(HealthDay News) — A combination vaccine significantly improves overall survival compared with a single-component vaccine in patients with metastatic pancreatic ductal adenocarcinoma (PDA), according to a study presented at the American Society of Clinical Oncology’s annual Gastrointestinal Cancers Symposium, held from Jan. 16 to 18 in San Francisco.
Dung T. Le, M.D., from the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center in Baltimore, and colleagues randomly assigned 90 metastatic PDA patients (2:1) to receive two doses of GVAX (irradiated, GM-CSF-secreting allogeneic pancreatic cells) plus four doses of CRS-207 (live-attenuated Listeria monocytogenes expressing mesothelin) every three weeks or six doses of GVAX every three weeks. Low-dose cyclophosphamide was given before GVAX treatment.
After a median follow-up of 7.8 months, the researchers found that overall survival was significantly better in the GVAX plus CRS-207 group (6.1 versus 3.9 months; hazard ratio, 0.54). Overall survival was further improved when at least three doses were given (9.7 versus 4.6 months; hazard ratio, 0.44). The tumor marker CA19-9 stabilized in significantly more patients who received combination treatment (32 versus 13 percent). The side effects of the vaccine were relatively mild and resolved quickly. Patients were allowed to cross over to combination treatment based on the interim analysis.
“Cyclophosphamide/GVAX followed by CRS-207 shows extended survival with manageable toxicity in previously-treated metastatic PDA and warrants further study,” Le and colleagues conclude.
Several authors disclosed financial ties (including employment) to Aduro Biotech, the manufacturer of the vaccines.