ASH 2024 Myeloma Studies: My Top 10 Picks

As a doctor with a keen interest in myeloma who is looking ahead to the 2024 American Society of Hematology (ASH) annual meeting December 7-10 in San Diego, I’ve chosen 10 presentations that seem most likely to make the greatest impact on my thinking and practice.

First, let me place my selected studies in context by acknowledging my biases. As a clinician, I’m prone to choosing clinical rather than basic science or translational work — even if translational work might well end up exerting a pivotal impact on practice in the future. And now — in no particular order — here are my picks:

Frail patients are underrepresented in most myeloma studies, yet in this randomized trial for newly diagnosed myeloma, exclusively frail patients were enrolled. The trial compared daratumumab/lenalidomide to lenalidomide/dexamethasone, and the most recent follow/up shows a progression-free survival (PFS) (48.5 vs 21 months) and overall survival (OS) (not reached vs 36 months) benefit to daratumumab/lenalidomide. What I see in practice is that anti-CD38 monoclonal antibodies are the best-tolerated drugs in this space and should be the backbone of any regimen for frail patients. Steroids should be omitted as early as possible. Future trials may optimize what to give in addition to the anti-CD38 therapy, and how to adapt/escalate therapy to frailty and clinical status, as lenalidomide remains difficult for such patients to tolerate.

This is a randomized, phase 3 comparison of daratumumab to observation for patients with smoldering myeloma. The endpoint was PFS. For context, similar studies done in asymptomatic CLL have shown improved PFS, but not OS, and the authors of such studies have concluded that improvement in PFS alone should not justify a change in approach.

This study shows that daratumumab can improve laboratory markers and reduce progression (60-month PFS rates of 63.1% for daratumumab vs 40.8% with observation). However, several important caveats remain. The protocol only mandated spine/pelvis MRI imaging, not whole-body MRI imaging, and such imaging was only performed once a year, which may not be frequent enough to catch lesions at an earlier stage. These details have important implications, as previous research shows that up to half of lesions can be missed by doing only a spine MRI, as opposed to a whole-body MRI.

All of this means that had more comprehensive imaging been done, many more patients may have been diagnosed with myeloma. Such patients may have been undertreated, and single agent daratumumab, with a response rate of just 63%, may not have been enough. Conversely, some patients may also have been overtreated using this approach, as the protocol allowed patients who had been diagnosed with smoldering myeloma up to 5 years earlier to be enrolled. Many of these people could have had indolent disease for years prior to enrollment and may not have ever progressed. 

Further information is needed to help us understand this study better. What was the nature of the progression events: Asymptomatic lab changes or morbid end organ damage? Was daratumumab given when patients in the control arm progressed to myeloma? My concern is that if patients in the control arm do not universally receive modern daratumumab-containing therapies when they develop myeloma, then an overall survival advantage may be shown simply because patients in the intervention arm are getting a good drug earlier in the disease, while those in the control arm are not getting a good drug at all. Nevertheless, despite these limitations, it is likely this trial will lead to regulatory approval of daratumumab in this space, and lots of discussions from patients and clinicians alike.

Two chimeric antigen receptor therapy (CAR-T) products are currently approved for myeloma. Cilta-cel is clearly effective but is associated with problematic late-onset neurological toxicities. Ide-cel appears much less effective. There is clearly a need for a product that is both effective and safe.

Anito-cel has two relevant abstracts this meeting that show much promise. Extended follow-up of anito-cel from its first in human study shows a promising 27-month PFS of 52%, and with no cases of delayed neurotoxicity. I also eagerly await further information from the registrational single-arm study of anti-cel being presented at ASH 2024, which should (hopefully) lead to its accelerated approval.

This elegant study of over 9,000 people with vertebral fractures shows that absolute risks for myeloma were 0.43% and 0.63% in women and men with grade 2-3 fractures, respectively, indicating that there is likely little benefit in evaluating asymptomatic individuals with incidentally discovered vertebral fractures for myeloma, unless other features are present. Spread the word.

