May 27, 2022
Dr. John Sweetenham, of the UT Southwestern’s Harold C. Simmons Comprehensive Cancer Center, and Dr. Marc Braunstein, of NYU Langone Health, discuss key data from the CAPTIVATE and GRIFFIN trials and other compelling studies in hematologic malignancies featured at the 2022 ASCO Annual Meeting.
Dr. John Sweetenham: Hello. I'm John Sweetenham, the associate director for Clinical Affairs at UT Southwestern Harold C. Simmons Comprehensive Cancer Center and host of the ASCO Daily News podcast.
For my guest today, I'm pleased to introduce Dr. Marc Braunstein, a hematologist, and oncologist at NYU Perlmutter Cancer Center. We'll be discussing key posters on advances in hematologic malignancies that will be featured at the 2022 ASCO Annual Meeting.
Our full disclosures are available in the show notes and disclosures of all guests on the podcast can be found on our transcripts at asco.org/podcasts.
Marc, it's great to have you on the podcast today.
Dr. Marc Braunstein: Thank you, John. It’s a pleasure to be here.
Dr. John Sweetenham: So, Marc, there are going to be some very interesting abstracts with some provocative results presented at the ASCO Annual Meeting this year. I know we've selected a number of these to speak about today, beginning with Abstract 8027 on the subject of multiple myeloma. And this I think is a long-term follow-up study for long-term survivors of multiple myeloma more than 12 years out now. Can you comment on this and let us know what you believe the key takehomes from this study are?
Dr. Marc Braunstein: Sure. Absolutely, John. So, this was a prospective registry that has been in place since 2009, and it's composed of various practice settings, but primarily community practices where most patients get their myeloma care. And what they did was they looked at about 1,400 patients with newly diagnosed multiple myeloma across 250 sites in the U.S. between 2009 and 2011 who were included in the registry. The participants also filled out the quality-of-life surveys, and they compared a group of long-term survivors who had more than 8 years of follow-up to patients who were not long-term survivors below that 8-year threshold.
So, about 20% were in the long-term survival group and 80% in the non-long term survival group. And they basically characterized those 2 groups. What they found was that the individuals who did have long-term survival were generally younger—median age of 62 versus 68, and had better performance status, were more likely to receive stem cell transplants, about 66 versus 60%.
And therefore, the implication of this is that patients who fit those criteria may have a better prognosis in addition to the other cytogenetics and other factors we use as prognostic indicators. And what was also interesting was that the 8-year overall survival of the overall group was about 36%.
So, we still have room to go in terms of bringing new therapies to extend survival in this condition. And only 20% of the total population were long-term survivors at that 8-year threshold. So, those were the general findings of the abstract.
Dr. John Sweetenham: Do you think it gives us new information on patient selection for more intensive therapies upfront?
Dr. Marc Braunstein: Well, I think it certainly tells us which patients are more likely to have longer-term survival. I think we know in multiple myeloma that it's essential to really use the patient's presenting features, their disease features, their comorbidities, and their degree of fitness or frailty to guide how intensive a therapy or regimen we can devise for that individual patient. But I think it certainly says that if you have a patient who is on the younger side of the spectrum, who is eligible for stem cell transplant, who has a better performance status, those are the patients that are more likely to have the long-term survival. It doesn't necessarily say that if you're not in that category, you won't have long-term survival, but on average, those were the patients who fared better in the long term.
Dr. John Sweetenham: Okay. So, staying for a little while on the subject of multiple myeloma, Abstract 8037 is really addressing a very different question. It's the application of circulating tumor DNA analysis and its association with relapse in patients with refractory myeloma. Would you comment a little on this and maybe let us know what you think the significance of this will be for the future?
Dr. Marc Braunstein: Sure. My colleagues in the solid tumor space are using circulating tumor DNA regularly and in the myeloma field, we're a little bit jealous of them.
So, it's helpful to have a study like this that's looking at circulating peripheral blood markers, in this case circulating tumor DNA, to help guide various prognostic or predictive indices that will help us guide therapeutic decisions.
So, this was a study where they looked at patients who were enrolled in a phase 2 study of a free-drug regimen of carfilzomib-thalidomide-dexamethasone the MM17 study, and they took 50 transplant eligible multiple myeloma patients who were refractory to their first line of therapy, and they collected bone marrow samples and peripheral blood at 3 time points at the third cycle of treatment and at the end of the study or at the point of refractoriness to that regimen.
