Efficacy and Safety of a New Sustained-release Pregabalin Formulation Compared With Immediate-release Pregabalin in Patients With Peripheral Neuropathic Pain: A Randomized Noninferiority Phase 3 Trial

Objective: This study investigated whether a new sustained-release (SR) pregabalin formulation is noninferior to immediate-release (IR) pregabalin in alleviating peripheral neuropathic pain in Korean patients. Materials and Methods: This was a randomized, double-blind, active-controlled phase 3 study of patients with diabetic peripheral neuropathy or postherpetic neuralgia from 41 sites in South Korea in 2017-2018. Eligible patients were randomized (1:1) to receive once-daily SR pregabalin or twice-daily IR pregabalin (150 to 600 mg/d) in a double-dummy manner for 12 weeks according to a stratified permuted block randomization scheme. The primary endpoint was the Daily Pain Rating Scale score at the end of treatment, averaged from the last 7 available scores. Results: A total of 319 of 371 (86.0%) randomized patients completed the 12-week treatment (SR pregabalin: n=154; IR pregabalin: n=165; per-protocol set: n=296). The least square mean difference between both groups for the primary endpoint was 0.06 (SE 0.19); (95% confidence interval -0.31 to 0.42), with the lower limit of the confidence interval above the pre-specified margin (-0.78; P noninferiority<0.0001). Drug-related treatment-emergent adverse events (TEAEs) were comparable between both groups. The incidence of drug-related TEAEs leading to treatment discontinuation was low (SR pregabalin: 2.7%; IR pregabalin: 1.1%). No serious drug-related TEAEs or deaths occurred. Discussion: The results demonstrate that the new once-daily SR pregabalin formulation is noninferior to twice-daily IR pregabalin in reducing peripheral neuropathic pain and is well tolerated in Korean patients with diabetic peripheral neuropathy or postherpetic neuralgia after 12 weeks of treatment.