FDA Approves Iberdomide, A New Multiple Myeloma Treatment

In August 2026, the US Food and Drug Administration (FDA) granted accelerated approval for a new oral multiple myeloma treatment, iberdomide (also known as Zenbexus), to be used together with daratumumab, hyaluronidase-fihj and dexamethasone. This provides a new treatment option for patients who have not yet responded to other treatments.

To achieve accelerated approval, iberdomide was given priority review by the FDA, and labelled as a breakthrough therapy and orphan drug, as it treats a rare, serious and life-threatening disease.

Multiple myeloma is a rare disease that occurs in around 10% of blood cancer cases. It starts in the plasma cells, a type of white blood cell found in the bone marrow. These cells are typically involved in defending the body from infections.

Currently, there are no routine screening tests available for multiple myeloma. Cases are usually detected through routine blood tests, if results show elevated protein levels or abnormal kidney function.

Iberdomide belongs to ​a new class of drugs called cereblon E3 ligase modulatory drugs (CELMoDs). It works by targeting the cereblon protein, helping the body break down myeloma cancer cells faster than older treatments.

Its efficacy is being evaluated in a few trials, including the EXCALIBER-Maintenance (NCT05827016) and EXCALIBER-RRMM (NCT04975997) trials.

The lead investigator of the EXCALIBER-RRMM trial and chief medical officer of the Winship Cancer Institute of Emory University, Sagar Lonial, MD, FACP, FASCO, shared: “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.”

According to him, the strong results observed indicated potential for “a new treatment foundation in multiple myeloma”.

While approval for iberdomide has been accelerated, the prescribing information for the drug includes a warning for potential harmful effects on a developing fetus (also known as embryo-fetal toxicity), as well as risks of thromboembolism (blood clot formation in a blood vessel). There is also a risk of neutropenia (low white blood cells), infections, and secondary primary cancers.

Due to the risk of embryo-fetal toxicity, iberdomide can only be accessed through a restricted distribution program: the ZENBEXUS Risk Evaluation and Mitigation Strategy. This helps to control the chain of supply so that the drug is only provided to patients after evaluation by an authorized physician, reducing the risk of adverse side effects occurring.