Dr Weinberg on the Efficacy of BXCL701 Plus Pembrolizumab in Pretreated, Metastatic PDAC

"Of note, we had 3 patients with durable stable disease [lasting 6 months or longer], and we showed [via a patient case] that in [patients with] microsatellite-stable metastatic pancreatic cancer, we can shrink tumors not just in the lymph nodes, but also in the liver, which has historically been resistant to targeting with immunotherapy.”

Benjamin A. Weinberg, MD, FACP, an associate professor of medicine in the Division of Hematology and Oncology of the Lombardi Comprehensive Cancer Center at Georgetown University, discussed preliminary efficacy and safety findings from the ongoing phase 2 EXPEL PANC trial (NCT05558982) evaluating BXCL701 in combination with pembrolizumab (Keytruda) in patients with metastatic pancreatic ductal adenocarcinoma (PDAC) following progression on first-line chemotherapy.

The study enrolled 19 patients and followed a Simon two-stage design with a primary end point of progression-free survival (PFS) at 18 weeks. Findings presented at the 2025 ESMO Gastrointestinal Cancers Annual Congressshowed that as of data cutoff, response-evaluable patients (n = 18) experienced a 17% overall response rate (ORR) and a 39% disease control rate (DCR); all responses were partial, and 4 patients achieved stable disease or better at the 18-week assessment. The median PFS was 2.3 months (95% CI, 1.58-5.29), and the median overall survival (OS) was not reached (NR; 95% CI, 4.54-NR). Three patients were free from progression for at least 6 months.

Weinberg also noted that the regimen was well tolerated, with no new safety signals observed. Baseline and on-treatment tumor biopsies are being collected to investigate biomarkers of therapeutic response and resistance, aiming to refine patient selection for future trials. The study remains ongoing, with additional patients needed to determine whether the trial meets the prespecified efficacy threshold to advance beyond stage 1.

According to Weinberg, the findings suggest potential clinical activity of BXCL701 plus pembrolizumab in this setting. During the presentation, he spotlighted at patient case from the study and highlighted the efficacy of the combination in a patient with microsatellite-stable (MSS) metastatic PDAC. Findings from the study thus far have shown the potential for the combination to elicit antitumor activity in patients with MSS metastatic PDAC, he concluded.