By Sara Freeman
GLASGOW, United Kingdom -- August 20, 2008 -- Topical treatment with a 5% lidocaine medicated patch is as effective as systemic therapy with pregabalin in the treatment of postherpetic and diabetic neuropathic pain, according to the results of the first phase 3 study to directly compare these 2 treatments.
Ralf Baron, MD, University Hospital of Schleswig-Holstein, Kiel, Germany, presented these multicentre trial data here at the 12th World Congress on Pain (WCP).
While the 2 treatments alleviated to a similar extent the pain associated with postherpetic neuralgia (PHN) and painful diabetic polyneuropathy (DPN), Dr. Baron said, the lidocaine patch had a better tolerability profile as compared with pregabalin.
In total, 88 patients with PHN and 193 with DPN were randomised to 4 weeks of treatment with the lidocaine patch (n = 144) or pregabalin (n = 137). The dose of pregabalin was titrated upwards to reach a clinical effect. Patients who dropped out of the pregabalin arm due to adverse effects were allowed to use the lidocaine patch.
According to a per protocol analysis, a similar number of patients in the 2 treatment arms responded to treatment at 4 weeks (65.3% and 62.0% respectively, P = .00656). Looking at data in patients with PHN separately, 62.2% of patients treated with the patch responded to treatment versus 46.5% of those treated with pregabalin. The respective percentages for patients with DPN were 66.7% and 69.1%.
In patients with PHN, the proportion of patients who achieved a 30% to 50% or greater reduction in pain as assessed by an 11-point Numerical Rating Score (NRS-3) was nonsignificantly higher in the topical lidocaine arm compared with the pregabalin arm (57.8% vs 48.8% for <=30% reduction and 35.6% vs 20.9% for <=50% reduction). Similar findings were observed in patients with DPN.
"This was an open study, so there are some caveats in the interpretation of the results," Dr. Baron said in an interview. "In principle, however, it's a real-life study, so it's how doctors would use treatment."
He added that data from a subsequent combination phase of the study, where the lidocaine patch was added to pregabalin therapy or vice versa, were particularly interesting. These data showed that the combination of the 2 treatments is effective, and that adverse events are less likely to occur when pregabalin is used first, he said.
Fewer drug-related adverse events were observed during the comparative phase of the study, and results favour the use of the lidocaine plaster over pregabalin, Dr. Baron said. Drug discontinuation was more likely with the systemic than topical approach, he added.
Commenting on the study, Michael Serpell, MD, Gartnavel General Hospital, Glasgow, United Kingdom, said: "Until now we have lacked enough evidence of comparator data between monotherapies in neuropathic pain. The evidence from this study now represents a major step forward."
The study was sponsored by Grünenthal GmbH.
[Presentation title: Efficacy and Tolerability of a 5% Lidocaine Medicated Plaster vs Pregabalin in Patients With Post-Herpetic Neuralgia (PHN) and Painful Diabetic Polyneuropathy (DPN): Results From an Interim Analysis of a Randomized, Controlled Trial. Abstract PW228]
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