MA08.06 Impact of Depth of Response (DpR) on Survival in Patients with Advanced NSCLC Treated with First-Line Chemotherapy

Abstract

DpR, defined as maximum tumor shrinkage, has emerged as a potential predictor for long-term treatment outcome across multiple tumors, including NSCLC treated with immunotherapy or targeted therapy. This exploratory analysis evaluated whether DpR correlated with survival in patients with advanced NSCLC treated with platinum-doublet chemotherapy in a phase III randomized clinical trial. Patients received first-line nab-paclitaxel 100 mg/m2 weekly or paclitaxel 200 mg/m2 q3w, both + carboplatin AUC 6 q3w. The current analysis evaluated DpR as best percent change from baseline in total target lesion length during treatment. For patients with tumor shrinkage, data were grouped into quartiles based on maximum percent shrinkage from baseline (Q1: > 0%-≤ 25%; Q2: > 25%-≤ 50%; Q3: > 50%-≤ 75%, Q4: > 75%) and compared with data from patients with no change or tumor growth (NC/G). Tumor measurement by independent review (baseline and postbaseline) was evaluable in 959 patients pooled across treatments. The median (Figure) and 1-year OS increased with each quartile vs NC/G (NC/G: 4.8 months and 17%; Q1: 10.4 months and 44%; Q2: 14.5 months and 62%; Q3: 19.3 months and 71%; Q4: 23.5 months and 70%) with HRs for OS vs NC/G of 0.42 for Q1 (95% CI, 0.33-0.53; P < 0.0001), 0.28 for Q2 (0.22-0.36; P < 0.0001), 0.23 for Q3 (0.16-0.31; P < 0.0001), and 0.19 for Q4 (0.11-0.33; P < 0.0001), respectively. Similar findings were observed for all quartiles vs NC/G for age (≥ 70 and < 70 years) and histology (squamous and nonsquamous) in subset analyses (P < 0.05 for all comparisons). DpR was associated with increased OS in patients with advanced NSCLC receiving first-line platinum-based doublet chemotherapy, regardless of age or histology. These findings underscore the importance of evaluating quality of treatment response in this patient population.