ASCO Daily News Novel Approaches in Hematologic Malignancies at ASCO24
Dr. John Sweetenham and Dr. Marc Braunstein look ahead at key abstracts across the spectrum of hematologic malignancies that will be presented at the 2024 ASCO Annual Meeting, including the OPTIC trial in chronic myeloid leukemia, treatment options for transplant-ineligible patients with multiple myeloma, and the 7-year analysis of the ECHELON-1 trial in classical Hodgkin lymphoma.
TRANSCRIPT
Dr. John Sweetenham: Hello, I'm Dr. John Sweetenham from UT Southwestern's Harold C. Simmons Comprehensive Cancer Center and the host of the ASCO Daily News Podcast. I'm delighted to be joined again this year by Dr. Marc Braunstein, a hematologist and oncologist at the NYU Perlmutter Cancer Center in New York. We're going to be discussing some of the key abstracts in hematologic malignancies that will be featured at the 2024 ASCO Annual Meeting.
Our full disclosures are available in the transcript of this episode, and disclosures of all guests on the podcast are available at asco.org/DNpod.
Marc, it's great to have you back on the podcast.
Dr. Marc Braunstein: It's a pleasure to be back, John.
Dr. John Sweetenham: There are some exciting abstracts to be presented at this year's meeting, and I would like to begin, if we can, with Abstract 6501. As you know, this reports the four-year results from the OPTIC trial of ponatinib in patients with chronic-phase CML and the T315I mutation. Can you tell us about the trial and about these latest follow-up results?
Dr. Marc Braunstein: Sure. Well, we've made tremendous progress in managing patients with CML in the past two decades using these oral tyrosine kinase inhibitors such as ponatinib. Ponatinib is a third-generation TKI that has activity in both Philadelphia-positive ALL as well as CML, and can overcome the resistance mutation you mentioned, called the T315I mutation, which is sometimes found following prior TKI therapy. The OPTIC study is a multicenter phase 2 randomized study of various doses of ponatinib in 283 chronic phase CML patients who had received 2 or more prior lines of therapy or those who had the presence of a T315I mutation, with the current analysis examining the major remission at 48 months, PFS, as well as OS. Of note, in this study, after patients have achieved a major remission with a transcript level of 1% or less, the study allowed for dose reduction of ponatinib from the original dose of either 45 milligrams or 30 milligrams to a reduced dose of 15 milligrams.
So, when we look at the results, we find that the patients who had the highest overall response rates and higher rates of molecular remission were those who received the 45-milligram dose. And remember, these patients were allowed to be dose-reduced to the 15-milligram dose once they achieved a molecular remission of 1% or less. In addition, the rates of overall survival were highest in the 45-milligram dose as well. When looking at the T315I subgroup, the rates of molecular remission, the depth of remission, and the rates of progression-free survival, in general, were lower in that subgroup, but still higher in the 45-milligram dose than the 35- milligram dose.
Furthermore, when looking at the rates of treatment-emergent adverse events leading to discontinuation, they were 8% in the 45-milligram dose compared to 14% in the 30-milligram dose and 5% in the patients who only received the 15-milligram dose. The authors have concluded that the 45-milligram dose, with the potential to be reduced to 15 milligrams after achieving 1% or less of the BCR-ABL transcript level, seems to be the right balance between efficacy and safety.
Dr. John Sweetenham: Thanks, Marc. In the longer term, do you think that this study will, in any way, affect the position of ponatinib in the treatment algorithm for CML? Is it going to remain as a second or third-line option, or do you think there's any chance it will be moved up?
Dr. Marc Braunstein: Well, that's a great question. There are other TKIs, such as asciminib, that also target the T315I mutation, and that mutation tends to develop after prior first-line or second-line TKI therapy. But given its activity in both ALL and CML, I think it's certainly reasonable to expect that ponatinib will be used in earlier lines of therapy given its efficacy in later lines.
Dr. John Sweetenham: Let's change gears and move the focus to acute myeloid leukemia. There has been a lot of discussion around frailty in many different malignancies, but the impact of frailty on outcomes in AML is maybe something that hasn't been quite so well studied. In Abstract 6506, investigators did a population-based study in Ontario, Canada, that assessed the patient's frailty risk and the impact that might have on outcomes. What are your takeaways from this study, and how do you think these data will help optimize treatment decisions?
