Open AccessAll in the Levels—Programmed Death‐Ligand 1 Expression as a Biomarker for Immune Checkpoint Inhibitor Response in Patients with Gastrointestinal Cancer
Author(s) -
Das Satya,
Cimino Sarah,
Davis Shemeka,
Ciombor Kristen
Publication year - 2021
Publication title -
the oncologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.176
H-Index - 164
eISSN - 1549-490X
pISSN - 1083-7159
DOI - 10.1002/onco.13526
Subject(s) - pembrolizumab , medicine , biomarker , cancer , immune checkpoint , oncology , microsatellite instability , pd l1 , immunotherapy , response evaluation criteria in solid tumors , immune system , immunology , chemotherapy , phases of clinical research , microsatellite , gene , biochemistry , chemistry , allele
Immune checkpoint inhibitors (ICIs) benefit patients with rare subsets of gastrointestinal (GI) cancer. Significant interest exists to identify predictive biomarkers that may increase the applicability of ICI therapy for these patients. Programmed death ligand 1 (PD‐L1) is one such candidate; however, this biomarker has well‐chronicled limitations. Combined positive score (CPS) ≥1 is the minimum PD‐L1 expression threshold necessary for patients with gastric or gastroesophageal junction (GEJ) cancer to qualify for treatment with pembrolizumab; however, studies suggest that patients with higher CPS scores may derive greater benefit. We present the cases of two patients, both with low tumor mutational burden, microsatellite stable, and CPS ≥70 GI tumors (cholangiocarcinoma and GEJ cancer), who have achieved excellent tumor control with pembrolizumab. We postulate that, by testing for CPS in all patients with GI cancer and identifying a CPS threshold predictive of ICI response, PD‐L1 expression could identify the patiets with GI cancer, in tissue agnostic fashion, who could benefit from ICI therapy.