Supplementary Table from Phase IB Study of GITR Agonist Antibody TRX518 Singly and in Combination with Gemcitabine, Pembrolizumab, or Nivolumab in Patients with Advanced Solid Tumors
posted on 2023-03-31, 23:44authored byDiwakar Davar, Roberta Zappasodi, Hong Wang, Girish S. Naik, Takami Sato, Todd Bauer, David Bajor, Olivier Rixe, Walter Newman, Jingjing Qi, Aliya Holland, Phillip Wong, Lianna Sifferlen, Diane Piper, Cynthia A. Sirard, Taha Merghoub, Jedd D. Wolchok, Jason J. Luke
Supplementary Table from Phase IB Study of GITR Agonist Antibody TRX518 Singly and in Combination with Gemcitabine, Pembrolizumab, or Nivolumab in Patients with Advanced Solid Tumors
Funding
NCI
ETCTN Pittsburgh Cancer Consortium
NIH
History
ARTICLE ABSTRACT
TRX518 is a mAb engaging the glucocorticoid-induced TNF receptor−related protein (GITR). This open-label, phase I study (TRX518-003) evaluated the safety and efficacy of repeated dose TRX518 monotherapy and in combination with gemcitabine, pembrolizumab, or nivolumab in advanced solid tumors.
TRX518 monotherapy was dose escalated (Part A) and expanded (Part B) up to 4 mg/kg loading, 1 mg/kg every 3 weeks. Parts C–E included dose-escalation (2 and 4 mg/kg loading followed by 1 mg/kg) and dose-expansion (4 mg/kg loading) phases with gemcitabine (Part C), pembrolizumab (Part D), or nivolumab (Part E). Primary endpoints included incidence of dose-limiting toxicities (DLT), serious adverse events (SAE), and pharmacokinetics. Secondary endpoints were efficacy and pharmacodynamics.
A total of 109 patients received TRX518: 43 (Parts A+B), 30 (Part C), 26 (Part D), and 10 (Part E), respectively. A total of 67% of patients in Parts D+E had received prior anti–PD(L)1 or anti–CTLA-4. No DLTs, treatment-related SAEs, and/or grade 4 or 5 AEs were observed with TRX518 monotherapy. In Parts C–E, no DLTs were observed, although TRX518-related SAEs were reported in 3.3% (Part C) and 10.0% (Part E), respectively. Objective response rate was 3.2%, 3.8%, 4%, and 12.5% in Parts A+B, C, D, and E, respectively. TRX518 affected peripheral and intratumoral regulatory T cells (Treg) with different kinetics depending on the combination regimen. Responses with TRX518 monotherapy+anti–PD1 combination were associated with intratumoral Treg reductions and CD8 increases and activation after treatment.
TRX518 showed an acceptable safety profile with pharmacodynamic activity. Repeated dose TRX518 monotherapy and in combination resulted in limited clinical responses associated with immune activation.See related commentary by Hernandez-Guerrero and Moreno, p. 3905