What’s the latest chronic lymphocytic leukemia (CLL) treatment and research news out of the American Society of Clinical Oncology (ASCO) 2021 meeting? Dr. Paul Barr shares study results and explains how they could impact CLL care.
Dr. Paul Barr is Professor of Hematology/Oncology at University of Rochester Medical Center. Learn more about Dr. Barr, here.
I’m Katherine Banwell, your host for today’s program. Joining me is Dr. Paul Barr. Dr. Barr, would you please introduce yourself?
Sure. Hi, Paul Barr from the University of Rochester. Glad to be here.
Thank you so, much. Cancer researchers came together recently to share findings at the annual American Society of Clinical Oncology meeting, also known as ASCO. Is there news from the meeting that CLL patients should know about?
There is. It seems like at every major meeting, we have a potentially practice-changing dataset that we like to scrutinize and talk about. This ASCO is no exception. I think probably the most impactful abstract was a report.
The first time we’ve seen the results from a study that was called The ELEVATE Relapsed Refractory Study. This was a randomized trial, enrolling previously treated CLL patients who had high-risk disease and randomizing them to two of our very important BTK inhibitor treatments.
Half the patients got acalabrutinib (Calquence), and the other half received ibrutinib (Imbruvica). And both groups were treated until the drug essentially either stopped working, the disease became resistant or was stopped for side effects. So, this was a study we have waited on the results for a long time given that we don’t often see these randomized studies comparing two such active agents. And the results showed us that both drugs work really almost equally as well.
The progression-free survival or the roughly the average amount of time patients are taking the drug was just over three years, 38 months in both arms. So, they really work very well and equally as well. But we did see less side effects with the acalabrutinib. And one of the most important side effects that the study was powered around was, atrial fibrillation or flutter.
There was less AFib or less new AFib in patients that were treated with the acalabrutinib. There was also less minor bleeding, arthralgia, diarrhea. So, a number of, perhaps less severe type side effects, were less common. There was more headache and more cough in the acalabrutinib-treated patients. But I think overall, most of us took from this abstract that both drugs work exceptionally well.
And overall, are very well tolerated treatments although there does look to be lower rates of a number of important side effects with acalabrutinib.
Dr. Barr, is there any other news from the conference that patients should know about?
There is. I’ll give you a couple other additional findings. One was an update of a study, we’ve seen the results before. It’s sort of a partner study to the one I just mentioned. It was called The ELEVATE TN or ELEVATE Treatment Naive Study.
These were previously untreated patients, treated with an old standard, randomized study where the patients received either chlorambucil-based therapy (Leukeran). It was combined with a CD20 antibody obinutuzumab (Gazyva). The second arm was single agent acalabrutinib and the third arm was acalabrutinib plus obinutuzumab. Not surprisingly both of the acalabrutinibs continue to perform very well. The treatments work much better than chlorambucil. But now, we have four-year data. And that’s important for us to really understand what to expect as time goes on.
And I think that the major take-homes are that, acalabrutinib continues to work very well in the first-line setting. There is a hint that acalabrutinib, I’m sorry, that obinutuzumub may prolong the remissions, which is a little bit surprising to us.
But again, small differences in the study weren’t powered to really look at that comparison. And also, the major take home from that dataset is that the safety still looks very good at four years for the patients receiving acalabrutinib. So, I think that continues to shape our practice. And I think the last dataset or abstract to comment on, was one actually we saw at a different meeting at the European Hematology Association meeting, EHA. And this was another randomized study comparing two different BTK inhibitors in relapsed CLL patients.
This one compared ibrutinib and zanubrutinib (Brukinsa). Like acalabrutinib, zanubrutinib is another more specific BTK inhibitor. And when you compare it to ibrutinib and perhaps somewhat similarly to The ELEVATE Relapsed Refractory Study in this zanubrutinib-ibrutinib comparison, so-called ALPINE study, we saw similar efficacy.
Zanubrutinib actually looked like it performed a little better than ibrutinib, but also again here, lower rates of side effects. So, the theme continues for the more specific BTK inhibitors. They seem to work just as well, maybe a little better in some respects, compared to Ibrutinib and somewhat lower rates of side effects. So, when you put it all together, all of the BTK inhibitors work exceptionally well.
We have varying degrees of follow-up and confidence. We have the most follow-up in our ibrutinib treated patients so, we know what to expect for patients six, seven years out after being on ibrutinib.
But we’re now seeing in these earlier studies that lower rates of various toxicities for the newer more specific BTK inhibitors. So, kind of a long-winded answer to your simple question, but hopefully that shows how the new and emerging data continues to shape how we take care of patients.