The phase 3 ATLAS trial backs MRD-guided maintenance intensification in myeloma.
Carfilzomib–lenalidomide–dexamethasone maintenance has delivered a decisive progression-free survival advantage over lenalidomide alone following autologous haematopoietic stem-cell transplantation (HSCT) in newly diagnosed multiple myeloma.
That’s the primary analysis of the phase 3 ATLAS trial, with signals of overall survival benefit emerging on longer follow-up.
Results of the trial have been published this month in The Lancet Haematology.
“Lenalidomide maintenance has long been a preferred treatment after autologous haematopoietic stem-cell transplantation (HSCT) in patients with multiple myeloma,” the researchers wrote.
“Multidrug treatments are emerging as an alternative to lenalidomide alone. We aimed to compare carfilzomib–lenalidomide–dexamethasone (KRd) with lenalidomide alone in patients with multiple myeloma after autologous HSCT.”
In the open-label, randomised study of 180 patients across the USA and Poland, KRd reduced the risk of progression or death by 54% compared with lenalidomide monotherapy (hazard ratio 0.46, 95% CI 0.30–0.70; log-rank p=0.0002), translating into a near doubling of median progression-free survival to 72.8 months versus 37.3 months.
Four-year progression-free survival reached 67.5% with KRd compared with 38.0% with lenalidomide alone (p<0.0001) after a median follow-up of 69 months.
The trial is the first phase III study to directly test a multi-agent maintenance regimen against lenalidomide alone after transplant, independent of induction strategy, addressing a long-standing evidence gap in post-HSCT management.
Investigators embedded measurable residual disease (MRD)-guided de-escalation into the protocol, allowing standard-risk, MRD-negative patients in the KRd arm to step down to lenalidomide after cycle eight, an approach that did not erode efficacy despite nearly half of eligible patients transitioning early.
Depth of response tracked with clinical benefit. Complete response or better occurred in 91% of patients receiving KRd versus 77% with lenalidomide (p=0.013), and MRD negativity rates were consistently higher with the triplet at cycle 6 (49% vs 33%), at best response (73% vs 48%), and when sustained for at least 12 months (49% vs 22%).
These gains extended across most prespecified subgroups, including patients with high-risk cytogenetics, although the study was not powered for definitive subgroup comparisons.
Overall survival curves separated late, a pattern familiar in myeloma trials, but favoured KRd with a hazard ratio of 0.49 (95% CI 0.26–0.90; p=0.020).
Weighted analyses accounting for non-proportional hazards yielded similar estimates, reinforcing the likelihood of a real survival effect, albeit one that remains supportive rather than definitive, given study power constraints.
Toxicity was higher with intensification but broadly manageable, the researchers noted. Grade 3–4 adverse events occurred in 75% of KRd-treated patients versus 68% with lenalidomide, with neutropenia the most common severe event in both groups (48% vs 59%).
Thrombocytopenia and respiratory infections were more frequent with KRd, and serious adverse events occurred in 30% versus 23% of patients. Treatment discontinuation due to adverse events was not increased with KRd, and no new safety signals emerged with extended follow-up.
Clinically, ATLAS reframed maintenance as a dynamic, biology-guided phase rather than a fixed monotherapy default.
By combining early intensification with MRD-directed de-escalation, the regimen offered a template for tailoring duration and intensity to risk, potentially limiting cumulative toxicity without sacrificing disease control.
“With long-term follow-up, ATLAS shows that carfilzomib–lenalidomide–dexamethasone maintenance significantly prolongs progression-free survival and provides evidence for improved overall survival compared with lenalidomide alone, with clear benefit in MRD-positive patients and higher MRD negativity rates in those with high-risk cytogenetics,” the researchers wrote.
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“Importantly, the protocol incorporated MRD-guided de-escalation, providing unique evidence on tailoring maintenance intensity.”
The findings aligned with results from the FORTE, CASSIOPEIA and AURIGA trials, but uniquely isolated the contribution of a proteasome inhibitor–based triplet in the maintenance setting.
Questions remain about generalisability in the era of anti-CD38–based quadruplet induction, which was not standard during accrual, and about optimal sequencing when patients receive more intensive frontline therapy.
“A limitation of the ATLAS study is the shift in induction therapy from primarily triplet therapies containing bortezomib to anti-CD38 antibody-based quadruplet therapy,” the researchers wrote.
“The ATLAS study showed the benefit of treatment intensification in the maintenance setting after triplet induction. Whether the addition of a proteasome inhibitor after autologous HSCT remains beneficial after quadruplet induction is currently unknown, with alternative intensification strategies after quadruplet induction under investigation.”
Despite this, they said, the magnitude and durability of benefit seen in ATLAS make a strong case for moving beyond uniform lenalidomide maintenance, particularly in patients with residual disease or high-risk features.
“The superior efficacy of carfilzomib–lenalidomide–dexamethasone after autologous HSCT in patients with newly diagnosed multiple myeloma within an MRD-adapted and risk-adapted de-escalation for tolerability provide a framework for maintenance intensification within contemporary, CD38-inclusive treatment paradigms,” the researchers concluded.
