Initial treatment with lenalidomide (Revlimid), tafasitamab (Monjuvi), rituximab, and acalabrutinib (Calquence) led to complete responses (CRs) in 64% of patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL), according to results from cohort 1 of the . The phase II findings, presented at the recent American Society of Hematology (ASH) annual meeting, tested a response-adapted approach, with only two cycles of chemotherapy given to those in CR after initial treatment with the quadruplet regimen alone.
In this second of four exclusive episodes, 51˶ brought together three expert leaders in the field, all from The Ohio State University Wexner Medical Center in Columbus -- moderator , is joined by , and -- for a virtual roundtable discussion on the Smart Stop results.
You can watch the first video in the series here.
Following is a transcript of their remarks:
Maddocks: Let's move on to the next study, it was a little bit different study, frontline study in diffuse large B-cell lymphoma considering at least part non-chemo-therapy based. So the Smart Stop study was presented -- lenalidomide, tafasitamab, rituximab, and acalabrutinib alone and with combination chemotherapy for the treatment of newly diagnosed diffuse large B-cell lymphoma.
So as a setup to this trial, we had the Smart Start study presented by Dr. Westin, which looked at the combination of rituximab, lenalidomide, and ibrutinib [Imbruvica] as a lead-in in patients with diffuse large B-cell lymphoma. And then the plan was for those patients to go on and receive all six cycles of chemoimmunotherapy, so non-chemo lead-in, but still receive the six cycles of chemotherapy. This showed very promising outcomes with a 2-year progression-free survival of a little over 90% in patients and really kind of set up this Smart Stop trial. So thoughts on this trial?
Sawalha: Yeah, I think very exciting data, very interesting concept potentially paving the way to hopefully one day chemo-free approach to diffuse large B-cell lymphoma and other aggressive B-cell lymphomas as well.
So 19 out of the 30 patients were able to receive only two cycles of CHOP [cyclophosphamide, doxorubicin, vincristine (Oncovin), and prednisone], and with the limited follow-up to date, remained in remission. I think that's very exciting. It looks like most patients are able to tolerate this regimen, so most patients were able to maintain more than 90% of the dose intensity of the targeted agents. Thirty percent of the patients were 70 years or older. I think that's encouraging to see that older patients are included in this patient population, the overall high-risk patient population. I think it's also important to note that most patients (83%) had non-GCB [non-germinal center B-cell] DLBCL or large B-cell lymphoma.
One kind of interesting side effect, which I don't think is surprising to us to see, is rash in more than 40%, including grade 3 in 13%, which we know can be seen especially when we combine lenalidomide with a BTK inhibitor.
But overall, as you mentioned, Dr. Maddocks, very high response rate, a CR rate of 93% by the end of the second of two cycles of CHOP in combination with the targeted agents and then a CR rate of a 100% at the end of treatment for a subset of patients; only 22 patients that reached that point. So very encouraging. I would like to see these data also be... see similar responses in a multicenter hopefully setting rather than a single-center study.
Bond: Yeah, and I think it's exciting to see the BTK [Bruton's tyrosine kinase] inhibitors still being looked at in diffuse large B-cell lymphoma. I think there's a lot going on in diffuse large B-cell lymphoma, a lot of classes of drugs being developed when we just spoke about bispecifics and we'll be speaking about CAR-T. But I think that there was other data as well trying to look at the role of BTK inhibitors.
I think this is one potential path forward where you have a targeted combination therapy that has a time-limited approach frontline. And so I think with acalabrutinib, the earlier stage in diffuse large B-cell lymphoma with ibrutinib, which we know has more side effects, at least cardiovascular side effects compared to acalabrutinib, tends to be a little bit harder to tolerate. So I think looking at acalabrutinib in combination and these newer second generation BTK inhibitors is an attractive option.
I think it's promising and I think we hope we see more in the frontline with the BTK inhibitors or in other settings that we're able to bring these to patients, because I think right now in clinical practice, for the most part, BTK inhibitors have really fallen out of practice in large B-cell lymphoma, but there may be a path to bring them back in if we have effective combination regimens like this that really show more definitive efficacy.
Maddocks: Yeah, I think this is really interesting too because they plan on looking at not just response-adapted [reduction], but potentially receiving no chemoimmunotherapy with this non-chemotherapy approach. So we'll look forward to longer follow-up on this study and further results. As you mentioned Dr. Sawalha, hopefully in larger populations of patients in a multicenter fashion.