Abstract 68P
Background
Orient-31, the first phase III trial to confirm the progression-free survival (PFS) benefit of IO in patients (pts) with EGFR-TKI-resistant NSCLC, also showed that 74 (46%) of the pts in the chemo group received subsequent IO. Here we undertook a post-hoc analysis to further investigate the OS benefit of IO in EGFR-TKI-resistant NSCLC pts who have received chemo treatment.
Methods
We conducted a post-hoc analysis of the chemo group from Orient-31 trial based on whether patients received IO therapy after progression. The balance of baseline characteristics between the IO and Non-IO groups was assessed using Pearson’s chi-square test, and treatment regimens post-chemo progression were analyzed. The primary endpoint was OS, measured from first new therapy after chemo failure to death. Treatment effects were estimated using unstratified Cox proportional hazard model; medians were estimated using the Kaplan–Meier method.
Results
Baseline characteristics were balanced across IO group(N=74) and Non-IO group(N=88), with a median follow-up of 14.4 months (IQR 9.8–23.8). PFS during chemo showed no difference between the two groups (p=0.85), with a median PFS of 4.4 months (95% CI 4.2, 5.6) in IO group and 4.1 months (95% CI 3.1, 5.4) in Non-IO group. After chemo progression, among IO group and Non-IO group, the proportions receiving EGFR-TKI therapy were 31 (42%) and 29 (33%) (p=0.24), chemo ± bevacizumab were 38 (51%) and 22 (25%) (p < 0.01), other anti-angiogenic therapies were 28 (38%) and 12 (14%) (p < 0.01), and other targeted therapies were 4 (5.4%) and 6 (6.8%)(p=0.71) respectively. Median OS was 16.7 months (95% CI 14, NA) in IO group vs 7.8 months (95% CI 5.7, 13.8) in Non-IO group, HR 0.46 (95% CI 0.30, 0.71, p=0.001). The Cox multivariate analysis revealed that immunotherapy is significantly associated with a decreased risk of death (HR 0.52, 95% CI 0.32–0.86, p=0.011).
Conclusions
In this post-hoc analysis, significantly improved OS was observed in pts who crossed over to receive IO after progression on chemo. The results suggest that for EGFR-TKI resistant pts, receiving immunotherapy in later line treatment can still provide survival benefit.
Clinical trial identification
NCT03802240.
Legal entity responsible for the study
The authors.
Funding
Innovent Biologics, Suzhou, China.
Disclosure
All authors have declared no conflicts of interest.