A randomized phase II trial comparing different schedules of nab-paclitaxel (nabP) combined with gemcitabine (GEM) as first line treatment for metastatic pancreatic adenocarcinoma (mPDAC).

Background: NabP+GEM chemotherapy improves survival compared with GEM monotherapy as treatment for mPDAC. A PDAC mouse model suggested that nabP potentiates GEM activity by reducing cytidine deaminase levels and scheduling may be critical to optimise clinical benefit. Methods: Patients (pts) were randomised to receive standard concomitant (CON) nabP+GEM or sequential (SEQ) administration, with nabP given 24 hours before GEM. After 6 cycles, pts benefiting from treatment could continue the same regimen until disease progression. The primary endpoint was progressionfree survival (PFS) by RECIST v1.1; secondary endpoints included safety, objective response rate (ORR), overall survival (OS) and quality of life (QoL). Serial blood and baseline tumour samples were collected for exploratory biomarkers. Results: Between March 2014 and 2016, 146 pts (71 SEQ, 75 CON) were recruited. Median age (range) was 66 (45‐82) years; Karnofsky performance status was 70 (in 12% pts), 80 (27%), 90 (38%) or 100 (24%); 47% had pancreatic head primaries; 84% had liver metastases. Median no. cycles received was 4 SEQ, 3 CON; 51 pts (35%) received ≥6 cycles of treatment (42% SEQ, 28% CON). A 24+2hr interval was achieved in > 90% SEQ admin. Grade ≥3 adverse events experienced by ≥10% pts (SEQ, CON) were Feedback neutropaenia (54%, 30%; p = 0.003), febrile neutropaenia (12%, 12%), fatigue (22%, 15%), vomiting (7%, 11%) and anaemia (10%, 5%). G‐CSF was administered at local investigator's discretion to 35 pts (23 SEQ, 12 CON; p = 0.015). To date, 112 pts have died. 6 month (m) PFS by SEQ and CON arms were 47% and 33%; median PFS were 5.8 and 4.0m; hazard ratio (HR) = 0.66, 95% CI = 0.46‐0.95; 12m OS by SEQ and CON arms were 29% and 26%; median OS were 10.1 and 7.9m; HR = 0.88, 95% CI = 0.61‐ 1.29. ORR was 50% SEQ and 33% CON (p = 0.065). Mean baseline QoL Global health status score was 60.6 SEQ and 63.4 CON. The mean change in QoL score from baseline at 24 weeks was ‐2.1 SEQ and ‐12.1 CON. Conclusions: Sequential delivery of nabP combined with GEM trended towards improving all clinically relevant efficacy end points: PFS, OS, and ORR. Translational correlates will be reported in due course.