Saturday, January 20, 2024

No Survival Benefit with Rituxan Maintenance

The Journal of Clinical Oncology published the results of a study a few days ago that looked at long-term benefits of Rituxan Maintenance. The article is called "Long-Term Follow-Up of the RESORT Study (E4402): A Randomized Phase III Comparison of Two Different Rituximab Dosing Strategies for Low–Tumor Burden Follicular Lymphoma." The big news from the study is that there doesn't seem to be a survival benefit from Rituxan Maintenance in low-tumor burden Follicular Lymphoma patients. 

A few things need some explaining here. 

First, Rituxan Maintenance is a type of treatment where patients first receive a treatment that includes Rituxan (also know as Rituximab and Mabthera), a monoclonal antibody. The treatment could be just Rituxan, or it could be Rituxan combined with something else (like R-CHOP or R-Bendamustine). For this particular study, the patients received only Rituxan, once a week for four weeks. The "maintenance" part comes next, after the initial treatment -- patients receive just Rituxan on a regular schedule for a certain time period. For this study, the patents recieved Rituxan every 13 weeks until they need treatment again. (Some Rituxan Maintenance studies have a different dosing schedule, like every 2 months for 2 years, and then no more.)

The idea behind Maintenance is that the regular doses of Rituxan will help "clean up" any leftover cancer cells, or any new cells that develop. It's always been kind of controversial, with some studies showing a benefit and others showing no benefit, and others showing a small benefit but asking if the additional cost and additional weakening of the immune system is worth it (Rituxan reduces cancerous B cells, which are part of the immune system, but also healthy B cells).

For what it's worth, my own treatment, 14 years ago, was 6 weekly rounds of Rituxan. I haven't needed treatment since. I do remember asking my oncologist, as we discussed treatment, if we should consider doing maintenance. Back then, he told me that there was good evidence that maintenance helped people who had received immunochemotherpay (R-CHOP or R-Bendamustine, or back then, R-CVP, which is less common these days), but less evidence that there was a benefit for people who received only Rituxan.

What seemed like the case, 14 years ago, is confirmed by this research, which looked at a long-term follow-up of patients like me, with low tumor burden, receiving only Rituxan.

I'll repeat this, because I think it's important -- this study looked only at low-tumor burden FL patients who received only Rituxan. There's a whole other body of research on patients who had high tumor burden, or who received other treatments (though they are controversial in their own ways -- you can search for what I have written about them over the years). 

For this study, 289 FL patients were divided into two groups, as I mentioned above. The first group received four weeks of Rituxan, and then no other treatment until their disease returned and got bad enough to need treatment. The second group received Rituxan, and then more Rituxan every 13 weeks until it stopped working and they needed a different treatment. 

The Maintenance group did have some benefits to their treatment. After 7 years, 83% of the patients who had received Maintenance had still not needed a second treatment. In the first group, only 63% of patients had been able to avoid treatment.

Also, some patients had their disease return, even though they didn't need a second treatment yet. After 7 years, 71% of the Maintenance group had not had their disease return, while only 37% of the non-Maintenance group remained in remission.  

But it was Overall Survival that showed no difference. After 10 years, 83% of the Maintenance group was still alive, as was 84% of the non-Maintenance group. 

And the OS was what the researchers focused on. And of course, that's important. We all want to live longer. But I think the other numbers are important, too, and I have some thoughts about them.

This seems like a good time to remind you all that I am not an oncologist or a cancer researcher. The best person to talk to about treatment decisions is your own oncologist.

It seems to me that patients who receive only Rituxan are in a situation where they have a less aggressive version of FL. This was certainly the case for me. And while we do have some treatments that have the potential for very long-term remission, or even A Cure, we're not really there yet. So there may be some FL patients whose goal is to stay in remission for as long as possible. They know (or assume) that they will eventually need treatment again, and they want to delay it as long as possible. Maybe a Maintenance strategy is the best way to do that -- a relatively less aggressive treatment at first (compared to something like traditional chemo), followed by less aggressive treatments for a while. Of course, doing this also costs money, and increases the chance for infection, but also holds off more aggressive treatment for a while.

I'm not endorsing Rituxan Maintenance for anyone. I'm not endorsing any particular treatment at all. My point is not only that your oncologist is the best person to talk to about this, but also that your a very specific discussion of your goals should be a part of that conversation. Not everyone is looking for A Cure. Maybe your life style or your overall health make that difficult. But that's the ind of topic that should be a part of your oncologist visits. It is for mine. Even after 16 years, I want to know what the next steps might be, if I ever need them.

We are fortunate to have lots of choices. It's good to know what they are, and which is best for each of us.

 

3 comments:

  1. I found this a really interesting piece of research and I think its left me with the same thoughts. I felt the researchers conclusion made the big assumption that FL patients are solely seeking increased OS. Of course I want want to survive but as a patient with FL, the fact that the rituximab maintenance did not REDUCE OS or show increased adverse outcomes but does reduce the amount of interval treatment required actually seems like a real positive. The potential benefits of rituximab maintenance look even more positive if seen in the context of the encouraging emerging data on bispecifics. Of course bispecifics may not turn out to deliver as we hope they might but this data suggests there wouldn't be undue risks from the approach of using rituximab to control FL while we wait for the option of bispecifics. Of course this would cost money compared to watch and wait but it feels like something I would like to discuss with my oncologist

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  2. Helpful to point out that OS is influenced by age at diagnosis.

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  3. Anonymous,
    You know, I started to get more into Overall Survival, and what it is, and how to think about it. I've written about it a lot in the past. And you're absolutely right -- OS is influenced by age at diagnosis. In general, people who are later in life are likely to have comorbidities (other health problems) that influence their life expectancy. And since OS measures all deaths, not just deaths by a specific disease, it makes sense that older patients will have a lower OS. But it's also just pure math -- someone diagnosed at 40 (like me) already has an OS of 16 years. Someone diagnosed at 80 is less likely to live for that same period of time. It's a complicated statistic, which is partly why FL researchers push Progression Free Survival instead of OS as their yardstick, and why I think many patients want to think about treatment in different terms (Liz's comment here is an excellent example).
    It might be time for another of those "Overall Survival" posts that I like to write every now and then.
    Thanks for the comment.
    Bob

    And Liz, thanks for yours, too. I hope yu have a good talk with the onc, and that you're doing well. Thanks for reading.
    Bob

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