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


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Paul Ross1,Natalie Phillips2,Zarni Win2,Christopher Wadsworth2,Thankamma Ajithkumar3,Luigi Aloj3,Edmund Godfrey3,Chinenye Iwuji4,Rakesh Ganatra4,Sudarshan Kadri4,Marion Harris5,Daniel Croagh5,Morteza Aghmesheh6,Adnan Nagrial7,Nam Nguyen8,Mehrdad Nikfarjam9,Alain Hendlisz10,Thomas Maher11,Anna Kraszewski11,Harpreet Wasan2
1Guy's & St Thomas' NHS Foundation Trust, London, UK,2Imperial College Healthcare NHS Trust, London, UK,3Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK,4University Hospitals of Leicester NHS Trust, Leicester, UK,5Monash Health, Melbourne, Australia,6Southern Medical Day Care Centre, Wollongong, Australia,7Westmead Hospital, Sydney, Australia,8Royal Adelaide Hospital, Adelaide, Australia,9Austin Health, Melbourne, Australia,10Institut Jules Bordet Université Libre de Bruxelles, Brussels, Belgium,11OncoSil Medical Ltd., Sydney, Australia

Abstract

Background

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.

Method

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.

Results

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.)

Conclusion

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.