Dr. Monty Pal speaks with internationally acclaimed hematologists Dr. Vincent Rajkumar and Dr. Saad Usmani about the AQUILA trial in high-risk smoldering multiple myeloma, as well as advances in CAR-T and other evolving treatment strategies in the myeloma space.
TRANSCRIPT
Dr. Monty Pal: Hello everyone and welcome to the ASCO Daily News Podcast. I'm your host, Monty Pal. I'm a medical oncologist, underline medical oncologist, a professor, and vice chair of academic affairs at the City of Hope Comprehensive Cancer Center in Los Angeles. You're going to understand why I underlined "medical oncologist" there. I'm actually on the line today with two amazing hematologists. Today, we're going to actually explore treatments for high-risk smoldering multiple myeloma following the FDA's approval last year of daratumumab for the first-ever treatment of this indication.
Now, this is based on the AQUILA trial, and this represents a huge shift in our traditional watch-and-wait approach to active disease interception. We're going to consider whether this landmark trial published in The New England Journal translates to day-to-day practice. I think it does, and we'll certainly make an argument for that. And I'm so fortunate today to have two internationally acclaimed experts here in the conversation: Dr. Vincent Rajkumar, senior author on the manuscript, and Dr. Saad Usmani, also an expert in his own right in myeloma.
Dr. Rajkumar is the lead investigator of the AQUILA study. He's a professor of medicine and consultant in the divisions of hematology and hematopathology at the Mayo Clinic in Rochester, Minnesota. He actually chairs the Myeloma, Amyloidosis, Dysproteinemia Program. He is also editor-in-chief of the Blood Cancer Journal.
Dr. Usmani, he and I actually go way, way back. We actually did the AACR Molecular Biology in Clinical Oncology course, I want to say in 2006, so this is our 20-year anniversary, Saad. He's the chief of the myeloma service at the MSK Cancer Center and a professor of medicine at the Weill Cornell Medical College in New York.
Saad, Vincent, welcome.
Dr. Saad Usmani: Thank you so much for having me, Monty.
Dr. Vincent Rajkumar: Yeah, thanks, Monty. A pleasure to be here.
Dr. Monty Pal: Thanks. And just a quick note for our listeners, all of our disclosures are available in the transcript of this episode. First off, Saad, did I get that right? Was it 2006 when we did that course together?
Dr. Saad Usmani: Yeah, 20 years. We are coming up to our 20-year anniversary. It's remarkable to have seen our careers move the way they have, Monty.
Dr. Monty Pal: Oh my gosh. And for all the fellows who are on the line, that AACR Molecular Biology and Clinical Oncology course, it's sometimes overlooked. Wonderful primer on translational science.
Okay, now we're going to get to the heart of the matter here, the AQUILA trial. So this was a study, Vincent, that you led. I wonder if you'd walk us through the primary endpoints in the study. What are we looking at in the AQUILA trial specifically?
Dr. Vincent Rajkumar: Thanks so much. Again, as you mentioned, smoldering multiple myeloma has just been a condition that we watch and wait. And the first thing that I want to clarify here is that the AQUILA trial is looking at only a subset of smoldering multiple myeloma. That is the high-risk smoldering multiple myeloma. It was defined the way high-risk smoldering myeloma was defined at the time the trial was designed. It randomized 390 patients. One arm got daratumumab single agent in an attempt to delay progression to active myeloma and possibly prolong survival. And the other arm was the traditional observation. The primary endpoint, therefore, was time to active multiple myeloma. Other endpoints included time to when patients needed to start therapy for active multiple myeloma, which can vary based on physician judgment, and overall survival. Of course, response rate, complete response rate, and others were also endpoints.
Dr. Monty Pal: That's interesting. And you know, I wanted you to riff a little bit on this definition of high-risk smoldering myeloma. Can you tell our audience how that's sort of evolved over the years?
Dr. Vincent Rajkumar: Yes. I mean, if you step back, monoclonal gammopathy of undetermined significance has only a 1% per year risk of progression. Smoldering multiple myeloma, all comers have a 10% per year risk of progression. And over the years, trials have been done in the whole population, and then more recently, we felt we should really focus on the people with high-risk smoldering, defined as a 50-50 risk of progression in 2 years. That's like a 25% per year risk of progression in the first 2 years, which is a very high risk for the patient and something that would justify prophylactic intervention.
