AUSTIN, TX—Sublingual fentanyl tablets were generally well tolerated in patients with cancer-related breakthrough pain aged 65 years and older in conjunction with around-the-clock opioid treatment, investigators reported during the American Pain Society’s 30th Annual Scientific Meeting.

Srinivas R. Nalamachu, MD, of the International Clinical Research Institute, Overland Park, KS, and colleagues, conducted a pooled analysis of two Phase 3, multiple-dose studies to determine safety and tolerability of sublingual fentanyl tablet, a rapid-onset opioid for management of breakthrough pain in opioid-tolerant patients with stable chronic cancer pain.

In the Phase 3 studies, doses of sublingual fentanyl were individually titrated over two weeks (range, 100–800 mcg) and followed up in an open-label maintenance period of up to 12 months. In Study 1, maintenance treatment was preceded by a two-week double-blind, randomized, placebo-controlled period. Patients were instructed to place the tablets on the floor of the mouth directly under the tongue until completely dissolved. Adverse events (AEs) were analyzed by dose group (≤200mcg, 300–400mcg, and >400mcg).

A total of 270 patients received one or more doses of sublingual fentanyl. Of those ≥65 years, incidence of AEs was 80.7% overall and increased according to dose group (50.0%, 17.4%, and 90.3% in the ≤200 mcg, 300–400 mcg, and >400 mcg groups, respectively). The investigators noted these results may have been confounded by the tendency for patients to be on lower doses for shorter periods of time because of dose titration.

The most common AEs in patients aged ≥65 years included diarrhea (15.8%), nausea (15.8%), and fatigue (14.0%). Incidence of AEs was similar in patients aged 17–64 years; 166 (77.9%) experienced ≥1 AE; the most common of which were nausea (24.4%), vomiting (12.7%), and fatigue (11.3%). The majority of AEs in both populations were mild or moderate in severity. No treatment-related AEs at the application site (ie, the sublingual area of the mouth) were reported in either group. The study was funded by ProStrakan Group plc.