The medical journal Leukemia and Lymphoma recently published an article about the bispecific Odronextamab called "Comparative effectiveness of odronextamab monotherapy versus real-world systemic therapies in R/R follicular lymphoma." It says good things about Odronextamab, though it's the methods for the research that I find most interesting.
Odronextamab is a bispecific. If you need a reminder, bispecifics are kind of like monoclonal antibodies like Rituxan, in that they seek out a protein (CD20) on a cancer cell. But a bispecific also seeks out a protein (CD3 for Odronextamab) on a T cell (an immune cell). So it attaches to the cancer cell on ne end, and on the immune cell that can eliminate it on the other end. Bispecifics are one of those newer treatments that oncologists get very excited about (including my own oncologist).
Odronextamab was approved for use in Europe in 2024, though it has not yet been approved for use in the United States.
The study described in this article is interesting because of its methodology - the way it gathers and analyzes data.
Some more background: Clinical trials are considered most effective when they are randomized, two-arm studies. What this means is, the people running the trial will decide on criteria for the trial (which previous treatments the trial participants have received, or maybe certain health conditions). The idea is to make sure that everyone in the trial is as alike as possible, so they can be compared to one another easily. As patients sign up for the trial, they are randomly placed into two groups (the two "arms" of the study). One group receives the new treatment that is being tested. The other group receives the "standard of care" -- the treatment that they would have probably received if there was no trial, a treatment that is accepted as being the most effective available. (In Follicular Lymphoma, that's complicated, because there a whole bunch of treatments that are effective for different patients.) But the idea is, you have two groups of very similar patients, receiving two different treatments, so they can be compared easily. It's the best way to argue that one treatment is better than another.
But randomized, two-arm studies are large and expensive and take lots of time. So some clinical trials are one-arm studies instead -- everyone gets the new treatment.But then when it comes time to argue that this new treatment is better than the others, it's harder to do so, because there isn't a group already set to compare it to. So the researchers have to find a study that is kind of close, that was done sometime in the past, and compare it to that study. The problem is, it won't be an exact comparison, because unlike a two-arm study, that older study might have had different criteria. One-arm studies like this aren't considered as reliable (though there are plenty of approvals of new treatments based on one-arm studies, especially accelerated approvals).
The study in this article did something a little bit different. Instead of comparing the results of an Odronextamab trial (ELM-2, which looked at 128 patients with Relapsed/Refractory FL), it kind of created its own second arm. The researchers looked through electronic records to find patients who were treated at cancer centers similar to those in the ELM-2 study, who were R/R, and who were "real world," meaning they weren't part of another clinical trial. "Real world" research like this is less restrictive -- no criteria that exclude certain patients.
A small digression to help explain things. Are any of you baseball fans who love statistics? There's a baseball statistic called WAR, or Wins Above Replacement. It looks at a whole lot of statistics for an individual player, and then compares them to the average statistics for a player who would replace them if they had to leave the team. So WAR says "This player is valuable, because if he wasn't on the team and someone else was, the team would have lost 5 more games per year." It's all very theoretical, based on statistics. But it tries to show how things would be different under different circumstances.
This study seems to do the same thing. It's saying "Odronextamab is valuable because if it was available instead of these other treatments, this is how many more patients would have been successfully treated."
The "real world" patients' records were put together in something called the FLORA study. There were 88 patients who had received a total of 100 lines of treatment. Remember, these patients weren't part of a two-arm study, they were just regular FL patients whose records were examined years after they received treatment, which they received between 2015 and 2020. They received a wide range of treatments, mostly chemotherapy and immuno-chemotherapy, but also monoclonal antibodies, BCL-2 inhibitors, Stemm Cell Transplants, radiation, and some others.
The researchers found that, compared to the real world group, patients in the Odronextamab study did better. The Overall Response Rate was 80.5% for Odronextamab vs 52.7% for the real world group. The Complete Response Rate was 73.4% vs 33.6%. Median Progression Free Survival was 20.7 months vs 11.5 months. Time to Next Treatment was 40.4 months vs. 9.7 months.
The researchers recognzie that there are limitations with this research. For one thing, because it looks at patients from 2015 to 2020, it doesn't include any patients who received newer treatments like CAR-T or the other bispecifics that are now available. That might make things turn out differently. And, of course, because they are "real world" patients, they may have had health issues that would have made them ineligible for the ELM-2 trial. It's not really a fair comparison.
But the main ideas are still there. Odronextamab is an effective treatment for many patients, and safe enough to have already received European approval. And just like the theoretical statistical "Wins Above Replacement" in baseball, it's possible that some of the patients in the FLORA study would have had better outcomes with Odronextamab.
It's a very interesting study. I don't think it would hold up as a way to win FDA approval, but it does illustrate how effective Odronextamab is, and how great a need there is for more effective treatments for R/R FL.
I'm still looking out for news about Odronextamab being approved by the FDA. Maybe we'll get some updated news at ASCO in a few weeks.