Dr. Marc Braunstein: Yeah, I'm glad we're talking about this abstract John, because frailty scores are increasingly being used in hematologic malignancies to help guide goals and intensity of care. And as opposed to using age or performance status alone, these composite frailty assessment tools, such as the MFI tool that they used in this particular study, take into account multiple variables that are both physiologic, such as the patient's comorbidities, as well as social, and what kind of support system do they have, and things of that nature. And that accounts for their overall fitness. So, in this retrospective cohort study that was a population-based study in Ontario between 2006 and 2021, they looked at 5,450 patients retrospectively with acute leukemia and grouped those patients into 3 categories based on this frailty index. Patients who are either fit, somewhere in the middle between fit or frail, which they call pre-frail, or frail. And they looked at outcomes such as overall survival, comparing patients who got intensive chemotherapy regimens for induction or those who got non-intensive therapy for induction. Patients in either group could have been assigned to either fit, pre-frail, or frail although there are much more fit patients than those who got intensive induction.
And so, looking at their findings, it was noted that patients who were in the frail category, not entirely unexpectedly, had lower overall survival when compared to those who were fit or pre-frail. I think the value of a study like this is not just to highlight the benefit of frailty scores to help predict which patients may ultimately have a shorter survival, but also to help potentially guide which patients may be more suitable for intensive versus less intensive induction. I will note that this study was conducted in an era where we didn't have the same sorts of less intensive induction that are very effective in less fit patients, such as the combination of azacytidine and venetoclax, which is commonly used in less fit patients nowadays. So, the study may encompass patients who didn't have access to that therapy because it wasn't available during that time. But I think it still, overall, does highlight the fact that assessing fitness or frailty in acute myeloid leukemia is important for predictive value.
Dr. John Sweetenham: I agree. Marc, I don't know what your thoughts are on this, but it goes either way. I mean, I think that, if I remember the numbers correctly, 25% of fit patients received non-intensive therapy. So, is there a missed opportunity there for that group of patients who actually may have tolerated the intensive therapy but it was never offered?
Dr. Marc Braunstein: That's an excellent point, John, and I think that highlights the importance of frailty indices because they take into account much more than one particular factor, or even just a subjective assessment of the patient in real time when they're first presenting. And they may have disease-specific features that are decreasing, say one element of their assessment such as their performance status. So, really taking these composite fitness scores into account may actually allow you to escalate therapy in a patient who may actually be fit but maybe perceived as less fit when they present.
Dr. John Sweetenham: Yeah. So, I think, as you mentioned, there are better treatment options out there now maybe than there were at the time this study was conducted. Nevertheless, there may still be that opportunity for more intensive therapy for some of these patients when they are more holistically assessed.
Let's move on and switch gears once again and talk about a study in multiple myeloma, the so-called IMROZ study, which is Abstract 7500. So, this is a study looking at treatment options for transplant-ineligible patients with newly diagnosed multiple myeloma. Some of these patients may not have a chance for subsequent therapy if they are not eligible for transplant. What are your thoughts on this study? Do you think we're closer to a new standard of care for patients who are not going to proceed to an autologous stem cell transplant?
Dr. Marc Braunstein: It seems like every year there's a new standard of care for newly diagnosed multiple myeloma because there's so much data emerging, which is just wonderful. So, I think as background, at the 2023 ASH meeting, the IsKia study was presented, which is a randomized phase 3 study in newly diagnosed transplant-eligible patients. And that was using isatuximab with carfilzomib, lenalidomide, and dexamethasone upfront and that study did show a benefit in terms of reducing minimal residual disease compared to carfilzomib, lenalidomide, and dexamethasone alone. But that study was looking at fit newly diagnosed patients who were going on to stem cell transplant. Right now, the standard of care for patients who are not eligible for transplant is generally to use a 2 or 3-drug regimen, such as daratumumab, lenalidomide, and dexamethasone, based on the phase 3 MAYA study. But this study is really unique in that it looks at using a quadruplet regimen in patients who are transplant ineligible or not intended to go for transplant.
So, the phase 3 IMROZ study was a randomized study of 446 patients that compared isatuximab, bortezomib, lenalidomide, and dexamethasone to bortezomib, lenalidomide, and dexamethasone alone. So, a quad versus a triplet regimen. The primary endpoint in this study was progression-free survival, but they also looked at secondary endpoints, such as complete response rate and minimal residual disease negativity.