They collected about 187 samples in total. They used a sequencing technique to determine the variance of 22 gene signatures known to be mutated in multiple myeloma. And what they found was a particular gene signature that was associated with shorter progression-free and overall survival in that phase 2 study. And those genes included known oncogenic drivers, including BRAF genes, ATM, and P53.
What was particularly interesting among the circulating tumor DNA mutations was that they were found in about 88% of patients at the start of the study. So, what that tells us is, number 1, circulating tumor DNA offers a wealth of information that can be highly valuable in multiple myeloma, which is a disease where we typically rely on the bone marrow to assess the status of the plasma cells and status of the mutation profile.
And number 2, that many of these mutations may be present earlier on in a disease that we know evolves in a clonal way that leads to disease progression. So, I think there's still a lot of information we have to learn about the utility of circulating tumor DNA in myeloma, but this study certainly shows that there's a lot to be explored in terms of the mutational profile and peripheral blood in myeloma.
Dr. John Sweetenham: A couple of questions that arise for me out of this study. First of all, do you think this is going to have any implications for future study design and patient selection?
Dr. Marc Braunstein: Definitely. I think the whole field in multiple myeloma is progressing quickly in terms of how we assess response, how we use minimal residual disease, and moving more towards using novel markers in peripheral blood, including mass spectrometry, and now perhaps circulating tumor DNA to look at surrogate markers for survival.
And so, what this abstract is showing is that we could potentially use circulating tumor DNA both as prognostic markers, potentially as disease response markers, and prognostic markers to guide which patients may be more likely to have shorter survival. So, I think this has a lot of implications for how we design future studies.
Dr. John Sweetenham: Yeah. And the second question, do you think this is the beginning of the end of bone marrow analysis in multiple myeloma?
Dr. Marc Braunstein: So, I can tell you if it is, patients I think will be very happy and so will clinicians because we really want to know at the core what the degree of residual disease is in a patient. And right now, the only way to do that is through a bone marrow biopsy.
And so, I think that this is the beginning of the use of peripheral blood studies with higher resolution to allow us to gain more information on patients that hopefully will allow us to obviate the need for more invasive testing like bone marrow biopsies.
Dr. John Sweetenham: Yeah, absolutely. Thanks. Just changing gears now, moving on to Abstract 7050. This is an abstract that addresses what I think we'd all agree is becoming an increasingly important question in the management of chronic myeloid leukemia (CML), and that is number 1, is it safe to discontinue therapy in responding patients? And number 2, when is it safe to discontinue that therapy?
Dr. Marc Braunstein: So, this is an abstract that is looking primarily at CML. You know that we're making a lot of progress when we can begin to talk about discontinuation and de-escalation of therapy.
And so, in the field of CML, the use of tyrosine kinase inhibitors (TKIs) and the targeting of the BCR-ABL mutation has brought about tremendous progress in patients in the chronic phase.
So, there have been several retrospective studies that have looked at the role of discontinuing one of the TKIs. Most of the studies have focused on imatinib since that was the first one that was discovered, but they've looked at others in the class as well.
What struck me the most is that there's a remarkable consistency between these studies. So, when you discontinue one of these TKIs, the percentage of patients who remain in remission is somewhere between 40 to 50%. And what this abstract looked at was a single institution retrospective assessment of 284 patients with CML, between 1999 and 2017, who were treated with a TKI for their CML and then subsequently discontinued the therapy.
Now, what's worth noting in the various studies that have looked at discontinuation therapy is that patients who were taken off of the TKI generally were in a good molecular remission, MR 4 or 4.5, for at least 2 or 3 years. And in this study, about 70% of patients had electively discontinued and 24% of patients stopped due to adverse events.
So, it wasn't necessarily guided by their response to treatment at the time of discontinuation. What they found actually was fairly consistent with the literature that at a median follow-up of 36 months after TKI discontinuation, about 19% lost their molecular remission and 88% had achieved a molecular remission after resuming therapy. And that is consistent with the literature that fortunately, even if a patient loses their molecular remission off of the TKI therapy, the majority of patients will go back into molecular remission when you re-challenge them.
Dr. John Sweetenham: Important data, indeed. And you know, on something of a similar theme, the next abstract that we're going to look at is the Abstract 7519. In this case, in chronic lymphocytic leukemia (CLL), and certainly, those of us who remember when ibrutinib was initially introduced into the second-line treatment of CLL, didn't really know whether discontinuation or fixed duration treatment with agents like this was going to be something that we could pursue or whether treatment with these drugs was going to be indefinite. This abstract certainly addresses that specific question, and again, I’m interested in your insights into this.