And that definition initially was based on just high levels of monoclonal protein like more than 3 grams, the IgA subtype of myeloma, the suppression of uninvolved immunoglobulins. Others have used bone marrow flow cytometry markers, cytogenetics. Those combinations of factors were available at the time the AQUILA trial was designed, and a select combination was used. Later on, we found that we could match almost all of that in a very simple risk stratification using just the percentage of bone marrow plasma cells, the level of the M-spike, and the free light chain ratio, all three of which are available to all patients with smoldering at the time of diagnosis. So you don't need any special testing. So more than 20% plasma cells, more than 20 for the light chain ratio, and more than 2 grams for the M-spike. If someone has any two of the three, that is high-risk smoldering multiple myeloma according to the IMWG, but that definition, of course, came in 2020 after the AQUILA trial completed accrual.
Dr. Monty Pal: That's interesting because this sort of flips the traditional paradigm where biomarkers get more and more complex as time goes on. Am I right in saying this sort of simplifies things a little bit? It uses standard laboratory or clinical parameters to gauge this category?
Dr. Vincent Rajkumar: Absolutely. People were using suppression of uninvolved immunoglobulins, and those levels are not standardized, often vary by race. Also, the other aspect was the abnormal plasma cells on flow cytometry. Again, labs define it differently. So this makes it much more simple. But the IMWG also did a separate exploratory cohort within that paper where we added cytogenetics and we added scoring systems to improve on this further. So it simplified it for regular clinical practice and for like trials. But if you have a patient in front of you, the IMWG paper also has more complex scoring systems where you can take more than 20; 21 is more than 20, so is 51. And so, you can use the actual numbers that a patient has, additional variables like cytogenetics, and get a more refined estimate of what is the true risk of progression.
Dr. Monty Pal: That's really helpful. Now, you told us about the primary endpoints, you've helped us define high-risk smoldering myeloma. Can you give us a sense of the top-line results from AQUILA?
Dr. Vincent Rajkumar: Yes, I think the most important one was the primary endpoint, time to multiple myeloma, was at 5 years, the progression-free survival was 63% in the daratumumab arm compared to 41% in the observation arm. So, you know, approximately 60% of patients in the observation arm had already progressed by 5 years. And that number was about 40% for the daratumumab arm. We also looked at time to starting myeloma therapy, which is clinically actually quite meaningful because, you know, myeloma therapy means patients get a quadruplet for induction, they get stem cell transplant, they get endless maintenance, they get ongoing therapy virtually for the entire duration. So, preventing the need for myeloma therapy is in and of itself, I think, a major endpoint. And that at 3 years, 40% of people in the observation arm required full myeloma therapy compared to only 20% in the daratumumab arm. So there's a significant reduction in the risk of developing active myeloma as well as the need for myeloma therapy by using a time-limited 3 years of daratumumab single agent.
Dr. Monty Pal: Perfect summary of the results. And maybe, Saad, I'm going to bring you into the conversation now. How does this sort of influence your day-to-day practice for smoldering myeloma? Is this something that you've incorporated for that high-risk subset?
Dr. Saad Usmani: Thank you, Monty, and I agree. I think that's a really nice summary from Vincent. This study is very important for several reasons. It's actually the third clinical trial that has demonstrated that patients who are in the high-risk smoldering myeloma category benefit from an early intervention that delays the progression to active myeloma or to end-organ damage. And so having a nuanced discussion with our patients in the clinic becomes very important. Having this discussion around as an option becomes very important. And like Vincent said, when we look at that high-risk smoldering myeloma patient population, someone who has 22, 23% plasma cells versus, you know, 45, 50, you know, it's going to be a different discussion each time. But I think it's a very important first step. And I think this sets up the stage for us to design clinical trials where we can ask other questions on what would be better than daratumumab alone in terms of delaying progression in these patients.
The other thing that I do want to highlight, and Vincent touched upon this a little bit, that the treatment in this clinical trial was for a fixed duration of treatment. So it was not forever treatment. This is maybe something that Vincent, you can even comment on a little bit more because the question we get after having this discussion is, "Okay, what do we do with patients who are going to be progressing to active myeloma?" Whether we can utilize anti-CD38 therapies for those. So Vincent, I would love your take on this too.
