Jun 2024
22m 10s
Drs. John Sweetenham and Marc Braunstein discuss practice-changing studies in hematologic malignancies that were featured at the 2024 ASCO Annual Meeting, including the ASC4FIRST trial in chronic myeloid leukemia and IMROZ and CARTITUDE-4 in multiple myeloma.
TRANSCRIPT
Dr. John Sweetenham: Hello, I'm Dr. John Sweetenham from UT Southwestern’s Harold C. Simmons Comprehensive Cancer Center and host of the ASCO Daily News Podcast. On today's episode, we'll be discussing practice-changing abstracts and other key advances in hematological malignancies that were featured at the 2024 ASCO Annual Meeting. Joining me for this discussion is an old friend, Dr. Marc Braunstein, a hematologist and oncologist from the NYU Langone Perlmutter Cancer Center.
Our full disclosures are available in the transcript of this episode.
Marc, it’s great to have you back on the podcast again. There were some important studies in the heme space at the Annual Meeting this year, and we're very pleased that you're able to share your takeaways.
Dr. Marc Braunstein: Thank you, John. It's great to be back again.
Dr. John Sweetenham: Let's start out, Marc, with LBA6500. This abstract reports the primary results of the ASC4FIRST trial, and this was a trial comparing asciminib with investigator selected tyrosine kinase inhibitors in newly diagnosed patients with chronic myeloid leukemia. Could you tell us a little about the trial and how you think it's going to impact clinical practice?
Dr. Marc Braunstein: Absolutely. So, asciminib is an oral tyrosine kinase of the ABL kinase domain. As we know in CML, the BCR-ABL translocation is characteristic of the disease, and asciminib is approved for chronic phase CML with a T315I resistance mutation or for patients who have received 2 or more prior lines of therapy. So the ASC4FIRST trial was a randomized trial of 405 patients with newly diagnosed chronic phase CML who are randomized one to one to receive either asciminib at 80 milligrams once daily, or investigator’s choice of a first generation TKI imatinib or one of three second generation TKIs nilotinib, dasatinib, or bosutinib. The primary endpoint of the study was the major molecular response, or MMR, at 48 weeks. Pretty much, the study met its primary endpoint with a 67% rate of MMR at 48 weeks, with asciminib versus 49% in patients treated with the investigator's choice of TKI. And in addition, the major molecular remission or MMR of 4.5, which is a deep remission, those rates were higher as well, with asciminib versus investigator’s choice at a rate of 39% versus 21% when comparing the groups. Furthermore, when we looked at toxicity, there were fewer grade 3 or higher adverse events, with the asciminib at 38% versus either 44% with the first generation, or 55% with the second generation TKI, and fewer discontinuations as well with asciminib.
So I think this abstract is practice-changing. I think it offers compelling data to use asciminib upfront for chronic phase CML. Those who don't agree with that sentiment might argue that we want to see longer term follow up. There's a planned follow-up at 96 weeks. We would want to see the rate of progression to acute myeloid leukemia and of course overall survival as well. But I think the abstract certainly shows an improvement in outcomes with asciminib versus our current array of TKIs.
Dr. John Sweetenham: Yeah, I think it certainly is, at least at minimum, potentially practice changing. I agree with you. Just one question, and this may be a little bit speculative, but do you have any thoughts about treatment free survival with asciminib and how that might line up against some of the other TKIs?
Dr. Marc Braunstein: Yeah, that's a great question. The abstract did not necessarily address that, patients were treated until progression, but we know that with the current landscape of TKIs, that in patients who have achieved a deep MR of 4 or 4.5 for at least 2 years who discontinue their TKI, the rate of relapse is about 50%. The current study, the ASC4FIRST, doesn't address that, but I think it's a really good question about whether, for those patients who have achieved a deep remission, whether they can eventually stop asciminib down the line.
Dr. John Sweetenham: Yeah, I guess it's one of those ‘watch this space’ things.
So we'll see how the data mature out. And let's move on to what I think is another potentially practice-changing study, at least in certain parts of the world. And that's [the] LBA7000 study in classical Hodgkin lymphoma. As you remember, this was a German Hodgkin lymphoma study group trial which looked at the tolerability and efficacy of a novel regimen, BrECADD versus eBEACOPP for patients with advanced stage classical Hodgkin lymphoma in their study, which is known as GHSG HD21. Can you give us your thoughts and take home messages from this trial?
Dr. Marc Braunstein: Yeah, John, absolutely. So the German HD21 study is a phase 3 study of 1,500 patients with classical Hodgkin lymphoma. The majority were stage 3 or 4, 84%, that compared two regimens BEACOPP to BrECADD. The major difference between these 2 groups being that the newer BrECADD regimen swaps out bleomycin for brentuximab vedotin, which is an anti-CD30 antibody drug conjugate. Also, in the BrECADD regimen they eliminate vincristine that's incorporated into BEACOPP. Those are kind of the global differences between these 2 regimens. And when comparing these, they looked at the primary endpoint of progression-free survival. Of note, in this study there was a PET adjusted approach where if patients achieved interim PET negativity after 2 cycles, that was followed by an additional 2 cycles of their treatment as opposed to 4 cycles if they were PET positive after the initial 2 cycles of their respective treatment. And of note, there were similar rates of PET2 negativity between both arms, about 58% in both arms.
So at a median follow-up of 48 months, the 4-year progression-free survival was significantly better with the brentuximab containing BrECADD regimen at 94% versus 91% with a hazard ratio of 0.66. And the overall survival of the BrECADD arm was 98.6%, which is very high and impressive. The 4-year overall survival was similar between the arms at around 98%, but of note, there were fewer severe adverse events with BrECADD, the brentuximab containing arm versus BEACOPP at about 42% versus 59% and interestingly less peripheral neuropathy with the brentuximab containing BrECADD. So we're doing extremely well in treating advanced stage classical Hodgkin lymphoma. So the bar is set very high. But in this study, the rates of progression-free survival and overall survival are very impressive.
While these intensive regimens tend to be used outside of the U.S., there are several notable benefits of the study, including greater than 50% PET2 negativity and high rates of progression-free survival at 4 years. In discussing this abstract, it's worth noting that there are other competing regimens, if you want to call it that, that are more commonly used in the U.S. So the ECHELON-1 study looked at brentuximab AVD compared with ABVD with bleomycin and it was a 94% versus 89% 6-year overall survival rate favoring the brentuximab containing A+AVD regimen. And lastly, more recently, the SWOG S1826 study that hasn't been published but was presented in abstract form looked at nivolumab AVD versus brentuximab AVD at a median follow up of 12 months showed a progression-free survival of 94% versus 86%. And that study still has yet to be published and needs to mature. But both of those regimens are in the NCCN guidelines. So, we're definitely pushing the bar higher in terms of improving responses in treating advanced classical Hodgkin lymphoma.
Dr. John Sweetenham: I think that there's no question that these results from BrECADD are very impressive. But I'm taken back to what I think has been a kind of philosophic discussion in Hodgkin lymphoma now for a number of years about balancing disease control and efficacy against the potential short-term and long-term toxicity of the regimens, particularly when you have very effective salvage therapies for those patients who may suffer a relapse. So I think that this is a discussion over whether you take a very intensive, upfront approach to Hodgkin lymphoma versus something that may be less and slightly less intensive. I suspect that's a discussion that's going to continue for a long time. I don't know what you feel, but my own feeling about this is that this study will likely have a major influence over treatment of Hodgkin lymphoma, particularly in western Europe. Less likely in the US.., I would think. I don't know what your thoughts about that are.
Dr. Marc Braunstein: Well, it's a great question. In SWOG S1826, that study did include pediatric patients. In HD21, the median age was 31 and did not include pediatric patients. So I think we have to be selective in terms of fitness and which patients may be better suited for different regimens. But I think what all these studies show is certainly when we incorporate novel immunotherapies, whether it's brentuximab vedotin, nivolumab, we improve progression-free survival and even overall survival.
Dr. John Sweetenham: Absolutely.
So let's shift gears now and take a look at Abstract 7500, the IMROZ study. This was the study of isatuximab, bortezomib, lenalidomide and dexamethasone versus VRD alone for transplant ineligible patients with newly diagnosed multiple myeloma. I know we discussed this in our preview podcast a few weeks back, Marc, but I just wonder now, having seen the data in more detail, what do you think of the important takeaways? And again, are we looking at a new standard of care?
Dr. Marc Braunstein: You know, there are many standards of care in multiple myeloma, but we're always looking to make improvements on the regimens we have at our disposal. So, just to recap, IMROZ is a phase 3 randomized study of the anti-CD38 monoclonal antibody isatuximab with the backbone of bortezomib, lenalidomide, dexamethasone or VRD versus VRD alone, specifically, in transplant ineligible newly diagnosed multiple myeloma patients age less than 80. They studied 446 patients in this study, randomized 3 to 2 to Isa-VRD versus VRD alone, with the primary endpoint of progression free survival. Now, similar to other studies where they included a monoclonal antibody up front, the study met its primary endpoint of improving progression-free survival with the quad regimen containing the monoclonal antibody isatuximab versus VRD alone.
So what was interesting about the study, it's really the first of its kind to be presented that specifically looked at transplant ineligible patients, which is presumably a less fit or perhaps more frail population that wouldn't go on to consolidation with stem cell transplant. And in this study, the progression-free survival at 5 years was 63% versus 45%, clearly superior when you included isatuximab. And the rates of complete remission and MRD negativity were all significantly improved, too. However, that was also met with slightly more grade 3 or higher treatment emergent adverse events, 92% versus 84% in the control arm. There are also 11% grade 5 treatment emergent adverse events with the isatuximab group versus 5.5% with VRD alone. Although there was no major difference in treatment discontinuation. One small caveat worth noting, too, is that high-risk patients in this study, when presented at ASCO, did not necessarily show a difference in benefit, although there wasn't necessarily a detriment either.
So, John, I think that clearly quadruplet regimens are superior in outcomes of efficacy to triplets, even in transplant-ineligible patients. But I think we have to tailor these treatments to individual patients because I think when it comes to transplant-ineligible patients, it's a spectrum of patients who may be more or less fit for quad regimens versus triplet regimens. It's also worth noting, though, that in this study, the patients are really only getting a quad regimen for 4 cycles. They get their Isa-VRD, and then you drop the bortezomib. So when we think about quads, it's not that they're getting the quad regimen indefinitely, it's really for the induction cycles. But still, I think we have to be aware of potential safety issues.
Dr. John Sweetenham: Okay, great. And let's stay on the theme of multiple myeloma, Marc, and talk a little bit about Abstract 7504, which was a subgroup analysis of the CARTITUDE-4 study. This is a report on the use of ciltacabtagene autoleucel versus standard of care in patients with functional high risk multiple myeloma. Can you give us your thoughts on this and maybe put it into a bit of context for us?
Dr. Marc Braunstein: Absolutely, John. It's really a great time to be in the field of multiple myeloma. We're making tremendous progress, but when we think about one of the unmet needs, it's just consistently the high-risk patients who have shorter responses and are at higher risk for poorer outcomes. Just to review, cilta-cel is one of the 2 available anti-BCMA CAR T-cell products available for the treatment of relapsed or refractory multiple myeloma. Very recently, the FDA approved cilta-cel for lenalidomide refractory patients after 2 or more prior lines of therapy based on the CARTITUDE-4 study, which was published by San-Miguel and colleagues in New England Journal of Medicine in July 2023. And that study randomized 419 patients with multiple myeloma with 1 to 3 prior lines of therapy to receive either cilta-cel or physician's choice of standard of care, which was either 1 of 2 triplet regimens, a pomalidomide, bortezomib, dexamethasone or daratumumab, pomalidomide and dexamethasone. It's worth noting that about 25% of the patients in the CARTITUDE-4 study had prior anti-CD38 antibody treatment previously and the carfilzomib was not included in one of the standard-of-care arms, and we know that those regimens containing carfilzomib do increase survival in relapsed myeloma.
Nevertheless, the primary outcome of progression-free survival was not reached in the CAR T-cell arm versus 11.8 months in the standard-of-care arm, with a significant reduction in progression of 74%. So clearly a positive study and CAR T-cell therapy is included in the NCCN guidelines for patients who have an early relapse from their myeloma. The current abstract by Costa et al focused specifically on a subgroup of 79 patients from CARTITUDE-4 in second line of treatment and looked at what they called functional high-risk myeloma, defined as progression of disease within 18 months of initial treatment or after stem cell transplant. Again, the study showed a retained benefit of cilta-cel with significant improvement in progression-free survival either not reached or 12 months with the control standard of care arm, as well as complete remission rate and rates of MRD negativity of 65% versus 10% in the control.
The overall survival outcome was still immature and not presented. Nevertheless, cilta-cel is clearly superior to standard-of-care triplet regimens. I think that for patients with high risk, they clearly derive a benefit from CAR T-cell therapy if they have short progression-free survival after initial therapy.