Just to quickly highlight the results and then discuss the standard of care, the median duration of treatment in this study was 53 months in the quad regimen and 31 months in the control arm. At a median follow-up of about 60 months, the progression-free survival was not reached with the quad regimen versus 54 months in the triplet, and that was a significant difference. In addition, the safety profile was pretty much consistent with the class, there were a bit more grade three or higher treatment-emergent adverse events with the ESA-containing regimen, 92% versus 84%, but no difference in adverse events leading to discontinuation in either arm.
So, this study is certainly compelling in terms of using quadruplet-based regimens that contain an anti-CD38 monoclonal antibody for newly diagnosed patients who are not intended to undergo transplant. I think at the meeting, I will be interested to see the patient population that was included. Patients who are over the age of 80, for example, are excluded. So, I would like to know more about their fitness level and performance status. But I think it's clear, John, that using quad regimens over triplet regimens is just consistently superior in terms of efficacy outcomes.
Dr. John Sweetenham: Right. I guess that, even though maybe we can't focus on the specific agents right now, it looks as if quad regimens are going to be the standard of care regimens for the future in this group. Do you think that is fair?
Dr. Marc Braunstein: Very likely.
Dr. John Sweetenham: Absolutely. Well, that's a pretty challenging group of patients.
And so to move on again, let's talk about another, perhaps equally challenging group - patients with mantle cell lymphoma, particularly those who carry certain mutations. The so-called SYMPATICO study, which is reported in Abstract 7007, presents data on the efficacy and safety of ibrutinib and venetoclax in patients with mantle cell lymphoma who carry a TP53 mutation. We know that this mutation confers a high risk of early progressive disease and poorer outcomes when these patients are treated with standard chemoimmunotherapy for mantle cell. Trials to date have been limited to small single-arm studies. Can you tell us a little bit about this study and the outcomes and what you think it means for the future?
Dr. Marc Braunstein: As a background, although BTK inhibitors such as ibrutinib have yet to be approved for newly diagnosed mantle cell lymphoma, acalabrutinib and zanubrutinib, which are second-generation BTK inhibitors, are FDA-approved for previously treated mantle cell lymphoma. Ibrutinib was withdrawn from the market. The lead author of this abstract, Dr. Michael Wang, had presented a late-breaking data from the phase 3 SYMPATICO trial at ASH last year, in which 267 patients with relapsed or refractory mantle cell lymphoma after one to five prior lines of therapy were randomized to receive the combination of ibrutinib plus the BCL-2 inhibitor venetoclax or ibrutinib plus placebo. That study showed there was a 32 versus 22-month progression-free survival with a hazard ratio of 0.65 at a median follow-up of 51 months, indicating the PFS benefit of the combination of ibrutinib and venetoclax compared to ibrutinib with placebo.
So that leads us to this subgroup analysis in the current study being presented at ASCO, in which they looked at a subgroup of patients with mantle cell lymphoma who are at very high risk for treatment failure and early relapse - those are patients who have a mutation in TP53, which again is high risk for treatment failure. This abstract examined an open-label cohort of 44 first-line patients, as well as 75 patients who were in the relapse/refractory cohort, and compared to patients who either did or did not have the P53 mutation. When we look at the progression-free survival outcomes, the median progression-free survival in the first-line cohort of patients who did not have a P53 mutation was not reached, whereas those with the P53 mutation had a median progression-free survival of 22 months, which is still meaningful but still less than those who did not have a P53 mutation. Which again is not entirely unexpected. But the overall response rate of the combination of ibrutinib and venetoclax was very high at 90%, and the median duration of response was about 21 months.
Now comparing this to the relapse/refractory cohort, in those without a P53 mutation, the progression-free survival of the combination of ibrutinib and venetoclax was about 47 months versus those who don't have the P53 mutation was about 21 months with an overall response rate of 80%. I think one takeaway looking at this comparison of the first-line and relapse/refractory setting is that patients seem to do very similar in terms of overall response rate and progression-free survival, whether they were in the first line or in the later lines of treatment if they had the P53 mutation, which says that the combination of ibrutinib and venetoclax is effective no matter which phase of the disease the patient might be in, indicating its overall activity and being strong.
Dr. John Sweetenham: Yeah, I thought that was an interesting observation, actually, how similar the outcomes were in those two groups.
