Real world efficacy and toxicity of consolidation durvalumab following chemoradiotherapy in older Australian patients with unresectable stage III non-small cell lung cancer

Introduction: Consolidation durvalumab following platinum-based chemoradiotherapy (CRT) significantly improved overall survival for patients with unresectable stage III non-small cell lung cancer (NSCLC) in the PACIFIC trial. However, older patients were underrepresented in PACIFIC, and subsequent analyses suggested trends toward poorer survival and increased toxicity in patients aged ≥70 years old. We assessed the effectiveness and safety of consolidation durvalumab following CRT in older Australian patients with unresectable stage III NSCLC. Materials and Methods: This retrospective observational study was conducted across seven sites in Sydney, Australia between January 2018 and September 2021. All adult patients with unresectable stage III NSCLC who received platinum-based chemoradiotherapy followed by at least one cycle of consolidation durvalumab were included. Older patients were defined as being ≥70 years old. Results: Of 152 patients included in the analysis, 42.8% (n = 67) patients were 70 years or older. Median follow-up was 26.1 months. The two-year overall survival and median PFS was similar between older and younger patients. At two years, 74.8% (95% confidence interval [CI]: 65.4–84.2%) of patients <70 years old and 65.2% (95% CI: 53.4–77.0%) of older patients were alive (p = 0.07; hazard ratio [HR] 1.64, 95% CI: 0.95–2.81). Median progression-free survival (PFS) in patients <70 years was 30.3 months (95% CI: 22.2–38.4 months) compared with 26.7 months (95% CI: 12.8–40.6 months) in older patients (p = 0.22; HR 1.46, 95% CI: 0.80–2.65). Toxicity was also similar, with 11.5% of patients <70 years old and 18.5% of older patients experiencing grade 3–4 adverse events (AEs; p = 0.23); 16.1% and 24.6% of the patients, respectively, discontinued treatment due to toxicity (p = 0.19). Grade 3–4 AEs and treatment discontinuation were associated with Charlson Comorbidity Index >5 (p = 0.011) and chronic obstructive pulmonary disease diagnosis at presentation (p = 0.002), respectively. Discussion: Older Australian patients receiving consolidation durvalumab following CRT experienced comparable outcomes to their younger peers. Comorbidity burden may be more important determinants of treatment tolerance than chronological age.