Data from a Phase 1b Study of Quemliclustat-Based Regimens Showed Promising Overall Survival in Treatment-Naïve Metastatic Pancreatic Cancer

Arcus Biosciences, Inc. (NYSE:RCUS) today announced promising overall survival data from ARC-8, a Phase 1b study that is being co-developed with Gilead Sciences. ARC-8 is the study of quemliclustat, an investigational small molecule CD73 inhibitor, plus chemotherapy with or without zimberelimab, an investigational anti-PD-1 antibody, in patients with previously untreated metastatic pancreatic ductal adenocarcinoma (mPDAC). The results will be presented during the 2024 American Society of Clinical Oncology Gastrointestinal Cancers Symposium (ASCO GI).

“A quemliclustat-based regimen appears to meaningfully prolong survival compared to what we typically observe in patients with mPDAC who receive chemotherapy alone, the standard of care for more than 30 years,” said Zev A. Wainberg, MD, MSc, Co-Director of the GI Oncology Program at University of California Los Angeles and a principal investigator of the ARC-8 trial. “CD73 is highly expressed on pancreatic cancer cells, and I am encouraged to see early evidence that inhibiting CD73 with a small molecule has the potential to improve outcomes for people with mPDAC, without an observed clinically meaningful increase in toxicity, when combined with standard of care chemotherapy relative to historical data for chemotherapy alone.”

The results to be presented include data from all patients (n=122) with treatment-naïve (first-line) mPDAC who received 100mg of quemliclustat plus chemotherapy with or without zimberelimab in the dose-escalation, dose-expansion and randomization cohorts of ARC-8. The data cutoff was June 19, 2023. Median overall survival (mOS) data for both quemliclustat-based regimens were numerically greater than historical benchmark data for chemotherapy alone, which has shown a mOS of approximately nine months.

An analysis was performed by the Medidata AI team, part of Medidata, a Dassault Systèmes company, whereby they constructed a Synthetic Control Arm of patients who were treated with gemcitabine/nab-paclitaxel in Phase 2 and 3 clinical studies in the first-line metastatic pancreatic cancer setting, on a post-hoc basis. Patients from these studies were matched 1:1 to the pool of 122 patients treated with the 100 mg quemliclustat-based regimens in ARC-8, based on demographics and key baseline characteristics such as ECOG performance status, liver metastasis, and history of prior surgery. The matched SCA was constructed based on a pre-specified analysis plan before OS data were unblinded and analyzed by the Medidata AI team. The analysis showed that the patients in ARC-8 lived longer than patients from the matched control arm. Specifically, these results showed that patients in ARC-8 experienced a: