Litgenprostucel-L/GALGENPROSTUCEL-L

The identification of biomarkers for patient stratification is fundamental to precision medicine efforts in oncology. Here, we identified two baseline, circulating immune cell subsets associated with overall survival in patients with metastatic pancreatic cancer who were enrolled in two phase II randomized studies of GVAX pancreas and CRS-207 immunotherapy. Single-cell mass cytometry was used to simultaneously measure 38 cell surface or intracellular markers in peripheral blood mononuclear cells obtained from a phase IIa patient subcohort (N = 38). CITRUS, an algorithm for identification of stratifying subpopulations in multidimensional cytometry datasets, was used to identify single-cell signatures associated with clinical outcome. Patients with a higher abundance of CD8+CD45RO−CCR7−CD57+ cells and a lower abundance of CD14+CD33+CD85j+ cells had improved overall survival [median overall survival, range (days) 271, 43–1,247] compared with patients with a lower abundance of CD8+CD45RO−CCR7−CD57+ cells and higher abundance of CD14+CD33+CD85j+ cells (77, 24–1,247 days; P = 0.0442). The results from this prospective–retrospective biomarker analysis were validated by flow cytometry in 200 patients with pancreatic cancer enrolled in a phase IIb study (P = 0.0047). The identified immune correlates provide potential prognostic or predictive signatures that could be employed for patient stratification.

Limited options exist for patients with advanced pancreatic cancer progressing after 1 or more lines of therapy. A phase II study in patients with previously treated metastatic pancreatic cancer showed that combining GVAX pancreas (granulocyte-macrophage colony-stimulating factor-secreting allogeneic pancreatic tumor cells) with cyclophosphamide (Cy) and CRS-207 (live, attenuated Listeria monocytogenes expressing mesothelin) resulted in median overall survival (OS) of 6.1 months, which compares favorably with historical OS achieved with chemotherapy. In the current study, we compared Cy/GVAX + CRS-207, CRS-207 alone, and standard chemotherapy in a three-arm, randomized, controlled phase IIb trial.

Patients with previously treated metastatic pancreatic adenocarcinoma were randomized 1:1:1 to receive Cy/GVAX + CRS-207 (arm A), CRS-207 (arm B), or physician's choice of single-agent chemotherapy (arm C). The primary cohort included patients who had failed ≥2 prior lines of therapy, including gemcitabine. The primary objective compared OS between arms A and C in the primary cohort. The second-line cohort included patients who had received 1 prior line of therapy. Additional objectives included OS between all treatment arms, safety, and tumor responses.

The study did not meet its primary efficacy endpoint. At the final study analysis, median OS [95% confidence interval (CI)] in the primary cohort (N = 213) was 3.7 (2.9–5.3), 5.4 (4.2–6.4), and 4.6 (4.2–5.7) months in arms A, B, and C, respectively, showing no significant difference between arm A and arm C [P = not significant (NS), HR = 1.17; 95% CI, 0.84–1.64]. The most frequently reported adverse events in all treatment groups were chills, pyrexia, fatigue, and nausea. No treatment-related deaths occurred.

The combination of Cy/GVAX + CRS-207 did not improve survival over chemotherapy. (ClinicalTrials.gov ID: NCT02004262)See related commentary by Salas-Benito et al., p. 5435