Dr. Marc Braunstein: Sure. So, this is an abstract looking at CLL, where we've really begun to move away from chemotherapy, and we have a variety of targeted oral therapies that target the underlying pathology of this leukemia.
And so, as you mentioned, ibrutinib is approved both in the relapsed and more recently in the frontline setting, wherein the RESONATE-2 study that was published in the New England Journal of Medicine in 2015, there was actually an overall survival benefit of ibrutinib even in higher-risk patients.
So, the CAPTIVATE study is an ongoing phase 2 study that is looking at whether we can improve the efficacy of single-agent ibrutinib in the first-line setting when combined with venetoclax.
Ibrutinib targets protein tyrosine kinase and venetoclax targets Bcl-2, and that combination is hypothesized to further weaken the resistance of CLL and lead to better outcomes.
So, this was a multicenter phase 2 study. And in this abstract, they looked at the 3-year follow-up of patients who were actually able to discontinue therapy on this regimen. So, just as a bit of background, ibrutinib is typically continued until progression, and venetoclax as it's been studied in the first-line setting with obinutuzumab is given for about 12 months.
So, in this study, at 3-year follow-up, they looked at the patients in the cohort who were off therapy and looked at the percentage of patients who maintained a complete remission at 3 years. And that complete remission rate was about 57%.
The majority of patients, greater than 95% of patients, were alive at 3 years even in the high-risk cohort. So, I think the implications of the study is that upfront or oral targeted therapies when you combine ibrutinib and venetoclax really produce tremendous responses that are durable, and it's found even in the high-risk patients who are expected not to do quite as well at 3 years.
Dr. John Sweetenham: Yeah, I agree. I think it's very reassuring actually to see these durable responses with this fixed duration regimen. And to conclude, Abstract 8011 was an abstract which addressed treatment in the first-line setting for multiple myeloma. And again, I wonder if you could comment on this study.
Dr. Marc Braunstein: Sure! So, this is a study looking at the GRIFFIN regimen, which was a phase 2 randomized study of daratumumab (DARA), plus lenalidomide, bortezomib, and dexamethasone.
So, DARA RVd versus RVd alone. In that study, the primary endpoint was stringent, complete remission, and it has been previously presented and published that the stringent complete remission (CR) rate was significantly improved, 42% versus 32%, when you include daratumumab upfront.
In this abstract, they looked at the sustained rate of minimal residual disease negativity, which is basically the deepest possible remission you can achieve in upfront therapy and in myeloma.
What they found was that, again, when you looked at the quadruplet regimen versus the triplet regimen, the rates of minimum residual disease (MRD) negativity were just improved with the quad regimen.
So, at a median follow-up of 38.6 months, there were about 54 versus 20% of patients who were MRD negative at 12 months amongst the patients who had achieved a CR, and 59 versus 17% MRD negative among the patients who achieved a stringent CR favoring the daratumumab arm.
So, I think this abstract shows the benefit of including a monoclonal antibody upfront in newly diagnosed patients with myeloma combined with stem cell transplant and maintenance, allowing for sustained MRD negativity.
Dr. John Sweetenham: Do you think this represents a new standard of care?
Dr. Marc Braunstein: I do. At our institution, we've adopted this regimen for most newly diagnosed transplant-eligible patients. I think the data clearly show an improved depth of response and MRD negativity rates, and I think that there are a number of ongoing studies looking at the role of monoclonal antibodies in the maintenance phase as well.
I'm especially excited this year, at ASCO Annual Meeting there's a plenary session involving myeloma looking at patients who received RVd upfront and then went for transplant. But I think we can improve on that regimen by including monoclonal antibodies and immunotherapies upfront, and I do think it represents a new era of immunotherapies in multiple myeloma.
Dr. John Sweetenham: Well, thanks, Marc. I mean, to your last point, it sounds as if there is a lot, including these abstracts, to look forward to at the upcoming ASCO meeting. So, we really appreciate you sharing your insights into these abstracts with us today.
Dr. Marc Braunstein: Sure. My pleasure. Thank you for having me, John.
Dr. John Sweetenham: And thank you to our listeners for joining us today. You'll find links to the abstract discussed today on 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.
Disclosures:
Dr. John Sweetenham:
Consulting or Advisory Role: EMA Wellness
Dr. Marc Braunstein:
Consulting or Advisory Role: Celgene, Janssen, AstraZeneca, Amgen, Takeda, Verastem, Celgene, Janssen, Karyopharm Therapeutics, Epizyme, Morphosys, Takeda, Pfizer
Research Funding (Inst): Janssen, Celgene/BMS
Travel, Accommodations, Expenses: Takeda
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