Adding Amgen’s immunotherapy drug Imdelltra to AstraZeneca’s Imfinzi slashed the risk of death by 58% in patients with extensive-stage small cell lung cancer, according to late-stage trial results. The maintenance regimen extended median overall survival to 21.1 months compared with 12.7 months using AstraZeneca’s drug alone.
In Plain English: The Clinical Takeaway
- Mechanism of action: Imdelltra binds to a protein called DLL3 on tumor cells and CD3 on T cells, drawing the body’s immune system directly into contact with the cancer to destroy it.
- Maintenance therapy: The combination was tested on patients who had already received initial chemotherapy and Imfinzi, and whose cancer had not progressed further.
- Survival impact: Nearly 80% of patients taking both drugs survived to one year, compared with 53% receiving Imfinzi alone.
Extending Survival in Aggressive Small Cell Lung Cancer
Small cell lung cancer remains notoriously difficult to treat because the fast-growing disease typically returns or progresses within months, even after initial chemotherapy succeeds. Approximately 31,000 new cases are diagnosed annually in the U.S., with 60% to 70% presenting as extensive-stage disease that has spread beyond the original lung site. Dr. Jacob Sands, associate chief of the Lowe Center for Thoracic Oncology at Dana-Farber Cancer Institute and lead trial investigator, noted that while immunotherapy has helped a small subset of patients achieve long-term control, most do not experience durable benefits.
The late-stage trial evaluated whether adding Amgen’s Imdelltra to AstraZeneca’s Imfinzi as a maintenance therapy could improve outcomes. The regimen extended median overall survival to 21.1 months, up from 12.7 months with Imfinzi alone. Dr. Paul Burton, Amgen’s chief medical officer, stated that the data could transform the standard of care and potentially convert an aggressive malignancy into a chronic disease.
| Treatment Regimen | Median Overall Survival | One-Year Survival Rate |
|---|---|---|
| Imdelltra plus Imfinzi (Combination) | 21.1 months | Nearly 80% |
| Imfinzi Alone (Control) | 12.7 months | 53% |
Cellular Targets and Early Treatment Trajectories
The therapeutic efficacy of the combination relies on complementary biological pathways. Imfinzi is an immunotherapy that blocks PD-L1, a protein utilized by cancer cells to evade immune detection, effectively removing the brakes on the patient’s immune response. Concurrently, Imdelltra acts as a bispecific engager, attaching to DLL3 on cancer cells and CD3 on T cells to bridge the immune cells directly to the tumor.
Trial results indicated that the survival benefit extended across patient subgroups, including individuals whose cancer had metastasized to the brain or liver—organs typically associated with poorer prognoses. Researchers presented these findings at the European Society for Medical Oncology Congress. Amgen reported that Imdelltra generated $627 million in global sales in 2025 and posted $288 million in the second quarter, positioning the treatment to surpass the $1 billion blockbuster threshold.
Contraindications & When to Consult a Doctor
Imdelltra is currently approved specifically for patients whose small cell lung cancer has progressed while they are on, or after, platinum-based chemotherapy.
Kate Brenan, a 44-year-old mother of two from Denver diagnosed with extensive-stage small cell lung cancer in early January 2024, began receiving Imdelltra in September 2024 after undergoing chemotherapy and radiation. She has maintained no evidence of disease since starting the therapy.
References
- European Society for Medical Oncology Congress Clinical Trial Presentations
