Gastroretentive Gabapentin for PHN Effective in Real-World Practice
LAS VEGAS—Gastroretentive gabapentin (Gralise) is a safe and effective treatment option that significantly reduces pain intensity but also improves patients' quality of life according to data presented by Matthew Clark, MS, of Depomed, Inc., and colleagues from the A&A Pain Institute of St. Louis, Missouri.
Clinical trials do not always accurately reflect the efficacy and safety of a drug in real-world clinical practice. Researchers conducted a phase 4 open-label, multicenter study to evaluate the efficacy of 1800 mg/day of gastroretentive gabapentin in a relatively unselected group of 197 patients with active postherpetic neuralgia (PHN).
Patients received a dosage of 1800 mg/day for 6 weeks following a 2-week titration period for total treatment of 8 weeks. Pain intensity and interference with daily life was assessed at each office visit using a visual analog scale (VAS) and the Brief Pain Inventory (BPI). At Week 8, Patient/Clinician Global Impression of Change (PGIC/CGIC) scales were completed. Adverse events (AEs) were assessed at the Week 2, Week 8, and post-tapering phone visits.
Results showed that gastroretentive gabapentin reduced pain intensity. Study investigators reported a mean percent change in VAS scores from baseline of -26.5% at Week 2 and -30.6% at Week 8. The proportion of patients with 30% or greater reduction in VAS scores from baseline was 45.8% at Week 2 and 53.2% at Week 8. The proportion of patients with 50% or greater reduction in VAS scores was 40.5% at Week 2 and 33.2% at Week 8.
Pain scores (worst, least, average, and current pain) on the BPI were all significantly reduced by Week 2 and Week 8 (all P<0.0001). All BPI interference scores (general activity, mood, walking ability, normal work, relationships, sleep, and enjoyment of life interference scores) and the average of the BPI interference scores were also significantly reduced at Week 2, and continued to decrease until Week 8 (all P≤0.0001). For the PGIC and CGIC, 51.1% and 53.3% of patients, respectively, were considered "Very much" or "Much" improved at Week 8 compared with symptoms at study entry.
Treatment with 1800 mg/day of gastroretentive gabapentin was generally well tolerated. The most common treatment-related AEs were dizziness (13.7%) and somnolence (5.6%). A total of 100 (50.8%) patients reported at least one AE, and 37 (18.8%) patients discontinued the study due to AEs. No patient died and 5 (2.5%) patients experienced serious AEs (none was deemed by investigators to be related to treatment. The prevalence of all AEs decreased rapidly, and by the end of the titration period had reached sustained low levels of ≤1.5%.