Introduction: This long-term, open-label, multicenter study was conducted to evaluate the safety and tolerability of treatment with fentanyl buccal tablet (FBT) to manage breakthrough pain (BTP) in opioid-tolerant patients with chronic cancer pain [1].

Materials and Methods: Adults taking around-the-clock opioids for persistent pain (intensity ≤7; 0–10 scale) and experiencing 1–4 BTP episodes/day were maintained at their successful FBT dose from 1 of 2 previous clinical studies [2,3] (rollover patients, n=120) or titrated to a successful FBT dose (100–800 µg) (treatment-naive patients, n=110; retitrated rollover patients, n=2). Monthly assessments included BTP episodes/day, FBT dose/day, and adverse event (AE) recording. The protocol was approved by the appropriate IRBs, and patients provided written informed consent.

Results: 197 patients entered the dose-maintenance phase, including 79 patients who achieved a successful FBT dose during titration. During maintenance, median duration of FBT exposure was 122 days (range, 1–698; 36 patients [18%] had exposure ≥12 months); mean ± SE dose/BTP episode was 554.8 ± 18.6 µg; and the final dose was the same as the initial successful dose for 136 (69%) patients (this includes patients with dose changes during the study who shifted back to the initial dose). Discontinuations included 3 patients for lack of efficacy and 71 for AEs. AEs were typical of opioid use and consistent with those observed in short-term studies (titration: nausea 27, vomiting 4, dizziness 29; maintenance: nausea 62, vomiting 47, dizziness 20). Overall, serious AEs included disease progression (62) and pneumonia (16); all serious AEs were deemed by investigators to be unrelated to study medication except drug withdrawal syndrome in one patient.

Conclusions: FBT was generally safe and well tolerated in the treatment of BTP in this study, the largest and longest FBT study in cancer patients to date.