Iberdomide

Drug Overview

Iberdomide (also known by its development code CC-220) is a next-generation oral Immunotherapy agent being developed by Bristol Myers Squibb for the treatment of multiple myeloma  a blood cancer that forms in plasma cells inside the bone marrow. It belongs to a powerful new class of medicines called CELMoD agents (Cereblon E3 Ligase Modulators), which are a more advanced evolution of older immunomodulatory drugs like lenalidomide and pomalidomide.

What makes iberdomide especially significant is its ability to work in patients whose disease has stopped responding to those older drugs  an urgent unmet need in myeloma care. In February 2026, the FDA accepted a New Drug Application (NDA) for iberdomide, marking a major milestone on its path to full approval.

• Generic Name: Iberdomide (CC-220)
• US Brand Name: Not yet assigned (investigational)
• Drug Class: CELMoD Agent / Cereblon E3 Ligase Modulator / Immunotherapy / Targeted Therapy
• Route of Administration: Oral (tablet, taken by mouth)
• FDA Approval Status: Not yet approved. The FDA accepted the NDA on February 17, 2026, with a PDUFA target action date of August 17, 2026. The application has received Breakthrough Therapy Designation and Priority Review.

What Is It and How Does It Work? (Mechanism of Action)

To understand iberdomide, it helps to know what keeps myeloma cells alive. Deep inside plasma cells, two proteins called Ikaros (IKZF1) and Aiolos (IKZF3) act like “survival switches.” When these proteins are active, they drive myeloma cell growth, help cancer cells resist treatment, and suppress the immune system’s ability to fight back. Older immunomodulatory drugs (IMiDs) were the first medicines to target these proteins  but they do so weakly and imprecisely.

Iberdomide is a next-generation molecular glue degrader engineered to solve this problem. Here is exactly how it works:

Binding to Cereblon with Higher Affinity: Iberdomide binds to a protein called Cereblon (CRBN), which is part of a larger protein disposal machine inside the cell called the CRL4 E3 ubiquitin ligase complex. Iberdomide binds to cereblon with more than 20 times greater affinity than lenalidomide or pomalidomide, triggering a stronger and faster molecular response.

Targeted Protein Degradation: Once iberdomide locks onto cereblon, it changes cereblon’s shape. This shape change forces the Ikaros and Aiolos proteins to bind to cereblon, where they are immediately tagged with a chemical label called ubiquitin  essentially a “destroy this” signal. The tagged proteins are then sent to the cell’s recycling center, the proteasome, where they are broken down and eliminated.

Killing Myeloma Cells: With Ikaros and Aiolos gone, the myeloma cell loses two of its most important survival signals. This triggers direct cancer cell death (apoptosis) and blocks the expression of cancer-driving genes like IRF4 and c-Myc.

Activating the Immune System: Iberdomide simultaneously stimulates T-cells and Natural Killer (NK) cells in the bone marrow  the body’s own cancer-fighting soldiers  increasing their number and pushing them into an active, aggressive state. Importantly, research published in 2024 showed that iberdomide prevents T-cell exhaustion, keeping immune cells functional and effective over time.

FDA Approved Clinical Indications

Oncological Uses (Under FDA Review as of 2026):

• Relapsed or refractory multiple myeloma (RRMM) in adults who have received 1 to 2 prior lines of therapy, in combination with daratumumab and dexamethasone (IberDd regimen)  NDA under FDA review, PDUFA date August 17, 2026
• Post-autologous stem cell transplant (ASCT) maintenance therapy in newly diagnosed multiple myeloma  Under investigation in the EXCALIBER-Maintenance trial (NCT05827016)

Non-Oncological Uses:

• There are currently no approved or investigated non-oncological indications. Research interest exists in autoimmune conditions driven by IKZF1/IKZF3 dysregulation, but no clinical trials have been initiated in this area.

Dosage and Administration Protocols

Iberdomide is taken orally on days 1 to 21 of a repeating 28-day treatment cycle, followed by 7 days off. During the phase 3 EXCALIBER-RRMM trial, dose optimization identified 1.0 mg daily as the recommended phase 3 dose based on the best balance of safety, efficacy, and pharmacokinetics. No standard dose adjustments for renal or hepatic impairment have been established yet, as these will be defined in the final prescribing information upon FDA approval.

Clinical Efficacy and Research Results

Iberdomide’s clinical story is built on a strong and growing body of evidence. In the pivotal phase 1/2 CC-220-MM-001 trial (NCT02773030), 197 heavily pretreated patients with relapsed or refractory myeloma received iberdomide plus dexamethasone. The overall response rate (ORR) was 32% in the dose-escalation cohort and 26% in the dose-expansion cohort  meaningful results in patients who had received a median of 5 to 6 prior lines of therapy and whose disease had stopped responding to standard drugs.

