Full Breakdown
FDA Grants Accelerated Approval to Zenbexus (iberdomide) for Relapsed Multiple Myeloma
8/15/2026, 2:51:48 AM
Core Approval Details
On August 13, 2026, the U.S. Food and Drug Administration (FDA) granted accelerated approval to Zenbexus™ (iberdomide) with daratumumab, hyaluronidase-fihj and dexamethasone (ZDd) for adult patients with relapsed or refractory multiple myeloma who have received at least one prior line of therapy containing a proteasome inhibitor and an immunomodulatory agent. The decision was made under the FDA’s Project Orbis framework with Swissmedic collaboration and included Priority Review, Breakthrough Therapy, and Orphan Drug designations.
Trial Evidence and Efficacy Data
The approval relied on the Phase 3 EXCALIBER-RRMM trial (NCT04975997), a randomized, open-label study of 939 patients. The primary efficacy cohort comprised the first 420 patients randomized to iberdomide 1 mg + ZDd (n = 207) versus daratumumab + bortezomib + dexamethasone (DVd) (n = 213).
- MRD-negative complete response (CR) at any time: 41 % (95 % CI 34-48) vs. 21 % (95 % CI 15-27) (p < 0.0001).
- Among CRs, 89 % in the iberdomide arm were MRD-negative versus 83 % in the control arm.
- Discontinuations due to adverse reactions: 7.8 % of iberdomide-treated participants.
- Fatal adverse reactions: 4.9 % of iberdomide-treated participants, with sepsis the only event affecting more than one individual.
Progression-free survival (PFS) and overall survival remain co-primary endpoints for confirmatory approval.
Safety Profile and Regulatory Controls
Zenbexus carries boxed warnings for embryo-fetal toxicity and serious venous/arterial thromboembolism, plus warnings for neutropenia, infections, and secondary malignancies. Distribution is limited to the ZENBEXUS Risk Evaluation and Mitigation Strategy (REMS) program. The label recommends 1 mg oral iberdomide daily on days 1-21 of a 28-day cycle, combined with subcutaneous daratumumab + hyaluronidase-fihj (1,800 mg on specified days) and oral dexamethasone (20 mg or 40 mg on days 1, 8, 15, 22).
Common adverse reactions include upper respiratory infection, fatigue, musculoskeletal pain, pneumonia, and diarrhea; grade 3-4 neutropenia, leukopenia, and lymphopenia were also observed.
Market and Commercial Context
Zenbexus is priced at $28,000–$29,500 per 28-day cycle. William Blair projects U.S. sales exceeding $1 billion in 2031. The approval adds to Bristol Myers Squibb’s (BMS) myeloma portfolio, which has seen declines for Revlimid and Pomalyst due to generic competition. BMS is also advancing a second CELMoD, mezigdomide, with an FDA decision expected by May 13.
Official Statements & Responses
BMS noted Zenbexus as the first FDA-approved cereblon-modulating protein degrader (CELMoD) for multiple myeloma and highlighted its strategic importance. The FDA indicated that continued approval depends on verification of clinical benefit in confirmatory trials, particularly the PFS analysis. Project Orbis collaboration with Swissmedic was cited as a model for international oncology review.
Verbatim Quote
“The FDA approval of iberdomide marks the anticipated arrival of a new therapeutic class for relapsed or refractory multiple myeloma and has the potential to make a meaningful difference for patients,” — Sagar Lonial
Ongoing Evaluation and Future Outlook
The EXCALIBER-RRMM trial will continue to collect PFS, overall survival, and sustained MRD-negativity data to determine conversion to full approval. BMS plans to evaluate Zenbexus as maintenance after autologous stem-cell transplant and to compare it with Revlimid and Pomalyst in future studies. The upcoming FDA decision on mezigdomide (expected May 13) could further shape the CELMoD landscape.
