Sex Differences in the Efficacy of Immune Checkpoint Inhibitors in Neoadjuvant Therapy of Non-Small Cell Lung Cancer: A Meta-Analysis

Simple Summary Immune checkpoint inhibitors (ICIs) have transformed the treatment paradigm for metastatic non-small cell lung cancer (NSCLC) patients (IB-IIIA) with no targetable driver mutations. Although genetic and physiological factors could suggest a priori differences in response to ICIs regarding sex, there are few works addressing it, and the available results are confusing. It is well established that women have a more proficient immune system; thus, a higher immune editing level is needed to develop metastatic disease, which could explain their better responses in the early phases of disease. Furthermore, the encouraging results observed for metastatic disease have promoted the use of ICIs as neoadjuvant treatments. Here, we aimed to first review the landscape of current neoadjuvant settings used in resectable NSCLC patients, before analyzing whether sex may be a factor that modulates responses to ICIs. To this end, we have carried out a meta-analysis of the available data.Abstract Non-small cell lung cancer (NSCLC) is one of the world's leading causes of morbidity and mortality. ICIs alone or combined with chemotherapy have become the standard first-line treatment of metastatic NSCLC. The impressive results obtained have stimulated our interest in applying these therapies in early disease stage treatments, as neoadjuvant immunotherapy has shown promising results. Among many of the factors that may influence responses, the role played by sex is attracting increased interest and needs to be addressed. Here, we aim to first review the state of the art regarding neoadjuvant ICIs, whether they are administered in monotherapy or in combination with chemotherapy at stages IB-IIIA, particularly at stage IIIA, before analyzing whether sex may influence responses. To this end, a meta-analysis of publicly available data comparing male and female major pathological responses (MPR) and pathological complete responses (pCR) was performed. In our meta-analysis, MPR was found to be significantly higher in females than in males, with an odds ratio (OR) of 1.82 (95% CI 1.13-2.93; p = 0.01), while pCR showed a trend to be more favorable in females than in males, but the OR of 1.62 was not statistically significant (95% CI 0.97-2.75; p = 0.08). Overall, our results showed that sex should be systematically considered in future clinical trials settings in order to establish the optimal treatment sequence.