Prospective phase I study of nab-paclitaxel plus gemcitabine with concurrent MR-guided IMRT in patients with locally advanced or borderline resectable pancreatic cancer.

Abstract

TPS480 Background: Radiotherapy (RT) for locally advanced and borderline resectable pancreatic cancer (LABPC) is controversial as potential local control benefits are often obscured by high rates of distant progression. However, local failure remains a significant cause of morbidity among patients without distant progression after initial chemotherapy, although toxicity concerns may limit delivery of optimal systemic therapy concurrent with RT. Given known systemic efficacy and radiosensitization effects of nab-paclitaxel (A) with gemcitabine (G), we initiated a phase I study of nab-paclitaxel with gemcitabine (AG) and concurrent intensity modulated radiation therapy with magnetic resonance guidance (MR-IMRT) for LABPC. Methods: A planned 24 patients with LABPC will be enrolled to a phase I dose escalation trial using the Time-to-Event Continual Reassessment Method (TITE-CRM) design. Following one lead-in cycle of GA, MR-IMRT is administered daily with concurrent weekly GA for a total of 25 fractions in 5 weeks. The initial dose levels for RT and AG, respectively, are: 40 Gy MR-IMRT, 75 mg/m2 A and 600mg/m2 G. The maximum possible dose level is 60 Gy MR-IMRT, 100mg/m2 A and 1000mg/m2 G. To reduce toxicity risk, MR-IMRT volumes include the primary tumor only, with cine-MR used for intra-fraction tumor tracking in place of fiducial markers. The primary endpoint is determination of the maximum tolerated dose level, with secondary endpoints including rate of conversion to resectable disease, progression- free survival, overall survival, and patient reported quality of life. Clinical trial information: NCT02283372.