The phase 2 I2D study evaluated an all-oral combination of iberdomide, ixazomib, and dexamethasone in older patients at first relapse, publishing results in the Journal of Clinical Oncology in May 2024. The ORR reached 65%, with 36% of patients achieving a complete or very good partial response. At a 14-month median follow-up, the 12-month overall survival rate was 86%, progression-free survival was 52%, and duration of response was 76%.

Most recently, the landmark phase 3 EXCALIBER-RRMM trial (NCT04975997) announced in September 2025 that the IberDd regimen achieved a statistically significant improvement in MRD negativity  meaning far fewer detectable cancer cells remained after treatment  compared to the standard daratumumab, bortezomib, and dexamethasone regimen. Progression-free survival data continue to mature. A separate combination study presented at the 2025 ASH Annual Meeting showed an ORR of 95.5% when iberdomide was paired with the bispecific antibody elranatamab in 22 evaluable patients.

Safety Profile and Side Effects

Important Warning  Teratogenicity Risk: Like all cereblon-targeting agents in this drug class, iberdomide is expected to carry a serious risk of causing birth defects if taken during pregnancy, based on its structural and mechanistic similarity to thalidomide. Strict pregnancy prevention measures will be required. Patients and physicians should expect a risk evaluation and mitigation strategy (REMS) program upon approval.

Common Side Effects (>10%):

• Neutropenia (low white blood cell count)  the most frequent serious side effect; increases infection risk; requires routine blood count monitoring
• Anemia  low red blood cell counts; fatigue and weakness may result
• Thrombocytopenia  low platelet counts; monitor for unusual bruising or bleeding
• Infection  including serious bacterial infections; reported in 27% of patients in CC-220-MM-001
• Fatigue and diarrhea  typically low-grade and manageable

Serious Adverse Events:

• Grade 3–4 Neutropenia: Reported in 45% of patients in phase 1/2 trials; managed with growth factor support (e.g., G-CSF) and dose holds
• Serious Infections: Including sepsis; one treatment-related death from sepsis was reported in CC-220-MM-001; requires prompt antibiotic treatment
• Thromboembolic Events (Blood Clots): Preventive anticoagulation therapy is recommended for all patients on iberdomide

Management Strategies:

• For neutropenia: Monitor CBC weekly during early cycles; use G-CSF support as needed; hold or reduce dose for grade 3–4 events
• For infection: Begin broad-spectrum antibiotics promptly; delay treatment until resolution of serious active infections
• For clotting risk: Initiate prophylactic anticoagulation before starting treatment

Connection to Stem Cell and Regenerative Medicine

Iberdomide has a direct and clinically meaningful connection to stem cell therapy in myeloma. The EXCALIBER-Maintenance trial (NCT05827016) is currently comparing iberdomide head-to-head against lenalidomide as post-transplant maintenance therapy following autologous stem cell transplantation (ASCT) in newly diagnosed myeloma patients. Early phase 2 data from the EMN26 trial, reported in December 2023, demonstrated that iberdomide maintenance after ASCT produced a favorable safety profile alongside improved response deepening at 6 months. If confirmed, iberdomide could become the first CELMoD agent used in a post-transplant maintenance setting, fundamentally changing how patients are managed after stem cell transplantation.

Patient Management and Practical Recommendations

Pre-Treatment Tests:

• Complete blood count (CBC) with differential
• Comprehensive metabolic panel (CMP) including liver and kidney function
• Pregnancy test for women of childbearing potential  a negative result is mandatory before starting treatment
• Hepatitis B screening (HBsAg, anti-HBc)
• Baseline assessment of infection risk

Precautions During Treatment:

• Blood counts must be checked regularly, especially during the first few months of therapy
• Effective contraception is mandatory for all patients of reproductive potential during treatment and for a defined period after the last dose
• Male patients must not donate sperm during treatment

Do’s and Don’ts:

• DO take iberdomide at the same time each day on your scheduled dosing days
• DO report fever, chills, or signs of infection to your care team immediately
• DO attend all blood monitoring appointments without skipping
• DON’T become pregnant or father a child during treatment  serious birth defect risk
• DON’T miss doses without telling your oncologist
• DON’T take iberdomide outside of a supervised clinical trial or approved treatment program

Legal Disclaimer

The information in this guide is intended for educational purposes only and does not constitute medical advice, diagnosis, or a treatment recommendation. Iberdomide (CC-220) is an investigational drug that is not yet approved by the US Food and Drug Administration (FDA). Its NDA is currently under FDA review with a PDUFA date of August 17, 2026. Access to this medication is currently available only through participation in approved clinical trials or authorized investigational programs. Always consult a qualified oncologist or licensed healthcare professional before making any treatment decision. This content does not replace professional medical judgment.