On August 13, 2026, the U.S. Food and Drug Administration (FDA) granted accelerated approval to iberdomide (Zenbexus, Bristol Myers Squibb) combined with daratumumab and hyaluronidase-fihj (Darzalex Faspro) and dexamethasone for adults with multiple myeloma who have received at least one prior line of therapy including a proteasome inhibitor and an immunomodulatory agent. This new combination is called IberDd.
This is the first approval for a new class of medication called a cereblon E3 ligase modulator (CELMoD).
In a Bristol Myers Squibb press release about the approval, Sagar Lonial, MD said “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. The strong results observed with the CELMoD-based combination within a familiar triplet approach creates the potential for a new treatment foundation in multiple myeloma.” Dr. Lonial is a lead investigator in the EXCALIBER-RRMM clinical trial and the chief medical officer of the Winship Cancer Institute of Emory University.
How does IberDd treat multiple myeloma?
IberDd is a combination of three medications.
Iberdomide is an oral medication called a CELMoD. It works by changing how the immune system targets myeloma cells and slowing the growth of those cells.
Daratumumab and hyaluronidase-fihj is given as an injection under the skin (subcutaneous injection). It helps the immune system attack myeloma cells.
Dexamethasone is a steroid. It helps reduce inflammation and boosts the effect of the other drugs.
This combination is approved for patients who have already received at least one prior treatment that included a proteasome inhibitor and an immunomodulatory agent, two common types of multiple myeloma drugs, and whose cancer has come back or stopped responding (relapsed or refractory multiple myeloma).
What is an accelerated approval?
Accelerated approval is a faster FDA pathway used when a treatment shows strong early results on a measure, like MRD status, that is likely to predict long-term benefit. The company must continue studying the drug to confirm that it improves outcomes such as how long patients live without their cancer getting worse.
The study that led to approval
The approval was based on results from the ongoing phase 3 EXCALIBER-RRMM (NCT04975997) clinical trial. It compared IberDd to daratumumab, bortezomib, and dexamethasone (DVd), another standard treatment combination.
The study enrolled 939 adults with multiple myeloma that had relapsed after one or two prior treatments. People whose cancer no longer responded to a prior anti-CD38 antibody (a type of drug that includes daratumumab) or to bortezomib were not included in the study.
The trial had two parts.
In the first part, researchers tested three different doses of iberdomide combined with daratumumab and dexamethasone. They were compared to DVd to find the dose with the best balance of safety and effectiveness. They selected the 1.0 mg dose to study further. There were 279 patients enrolled in this stage.
In the second part, about 660 more patients were randomly assigned to receive either IberDd with the 1.0 mg dose or DVd.
The main results supporting this approval come from the first 420 patients randomized to IberDd (207 patients) or DVd (213 patients) across both parts of the study. Patients who took IberDd were more likely to reach minimal residual disease (MRD)-negative complete response. An MRD-negative complete response means:
Highly sensitive tests did not find any remaining cancer cells in the bone marrow.
There were no signs of cancer on standard tests.
In the study, 41% of patients on IberDd had an MRD-negative complete response, compared to 21% of patients on DVd.
Researchers are still collecting progression-free survival data, which is how long patients live without the cancer getting worse. Other outcomes, including overall survival and quality of life, are being tracked as secondary measures.
What are the risks of iberdomide?
Iberdomide carries a boxed warning, the FDA's strongest safety warning. This is because it can cause:
Serious birth defects or loss of pregnancy
Blood clots in the veins and arteries (venous and arterial thromboembolism).
Because of the pregnancy risk, iberdomide is only available through a restricted program called the ZENBEXUS REMS (Risk Evaluation and Mitigation Strategy). This program requires patients and prescribers to meet specific safety requirements before the medication can be dispensed.
The prescribing information also includes warnings about neutropenia (low levels of white blood cells that raise the risk of infection), other infections, and the possibility of developing a new, unrelated cancer later on.
IberDd dosing information
Iberdomide is taken by mouth once a day at 1 mg, on days 1 through 21 of a 28-day treatment cycle, with or without food. Daratumumab and hyaluronidase-fihj is given as an injection under the skin, and dexamethasone is taken by mouth, both on a set weekly schedule that becomes less frequent over time. Patients continue treatment until the cancer gets worse or side effects become too difficult to manage.
Next steps for people living with multiple myeloma
If you or a loved one has relapsed or refractory multiple myeloma and has already tried a proteasome inhibitor and an immunomodulatory agent, ask your care team whether IberDd could be an option for your treatment plan.
Questions to ask your care team about IberDd
Is IberDd a good fit for my type and stage of multiple myeloma?
What side effects should I watch for, and when should I call the clinic?
Since this medication has a boxed warning, what does the REMS program require of me?
How will my care team check for minimal residual disease during treatment?
How often will I need blood tests or other monitoring while on this treatment?
A note on the research
This approval is based on early results measuring MRD-negative response. Longer-term data on progression-free survival, overall survival, and quality of life from EXCALIBER-RRMM are still being collected and will help confirm the full benefit of this treatment over time.
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