NRG Oncology NRG-GI007 trial-in-progress: Phase I study of OBP-301 (Telomelysin) and definitive chemoradiation (CRT) for patients with locally advanced esophageal and gastroesophageal adenocarcinoma who are not candidates for surgery.

Abstract

TPS262 Background: Definitive CRT is a standard-of-care for patients with medically inoperable esophageal cancer (EC, NEJM 326:1593). The NRG/RTOG 0436 study of cisplatin/paclitaxel and RT (+/- cetuximab) as definitive therapy showed that about ½ of patients have locally persistent disease (JAMA Oncol 3:1520). OBP-301 is a conditionally-restricted, replication-competent adenovirus derived from human adenovirus type 5 (Ad-5) that adds a human Telomerase Reverse Transcriptase (hTERT) gene promoter; it replicates only in tumor cells to cause lysis. It may enhance RT and may cause immunogenic cell death. A phase I study with RT in Japanese patients with inoperable EC showed tolerability and activity. Methods: In NRG-GI007, OBP-301 is added to weekly carboplatin/paclitaxel and RT to 50.4 Gy (1.8 Gy/fx ×28 fx) for patients with medically inoperable esophageal or gastroesophageal junction (GEJ) adenocarcinoma. Patients receive intratumoral OBP-301 1×1012 virus particles (vp)/ml via endoscopy (EGD) 3 days prior to CRT, then at days 12 and 26 of CRT, for a total of 3 doses. Restaging with PET and EGD occur 6-8 weeks later. Blood and tumor tissue are collected for immune- and viral-based correlative assays. Patients must be assessed to be medically inoperable and have ECOG performance status <1. The primary endpoint is safety, and clinical complete response (cCR) rate is a secondary endpoint. Initially, 6 patients are enrolled. If protocol-defined dose-limiting toxicity (DLT) occurs in <1 of 6 patients, the dose will be deemed to be safe and 9 more will be enrolled to further assess safety and obtain a preliminary assessment of cCR rate. If >2 of 6 patients have DLT, the dose of OBP-301 is reduced to 1×1011 vp/ml and another 6 patients will be treated. If <1 of 6 patients has a DLT at the lower dose, that dose will be deemed to be safe and 9 more will be enrolled. If >2 of 6 patients have DLT, then neither dose level will have met the safety rule and the trial will be ended. This trial opened to accrual on June 29, 2020. Clinicaltrials.gov NCT04391049. Funding: This project was supported by grants U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC), U24CA180803 (IROC), from the National Cancer Institute (NCI) and Oncolys BioPharma. Clinical trial information: NCT04391049.