ASCO Review: Clinical Trials and Surrogate Endpoints

As I said in my last post, this is kind of a lean year for Follicular Lymphoma at ASCO. There are far fewer presentations on FL than there have been in the recent past. And no "blockbusters" -- no major studies that are being presented with new information about new treatments that we haven't seen much of (though there is one that presents data for a new treatment that I will get to soon).

Instead, most of the the FL presentations at ASCO are about refinements -- new information about treatments we are already familiar with. In truth, that's what most ASCO (and ASH) presentations every year are about anyway, and that's not a bad thing. Clinical trials can only give us a certain amount of information, and after a treatment has been approved, there's still plenty we need to know about long-term effectiveness and side effects and "real world" factors. 

So while there isn't too much this year with a high "wow factor," there is some interesting stuff to talk about.

One study is called "The clinical trials landscape in follicular lymphoma: A systematic review." It looks at how clinical trials for FL treatments are conducted and the complications that come with a disease like ours.

Some background: a clinical trial is a way of systematically testing a treatment, and ideally allows us to compare treatments to one another by looking at effectiveness and safety. The problem comes in how effectiveness is measured.

In an ideal world, we would measure by Overall Survival, or OS. In other words, we look at how many people are still alive at the end of the trial, and if there are more alive than there were in a trial for a different treatment, then we know the new treatment is better. That seems like the best way to measure the effectiveness of a cancer treatment -- it keeps people alive.

The problem, at least for FL treatments, is that FL patients tend to live a long time. The median OS, as presented by the researchers who did this study, is "over 15 years." So more than half of FL patients will live for more than 15 years after diagnosis. That's great for us patients, but less great for those who are developing treatments.

The reason is practical. If researchers have to wait 15 or more years to accurately measure OS, that means it's going to be even longer before they can get approval for their treatment and start making money off of it. That's a legitimate concern. As much as I'd love people to develop treatments based only on their love of science and their genuine concern for cancer patients, the reality is that someone has to pay for all of that research, and they want there money back. If they have to wait 15-20 years, there is much less incentive for them to invest in the first place. That's the reality.

So researchers develop "surrogate endpoints." They try to find some other way of measuring effectiveness that won't take so long. So they can say to the FDA or other regulator, "Our surrogate endpoint is 5 year PFS. If someone is able to go for 5 years without the disease progressing, then we can assume they will have a long Overall Survival." It's not a perfect system.

This ASCO presentation looks at the different surrogate endpoints that researchers have been using in FL trials. It identified 28 phase III clinical trials involving FL. It found that 79% of the trials used Progression Free Survival as its primary endpoint, with 18% using Overall or Complete Response Rate. Other surrogate endpoints included Progression Of Disease within 24 months (POD24), Complete Response at 30 months (CR30), and Minimal Residual Disease (MRD). 

About 50% of the trials included some measurement of Quality of Life, which wouldn't count as an effectiveness measure, but it's definitely a good thing to look at.

Also, about 50% of the trials involved CAR-T or Bispecifics, which brings up the possibility that Overall Survival for FL patients may increase even more. Again, that's an excellent problem for us to have, but it is still a problem, in terms of research. The researchers call for more research into how effective surrogate endpoints are, and perhaps finding new ones that will do a better job.

So while it is frustrating to know that our clinical trial system needs some improvement, it's also good to know that the reason is we are living longer, a s group. For now, that seems like a pretty good trade-off, but moving toward a more perfect system should remain the goal.

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One last reminder:

Remember that I'll be one of the speakers the Follicular Lymphoma Foundation's webinar, "FL Treatment Options – What You Need to Know," taking place Thursday, June 5, at 12:30 Eastern Time.

You can read more about the webinar and register at this link: https://us02web.zoom.us/webinar/register/2617476619964/WN_S3L8Al8tQAOjPWBy6ERxCw#/registration

There will be a recording posted later if you can't make it (or you're seeing this too late).

Hope to see you there!