Ifinatamab deruxtecan may benefit patients with recurrent or progressive ES-SCLC

Patients diagnosed with recurrent or progressive extensive-stage small cell lung cancer (ES-SCLC) may benefit from treatment with ifinatamab deruxtecan (I-DXd), a B7-H3–directed antibody–drug conjugate, according to data presented today at the International Association for the Study of Lung Cancer (IASLC) 2025 World Conference on Lung Cancer (WCLC) in Barcelona, Spain.

New data from the Phase 2 IDeate-Lung01 trial in 137 patients who had received ≥1 prior line of platinum-based chemotherapy showed a confirmed objective response rate (ORR) of 48.2% and a disease control rate of 87.6%, according to results presented by Myung-Ju Ahn, MD, Samsung Medical Center, Seoul, Republic of Korea.

Patients with ES-SCLC face poor prognoses and have limited treatment options. B7-H3 is overexpressed in all subtypes of SCLC, and its overexpression is associated with worse clinical outcomes, making it an attractive target for novel therapies. This analysis of IDeate-Lung01 included patients treated with I-DXd 12 mg/kg intravenously every three weeks during the dose optimization and extension parts of the study.

At the March 3, 2025 data cutoff, 137 patients had received I-DXd after one (23.4%), two (54.7%), or three (21.9%) prior lines of systemic therapy. After a median duration of follow-up of 12.8 months, median duration of response was 5.3 months, and median time to response was 1.4 months. Median progression-free survival (PFS) was 4.9 months, and median overall survival (OS) was 10.3 months. Clinical benefit was observed regardless of platinum sensitivity or number of prior treatments. For example, among the second-line subgroup (n=32), ORR was 56.3% and PFS and OS were numerically longer than in the overall population.

Treatment-related adverse events (TRAEs) of any grade occurred in 89.8% of patients, with 36.5% of patients experiencing a TRAE of grade 3 or higher, and 4.4% of patients experiencing grade 5 TRAEs. Adjudicated treatment-related interstitial lung disease/pneumonitis occurred in 17 patients, of which 6 cases were grade ≥3 severity. Safety findings were consistent with prior reports, with no new safety signals observed.

These results demonstrate the remarkable efficacy of ifinatamab deruxtecan in patients with ES-SCLC population who have a substantial unmet need. The manageable safety profile and high response rates support further investigation of I-DXd[RL1] in small cell lung cancer."

Dr. Myung-Ju Ahn, MD, Samsung Medical Center, Seoul, Republic of Korea