Zenbexus Approved for Relapsed or Refractory Multiple Myeloma
On Aug. 13, 2026, the US Food and Drug Administration (FDA) granted accelerated approval to Bristol Myers Squibb’s Zenbexus™ (iberdomide) in combination with daratumumab and hyaluronidase-fihj (Darzalex Faspro® – Johnson & Johnson Innovative Medicine) and dexamethasone for the treatment of adults who have multiple myeloma who have received at least one prior line of therapy including a proteasome inhibitor and an immunomodulatory agent. Zenbexus is the first approved agent in a novel oral drug class known as cereblon E3 ligase modulators (CELMoDs) that work by promoting the degradation of the Ikaros and Aiolos transcription factors, thereby inhibiting myeloma cell growth while enhancing anti-myeloma immune activity. The recommended dose is 1mg orally on days one through 21 of a 28-day cycle. Bristol Myers Squibb set the list price of Zenbexus at $29,500 per 28-day cycle and expects the drug to become available within the coming weeks. Full prescribing information is here.
At a Glance
- Brand Drug: Zenbexus™ (iberdomide)
- Manufacturer: Bristol Myers Squibb
- Date Approved: Aug. 13, 2026
- Indication: In combination with daratumumab and hyaluronidase-fihj and dexamethasone for adults who have multiple myeloma who have received at least one prior line of therapy including a proteasome inhibitor and an immunomodulatory agent
- Dosage Forms Available: 0.75 and 1mg capsules
- Launch Date: In the coming weeks
- Estimated Annual Cost: $385,000
- FDA Designation: Accelerated Approval. Breakthrough Therapy. Priority Review. Orphan Drug. Risk Evaluation and Mitigation Strategy (REMS) program.
- Multiple myeloma is a blood cancer originating in the bone marrow and is the second most common hematologic malignancy in the US, with approximately 36,000 new cases diagnosed each year.
- Although there are several treatment options, multiple myeloma is incurable and most patients eventually relapse.
- Approval was supported by the ongoing phase III EXCALIBER-RRMM trial, in which the Zenbexus regimen significantly improved minimal residual disease (MRD) negativity. MRD refers to the small number of cancer cells that can remain in a patient’s body after treatment and are undetectable by conventional diagnostic methods. The MRD-negative complete response rate at any time was 41%, compared with 21% for daratumumab, bortezomib and dexamethasone, among patients who had received one to two prior lines of therapy.
- EXCALIBER-RRMM has dual primary endpoints of MRD negativity and progression-free survival (PFS) and remains ongoing to evaluate PFS, with additional endpoints including overall survival, overall response rate, safety and sustained MRD negativity.
- Because Zenbexus was cleared under accelerated approval, continued approval is contingent on confirmatory data.
- Zenbexus labeling carries two boxed warnings, one for embryo-fetal toxicity and another for serious venous and arterial blood clots, along with warnings and precautions for low white blood cell counts (neutropenia), infections and second primary cancers. Given the potential for fetal harm, the drug can be dispensed only through the restricted Zenbexus Risk Evaluation and Mitigation Strategy (REMS) program.
- Zenbexus enters a crowded relapsed/refractory market. It will primarily compete with multiple established triplet combination therapies, including those containing Darzalex Faspro® , Sarclisa® (isatuximab-irfc – Sanofi), Pomalyst® (pomalidomide – Bristol Myers Squibb/generics), Revlimid® (lenalidomide – Bristol Myers Squibb/generics), Kyprolis® (carfilzomib – Amgen), Empliciti® (elotuzumab – Bristol Myers Squibb) and Ninlaro® (ixazomib – Takeda). It will also compete with antibody-drug conjugate Blenrep® (belantamab mafodotin-blmf – GSK) and chimeric antigen receptor T-cell (CAR-T) therapies such as Carvykti® (ciltacabtagene autoleucel – Johnson & Johnson Innovative Medicine) and Abecma® (idecabtagene vicleucel – Bristol Myers Squibb), and the bispecific antibodies Tecvayli® (teclistamab-cqyv – Johnson & Johnson Innovative Medicine), Talvey® (talquetamab-tgvs – Johnson & Johnson Innovative Medicine), Elrexfio® (elranatamab-bcmm – Pfizer), and Lynozyfic® (linvoseltamab-gcpt – Regeneron).
- Mezigdomide, another CELMoD from Bristol Myers Squibb, is under FDA review for relapsed or refractory multiple myeloma. To be used in combination with Kyprolis® (carfilzomib) and dexamethasone, it has a target action date of May 13, 2027.