Averitas Pharma
Disclaimer: The CASPAR study explored outcomes associated with capsaicin 8% topical system (here referred to as high-concentration capsaicin topical system [HCCTS]) in patients with diabetic peripheral neuropathy (DPN) of the feet. The study examined outcomes beyond pain relief, including sleep, affective distress, quality of life, and concomitant pain medication use. While these outcomes were evaluated in the CASPAR study, HCCTS is not FDA-approved for these outcomes, and its safety and efficacy for them have not been established in phase 3 randomized trials. HCCTS is indicated in adults for neuropathic pain associated with postherpetic neuralgia (PHN) or diabetic peripheral neuropathy (DPN) of the feet. Consult the Important Safety Information and Full Prescribing Information for complete details on approved indications, safety, and risks. ---
Diabetic peripheral neuropathy affects up to half of individuals living with diabetes, with painful pathology developing in 30–50% of cases. Pain associated with painful diabetic peripheral neuropathy (PDPN) can significantly impair sleep, mood, and health-related quality of life (QOL).
The capsaicin 8% topical system, referred to here as high-concentration capsaicin topical system (HCCTS), is approved in the USA for topical treatment for PDPN of the feet.
The CASPAR study was a retrospective, non-interventional, multi-cohort study using real-world data from the German Pain e-Registry. It included a subpopulation of 365 patients with PDPN of the feet who received between one and four HCCTS treatments and were followed up for 12 months (1 HCCTS: n=94, 2 HCCTS: n=88, 3 HCCTS: n=75, 4 HCCTS: n=108). The analysis aimed to assess the effects of repeated HCCTS treatments on pain, sleep, affective distress, QOL, and use of concomitant pain medication. Tolerability was also evaluated.
Study limitations: CASPAR is a real-world study, limited by its retrospective, non-randomized observational design. The non-interventional nature may have introduced selection bias among patients who were selected or voluntarily participated in the registry. The lack of a placebo potentially limits the interpretation. Causality cannot be established from the results of this study, and reverse causality (patients who received the most benefit being those who persisted) cannot be ruled out. In addition, this registry did not collect data on confounding factors such as glycemic control, alcohol or tobacco use, or nutritional status, which limits the interpretation of the results.
In the CASPAR study, clinical benefits were observed after one treatment with further improvements seen following repeated applications in patients with PDPN of the feet, whereas patients who discontinued HCCTS lost benefits over time.
In patients with PDPN of the feet, statistically significant reductions in mean 24- hour average pain intensity (API) were seen by Month 3 after one application of HCCTS compared with baseline (p<0.001). Further reductions in API were seen with ongoing HCCTS treatments, whereas API increased in patients who discontinued treatment. Furthermore, a reduction of concomitant pain medication use was observed with ongoing HCCTS treatments.
Improvements in sleep impairment, mood, and health-related QOL were reported by Month 3 following one treatment with HCCTS, and further improvements were seen with ongoing treatments. Patients who discontinued treatment lost some benefits by Month 12.
The tolerability of the HCCTS in the CASPAR study was consistent with its known safety profile. Reported adverse drug reactions were transient, local application site reactions (including pain, erythema, and burning sensation), which improved or resolved over time. Refer to Table 1 in the publication for a summary of adverse drug reactions and treatment discontinuation rates.
Key takeaways: In the CASPAR study, the following outcomes were observed in patients with PDPN of the feet who were treated with HCCTS:
--- Footnote: API, average pain intensity; FDA, US Food and Drug Administration; HCCTS, high-concentration capsaicin topical system; PDPN, painful diabetic peripheral neuropathy; QOL, quality of life; USA, United States of America.
Überall M et al. BMJ Open Diabetes Res Care. 2025;13:e004864.
N/A-07-25-0011 | August 2025
Explore key insights from the CASPAR study on patients with PDPN of the feet treated with capsaicin 8% topical system
View visual abstract on the impact of ongoing treatments with capsaicin 8% topical system on patient-reported outcomes in patients with PDPN of the feet
Information updated in August 2025.
INDICATION
In the USA, capsaicin 8% topical system is indicated for the treatment of neuropathic pain associated with postherpetic neuralgia (PHN) and neuropathic pain associated with diabetic peripheral neuropathy (DPN) of the feet.
