A single-arm, prospective, multicenter study on the efficacy and safety of low-dose transdermal fentanyl patch in opioid-naive patients with moderate to severe cancer pain.

e24149 Background: The efficacy and safety of low-dose fentanyl transdermal patch (TDF) in the treatment of opioid-naive patients with moderate-to-severe cancer pain has no tyet been confirmed. There are little international studies, and none in mainland China. The aim of this study was to explore the effect and tolerability of low dose of TDF in opioid-naive patients with Chinese moderate-to-severe cancer pain, and evaluate the influence on quality of life and cognitive function. Methods: A prospective, single-arm, non-randomized, open-label, multicenter trial was conducted with 285 opioid-naivepatients with moderate-to-severe cancer pain in 14 tertiary hospitals in mainland China. The initial analgesic dose of TDF was 12.5 µg/h, pain assessment (pain score, pain relief and pain response rate) was performed every 3 days for a total of 9 cycles.Adverse reactions and events were monitored over 24 days. In the meantime, quality of life and cognitive function of patient were evaluated with EORTC QLQ-C30 and MMSE. Results: 285 patients with 267(92.00%) completed the trial were enrolled. The average age was 60 (range 28-87) and the average effective therapeutic dose was 6.3±6.08mg.The total pain relief rate was 98.12% (mean pain score ±SD, 5.7±0.89 vs 3.9±1.28; P < 0.001). The efficacy of low-dose TDF on pain relief was consistent in groups separated by gender (p < 0.001), age (p < 0.001), types of cancer (p < 0.001), and baseline pain intensity (p < 0.001). There were 79 patients (29.59%) in the low-dose subgroup, and the pain response rate of the low-dose subgroup was better than other dose groups within one week (p = 0.0018).The adverse effects were mild. The most common adverse reactions are constipation 7.87%, followed by nausea 11.24%, vomiting 4.12%, drowsiness 1.87% and urine retention 1.5%.There was no difference in the incidence of adverse reactions between the low-dose subgroup and the other groups (p > 0.05). Meanwhile, TDF improved the quality of life of patients with moderate-to-severe cancer pain (mean± SD: 46.44±16.96 vs. 67.04±18.02;p < 0.05), without impairing cognitive function(mean ±SD, 29.13±1.54 vs. 28.98±1.99; p > 0.05). Conclusions: Low-dose TDF is effective for opioid-naive patients with moderate-to-severe cancer pain. Adverse reactions are mild and the quality of life of patients is improvedwith little losson cognitive function. Further randomized controlled studies are warranted to investigate the value of low-dose TDF in the treatment of opioid intolerant cancer pain. Clinical trial information: ChiCTR-ONC-17014080 .