I-DXd Earns FDA Priority Review in Extensive-Stage Small Cell Lung Cancer

The FDA has granted priority review to a biologics license application (BLA) seeking approval for ifinatamab deruxtecan (I-DXd) as a treatment for those with extensive-stage small cell lung cancer (ES-SCLC) following progression on or after platinum-containing chemotherapy, according to a press release from the developer, Daiichi Sankyo.¹

The agency has assigned a Prescription Drug User Fee Act date of October 10, 2026, for approving I-DXd in this patient population. The BLA will be assessed as part of the Real-Time Oncology Review program and Project Orbis, which are collectively intended to bring novel cancer therapies to patient as soon as possible.

“The FDA’s granting of priority review for ifinatamab deruxtecan marks a significant milestone in our effort to provide new and innovative treatment options for patients with [ES-SCLC],” John Tsai, MD, global head of Research & Development at Daiichi Sankyo, stated in the press release.¹ “We look forward to continuing to work with the FDA to bring this potential first-in-class B7-H3–directed DXd antibody drug conjugate to patients as quickly as possible.”

Supporting data for the BLA came from the phase 2 IDeate-Lung01 trial (NCT05280470) assessing I-DXd in patients with previously treated ES-SCLC as well as the pan tumor phase 1/2 IDeate-PanTumor01 trial (NCT04145622). Updated findings from the IDeate-Lung01 trial were published in The Journal of Clinical Oncology.²

Among 137 patients who received 12 mg/kg of I-DXd across parts 1 and 2 of the study, the confirmed objective response rate (ORR) was 48.2% (95% CI, 39.6%-56.9%), with a disease control rate (DCR) of 87.6% (95% CI, 80.9%-92.6%). Additionally, the median progression-free survival (PFS) per blinded independent central review (BICR) was 4.9 months (95% CI, 4.2-5.5), and the median overall survival (OS) was 10.3 months (95% CI, 9.1-13.3).

Safety data revealed any-grade treatment-related adverse effects (TRAEs) in 89.8% of the study population; 36.5% of patients experienced grade 3 or higher toxicities. The most common TRAEs of any grade included nausea (43.1%), anemia (34.1%), and neutropenia (34.3%). Of note, treatment-associated interstitial lung disease (ILD) or pneumonitis based on adjudication committee evaluation occurred in 12.4% of patients.

“[T]his phase 2 trial demonstrated the promising efficacy of I-DXd [at] 12 mg/kg in patients with previously treated ES-SCLC. ILD was confirmed as an important identified risk that, to reduce the risk of serious adverse outcomes, warrants comprehensive education and surveillance to allow prompt identification and management using established guidelines,” lead study author Charles M. Rudin, MD, PhD, Cancer Center deputy director, co-director at Druckenmiller Center for Lung Cancer Research, and Sylvia Hassenfeld Chair in Lung Cancer Research at Memorial Sloan Kettering Cancer Center, wrote with coauthors in the publication.² “Although the safety profile does require monitoring for ILD, it is manageable with due care, so the overall benefit-risk profile of the 12-mg/kg dose is favorable.”

In the international, open-label, phase 2 IDeate-Lung01 trial, investigators assessed I-DXd among patients with ES-SCLC across 2 parts. In the dose-optimization phase of the study, patients were randomly assigned to I-DXd at 8 mg/kg or 12 mg/kg. In the extension phase, patients received the agent 12 mg/kg based on results from part 1 of the trial.

The trial’s primary end point was confirmed ORR based on BICR evaluation using RECIST v1.1 criteria. Secondary end points included DCR, duration of response, time to response, and PFS. Patients 18 years and older with histologically or cytologically confirmed ES-SCLC who received at least 1 prior line of platinum-based chemotherapy and at least 3 prior lines of systemic treatment were eligible for enrollment on the trial.

References

1. Ifinatamab Deruxtecan granted priority review in the U.S. for adult patients with previously treated extensive-stage small cell lung cancer who experienced disease progression on or after platinum-based chemotherapy. News release. Daiichi Sankyo. April 13, 2026. Accessed April 14, 2026. https://tinyurl.com/4txu4rr9
2. Rudin CM, Johnson ML, Paz-Ares Let al. Ifinatamab deruxtecan in patients with extensive-stage small cell lung cancer: primary analysis of the phase II IDeate-Lung01 Trial. J Clin Oncol. 2026;44(4):261-273. doi:10.1200/JCO-25-02142.