Multicenter, single-arm phase II study of modified carboplatin/ nab-paclitaxel in untreated performance status 2 patients with advanced non-small cell lung cancer: TORG1426

Background: Currently, only a few treatment options exist for performance status (PS) 2 patients with advanced non-small cell lung cancer (NSCLC), whereas the carboplatin/nab-paclitaxel (CBDCA/nab-PTX) regimen is attracting attention as a standard of care for PS 0–1 patients because of its wide suitability and modest risk of peripheral neuropathy. However, the treatment dose and schedule should be optimized for PS 2 patients. Therefore, we planned a single-arm phase II study to characterize the efficacy and tolerability of our modified CBDCA/nab-PTX regimen for untreated PS 2 patients with advanced NSCLC. Methods: Enrolled patients were treated with CBDCA (area under the curve 5 on day 1) plus nab-PTX (70 mg/m² on days 1, 8, and 15) every 4 weeks for up to six cycles. The primary endpoint was the progression-free survival (PFS) rate at 6 months. As exploratory analyses, the reasons for PS 2 (disease burden versus comorbidities/indeterminant) and the Charlson Comorbidity Index (CCI) were evaluated as efficacy indicators. Results: This study was terminated early because of slow accrual. Seventeen patients [median age, 68 years (range, 50–73 years)] received a median of three cycles. The 6-month PFS rate, median PFS, and median overall survival were 20.8% [95% confidence interval (CI): 0–41.6], 3.0 months (95% CI: 1.7–4.3), and 9.5 months (95% CI: 5.0–14.0), respectively. Exploratory analyses suggested better overall survival in patients whose PS was not attributable to the disease burden (median, 9.5 vs. 7.2 months) or whose CCI was ≤3 (median, 15.5 vs. 7.2 months). Grade 3–4 adverse events occurred in 12 (71%) patients, and grade 5 pleural infection occurred in one (6%) patient. Meanwhile, only one (6%) patient each experienced grade 1 peripheral neuropathy and grade 2 interstitial pneumonitis. Conclusions: No conclusion could be drawn from this study because of its early termination. However, our modified CBDCA/nab-PTX regimen might be useful for PS 2 patients who hesitate to use regimens other than nab-PTX, and particularly patients concerned about peripheral neuropathy or interstitial pneumonitis. The potential role of PS 2 and CCI as efficacy predictors for this regimen should be further examined.