Mezigdomide

Bristol Myers Squibb (NYSE: BMY) reported that mezigdomide, its oral cereblon E3 ligase modulator (CELMoD), cut the risk of disease progression or death by 52% versus carfilzomib and dexamethasone alone in relapsed or refractory multiple myeloma, delivering the first Phase III readout for any CELMoD agent and handing BMS a potential new commercial pillar as its immunomodulatory drug franchise faces generic erosion from lenalidomide biosimilars. The data were the subject of a late-breaking oral presentation at the 2026 American Society of Clinical Oncology (ASCO) summit meeting. The SUCCESSOR-2 trial is a seamless Phase II/III, multicenter, randomized, open-label study that enrolled 479 patients with relapsed or refractory multiple myeloma, randomized to mezigdomide plus carfilzomib and dexamethasone (MeziKd, n\=288) or carfilzomib and dexamethasone alone (Kd, n\=191). The population was heavily pretreated and largely refractory to current standards: 92.1% were triple-class-exposed, 85.8% were refractory to an anti-CD38 monoclonal antibody, and 75.8% were refractory to lenalidomide — the very drug class from which mezigdomide descends. The primary endpoint was met decisively. Median progression-free survival reached 18 months with MeziKd versus 8.3 months with Kd (HR: 0.48; 95% CI reported; p \< 0.0001), a hazard ratio that corresponds to a 52% reduction in the risk of progression or death at a median follow-up of 10.6 months. Overall response rate was 80.2% with MeziKd versus 53.4% with Kd, and complete response or better was achieved in 26.7% versus 8.9%. Median overall survival had not yet been reached in either arm. The results were presented as a late-breaking oral at Bristol Myers Squibb ASCO 2026 (#LBA7506). The safety profile carries a meaningful hematologic burden. Grade 3–4 treatment-emergent adverse events occurred in 83.7% of MeziKd patients versus 56.5% on Kd. Neutropenia was the dominant toxicity, appearing in 61.1% of the MeziKd arm versus 9.1% on Kd, and Grade 3–4 infections occurred in 34.0% versus 15.6%. BMS described the profile as consistent with mezigdomide’s known safety profile, and notably 52.4% of MeziKd patients remained on treatment at data cutoff versus 31.4% on Kd, suggesting tolerability sufficient for continued dosing in a substantial proportion of patients. Competitive context and outlook The SUCCESSOR-2 trial results arrive at a moment when the relapsed refractory multiple myeloma treatment landscape is undergoing rapid reorganization. Bispecific T-cell engagers — including Janssen’s Tecvayli (teclistamab), Janssen’s Talvey (talquetamab), and Pfizer’s Elrexfio (elranatamab) — have reshaped late-line practice since 2023, while the CAR-T therapies Janssen and Legend Biotech’s Carvykti (ciltacabtagene autoleucel) and BMS’s own Abecma (idecabtagene vicleucel) have moved into earlier relapse settings following label expansions in 2024. Against this backdrop, mezigdomide’s oral administration, outpatient delivery, and activity in a predominantly anti-CD38-refractory and lenalidomide-refractory population position it as a chemotherapy-free oral option that does not require the manufacturing lead times of CAR-T or the step-up hospitalization protocols associated with bispecifics. CELMoD therapy in RRMM builds on the mechanistic foundation established by lenalidomide and pomalidomide but with substantially greater potency. Mezigdomide is optimized for maximal and rapid degradation of Ikaros and Aiolos transcription factors, proteins essential for myeloma cell survival, and preclinical data suggest it also reinvigorates exhausted T cells — a property that may become clinically relevant as the field increasingly uses it alongside immunotherapy backbones. The carfilzomib and dexamethasone combination was a deliberate design choice: Kd is an established standard of care in second- and third-line RRMM, making it a credible comparator and the PFS improvement over it directly interpretable for practicing oncologists. Cross-trial comparisons are limited by differences in patient populations, prior therapy exposure, and follow-up duration, but the 18-month median PFS in a population that was more than 85% anti-CD38-refractory compares favorably to historical benchmarks for pomalidomide-based triplets in similar settings. The ORR of 80.2% and the complete response rate of 26.7% are also notable in a population where most patients had already received two or more prior lines including an IMiD and an anti-CD38 antibody. BMS has indicated it will share the SUCCESSOR-2 data with health authorities, and a regulatory submission appears imminent. A second ongoing Phase III trial, SUCCESSOR-1, is evaluating mezigdomide in a separate RRMM combination, broadening the potential label scope. The company has framed mezigdomide as the centerpiece of its next-generation targeted protein degradation platform, which also encompasses ligand-directed degraders and degrader antibody conjugates — modalities that have not yet generated pivotal data but represent BMS’s long-term bet on cereblon biology beyond the IMiD era. For BMS, the commercial stakes are substantial. Revlimid (lenalidomide) generic entry has been eroding one of the company’s most durable revenue streams, and pomalidomide faces its own competitive pressure from bispecifics in later lines. Mezigdomide, if approved, would enter a market where oral convenience, outpatient administration, and activity in anti-CD38-refractory disease are genuine differentiators — though the neutropenia rate will require careful management and may limit use in older or frailer patients without growth factor support. The next milestone is a regulatory filing, with the timeline to be confirmed following health authority discussions. Your email address will not be published. Required fields are marked * Comment * Name * Email * Website Copyright © 2026. AllSci Corp. All rights reserved.

