Anti-PD-1 antibody combined with albumin-bound paclitaxel and gemcitabine (AG) as first-line therapy and Anti-PD-1 monotherapy as maintenance in metastatic pancreatic ductal adenocarcinoma (PDAC).

Abstract

e16218 Background: Two studies in ASCO 2018 showed the preliminary efficacy of PD-1 inhibitor and AG as first-line therapy for advanced pancreatic cancer, the disease control rate (DCR) was up to 100%. However, in a phase 1 study of nivolumab plus nab-paclitaxel and gemcitabine in advanced PDAC, the objective response rate (ORR) was only 18%, and the progression-free survival (PFS)/overall survival (OS) were 5.5/9.9 months, which was quite different from what had been reported before in ASCO. All the patients received continuous chemotherapy, and the tolerance was poor. Recently, maintenance therapy on pancreatic cancer was widely investigated in clinical trials. The present study explored the camrelizumab (anti-PD-1 antibody) combined with AG as the first-line treatment, and camrelizumab as maintenance therapy for metastatic PDAC (mPDAC) among Chinese patients. Methods: In this single-arm, single-center, exploratory study, patients who were pathologically or cytologically diagnosed as mPDAC and had not received systemic treatment before, with an ECOG performance status of 0-1 would receive: albumin-bound paclitaxel 125 mg/m2 plus gemcitabine 1000 mg/m2 (days 1, 8), and camrelizumab, 200mg (day 1) for a 21-day cycle. After six cycles, if there was no evidence of disease progression, camrelizumab (200mg, every 21 days) monotherapy as maintenance therapy would be given. Primary endpoint was ORR assessed according to RECIST 1.1. The secondary endpoint was DCR, PFS, OS, etc. Safety was also assessed. Results: From July 3, 2019 to July 1, 2020, twenty patients were enrolled and received the study treatment. The median age was 63 years (range 33-78). Sixteen participants (80%) were male. Eleven patients (55%) received six cycles of camrelizumab combined with AG and subsequential maintenance therapy. Nineteen patients received at least one imaging evaluation, one patient (5%) achieved complete response, eleven (55%) patients achieved partial response, five (25%) patients were assessed as stable disease, and progressive disease was observed in two patients (10%) who died within 2 months. The ORR (primary endpoint) and DCR were 60% and 85%, respectively. The data of PFS and OS were immature. The most common AEs (all grade, grade≥3) were erythropenia (55%, 0%), leukopenia (45%, 10%), neutropenia (40%, 15%), anemia (30%, 5%), thrombocytopenia (30%, 5%). One patient received day 1 camrelizumab plus AG, and the day 8 therapy was skipped due to thrombocytopenia. During the second cycle, he presented with jaundice due to disease progression and died rapidly. Conclusions: The ORR and DCR of chemotherapy-naive mPDAC patients receiving camrelizumab plus AG were high. Safety findings were consistent with previous data observed from camrelizumab or AG treatment; with no unexpected safety signals. Clinical trial information: NCT04181645.