Evaluation of Major Pathologic Response and Pathologic Complete Response as Surrogate End Points for Survival in Randomized Controlled Trials of Neoadjuvant Immune Checkpoint Blockade in Resectable in NSCLC.

INTRODUCTION: Controversy remains as to whether pathologic complete response (pCR) and major pathologic response (MPR) represent surrogate end points for event-free survival (EFS) and overall survival (OS) in neoadjuvant trials for resectable NSCLC. METHODS: A search of PubMed and archives of international conference abstracts was performed from June 2017 through October 31, 2023. Studies incorporating a neoadjuvant arm with immune checkpoint blockade alone or in combination with chemotherapy were included. Those not providing information regarding pCR, MPR, EFS, or OS were excluded. For trial-level surrogacy, log ORs for pCR and MPR and log hazard ratios for EFS and OS were analyzed using a linear regression model weighted by sample size. The regression coefficient and R2 with 95% confidence interval were calculated by the bootstrapping approach. RESULTS: Seven randomized clinical trials were identified for a total of 2385 patients. At the patient level, the R2 of pCR and MPR with 2-year EFS were 0.82 (0.66-0.94) and 0.81 (0.63-0.93), respectively. The OR of 2-year EFS rates by response status was 0.12 (0.07-0.19) and 0.11 (0.05-0.22), respectively. For the 2-year OS, the R2 of pCR and MPR were 0.55 (0.09-0.98) and 0.52 (0.10-0.96), respectively. At the trial level, the R2 for the association of OR for response and HR for EFS was 0.58 (0.00-0.97) and 0.61 (0.00-0.97), respectively. CONCLUSIONS: Our analyses reveal a robust correlation between pCR and MPR with 2-year EFS but not OS. Trial-level surrogacy was moderate but imprecise. More mature follow-up and data to assess the impact of study crossover are needed.

Systematic review and meta-analysis of immune checkpoint inhibitors as single agent or in combination with chemotherapy in early-stage non-small cell lung cancer: Impact of clinicopathological factors and indirect comparison between treatment strategies.

BACKGROUND: In non-small cell lung cancer (NSCLC), the immune checkpoint inhibitors (ICI) revolution is rapidly moving from metastatic to early-stage, however, the impact of clinicopathological variables and optimal treatment sequencing remain unclear. METHODS: Randomized controlled trials (RCTs) in patients with early-stage NSCLC treated with ICI as single agent or in combination with platinum-based chemotherapy (PCT) were included. Primary outcomes were pathological complete response (pCR), event free survival (EFS) (neoadjuvant/perioperative), and disease-free survival (DFS) (adjuvant). Secondary outcomes were major pathological response (MPR), overall survival (OS), toxicity, surgical outcomes (neoadjuvant/perioperative); OS and toxicity (adjuvant). An additional secondary endpoint was to compare EFS and OS between neoadjuvant and perioperative strategies. RESULTS: 8 RCTs (2 neoadjuvant, 4 perioperative, 2 adjuvant) (4661 participants) were included. Neoadjuvant/perioperative ICI+PCT significantly improved pCR, EFS, OS, MPR and R0 resection compared to PCT. Adjuvant ICI significantly improved DFS compared to placebo. There was a significant subgroup interaction by PD-L1 status (χ2 = 10.72, P = 0.005), pCR (χ2 = 17.80, P < 0.0001), and stage (χ2 = 4.46, P = 0.003) for EFS. No difference according to PD-L1 status was found for pCR, with 14% of patients having PD-L1 negative tumors still experiencing a pCR. No interaction by PD-L1 status was found for DFS upon adjuvant ICI. Indirect comparison showed no difference in EFS and OS between neoadjuvant and perioperative ICI+PCT. CONCLUSIONS: PD-L1 status, pCR and stage impact on survival upon neoadjuvant/perioperative ICI. The restriction of neoadjuvant/perioperative ICI to PD-L1 + patients could preclude pCR and long-term benefit in the PD-L1- subgroup. Neoadjuvant and perioperative could be equivalent strategies.

Sex dimorphism and cancer immunotherapy: May pregnancy solve the puzzle?

In the immunoncology era, growing evidence has shown a clear sex dimorphism in antitumor immune response with a potential impact on outcomes upon immunecheckpoint blockade (ICI) in patients with cancer. Sex dimorphism could affect tumor microenvironment composition and systemic anticancer immunity; however, the modifications induced by sex are heterogeneous. From a clinical perspective, six metanalyses have explored the role of sex in cancer patients receiving ICI with conflicting results. Environmental and reproductive factors may further jeopardize the sex-related heterogeneity in anticancer immune response. In particular, pregnancy is characterized by orchestrated changes in the immune system, some of which could be long lasting. A persistence of memory T-cells with a potential fetal-antigen specificity has been reported both in human and mice, suggesting that a previous pregnancy may positively impact cancer development or response to ICI, in case of fetal-antigen sharing from tumor cells. On the other hand, a previous pregnancy may also be associated with a regulatory memory characterized by increased tolerance and anergy towards cancer-fetal common antigens. Finally, fetal-maternal microchimerism could represent an additional source of chronic exposure to fetal antigens and may have important immunological implications on cancer development and ICI activity. So far, the role of pregnancy dimorphism (nulliparous vs parous) in women and the impact of pregnancy-related variables remain largely underexplored in cancer patients. In this review, we summarize the evidence regarding sex and pregnancy dimorphism in the context of immune response and anticancer immunotherapy and advocate the importance of analyzing pregnancy variables on ICIs clinical trials.