Disappointing Results in Adolescent Pregabalin Study

While previous evidence has shown pregabalin (Lyrica/Pfizer) to be effective in assuaging pain among adults with fibromyalgia, there are no approved treatments for its symptoms in adolescence.

Pfizer funded a study regarding the efficacy of Lyrica among those aged 12 to 17 in hopes of eventually changing that. Unfortunately, no primary returns showed statistically significant improvement, though there was some silver lining in secondary metrics.

Published in Pediatric Rheumatology, the study had two phases and spanned three continents, drawing participants in the US, India, Taiwan, and the Czech Republic, and included 107 participants. A total of 80 participants completed the first study, which took place over 15 weeks. Randomized and double-blind, patients were given either an optimized pregabalin dose (75 to 400mg; 54 total, 44 completed) or a placebo (53 total, 36 completed). Patients were asked to maintain “pain diaries” where they assigned scores to their daily pain; the study sought to monitor changes in “mean pain score” week to week. Patients who completed the first part were given the option of continuing with the second portion of the study, a six-month open-label follow-up, and 63 of them did.

For the double-blind portion, the study found that “The trend toward improvement in mean pain score with pregabalin compared with placebo was not statistically significant.” Small consolation was found in secondary outcomes: “The change in weekly mean pain score with pregabalin was significantly greater than with placebo (P&thinsp;<&thinsp;0.05) for 10 of the 15 weeks assessed.”

The mean pain score improvements were more pronounced in the open-label second phase of the study, but 71.4% of participants noted at least one adverse event, ranging from dizziness, fatigue and nausea to, uncommonly, appendicitis and pneumonia. “The safety results in the double-blind and open-label studies were similar to the established safety profile in adults with FM,” the authors write, though reports of nausea among the adolescent participants (22.2%) was higher than in previous adult pregabalin studies (~8%).

The trial was difficult to organize, requiring over four years to recruit the initial 107 patients, and likely limited because of the under-recognition of fibromyalgia in adolescents. Though the overall result was disappointing, the article concludes: “We hope that this trial encourages further investigation into effective treatment options for adolescent patients with FM.”