Alternating application of gemcitabine/nab-paclitaxel (Gem/nab-Pac) and Gem monotherapy or continuous application of Gem/nab-Pac after induction treatment for first-line treatment of metastatic pancreatic cancer (mPC): First results from the randomized phase 2 ALPACA study from the German AIO study group (AIO-PAK-0114).
Authors: Dorman Klara , Boeck Stefan Hubert , Caca Karel , Reichert Maximilian , Ettrich Thomas Jens , Oettle Helmut , Waidmann Oliver , Modest Dominik Paul , Müller Lothar , Michl Patrick , Kanzler Stephan , Pink Daniel , Reinacher-Schick Anke C. , Geißler Michael , Pelz Henning , Kunzmann Volker , Held Swantje , Schichtl Thomas , Heinemann Volker , Kullmann Frank 
Published: January 2024

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Background: The aim of the ALPACA study was to investigate whether improved overall tolerability accompanied by prolonged treatment duration and increased efficacy can be achieved by alternating treatment cycles of Gem/nab-Pac and Gem monotherapy compared to standard continuous Gem/nab-Pac after a 3-month induction phase in patients with mPC. Methods: The randomized, multicenter phase 2 ALPACA trial of the German AIO study group enrolled patients with confirmed mPC in the first-line setting. After an induction phase with 3 cycles of standard dose Gem/nab-Pac (Gem 1000 mg/m2 and nab-Pac 125 mg/m2 on d1, 8, 15 of each 28-day cycle), patients were randomized (1:1) either to continue treatment with standard Gem/nab-Pac, or to receive alternating cycles of standard dose Gem/nab-Pac combination therapy and Gem monotherapy (Gem 1000 mg/m2 on d1, 8, 15 of each 28-day cycle). Primary study endpoint was overall survival (OS) after randomization. The trial was registered with ClinicalTrials.gov, NCT02564146. Results: Between May 2016 and May 2021, 325 patients were enrolled from 29 German centers. 6 of the enrolled patients did not start treatment within the study. Following 3 cycles of induction treatment, 174 patients (53.5%) could be randomized. Main reasons for premature dropout were death (24.8%), progression of disease (22.8%), and adverse events (15.9%). Median OS after randomization in the alternating treatment arm was comparable to the standard treatment arm (10.5 vs. 10.4 months; HR 0.903, 80% CI 0.723-1.128, p=0.5551). Likewise, median progression-free survival was comparable in both arms (5.5 vs. 5.3 months; HR 0.767, 95% CI 0.556-1.056, p=0.1017). Tolerability was improved for mPC patients treated with alternating cycles compared to standard therapy, especially regarding peripheral neuropathy (all grades, 44.7% vs. 52.5%), and occurrence of infections (all grades, 29.4% vs. 47.5%). Treatment duration after randomization was similar in both arms (3.25 vs. 3.02 months). Fewer patients receiving alternating treatment cycles dropped out of the study due to adverse events compared to patients treated with continuous Gem/nab-Pac (14.9% vs 27.5%). In return, these patients terminated the study slightly more often due to progression of disease (48.3% vs 42.5%). Conclusions: The ALPACA trial suggests that a dose-reduced regimen with alternating cycles of Gem/nab-Pac and Gem monotherapy after 3 induction cycles of standard Gem/nab-Pac is feasible and associated with an OS comparable to standard treatment while resulting in improved tolerability. Clinical trial information: NCT02564146 .