Breakthrough pain variability has no impact on response to sublingual fentanyl tablets or placebo

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AUSTIN, TX Variability in baseline breakthrough pain (BTP) has no impact on the analgesic response to sublingual fentanyl tablets or placebo, as demonstrated by an analysis presented at the American Pain Society's 30th Annual Scientific Meeting. Recent research had suggested that pain variability at baseline impacts response to active and placebo treatments in painful conditions (eg, fibromyalgia). This relationship had not been previously explored for BTP.

Julian Howell, MD, from ProStrakan, and colleagues performed a post hoc exploratory analysis of data from a Phase 3, randomized, placebo-controlled, multicenter trial evaluating the efficacy of sublingual fentanyl for the treatment of BTP in patients with cancer. The investigators sought to determine if a relationship exists between the variability in baseline pain intensity and treatment response in opioid-tolerant patients receiving sublingual fentanyl tablets for cancer-associated BTP.

In the study, patients were randomized to receive 10 doses of study medication (seven doses of sublingual fentanyl and three doses of placebo, in random order). A total of 64 patients were in the intent-to-treat population (received ≥1 dose). Pain variability was measured by the variance of pain intensity at baseline over all BTP episodes and compared with response to placebo and response to sublingual fentanyl.

Efficacy measures included the mean sum of pain intensity difference (SPID) at 30 minutes and the mean pain intensity difference at 10 and 15 minutes. Using linear regression, investigators evaluated whether a relationship exists between baseline pain intensity variability and the response to placebo, response to sublingual fentanyl, and the difference in response between treatments.

The study authors reported that there was no association between BTP variability at baseline and response to placebo, response to sublingual fentanyl, or difference in response for any measures of pain evaluated. For SPID30, the P value for response to sublingual fentanyl was P=0.978, response to placebo was P=0.702, and difference in response was P=0.868. The P value for mean pain intensity at 10 and 15 minutes were P=0.561 and P=0.825. The results of this exploratory analysis suggest that BTP variability at baseline has no impact on response to sublingual fentanyl or placebo.

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