Oncolys BioPharma Inc. announced that the results from an investigator-initiated phase II clinical trial for TelomelysinTM (OBP-301) in combination with pembrolizumab in advanced gastric and gastroesophageal junction (GEA) adenocarcinoma was presented at Society for Immunotherapy of Cancer (SITC) 2023, held in San Diego, California, from November 1st to 6th. The objectives of this clinical trial were to evaluate the safety and efficacy of Telomelysin in combination with pembrolizumab for patients with PD-L1 positive advanced gastric and GEJ adenocarcinoma, and is led by Dr. Manish Shah at Weill Cornell Medicine, Meyer Cancer Center, in New York, NY. Study results showed 2 patients with a partial response and 1 patient with a complete response out of 16 evaluable patients, thereby meeting the Simon two-stage threshold.

The responses were durable; two patients are currently without evidence of disease and the 3rd patient received 17 months of therapy before progression. One patient with brain metastasis demonstrated regression of metastatic disease following progression on immunotherapy alone. Complete response was associated with delayed increase in CD8 cytotoxic T cells, based on single cell RNA Seq expression.