We do need effective treatments for targets beyond just BCMA and GPRC5D. Cevostamab, a bispecific targeting FCRH5, represents another option, with updated data on 167 patients. With an overall response rate of 43% (duration of response, 10 months), and a response rate of about 30% in those with prior bispecific exposure, this data helps us contextualize expected benefits as we look forward to the eventual approval of this drug. The efficacy is relatively modest in those who have already progressed on bispecifics, but cevostamab would still be a welcome addition to our arsenal.

Our currently available GPRC5D bispecific (talquetamab) leads to high rates of skin, oral, and nail toxicity. This drug can also bring significant weight loss. These side effects make me consider that continuous targeting of GPRC5D through a bispecific may not be ideal, and that GPRC5D may be better as a one-time CAR T target. At ASH 2024, we will have 15-month follow-up data from BMS-986393, a GPRC5D CAR T. Response rates for this heavily pretreated population (76% of whom had triple refractory disease) were at 87%, with a median PFS of 14.5 months. Only 6% of patients experienced treatment-related weight loss, and nail (19%), skin (30%), and oral (31%) toxicities were relatively low. I look forward to updated data, as well as data on the resolution of the toxicities seen.

A truly effective drug given early can change the natural history of disease, even if patients in the control arm only receive the drug later. A case in point is daratumumab. The 5-year survival rate was 76.1% for the daratumumab/cyclophosphamide/bortezomib/dexamethasone arm and 64.7% for cyclophosphamide/bortezomib/dexamethasone arm. This happened despite the fact that 67% of the control arm patients (among those who received therapy) went on to receive daratumumab later in the disease course.

We often hear that we should treat SMM and not just watch carefully because fractures may suddenly happen, or a patient may end up on dialysis. What this retrospective study tells us that amongst 427 patients with SMM, 42 had progression to myeloma, and amongst those 42, only 1 developed renal dysfunction (unclear if this resolved), and only 1 had lytic lesions that were symptomatic. The remainder were all asymptomatic lab and imaging changes. This is a retrospective study, and one should assume that follow-up was thus highly variable. It does not appear that diffusion weighted whole-body MRI imaging (our most sensitive imaging test) was employed universally or very frequently. Nevertheless, these powerful findings reassure us that, with close observation, morbidity is unlikely. Our group has designed a prospective study incorporating frequent diffusion weighted whole body MRI imaging to formally test this hypothesis (SPOTLIGHT, NCT06212323). 

At every major meeting I am reminded of the disconnect between real-world efficacy and clinical trial efficacy. Case in point: In this Austrian experience, daratumumab/lenalidomide/dexamethasone led to a PFS of 22.7 months vs 61.9 months in the MAIA trial of daratumumab/lenalidomide/dexamethasone. Such a sobering difference! And if you think this is an isolated experience, even in a US real-world cohort, consider that in a recently published comparative study dara/len/dex underperformed, although the time to next treatment or death was longer (37.8 months).

We currently think that some of the scariest side effects of cilta-cel, such as delayed neurotoxicity, may be a consequence of a high number of cancer cells and may be prevented by better disease control at the time of infusion. This study, a sobering analysis of 52 patients with delayed neurotoxicity occurring after CAR T, included 8 patients (15%) who were not heavily pretreated, and all had less than 5% plasma cells at the time of infusion. None of these patients had extramedullary disease. This result worries me, especially because cilta-cel is being studied and is poised for future approval in earlier line settings. It suggests that this toxicity may not always be a product of disease burden, contrary to our current belief.

I will be paying close attention to these 10 myeloma studies at ASH 2024, where I look forward to meeting you and learning more. 

Dr Mohyuddin is assistant professor in the multiple myeloma program at the Huntsman Cancer Institute at the University of Utah, Salt Lake City. 

This article originally appeared on MDedge.com, part of the Medscape Professional Network.