Induction chemo-immunotherapy followed by chemo-radiotherapy and immunotherapy maintenance in stage III NSCLC (APOLO): a phase 2 trial

Unresectable stage III NSCLC standard treatment is chemo-radiotherapy (CT-RT) followed by immunotherapy (IO) with durvalumab. We investigated adding an induction phase with chemo-immunotherapy (ChIO). APOLO was a multicentre, single-arm, phase 2 trial (NCT04776447). Non-resectable stage IIIA–IIIC NSCLC patients received induction ChIO (atezolizumab + carboplatin + paclitaxel, for 3 cycles), followed by concurrent CT-RT (3 cycles), and IO maintenance (atezolizumab for 16 cycles). Primary objective was 12-month progression-free survival (PFS). Secondary endpoints included 12- and 24-month overall survival (OS), ORR, first-site failure pattern, and safety. Exploratory endpoints included PD-L1, TMB, and ctDNA. 38 patients were enrolled. Median follow-up was 29.6 months (data cutoff, February 2024). PFS was 68.4% (95% CI, 51.1–80.7) at 12 months (statistically significant compared to null hypothesis of 55%) and 50.0% at 24 months; OS was 86.8% and 60.5%, respectively. After induction, 18 (47.4%) had partial response, 14 (36.8%) stable disease, and 5 (13.2%) progressive disease. Overall, 18 patients had disease progression: 8 local (44.4%) and 10 distant (55.6%). Grade ≥3 TRAEs occurred in 11 (28.9%) during induction, 10 (26.3%) during CT-RT, and 2 (5.3%) during maintenance. ChIO induction before CT-RT and IO maintenance showed activity and safety, warranting confirmation in larger studies. Standard of care in patients with unresectable stage III non-small cell lung cancer (NSCLC) is concurrent chemo-radiotherapy followed by immunotherapy. Here, the authors report a phase II trial investigating induction chemo-immunotherapy (atezolizumab, carboplatin and paclitaxel) followed by concurrent chemoradiotherapy and immunotherapy maintenance in patients with stage III NSCLC.