CELMoD drugs, which have not yet had an FDA approval, are similar to the pharma\'s existing protein degraders Revlimid and Pomalyst.\n Bristol Myers Squibb may be leading the way when it comes to pursuing cereblon E3 ligase modulator (CELMoD) drugs, but today, the pharma is standing tall. BMS shared data at the American Society of Clinical Oncology annual meeting on Friday that demonstrated that its CELMoD candidate mezigdomide more than doubled progression-free survival in patients with relapsed or refractory multiple myeloma.The data come from the 479 patients analyzed in the phase 3 SUCCESSOR-2 trial testing mezigdomide in combination with Amgen’s Kyprolis and dexamethasone versus that pair alone.Patients in the mezigdomide arm lived without disease progression for an average of 18 months, compared to 8.3 months for those given just Kyprolis and dexamethasone. Overall, the mezigdomide regimen cut the risk of disease progression or death by 52%, BMS reported in a May 29 release.The pharma had previously announced that the trial hit its primary endpoint of progression-free survival, but is only now divulging the numbers behind the win.“It\'s incredibly exciting,” Anne Kerber, M.D., BMS’ head of late-stage development for hematology, oncology and cell therapy, told Fierce Biotech in an interview ahead of ASCO. Kerber highlighted the fact that mezigdomide managed to nearly triple the complete response rate to 26.7% compared to 8.9% in the control arm, despite patients in the study being heavily pretreated.It’s still too early to draw conclusions about overall survival rates, Kerber added, but so far it seems mezigdomide is having an effect there as well. “The overall survival data is immature, but we already start [to] see the curves separate at this very early point in time,” she told Fierce.Side effects were worse in patients treated with mezigdomide, with 83.7% of patients reporting grade 3 or 4 adverse events related to treatment in the mezigdomide arm vs 56.5% in the control cohort. This safety profile is consistent with prior trials, according to Kerber, and side effects were “nothing unexpected and very well manageable.”BMS plans to discuss the data with the FDA at some point in the future, Kerber said. The regulator is already considering another of the drugmaker’s CELMoD candidates, iberdomide, for approval in the same indication, with a decision expected by August 17.CELMoD drugs, which have not yet had an FDA approval, are similar to the pharma\'s approved protein degraders thalidomide, Revlimid and Pomalyst. In multiple myeloma, they are designed to target transcription factors called Ikaros and Aiolos, which the cancer relies on.“These compelling data further validate our targeted protein degradation platform, and cereblon as a critical therapeutic target in multiple myeloma,” Cristian Massacesi, M.D., BMS’ chief medical officer and head of development, said in the release. “Mezigdomide is a very potent, oral CELMoD and we’re committed to bringing it forward as a potential new standard of care for relapsed/refractory multiple myeloma across multiple settings,” Massacesi added.Kerber highlighted to Fierce that some of the patients in the SUCCESSOR-2 study had been previously treated with Revlimid and Pomalyst, but mezigdomide still worked. Mezigdomide is also more potent than iberdomide, but the two pair differently with existing medications, leaving room for both in the myeloma care landscape.Though mezigdomide development is for now focused on later lines of therapy, Kerber said BMS hopes to bring the molecule forward in the treatment paradigm in the same way iberdomide has been. “The concept in multiple myeloma is really to bring up your best treatments into as early [line] as possible, to really drive very long progression-free survival times,” Kerber said.Meanwhile, another CELMoD drug, golcadomide, is in the works for patients newly diagnosed with B-cell lymphoma, with fresh data also being shared at this month’s ASCO event.