Abstract 4024: Phase 1/2a LYM1002 study of ibrutinib (ibr) + nivolumab (nivo): Exome and gene expression profiling (GEP) analyses by histology and responder status

Abstract

Abstract A phase 1/2a study (LYM1002 [EudraCT 2014-005191-28]) of ibr (560 mg once daily) + nivo (3 mg/kg on a 14-day cycle) demonstrated acceptable safety and promising efficacy vs single-agent ibr in Richter’s transformation (RT), follicular lymphoma (FL), and diffuse large B-cell lymphoma (DLBCL). We examined potential biomarkers of treatment (tx) response using archived biopsy samples. GEP was used for DLBCL subtyping and to assess proportions of 22 distinct immune cells. Exome data were generated from 72 formalin-fixed paraffin-embedded samples, and sequencing analysis was used to identify mutations in genes of interest and assess somatic mutation burden. The correlations of immune cell proportions and gene variants were evaluated by investigator-assessed responses in each histology and by ongoing responses in DLBCL patients (pts; progression-free survival [PFS] > 24 months, n = 7 vs not, n = 20). In pts with available GEP and response data, overall response rates were 29.6% (8/27) for DLBCL, 43.5% (10/23) for FL and 81.3% (13/16) for RT. Proportions of CD8 and follicular helper T cells, M1 macrophages, and resting dendritic cells were higher in DLBCL responders vs nonresponders, while the proportion of regulatory T cells was decreased. These subsets did not differ by response in FL although an increase of CD4 memory resting T-cells was noted in responders. The trend toward increased follicular helper T cell and resting dendritic cell proportions in DLBCL pts was also associated with longer survival (PFS > 24 months) vs not. Gene variant data and responder status were available for 26 pts with DLBCL, 26 with FL, and 17 with RT. Comparison between responders and nonresponders showed that DLBCL pts with RNF213 (4/10 [40.0%] vs 1/16 [6.2%]) and KLHL14 (3/10 [30.0%] vs 0/16) mutations were more likely to respond to ibr + nivo. Conversely, nonresponders were associated with variants in EBF1, ADAMTS20, AKAP9, SOCS1, TP53, and genes in BCR pathways such as TNFRSF14, MYD88, and NFKB1B. BCL2 mutation in FL (9/12 [75.0%] vs 4/14 [28.6%]) and ROS1 mutation in RT (0/13 vs 2/4 [50.0%]) were associated with response; both are involved in the NF-kB pathway. In DLBCL, the most frequent gene mutations were RNF213, NBPF1, and BCL2 in pts who had PFS > 24 months (3/7 [42.9%] each), and KMT2D (8/20 [40.0%]) and CSMD3 (8/20 [40.0%]) in pts who did not. Somatic mutation burden was lower in responders vs nonresponders, especially in germinal center B-cell-DLBCL, and in DLBCL pts with PFS > 24 months vs not. In conclusion, we report gene variations among DLBCL, FL, and RT pts associated with response or durable PFS with ibr + nivo. While ibr inhibits Bruton’s tyrosine kinase-dependent pathways, we identify alternative gene pathway variants that may impact tx outcomes. Immune cell infiltration into the microenvironment relates to differential tx response with this immune combination and is histology dependent. Citation Format: Brendan Hodkinson, Michael Schaffer, Joshua Brody, Wojciech Jurczak, Cecilia Carpio, Dina Ben-Yehuda, Irit Avivi, Rao Saleem, Muhit Özcan, John Alvarez, Rob Ceulemans, Nele Fourneau, Sriram Balasubramanian, Anas Younes. Phase 1/2a LYM1002 study of ibrutinib (ibr) + nivolumab (nivo): Exome and gene expression profiling (GEP) analyses by histology and responder status [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4024.