Ifinatamab Deruxtecan Shows Promising Efficacy in Advanced Small Cell Lung Cancer

Patients with recurrent or progressive extensive-stage small cell lung cancer (ES-SCLC) may find a new treatment option in ifinatamab deruxtecan (I-DXd), an innovative B7-H3-targeted antibody-drug conjugate. This finding emerged from data presented at the International Association for the Study of Lung Cancer (IASLC) 2025 World Conference on Lung Cancer (WCLC) held in Barcelona, Spain.

The Phase II IDeate-Lung01 trial involved 137 patients who had undergone at least one prior line of platinum-based chemotherapy. Results showcased a confirmed objective response rate (ORR) of 48.2%, along with a disease control rate of 87.6%. The findings were shared by Dr. Myung-Ju Ahn from Samsung Medical Center in Seoul, South Korea.

Small cell lung cancer, particularly in its extensive stage, often presents a dire prognosis and limited treatment alternatives. Notably, the B7-H3 protein is overexpressed across all SCLC subtypes, which correlates with poorer clinical outcomes, making it a critical target for new therapeutic approaches.

The analysis of the IDeate-Lung01 trial focused on patients who received I-DXd at a dosage of 12 mg/kg intravenously every three weeks during the study's dose optimization and extension phases. As of the data cutoff on March 3, 2025, participants had received I-DXd after one (23.4%), two (54.7%), or three (21.9%) prior lines of systemic therapy. The median follow-up duration was recorded at 12.8 months, revealing a median response duration of 5.3 months and a median time to response of 1.4 months.

Moreover, the median progression-free survival (PFS) was reported at 4.9 months, while the median overall survival (OS) reached 10.3 months. Clinical benefits were observed regardless of the patients' platinum sensitivity or the number of previous treatments they had received. For instance, in the subgroup receiving second-line treatment (n=32), the ORR climbed to 56.3%, with PFS and OS values being numerically greater than those in the overall cohort.

Adverse events related to treatment (TRAEs) of any grade were reported in 89.8% of the patients, with 36.5% experiencing grade 3 or higher TRAEs and 4.4% encountering grade 5 TRAEs. Additionally, adjudicated treatment-related interstitial lung disease or pneumonitis was observed in 17 patients, with six of these cases classified as grade 3 or higher in severity.

The safety profile of I-DXd appeared consistent with previous reports, with no new safety signals identified during the study. The results underscore ifinatamab deruxtecan's significant efficacy in addressing the needs of patients with extensive-stage small cell lung cancer, a group that currently faces substantial unmet medical needs.

Given the manageable safety profile and the high response rates noted in the trial, there is strong support for further investigation of ifinatamab deruxtecan as a treatment option for small cell lung cancer.