96P Lung cancer in patients with a history of allogeneic hematopoietic cell transplantation: A retrospective cohort study with a focus on effectiveness and safety of immune checkpoint inhibitors

Background: Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative treatment for various hematologic conditions.As outcomes of HCT recipients have improved markedly over the past decades, secondary malignancies become a more relevant issue.In many solid tumors, including lung cancer (LC), immune checkpoint inhibitors (ICIs) can provide long-term disease control or even cure in some patients (pts).However, data on ICI efficacy in a post-HCT setting is limited, and the risk of graft-vs-host disease (GvHD) raises serious concerns about their use. Methods:We conducted a multinational retrospective cohort study to describe clinical outcomes of pts with a LC diagnosis after prior HCT.Pts with advanced/ metastatic (adv/m) disease were stratified by treatment and overall survival (OS) is reported.Frequencies of immune-related adverse events (IrAE), including new or worsening of preexisting GvHD, are shown by individual lines of therapy (LoTs).Results: A total of 72 pts from 17 centers across Europe were included.Pts had received HCT primarily for acute leukemia (56%) and MDS (11%).Median age at LC diagnosis was 63 years (interquartile range, 56-67) and median time from HCT to LC was 4.1 years (2.7-9.3).Most pts were active or former smokers (82%; 14% unknown).Of 52 patients with adv/m disease, 8 had small cell lung cancer (SCLC) and 44 had non-small cell lung cancer (NSCLC).Median OS in pts with adv/m SCLC was 5.8 months (95% confidence interval CI, 2.7-not calculable).Pts with adv/m NSCLC receiving ICI-based therapies (n=18) had a significantly longer OS than pts treated with chemotherapy alone (n=13) with a median OS of 17.9 vs. 4.7 months (hazard ratio, 0.22; 95% CI, 0.07-0.68;p=0.008).Across 62 individual LoTs evaluable for toxicity, grade 3-5 IrAE occurred in 2 of 25 pts receiving ICIs (8%) compared to 0 of 37 pts receiving other therapies. Conclusions:The findings of this largest study on LC in HCT recipients to date, strongly encourage the use of ICIs given the acceptable risk of IrAEs and potential long-term survival benefits.