Dr. Vincent Rajkumar: Yeah, I think, you know, the main philosophical change for me was previously, the thing was 'don't treat', and now for high-risk smoldering multiple myeloma, the question is, is daratumumab the best treatment or can we do something better? And those trials are thankfully ongoing. One of them has already completed accrual, isatuximab-len-dex versus len-dex. And another one is ongoing in ECOG, almost close to finishing accrual. And in the future, we'll be trying to see if we can use early intervention to even cure and prevent progression altogether.
So we are in this phase where we have one approved regimen, one approved drug, and we are not sure whether we can improve on that. The question is, "is a myeloma-like therapy better than monotherapy" would be the next question, and then what would we do further beyond that?
In this context, whenever we have patients like this, one of the questions that comes up, as Saad mentioned, is how does this affect newly diagnosed myeloma therapy if somebody has been treated for smoldering and things like that? How will they be considered for clinical trials? Would they be considered as relapse myeloma or still newly diagnosed myeloma? And those are important discussions for clinical trialists to keep in mind, but I think for clinical practice, your duty is to the patient in front of you. If they have high-risk smoldering myeloma and there's data that there's treatments that can delay progression significantly, delay the need for myeloma therapy significantly, that's the highest priority. We'll cross that bridge.
There are so few patients going on clinical trials right now that if such a patient were to later on progress and wants to enter in a newly diagnosed myeloma trial later, years later, we can figure that out later. I feel like the most important discussion is what to do for that patient today. I still prefer a clinical trial if one was available. If one was not available, I'd prefer early intervention, but have an informed discussion with the patient because some of them may wish to delay therapy still. Some of them may have very borderline numbers that you want to watch them closely. Some of them may be having other comorbidities that prevent need for therapy. Some of them maybe have had the smoldering for a long time and you already know it's stable. So a lot of factors go in, and I think it's not a one-size-fits-all.
Dr. Monty Pal: This is a terrific discussion, and you know, it sort of segues into maybe a question around biology. And this is something I was going to get to a little bit later, but Saad, I'm glad you brought it up. I'll liken it to the only thing I know, which is kidney cancer. So, you know, in kidney cancer, we use checkpoint inhibitors as adjuvant therapy. And there's this question of whether or not it breeds some resistance in the localized setting to ultimately what the patient might potentially be exposed to in the metastatic setting. Tell me your thoughts on this, Vincent, then maybe Saad separately. If you treat a patient with daratumumab in this high-risk smoldering setting, could it theoretically sort of limit options in the refractory setting now that we have regimens like DRBD that are kind of being utilized, or daratumumab with teclistamab? Vincent, I'll throw that to you first.
Dr. Vincent Rajkumar: This is a great question, and it's usually asked when we've done the lenalidomide trials actually. We try to put the question back. If that was your concern, how would you actually solve it? Is it really biology that's going to answer that? Or is it a randomized trial? So the experiment has been done three times now where early intervention has been given. And if there was some detriment because of that, that would be reflected in the overall survival. In all three trials, there's no such detriment seen. In the first lenalidomide-dex trial, there was an improvement in overall survival. In the AQUILA trial again, the confidence interval doesn't cross one, and patients had better long-term survival on AQUILA, but certainly not less. We've also examined PFS2 data, and that doesn't seem to be affected. So yes, there is a theoretical concern, and that concern cannot be allayed for new treatments which we have not even tried, like tec-dara, and whether that effect would be there or not. But so far, I don't see it. And I think the onus is on proof of that in order to prevent people from getting early therapy.
Dr. Monty Pal: Yeah. Saad, your thoughts on that? And before you jump in, I'll mention, we're kind of taking the same approach in kidney cancer, we're trying to really do studies to see whether or not, you know, immunotherapy rechallenge in these contexts, you know, really lends any substantial benefit. So far, the results have been interesting. I don't think we have enough numbers as yet to capture the impact of adjuvant therapy as it translates to metastatic, but I see so many similarities between the scenarios that you're facing in myeloma and what we're facing in RCC. Saad, your thoughts?
Dr. Saad Usmani: Thanks, Monty. I'll go back to something that Vincent alluded to a few minutes ago about the way that we risk-stratify patients within smoldering myeloma. Right now, we are relying more on a disease burden-based stratification looking at the percentage of plasma cells in the bone marrow, the monoclonal protein, as well as the involved light chain versus the uninvolved light chain ratio. However, there are efforts underway to actually incorporate genomics into that schema and try to refine that definition of high-risk smoldering. And there have been two papers that came out in the latter half of last year. In fact. Dr. Rajkumar and I are co-senior authors on one effort where we can identify genomic myeloma in patients in precursor conditions. One of the key things that came out of that effort was that within the high-risk smoldering myeloma category, about 90% of the patients are genomically myeloma. So this whole debate of whether we need to intervene for those patients, I think, you know, we have sufficient biologic evidence that yes, we need to intervene for those patients.
