Development and preliminary validation of an integrated efficacy-tolerability composite measure for the evaluation of analgesics.

The goal of this analysis was to develop and evaluate integrated measures of benefit and tolerability of analgesic drugs in clinical trials. We evaluated an efficacy-tolerability composite (ETC) measure combining different cutoff values for daily pain reduction (≥20%, ≥30%, or ≥50% pain reduction) and adverse events (AEs) (no AE, no or mild AEs, no or mild drug-related AEs). Nine ETC cutoff values (3 × 3) were tested using data from a randomized double-blind trial comparing tapentadol extended release (ER) (n = 310), oxycodone controlled release (CR) (n = 322), and placebo (n = 314) in subjects with chronic low back pain. Efficacy-tolerability composite scores were calculated as the mean number of days a subject met the ETC criterion divided by the number of days the subject was expected to be in study; ETC scores were then averaged in each treatment group. For all 9 ETC measures, validity was demonstrated by significant correlation of ETC scores with patients' Global Impression of change and with change from baseline in pain scores. Tapentadol ER ETC scores were statistically significantly higher than oxycodone CR ETC scores for 4 of the ETC measures. "No/mild drug-related AE and ≥20% pain reduction" demonstrated the best overall validity (correlation with patients' global impression of change) and responsiveness (discrimination between treatment groups), yielding a higher standardized effect size for tapentadol ER compared with placebo (0.19 [95% confidence interval: 0.031-0.346]) and with oxycodone CR (0.23 [95% confidence interval: 0.070-0.383]) than other cutoff values. Thus, we have identified herein a composite measure that seems to be a valid and responsive measure of the overall efficacy and tolerability of analgesics in clinical trials.

Predictors of Response in Patients With Postherpetic Neuralgia and HIV-Associated Neuropathy Treated With the 8% Capsaicin Patch (Qutenza).

OBJECTIVES: Qutenza is a high-dose capsaicin patch used to relieve neuropathic pain from postherpetic neuralgia (PHN) and HIV-associated neuropathy (HIV-AN). In clinical studies, some patients had a dramatic response to the capsaicin patch. Our objective was to determine the baseline characteristics of patients who best benefit from capsaicin patch treatment. METHODS: We conducted a meta-analysis of 6 completed randomized and controlled Qutenza studies by pooling individual patient data. Sustained response was defined as>50% decrease in the mean pain intensity from baseline to weeks 2 to 12, and Complete Response as an average pain intensity score≤1 during weeks 2 to 12. Logistic regression was used to identify predictors of response and Complete Response, and subgroups of patients who respond best to the capsaicin patch. RESULTS: Baseline pain intensity score (BPIS)≤4 was a predictor of Sustained and Complete Response in PHN and HIV-AN patients; absence of allodynia and presence of hypoesthesia, and a McGill Pain Questionnaire (MPQ) sensory score <22 were predictors of Sustained Response in PHN patients; female sex was a predictor of Sustained and Complete Response in HIV-AN patients. Thus, characteristics associated with the highest chance of responding to the capsaicin patch were, for PHN, BPIS≤4, MPQ sensory score≤22, absence of allodynia, and presence of hypoesthesia; for HIV-AN, they were female sex and BPIS≤4. Patients with these characteristics had a statistically significantly greater chance of responding to the capsaicin patch than other patients. DISCUSSION: We identified subpopulations of PHN and HIV-AN patients likely to benefit from the capsaicin patch.

Qutenza (capsaicin) 8% patch onset and duration of response and effects of multiple treatments in neuropathic pain patients.

INTRODUCTION: Qutenza (capsaicin) 8% patch is used to treat various neuropathic indications, including postherpetic neuralgia (PHN) and human immunodeficiency virus-associated neuropathy (HIV-AN). OBJECTIVES: We conducted a meta-analysis of Qutenza studies to describe clinical phenomena of effects of Qutenza treatment better, such as onset and duration of pain relief, and the need for retreatments. METHODS: The meta-analyses combined individual patient data (1313 participants with PHN and 801 with HIV-AN) from 7 completed randomized, double-blind, controlled studies. Studies had similar designs, and all used the Qutenza patch (8% capsaicin) and a low-dose control patch (0.04% capsaicin). A 30% response was defined as a ≥30% decrease in mean pain intensity score during week 2 to end of follow-up; complete pain relief was defined as an average pain intensity ≤1 during week 2 to end of follow-up. Duration of response was calculated using the data from long-term studies as the time from onset of response to offset of response, retreatment, or end of follow-up (whichever occurred first). RESULTS: Overall 44% of PHN and 41% of HIV-AN patients had a 30% response, and 11% and 7%, respectively, had complete pain relief 2 to 12 weeks after treatment with Qutenza. The mean (median) onset of response to Qutenza was 3.4 (1) days for PHN and 6.5 (4) days for HIV-AN (delayed due to an initial increase in discomfort). The mean (median) duration of response after 1 Qutenza treatment was 5 (3) months. Of the patients followed-up for 12 months, 40% PHN and 36% HIV-AN patients had a 30% response, and 9% and 10%, respectively, had complete pain relief from week 2 to end of follow-up. CONCLUSIONS: Qutenza is effective in a high proportion of patients. In patients who respond to Qutenza, analgesia starts within a few days of treatment and lasts on average 5 months.

Efficacy of Qutenza® (capsaicin) 8% patch for neuropathic pain: a meta-analysis of the Qutenza Clinical Trials Database.

Qutenza® is a capsaicin patch used to treat peripheral neuropathic pain, including postherpetic neuralgia (PHN) and human immunodeficiency virus-associated neuropathy (HIV-AN). The Qutenza Clinical Trials Database has been assembled to more fully characterize the effects of Qutenza. We conducted a within-subject meta-analysis of Qutenza studies to further define the medication's efficacy profile across studies. The meta-analysis combined individual patient data from randomized, controlled studies of Qutenza in peripheral neuropathic pain (1458 subjects treated with approved doses of Qutenza or control patches; 1120 with PHN and 338 with HIV-AN). These 7 studies had similar designs and were performed with the high-dose 8% capsaicin Qutenza patch and a 0.04% low-dose control patch. The difference between treatment groups for the primary efficacy end point of percentage change from baseline to weeks 2 to 12 on pain intensity score was calculated. Response was defined as a ≥ 30% decrease in mean pain intensity score during weeks 2 to 12. The overall between-group difference in percentage change from baseline in pain intensity was 8.0% (95% confidence interval 4.6, 11.5; P<.001), which statistically significantly favored Qutenza over low-dose control. Qutenza superiority was demonstrated for both PHN and HIV-AN patients for the primary end point and the end point proportion of 30% pain reduction response, and for PHN patients for the end point of proportion of 50% pain reduction response. These results confirm that Qutenza is effective for the treatment of both PHN and HIV-AN compared to low-dose control patch.