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).

4100 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 progression-free 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 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. Clinical trial information: ISRCTN71070888.