Effect of neoantigen reactive T cells combined with chemotherapy and radiation on survival in advanced pancreatic cancer.

Abstract

e15756 Background: Pancreatic cancer (PC) is one of the most aggressive and death-relating malignancy. Gemcitabine (GEM) is the key agent in the first-line standard regimen for advanced PC, which is mostly diagnosed at advanced stage and unsuitable for curative resection. The objective responsive rate (ORR) and medium progression free survival (PFS) of various GEM-based regimens are still unsatisfied. Therefore, development of new therapeutic modalities, including immunotherapy, is needed. This study is to investigate the efficacy, safety and clinical beneficial of combination neoantigen based immunotherapy with GEM and radiotherapy in locally advanced and metastatic PC patients. Methods: Three locally advanced unresectable and seven metastatic PC patients received at least two cycles of GEM (1000mg/m2 on day 1 and day 6), radiotherapy combing with neoantigen induced DC vaccination on day 7 and cytotoxic T lymphocyte transfer from day 12 to 15 (repeated every 21 days). The locally advanced unresectable PC patients received stereotactic body radiotherapy (SBRT) with a total amount of 50-66Gy during the first cycle. For metastatic patients, their partial lesions received a low dose radiation (0.5Gy bid*2days ) on day 10 and 11 in each cycle. Results: Two cases were observed with partial remission (PR), five with stable disease (sd), and three with progressive disease (PD). The disease control rate (DCR) was 70%. Median progression free survival (PFS) was 6.4 months. After the first treatment cycle, the total effectiveness for pain easement and increasing appetite are 100% (8/8)and 66.7%, respectively. Haematotoxicities with a 40% incidence rate were the most common adverse drug reactions. Two patients had grade 1 to 2 neutropenia, two with grade 3 to 4 thrombocytopenia. Three patients suffered grade 1 to 2 gemcitabine-induced skin rash. No treatment-related mortality occurred. Conclusions: Neoantigen reactive T cells combined chemoradiotherapy demonstrated an acceptable response and safety in advanced pancreatic cancer patients.