Dr. John Sweetenham: Thanks, Marc. So let's round this out by talking about another area of unmet need, I guess in a way in a difficult to treat patient group. And that's Abstract 7007, the SYMPATICO study. This is a study which looks at the efficacy and safety of ibrutinib and venetoclax in patients with mantle cell lymphoma who had a mutated TP53. Can you just briefly review this for us and tell us what you think we should be taking away from this studys?
Dr. Marc Braunstein: So, mantle cell lymphoma typically has an aggressive behavior, but the subgroup of patients with a P53 mutation tend to have the poorest outcomes and do represent an area of unmet need. Although BTK inhibitors are making important improvements in mantle cell lymphoma, they have yet to be approved in newly diagnosed mantle cell lymphoma. Acalibutinib and zanubrutinib are FDA-approved BTK inhibitors for previously treated mantle cell lymphoma. Ibrutinib was withdrawn from the market in the U.S. for mantle cell lymphoma. Dr. Michael Wang's group presented late-breaking data from the phase 3 SYMPATICO trial at ASH 2023, in which 267 patients with relapsed refractory mantle cell lymphoma were randomized to receive either ibrutinib plus the BCL2 inhibitor venetoclax or ibrutinib plus placebo after 1 to 5 prior lines of therapy. And that study showed a 32 versus 22 months progression-free survival at a median follow up of 51 months.
The current abstract, also by Dr. Wang and colleagues, looked at the subgroup of patients who had a P53 mutation and included an open label cohort of 44 patients in the first line of treatment and a relapse refractory cohort of 75 patients, and compared this subgroup of patients with P53 mutation to those without. When we look at the outcomes, the patients who did not have a P53 mutation clearly did better in terms of progression-free survival being not reached in first-line treatment compared to 22 months progression-free survival in those patients with first-line [treatment] with a P53 mutation. As well as in the relapsed refractory setting, the PFS without the P53 mutation was 47 months versus 21 months with the mutation. However, when you look at these patients treated with ibrutinib and venetoclax comparing whether they got treated in first line or the relapse refractory setting, the overall response rates are very similar at about 80% to 90% and the CR rates were very similar at about 55% to 58%, which to me suggests that although patients with P53 mutation do worse than those without it, whether they're treated in the first-line or the relapse setting with this combination of venetoclax, they tend to do somewhat similar, suggesting that you can overcome resistance to prior therapy in the relapse setting. So I think further data are certainly warranted to explore the role of combination therapies that include novel agents such as BTK inhibitors in the first line setting.
It's worth noting that the TRIANGLE study was recently published, and this study looked at including ibrutinib at various phases, including at induction in combination with intensive chemotherapy and during the maintenance phase. And that study showed encouraging outcomes in patients who received ibrutinib even without stem cell transplant compared to those who received stem cell transplant. So the role of BTKIs in mantle cell lymphoma is certainly evolving, and I think it offers a very effective intervention without the same kind of toxicities we see with cytotoxic chemotherapy that's traditionally used in mantle cell lymphoma. But I think the subgroup of patients with P53 mutation in this disease still represent an area of unmet need that unfortunately have worse outcomes. But novel agents may be able to overcome some of those adverse outcomes.
Dr. John Sweetenham: Yeah, I agree. I think these are intriguing data, and obviously it needs more follow-up and probably more prospective studies. But nevertheless, I think there are some signals there for sure that need to be followed up on.
Marc, as always, it's great to have your insights on key advances in the heme space from ASCO. An important year this year, and we really appreciate your time and effort in sharing with us your thoughts on what we've learned this year. So thank you as always.
Dr. Marc Braunstein: My pleasure.
Dr. John Sweetenham: And thank you to our listeners for joining us today. You'll find links to the abstract discussed today in the transcript of this episode. Finally, if you value the insights that you hear on the ASCO Daily News Podcast, please take a moment to rate, review and subscribe wherever you get your podcasts.
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Disclosures:
Dr. John Sweetenham:
Consulting or Advisory Role: EMA Wellness
Dr. Marc Braunstein:
Consulting or Advisory Role: Pfizer, Bristol-Myers Squibb/Celgene, Adaptive Biotechnologies, GlaxoSmithKline, ADC Therapeutics, Janssen Oncology, Abbvie, Guidepoint Global, Epizyme, Sanofi, CTI BioPharma Corp
Speakers’ Bureau: Janssen Oncology
Research Funding (Institution): Janssen, Celgene/BMS