Dr Johnson on the Initial Efficacy of Ifinatamab Deruxtecan in Refractory SCLC

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Melissa L. Johnson, MD, discusses findings from a subgroup analysis of outcomes with ifinatamab deruxtecan in patients with refractory small cell lung cancer, which she presented at the 2023 IASLC World Conference on Lung Cancer.


Melissa L. Johnson, MD, director, Lung Cancer Research, Sarah Cannon Research Institute; chair, Oncology Department, member, Medical Executive Committee, TriStar Centennial Medical Center, discusses findings from a subgroup analysis of outcomes with ifinatamab deruxtecan (I-DXd; DS-7300) in patients with refractory small cell lung cancer (SCLC), which she presented at the 2023 IASLC World Conference on Lung Cancer.

A phase 1/2 trial (NCT04145622) was conducted to assess the efficacy of I-DXd in heavily pretreated patients with various advanced solid tumors who were unselected for B7-H3 expression. After a median follow-up of 11.7 months, a subgroup analysis of response rates, survival outcomes, and responses based on B7-H3 expression was conducted in the SCLC cohort from part 1 of the study. Patients treated with a dose level of 6.4 mg/kg or less were deemed evaluable for efficacy in the subgroup analysis.

Results showed that I-DXd produced robust, durable responses in this patient subset (n = 22), Johnson states. A reduction in target lesions was seen in nearly all patients with post-baseline scans. At a median follow-up of 11.7 months, the objective response rate with I-DXd was 52.4%, and the median duration of response was 5.9 months. The median progression-free survival (PFS) was 5.6 months, and the median overall survival (OS) was 12.2 months. No new safety signals were observed with I-DXd and the regimen was deemed tolerable, she notes.

Amongst evaluable patients for in the B7-H3 analysis, B7-H3 expression was moderate to high, Johnson continues. No trends of association between best overall response, OS, or PFS and B7-H3 positivity or intensity were observed. Future confirmatory studies of I-DXd will be needed with a larger sample size to further assess the absence of this correlative relationship, Johnson states.

Overall, these findings support the ongoing phase 2 study (NCT05280470) of patients with second- or third-line extensive stage SCLC from this cohort, Johnson concludes.