PanCO: An Open-Label, Single-Arm Pilot Study of Phosphorus-32 Microparticles in Unresectable Locally Advanced Pancreatic Adenocarcinoma with FOLFIRINOX or Gemcitabine + Nab-Paclitaxel Chemotherapies
Session type: Poster / e-Poster / Silent Theatre session
LAPC is associated with a poor prognosis. Current standard treatment is limited to chemotherapy or chemo-radiotherapy. P-32 Microparticles is a brachytherapy device that implants a predetermined dose of P-32 into pancreatic tumours via endoscopic ultrasound (EUS) guidance. This reports the results of pilot study in combination with chemotherapy.
Patients received either GNP or FOLFIRINOX. P-32 was implanted at week 4 or 5. Dose of P-32 was calculated from tumour volume to deliver an absorbed dose of 100 Gy. Diffusion pattern of P-32 suspension was assessed by EUS and bremsstrahlung SPECT/CT. Toxicity was graded using CTCAE v4.0. Response was assessed using RECIST 1.1 with CT scans every 8 weeks and FDG-PET scans at baseline and week 12.
50 patients were enrolled (Intent-to-Treat population (ITT)) of which 42 were implanted with P-32 (Per Protocol population (PP)). 10 received FOLFIRINOX and 40 GNP. Median age was 65; 28 were male; all had a PS 0/1.
39 adverse events were related to study device/procedure of which 2 were grade 3 (abdominal pain, fatigue). No serious device- or radiation-related toxicities reported.
PP Local Disease Control Rate at Week 16 was 90%; 95% CI: 77-97% and at Week 24 was 71%; 95% CI: 55-84%.
Median change in tumour volume from Baseline to Week 16 and Week 24 was -38% (range +89% to -90%) and -27.5% (+139% to -79%).
Overall Response Rate (ORR) was 31%; 95% CI: 18-47%.
Ten (24%) patients underwent surgical resection with 8 achieving R0 margins.
Median Overall Survival (OS) was 16 months (PP population.)
The use of EUS-guided implantation of P-32 is feasible, with an acceptable safety profile in combination with first-line chemotherapy for LAPC patients. Encouraging OS, ORR and DCR are observed. Further follow-up to inform results of local progression free survival and progression free survival is warranted.
© 2019 American Society of Clinical Oncology, Inc. Reused with permission. This abstract was accepted and previously presented at the 2019 ASCO Annual Meeting. All rights reserved.