Introduction: Fentanyl buccal tablet (FBT), a novel opioid formulation, has proven efficacy in providing early-onset analgesia for cancer-related breakthrough pain (BTP).1,2 This pooled analysis reports the adverse events (AEs) observed with FBT in two randomized, double-blind, placebo-controlled trials of BTP.

Methods: Opioid-tolerant patients with cancer-related BTP (1-4 episodes/day) were enrolled into one of two IRB-approved studies. In both studies, an open-label dose titration phase (maximum FBT dose 800 µg) was followed by randomization to a sequence of 10 double-blind treatments (7 FBT, 3 placebo). AEs during titration and double-blind treatment are reported for these two phases combined.

Results: Two hundred forty-eight patients were titrated, and 164 progressed to double-blind treatment after having achieved a successful dose (dose strength providing sufficient analgesia within 30 minutes of administration for each of two consecutive BTP episodes without unacceptable AEs). AEs occurred in 72% of patients overall; 36% were considered related to FBT. Treatment-related AEs occurred at lower rates than overall AEs for several of the common (°Ý5%) AEs: dizziness (13% vs 17%), nausea (8% vs 17%), headache (4% vs 10%), fatigue (3% vs 10%), vomiting (2% vs 8%), constipation (2% vs 7%), asthenia (<1% vs 6%), and somnolence (4% vs 5%). Application-site AEs were reported in 7% of patients, all of which were treatment-related. Fourteen percent of patients had AEs leading to discontinuation. Serious AEs occurred in 10% overall; none were treatment-related. There were no reports of respiratory depression. Deaths, all attributed to disease progression, were reported for 16/248 patients.

Conclusion: FBT-related AEs, except for application-site AEs, were consistent with opioid therapy. No serious AEs or cases of respiratory depression were considered related to FBT. The most frequent treatment-related AEs (°Ý5%) were dizziness, nausea, and application-site AEs.