by it.