Pregabalin for peripheral neuropathic pain: a multicenter, enriched enrollment randomized withdrawal...

To date, published neuropathic pain randomized controlled trials of pregabalin have involved primarily diabetic peripheral neuropathy (DPN) and postherpetic neuralgia (PHN). This multicenter trial evaluated pregabalin in a broader range of neuropathic pain etiologies.

In this enriched enrollment randomized withdrawal trial, 256 patients received single blind, flexible dose pregabalin for 4 weeks; stable concomitant analgesics were allowed. One hundred sixty-five (65%) had a ≥30% pain improvement and 157 were randomized and treated, double blind, to either continue pregabalin (n=80) or to receive placebo (n=77) for 5 weeks.

Of the single blind responders randomized, 81% on placebo and 86% on pregabalin completed the double-blind phase. At the double-blind endpoint, mean (SD) pain scores were 2.9 (1.9) in the pregabalin group and 3.5 (1.7) in the placebo group (P=0.002). These modest yet significant pregabalin-placebo differences were observed within each of the subgroups of patients with a diagnosis of either DPN or PHN (P=0.03), and with other diagnoses (P=0.02). Significant differences were also observed in sleep interference, Hospital Anxiety and Depression Scale Anxiety and Depression subscales, and other secondary measures. In total, 28 out of 80 (35.0%) in the pregabalin group and 28 out of 77 (36.4%) in the placebo group had either a meaningful increase in pain or discontinued the double-blind phase. Adverse events were consistent with the known tolerability profile of pregabalin and led to discontinuation of 9 during the single-blind phase, and 5 and 2 patients from the placebo and pregabalin groups, respectively.

These results support previous evidence of pregabalin efficacy but further demonstrate efficacy and tolerability in a broader range of peripheral neuropathic pain conditions beyond just DPN and PHN.