A multicenter, open-label, phase II trial of S-1 plus carboplatin in advanced non-small cell lung cancer patients with interstitial lung disease

•The benefit of chemotherapy for advanced NSCLC patients with ILD remain unclear.•The efficacy of S-1 plus CBDCA in NSCLC patients with ILD was assessed in this study.•The overall response rate was 33.3%, which met the primary endpoint.•The incidence of AE-ILD was 6.1%, indicating the feasibility of S-1 plus CBDCA.•The combination of S-1 with CBDCA is a treatment option for NSCLC patients with ILD. The clinical benefit of chemotherapy and the appropriate regimen for non-small-cell lung cancer (NSCLC) patients with interstitial lung disease (ILD) remain unclear. To fulfill this unmet medical need, we conducted a phase II study to elucidate the efficacy of S-1 in combination with carboplatin (CBDCA) in NSCLC patients with ILD. A total of 33 advanced or recurrent NSCLC patients with ILD were prospectively enrolled in this multicenter, open-label, phase II study. Every 4 weeks, CBDCA at a dose of AUC 5 on day 1 and S-1 at a dose of 80 mg/m2 daily for 14 days were administered. The primary endpoint was the investigator-assessed objective response rate. The median age at initiating chemotherapy was 70. Sixteen patients (48.5%) had squamous cell carcinoma histology. With respect to the types of ILD, the usual interstitial pneumonia pattern was dominant (66.7%). The median number of cycles administered was 3, and the overall response rate and disease control rate were 33.3% and 78.8%, respectively. The median progression-free survival, the median survival time and the 1-year survival rate were 4.8 months, 12.8 months and 51.4%, respectively. Acute exacerbation of ILD caused by chemotherapy was noted in 2 patients (6.1%). This is the first prospective study designed to evaluate the efficacy of a specific chemotherapeutic regimen as the primary endpoint in patients with advanced NSCLC with ILD. The combination of S-1 with CBDCA may be a treatment option for advanced NSCLC patients with ILD (The clinical trial registration number: UMIN000011046).