Dr. Thierry Jahan on the CRS-207 Vaccine in Mesothelioma

Thierry M. Jahan, MD, a clinical professor in the Department of Medicine at the University of California San Francisco Helen Diller Family Comprehensive Cancer Center, discusses a phase Ib trial of CRS-207 in malignant pleural mesothelioma (MPM).

CRS-207 is a live-attenuated, double-deleted Listeria monocytogene engineered to express the tumor-associated antigen mesothelin. In the the phase Ib it was administered with chemotherapy to 38 patients with MPM. Of 34 evaluable patients, 59% (n = 20) had partial response posttreatment and 35% (n = 12) had stable disease, for an overall disease-control rate 94%.

There is a synergy between the exposure of the Listeria and the immunity that it triggers and the efficacy of the chemotherapy, said Jahan. The tumor-infiltrating lymphocytes (TILs) that are necessary to distribute the tumor are overexpressed and expanded through the vaccination, and this along with chemotherapy, is likely to improve the response rate, he said.

A global randomized trial is in the process of being implemented and should enroll its first patient sometime this year.