I think that the next real step, like Vincent stated, is how do we intervene in those patients? And those clinical trials kind of are ongoing. We will probably need to have more validation of those genomic models being incorporated, but that's what I see in the future. I wouldn't be concerned for the patients being seen today with that query about the disease biology evolving because if I'm seeing a patient today in March of the first quarter of 2026 and offering them monotherapy daratumumab in their high-risk smoldering situation for the next 3 years and then they progress to myeloma after another couple of years, we are talking about what would be the treatment options for them in 2031, 2032. So I think the field is moving so fast, we have a lot of novel therapies coming into that frontline setting rapidly, so our options at that time would be very different. So, you know, I just wanted to kind of set up the stage for saying, you know, our tools are getting better in delineating which patients will need that intervention. And then eventually, I think, you know, we'll have much better options for newly diagnosed myeloma patients at the time when they need it in the future.
Dr. Monty Pal: Just absolutely brilliant, absolutely brilliant. I love that summary. I think that you're absolutely right in saying that, you know, you've got to think about what you're going to do for that patient sort of in the moment, what's going to optimize their outcome and agree that the landscape is evolving very rapidly.
I'd be remiss, Saad, if I didn't ask you about something that I've been following in terms of your career trajectory. You've developed quite a reputation for your leadership in trials looking at CAR T-cell therapies for myeloma. Can you give us a sense of where that stands in broad terms?
Dr. Saad Usmani: Certainly, Monty. I think the CAR Ts have slowly made their way from late relapse to early relapse. And now we have clinical trials that have completed accrual in the frontline setting comparing them to standard-of-care treatment for both older myeloma patients or transplant-ineligible patients, as well as younger transplant-eligible patients where we're actually trying to replace transplants with BCMA-directed CAR T-cell therapies. The nuance there would be we want to equal or better the survival outcomes that we've accomplished without compromising on the safety side of things for patients. Those therapies are moving into earlier lines. And more excitingly, you know, that's just the first wave of CARs. The next wave of CAR technology is coming, and it's going to be in vivo CARs where we may not need lymphodepleting chemotherapy, we may not even need as stringent regulatory nuances that we do for cellular therapies today. So, you know, I think the field is moving rapidly, and it's going to be a very interesting landscape to see over the next 5 to 6 years.
Dr. Monty Pal: Yeah, you know, it's so interesting. I know in the solid tumor space, we're trying to replicate the success that you've had with CAR T and bispecifics, and I do see some light at the end of the tunnel. I'm seeing some really promising agents being developed, but clearly, we have so much to learn from our colleagues in hematology.
Well, I have to tell you, this has just been a phenomenal conversation. Vincent, congratulations on your leadership of the AQUILA trial. Clearly, a big paradigm shift in the field. Saad, thank you for offering your expert insights and really giving us also a glimpse at the future of myeloma. Really appreciate having you both on the podcast today.
Dr. Vincent Rajkumar: Thank you, Monty.
Dr. Saad Usmani: Thank you so much.
Dr. Monty Pal: And thank you so much to our listeners for your time today. Finally, if you value the insights that you hear from 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. Monty Pal:
Speakers' Bureau: MJH Life Sciences, IntrisiQ, Peerview
Research Funding (Inst.): Exelixis, Merck, Osel, Genentech,
Crispr Therapeutics, Adicet Bio, ArsenalBio, Xencor, Miyarsian Pharmaceutical
Travel, Accommodations, Expenses: Crispr Therapeutics, Ipsen, Exelixis
Dr. Vincent Rajkumar:
Honoraria: Research to Practice, Medscape
Patents, Royalties, Other Intellectual Property: Authorship Royalties from Up To Date
Dr. Saad Usmani:
Consulting or Advisory Role: Janssen Oncology, GlaxoSmithKline, Abbvie, Bristol-Myers Squibb/Celgene, Regeneron, AstraZeneca, Sanofi
Research Funding: Janssen Oncology, Bristol-Myers Squibb, K36 Therapeutics, Abbvie, Regeneron