Interchangeability of anti-PD1 antibodies in patients (pts) with metastatic NSCLC.

Abstract

e20553 Background: PD-(L)1 inhibitors are approved immunotherapy agents in treatment for mNSCLC, however, limited data exists about switching between different anti-PD1 antibodies. Our study aimed to evaluate the safety and efficacy of the interchangeability of nivolumab, pembrolizumab, and atezolizumab in patients (pts) with mNSCLC in the 2nd and 3rd line. Methods: We retrospectively evaluated data of pts with mNSCLC treated in four oncology centers in Moscow and SaintPetersburg (Russia). Inclusion criteria were as follows: histologically confirmed mNSCLC with no driver mutations, performance status ECOG 0-2, monotherapy of anti-PD(L)1 antibody, and switching to another PD(L)1 inhibitor for any reason except progression disease or toxicity after initiating of immunotherapy. The primary end-point was progression-free survival (PFS), and secondary end-points were the rate of all grades and grade 3-4 adverse events (CTC AE 5.0). A sample size of 83 achieves 80% power to detect an equivalence difference of 15% in 3-months PFS after the change of anti-PD1 antibody with a one-sided significance level of 0,05. Results: A total of 103 patients (27% female) were included with a mean age of 66 years (33-93). 0-1, 2, and ≥3 organs with metastases have 70 (68%), 17 (17%), and 16 (16%) pts, respectively. Performance status ECOG 0, 1, and 2 was in 16 (16%), 70 (68%), and 17 (17%) pts, respectively. 50 (48%) patients received pembrolizumab, 40 (39%) pts received nivolumab, and 13 (13%) pts – atezolizumab. 48 (47%) pts were switched to atezolizumab, 28 (27%) pts were switched to nivolumab, 26 (25%) pts – to pembrolizumab. The median duration of treatment with the first anti-PD(L)1 antibody was 6 months (1-53 months), with the second PD(L)1-inhibitor was 3 months (1-41 months). Within 3 months after 1 replacement of the drug, there were 77 (74,7%) pts without progression. With the median follow-up of 8 months (1-41), the estimated 3-month PFS was 79,3%. The efficacy of switching was not associated with the agent (HR 0,97, 95CI 0,68-1,38, p = 0,9). There were 2 cases of AEs of 3-4 grades when switching to the second drug. Conclusions: Switching from one anti-PD(L)1 antibody to another in pts with mNSCLC is possible in case of limited access to PD(L)1 inhibitors.