Treatment of peripheral neuropathic pain by topical capsaicin: Impact of pre-existing pain in the QUEPP-study

BACKGROUND: This study evaluates the impact of the duration of pre-existing peripheral neuropathic pain on the therapeutic response to the capsaicin 8% cutaneous patch. METHODS: The non-interventional QUEPP (QUTENZA – safety and effectiveness in peripheral neuropathic pain) study evaluated the effectiveness of Qutenza™ in 1044 non-diabetic patients with peripheral neuropathic pain, who received a single application. Follow-up visits were scheduled at weeks 1–2, 4, 8 and 12. A pre-defined co-analysis of changes in average pain intensity was performed based on the duration of pre-existing pain. RESULTS: In patients with pre-existing pain for <6 months, the mean relative change of the numeric pain rating scale score on days 7–14 to week 12 versus baseline was −36.6% [4.6 standard error of the mean (SEM); n = 105], −25.1% (1.9 SEM; n = 311) in patients with pain duration of 6 months to 2 years, −22.3% (1.6 SEM; n = 391) in patients with pain for >2–10 years, and −19.2% (2.6 SEM; n = 99) in patients with pain for >10 years. Thirty percent and 50% responder rates were 61.7% and 39.3% in patients with pre-existing pain for <6 months, 42.3% and 23.3% in patients with pain for 6 months to 2 years, 40.9% and 21.6% in patients with pain for >2–10 years, and 32.3% and 14.1% in patients with pain for >10 years. CONCLUSIONS: The highest treatment response to the capsaicin 8% cutaneous patch was observed in patients with a history of pre-existing peripheral neuropathic pain of less than 6 months, suggesting that early initiation of topical treatment might be indicated.