Background: The multi-centre two-stage SCALOP-2 trial (ISRCTN50083238) assessed whether dose escalation of consolidative chemoradiotherapy (CRT) or concurrent sensitization using the protease inhibitor nelfinavir improve outcomes in locally advanced pancreatic cancer (LAPC) following four cycles of gemcitabine/nab-paclitaxel.
Methods: In stage 1, the maximum tolerated dose (MTD) of nelfinavir concurrent with standard-dose CRT (50.4 Gy in 28 fractions) was identified from a cohort of 27 patients. In stage 2, 159 patients were enrolled in an open-label randomized controlled comparison of standard versus high dose (60 Gy in 30 fractions) CRT, with or without nelfinavir at MTD. Primary outcomes following dose escalation and nelfinavir use were respectively overall survival (OS) and progression free survival (PFS). Secondary endpoints included health-related quality of life (HRQoL).
Results: High dose CRT did not improve OS (16.9 (60 % confidence interval, CI 16.2-17.7) vs. 15.6 (60 %CI 14.3-18.2) months; adjusted hazard ratio, HR 1.13 (60 %CI 0.91-1.40; p = 0.68)). Similarly, median PFS was not improved by nelfinavir (10.0 (60 %CI 9.9-10.2) vs. 11.1 (60 %CI 10.3-12.8) months; adjusted HR 1.71 (60 %CI 1.38-2.12; p = 0.98)). Local progression at 12 months was numerically lower with high-dose CRT than with standard dose CRT (n = 11/46 (23.9 %) vs. n = 15/45 (33.3 %)). Neither nelfinavir nor radiotherapy dose escalation impacted on treatment compliance or grade 3/4 adverse event rate. There were no sustained differences in HRQoL scores between treatment groups over 28 weeks post-treatment.
Conclusions: Dose-escalated CRT may improve local tumour control and is well tolerated when used as consolidative treatment in LAPC but does not impact OS. Nelfinavir use does not improve PFS.
Keywords: Chemoradiotherapy; Dose escalation; Health-related quality of life; Nelfinavir; Outcomes; Pancreatic cancer; Survival; Toxicity.
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