FDA Approves Iberdomide: A New Oral Paradigm in Multiple Myeloma Care

The Food and Drug Administration (FDA) has granted accelerated approval to the first-in-class cereblon E3 ligase modulator (CELMoD) iberdomide (Zenbexus) in combination with daratumumab, hyaluronidase-fihj, and dexamethasone (IberDd) for adults with relapsed or refractory multiple myeloma (RRMM). Eligible patients must have received at least one prior line of therapy, including a proteasome inhibitor and an immunomodulatory agent (IMiD).

Mechanistic Breakthrough and Clinical Trial Foundation

Building on targeted protein degradation platforms, iberdomide degrades therapeutically relevant proteins previously considered undruggable. Unlike traditional IMiDs, iberdomide binds more tightly and precisely to the cereblon E3 ligase complex. This molecular precision allows the drug to overcome established treatment resistance to standard agents such as lenalidomide.

The regulatory decision was supported by safety and efficacy results from the Phase 3 EXCALIBER-RRMM trial (NCT04975997). In the primary efficacy population (n=420), patients treated with the IberDd combination achieved a highly statistically significant minimal residual disease (MRD)-negative complete response (CR) rate of 41% compared to 21% in patients receiving the daratumumab, bortezomib, and dexamethasone (DVd) comparator arm (p-value <0.0001). MRD negativity, measured by next-generation sequencing or flow cytometry, represents the presence of fewer than one cancer cell among 100,000 normal cells and serves as a highly sensitive predictor of prolonged clinical remission.

Dosing and Oral Care Convenience

The recommended iberdomide dosage is 1 mg administered orally once daily on Days 1 through 21 of a repeating 28-day cycle. This is combined with subcutaneous daratumumab and hyaluronidase-fihj and weekly oral dexamethasone.

According to Elise Curry, BA, BSN, RN, OCN, clinical trial nurse navigator with Blood Cancer United, this oral convenience significantly expands healthcare access for patients living in remote or rural regions who cannot easily relocate or travel weekly for clinic-based treatments. Surbhi Sidana, MD, Associate Professor of Medicine at Stanford University and chair of the American Society of Hematology’s Committee on Communications, notes that this oral option offers a critical alternative for frail or elderly patients who may not be eligible candidates for intensive cellular immunotherapies, such as CAR-T or bispecific antibodies.

Key Nurse-Led Interventions and Safety Guidelines

While iberdomide provides clinical convenience, oncology nursing teams must navigate distinct toxicities:

• Myelosuppression: Iberdomide is more myelosuppressive than older IMiDs. Severe neutropenia, anemia, and thrombocytopenia are common. Sidana recommends checking complete blood counts (CBCs) every week or two during the first two cycles, when the risk of cytopenias is greatest, to guide dose modifications or growth factor support.
• Infections: Serious infections are common, requiring immediate treatment holding and aggressive clinical management.
• Thrombosis Prophylaxis: Due to Boxed Warnings for venous and arterial thromboembolism, nurses must coordinate aspirin or anticoagulation therapy.
• Embryo-Fetal Toxicity: Iberdomide is highly teratogenic. Nurses must guide patients through the strict requirements of the restricted ZENBEXUS Risk Evaluation and Mitigation Strategy (REMS) program.

References

1. Food and Drug Administration. FDA grants accelerated approval to iberdomide with daratumumab and hyaluronidase-fihj and dexamethasone for multiple myeloma. Food and Drug Administration website. Published August 13, 2026. Accessed August 14, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-iberdomide-daratumumab-and-hyaluronidase-fihj-and-dexamethasone
2. Bristol Myers Squibb. U.S. Food and Drug Administration Accepts Bristol Myers Squibb's New Drug Application for Iberdomide in Patients with Relapsed or Refractory Multiple Myeloma. Press Release. Published February 17, 2026. Accessed August 14, 2026. https://news.bms.com/press-releases/press-release-details/2026/U.S.-Food-and-Drug-Administration-Accepts-Bristol-Myers-Squibbs-New-Drug-Application-for-Iberdomide-in-Patients-with-Relapsed-or-Refractory-Multiple-Myeloma/default.aspx