Dr. Marc Braunstein: No, I agree. And I think although patients with TP53 mutations did comparatively worse than those without the mutation according to progression-free survival, overall response rate, or complete remission rates, they did seem to be similar whether a patient was in first-line or relapsed refractory if they were P53 mutant and were treated with this combination. So, I think we need further data in the first line, such as the data that's awaiting publication from the TRIANGLE study, which is examining upfront ibrutinib. But certainly, BTK inhibitors have significant activity in either the first line or the relapse setting of mantle cell lymphoma.
Dr. John Sweetenham: Great. Thanks, Marc.
Let's wind up with one more abstract, and this is Abstract 7053. It's a 7-year analysis of the so-called ECHELON-1 study. This was a study comparing the standard of care, ABVD, with the same regimen with bleomycin substituted by brentuximab vedotin for patients with previously untreated advanced-stage classical Hodgkin lymphoma. The study at the time it was originally reported, resulted in a significant practice change in the first-line therapy of Hodgkin's lymphoma. We now have mature follow-up. What are your take-homes from this study?
Dr. Marc Braunstein: The ECHELON-1 study has certainly been a practice-changing clinical trial where, as you said, brentuximab with the backbone of AVD was compared to ABVD, which was the prior standard. And this was examined in newly diagnosed patients with classical Hodgkin lymphoma who were at advanced-stage, stage 3 or 4. The publication, first of the progression-free survival, and more recently, in the New England Journal of Medicine in 2022, where we saw the 6-year overall survival was 94% with the brentuximab-containing arm versus 89% in the control arm, established the brentuximab AVD, or otherwise called AAVD, as the standard of care in advanced stage newly diagnosed classical Hodgkin lymphoma. The current study is now reporting 7-year follow-up on about 1,300 randomized patients who were enrolled in this impressive study.
Though at a median follow-up of 89 months now, the 7-year overall survival was quite similar, 94% versus 89%, again favoring the brentuximab-containing arm. In particular, this was driven by patients who had stage 4 disease or those patients who were aged less than 60 in subgroup analyses. So, what I take away from this abstract in the 7-year follow-up of the ECHELON-1 is that brentuximab with AVD remains the standard of care for previously untreated advanced-stage classical Hodgkin lymphoma. It is worth noting that the SWOG S1826 study that was presented at ASCO last year compared nivolumab with AVD compared to brentuximab AVD and did show a slight PFS advantage of 94% versus 86% with nivolumab AVD. Obviously, these were different studies with different patient populations enrolled, so we're really just cross-comparing different studies. But I think brentuximab AVD, given the survival benefit that is retained now at seven years in the current abstract, still remains the standard of care for advanced-stage classical Hodgkin lymphoma. The role of immune checkpoint inhibitors like nivolumab is making headway in terms of treating newly diagnosed patients as well.
Dr. John Sweetenham: Yeah, thanks, Marc. I mean, one of the observations that I thought was of interest in this study was the outcome for patients who were PET-2 positive, when you compare AAVD and ABVD. It does seem as if even in those patients who are PET-2 positive, having had AAVD, they still apparently have a better outcome than those who received ABVD in that situation who were PET-2 positive. So, I think that's another interesting observation. I'm not quite sure what it means, except speaking to the overall superior efficacy of that regimen.
Dr. Marc Braunstein: You make a great point, John, because it's worth noting that in ECHELON-1, a PET scan was done after cycle 2, but the study was not PET-adapted. So even if you had a positive PET, you continued for the full six cycles of treatment. But PET-2 status is often used in various studies of Hodgkin lymphoma to guide whether to give additional cycles or escalate therapy. So, I think the benefit of presenting those subgroups is that even if you were PET-2 positive, you still did better by continuing on the brentuximab-containing regimen.
Dr. John Sweetenham: Yeah, exactly. I mean, the other important takeaway message, I think, is that the outcome for patients with advanced Hodgkin lymphoma seems to continue to steadily improve, which is great news and also really remarkable. And I'm excited to see there may be some additional data presented at one of the late-breaking abstracts in this year's meeting, so it will truly be interesting to see what that shows us as well.
Dr. Marc Braunstein: Incredible.
Dr. John Sweetenham: Well, Marc, as always, thank you for sharing your insights with us today on the ASCO Daily News Podcast. We look forward very much to hearing the updated data from these abstracts at the meeting.
Dr. Marc Braunstein: As do I and thank you so much for inviting me again.
Dr. John Sweetenham: And thank you to our listeners for joining us today. You'll find links to the abstracts 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