RCHOP + RIT + Rituxan Maintenance in FL

There was a lot of comment a few weeks ago when I wrote about CHOP vs RIT, so I thought I'd add more to that conversation.

A couple of weeks ago, The Lancet Haematology released the article "R-CHOP, Radioimmunotherapy, and Maintenance Rituximab in Untreated Follicular Lymphoma (SWOG S0801): A Single-arm, Phase 2, Multicentre Study."

This study is a little different from the one I wrote about last month. That study was a much longer follow up, and compared CHOP + Maintenance to CHOP + RIT + Maintenance.

This study from Lancet Haematology is a single-arm study -- it isn't comparing two treatments directly, but instead looks at just one group of patients. It also looks at a much shorter follow-up period (just 3 years).

Still, it has some interesting things to say.

The participants were Follicular Lymphoma patients who had not had any treatment. They were given R-CHOP for 6 cycles, followed by RadioImmunoTherapy within 12 weeks after the last CHOP dose (in this case, the RIT was ¹³¹iodine tositumomab, or Bexxar), and then up to 4 years of Rituxan Maintenance (every 3 months).

The results were about what we expect from RIT -- Progression Free Survival at 3 years was 90%.

The researchers' interpretation of the results is where it gets interesting. They say there was "near universal responses" from the R-CHOP and RIT. However, 84 patients signed up for the trial, 73 completed the R-CHOP and RIT, 69 registered for the maintenance, and only 41 completed all 4 years.

That's a big drop. The researchers note that most of the people dropping out the study did so during the maintenance phase, and suggest that 4 years might be too long for a lot of patients. (Standard length for maintenance is usually 2 years, though that can vary for different patients.)

There was a decent list of side effects from this treatment as well, mostly related to nerve issues and blood count drops (which are fairly typical for these treatments). But there were also 7 cases of patients developing another cancer in that 3 years, with 4 of them resulting in death, with 9 patients overall with "possible treatment-related deaths" (it's hard to know for sure, for example,  if the patient who died from cardiac arrest had that result from CHOP, which can cause heart damage).

This seems, at first, like bad news for Rituxan Maintenance (which is still kind of controversial). I think, though, that it says something about extra long Maintenance, rather than Maintenance in general. And it's worth pointing out that, even though a lot of patients didn't complete the full 4 years of Maintenance, it's possible that not all of them did so for health reasons -- some might just not have been able to commit to 4 years of doctor's appointments, or got good news after 2 years and decided that was plenty. So 4 years might be too long, but it could be for a bunch of reasons.

As for the RIT, this strikes me as more evidence that it works. (This is a good time to remind you all that I'm not a doctor or a cancer researcher, just a patient who reads a lot.) It fits with other studies of CHOP + RIT, in terms of PFS and side effects (secondary cancers have been reported with other studies of RIT as well).

Like with the other study from a few weeks ago, it frustrates me that a treatment that seems to work so well is not used more. There is a newer RIT treatment being tested in Europe called Betalutin that has shown some success in trials. One trial protocol suggests that it could be tested in clinical trials in the U.S., but I'm not sure anyone has enrolled yet. I'm looking into that a little more -- maybe I'll write about it soon. (I have a bunch of other posts already on my list.)

So, perhaps mixed results from this one, but still some good news, and worth looking to see if it goes to a phase III trial (which would be hard, since Bexxar isn't available anymore) or there is a longer-term follow up.