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Adding talazoparib to standard atezolizumab maintenance can improve progression-free survival (PFS) in patients with SLFN11-positive extensive-stage small cell lung cancer (ES-SCLC), a phase 2 trial suggests.
Patients who received talazoparib and atezolizumab maintenance had a 30% lower risk of progression or death than patients who received atezolizumab maintenance alone, the data showed.
These data were presented at the ASCO Annual Meeting 2023 by Nagla Fawzy Abdel Karim, MD, of Inova Schar Cancer Institute and the University of Virginia in Fairfax.
The phase 2 trial (ClinicalTrial.gov Identifier: NCT04334941) included 106 patients with SLFN11-positive ES-SCLC who had undergone induction with platinum chemotherapy, atezolizumab, and etoposide.
The patients were randomly assigned to maintenance with either atezolizumab plus talazoparib (n=54) or atezolizumab alone (n=52). Baseline characteristics were well balanced between the arms. Overall, the median age was 66.8 (range, 44.6-84.0) years, 52% of patients were men, and 25% had prior thoracic radiation.
At a median follow-up of 5.0 months, the median PFS was 4.2 months in the talazoparib arm and 2.8 months for patients who received atezolizumab alone (hazard ratio [HR], 0.70; 80% CI, 0.52-0.94; P =.056).
Subgroup analyses suggested that patients who received prior thoracic radiation, had brain metastases, and did not have liver or bone metastases had improved PFS outcomes.
Overall survival (OS) data were not mature, but there was no significant difference in OS between the arms. The median OS was 9.4 months in the talazoparib arm and 8.5 months for patients who received atezolizumab alone (HR, 1.17; 80% CI, 0.80-1.71; P = .30).
Grade 3 or higher hematologic adverse events (AEs) were more common in the talazoparib arm than in the atezolizumab-alone arm (50% and 4%, respectively; P <.0001). Rates of grade 3 or higher non-hematologic AEs were similar between the arms (15% and 13%, respectively).
Dr Karim noted that the increase in hematologic AEs in the talazoparib arm was expected and driven mainly by grade 3 anemia. The rate of grade 3 anemia was 37% in the talazoparib arm and 2% in the atezolizumab-alone arm.
Three patients discontinued treatment due to toxicity — 2 in the atezolizumab-alone arm and 1 in the talazoparib arm. There were no treatment-related deaths.
“This study demonstrates the feasibility of conducting biomarker-selected trials in small-cell lung cancer, paving the way for future evaluation of novel therapies in selected small-cell lung cancer populations,” Dr Karim said.
Disclosures: This research was partly supported by Genentech. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Karim NFA, Miao J, Reckamp KL, et al. SWOG S1929: Phase II randomized study of maintenance atezolizumab (A) versus atezolizumab + talazoparib (AT) in patients with SLFN11 positive extensive stage small cell lung cancer (ES-SCLC). ASCO 2023. June 2-6, 2023. Abstract 8504.
This article originally appeared on Cancer Therapy Advisor
