22 Association of a germline single nucleotide polymorphism (SNP) in the interleukin-7 (IL7) gene with immune-related adverse events (irAEs)
Authors: Saad Eddy , Mehrabad Elnaz Mirazei , Labaki Chris , Saliby Renée Maria , Semaan Karl , Eid Marc , Machaalani Marc , Chehade Razane El Hajj , Nawfal Rashad , Sun Maxine , Sharon Elad , Shah Parantu , Vemula Sai Vikram , Gupta Saurabh , Braun David , Van Allen Eliezer , Gusev Alexander , Choueiri Toni 
Published: August 2024

Abstract

Background
Adverse events (AEs) can limit treatment immune checkpoint inhibitors (ICI) efficacy and worsen patient outcomes. Our group recently identified a germline IL7 SNP as a potential biomarker for prediction of irAEs (Groha, Nat Med 2022). In the current study, we sought to replicate the association between this IL7 SNP (rs16906115) and AEs in two clinical trials of patients with cancer treated with ICI regimens.

Methods
In the CheckMate-025 (CM025) trial (NCT01668784), involving patients with metastatic renal cell carcinoma (mRCC) randomized to either nivolumab (NIVO) or everolimus (EVE), whole-exome sequencing (WES) data from tumor and peripheral blood samples were analyzed. The Cancer Genome Analysis pipeline was utilized to identify somatic alterations, and the STITCH pipeline was employed to determine SNP carrier status. In the BinTA-0037 (BTA-0037) trial (NCT03631706), focusing on patients with metastatic non-small cell lung cancer (mNSCLC), the carrier status of a surrogate SNP rs16906062 (R2=0.66) was determined from tumor WES in the pembrolizumab (PEMBRO) arm. Within each treatment arm, time to incident AEs were compared between carriers (SNP+) and non-carriers (SNP-) via multivariable Cox regression, controlling for age, sex, race, ECOG and sample purity. A SNP´treatment interaction term was also included in the entire CM025 cohort. Censoring for AEs occurred at death or last follow-up. A recurrent event analysis for AEs was conducted using the Andersen-Gill model, controlling for the same variables. Additionally, overall survival (OS) and progression-free survival (PFS) were also assessed.

Results
In total, 534 pts were included (NIVO: n=189, PEMBRO: n=152, EVE: n=193), among which 82 (15.4%) were SNP+. There were no differences in clinical and pathological characteristics between SNP+ and SNP-, except for sex (SNP+ 16.1% vs. SNP- 30.1% in females, P=0.046). Similarly, no differences in somatic alterations, including single nucleotide and copy number variants were seen between SNP+ and SNP- in CM025. SNP carrier status had no effect on OS nor PFS in all treatment arms (all P≥0.22). The rate of grade 2+ AEs was significantly higher in SNP+ vs. SNP- in the NIVO arm (Figure A, HR=2.91[1.48-5.72]), but not in the EVE (Figure B, control, non-ICI) arm (HR=0.63[0.3-1.29], SNP´treatment Pinteraction=0.002). Similarly, the rate of all grade AEs in the PEMBRO arm of BTA-0037 was higher in SNP+ vs. SNP- (Figure C, HR=2.30[1.60-4.60]). The rate of recurrent grade 2+ AEs was also significantly higher in SNP+ vs. SNP- in the NIVO arm (HR=3.43[1.83-6.43]), whereas a trend for fewer recurrent grade 2+ AEs was seen in SNP+ vs. SNP- in the EVE arm (HR=0.46[0.17-1.25], SNP´treatment Pinteraction=0.0005).
Figure: Kaplan-Meier curves showing the cumulative rate of adverse events in the NIVO (A) and EVE (B) arms of CM025, as well as the PEMBRO arm of BTA0037 (C), in SNP- and SNP+.

Conclusions
The IL7 SNP (rs16906115) is associated with significantly higher rates of grade 2+ AEs, including recurrent events, in pts with mRCC or mNSCLC treated with single agent PD-1 inhibitors but not with non-ICI regimens, with no effect on survival and efficacy outcomes. These results confirm the SNP’s predictive potential as a biomarker for irAEs to guide therapeutic decisions in pts treated with ICIs.