Botulinum Toxin for Chronic Neuropathic Pain

Recruiting

Brief Summary: Treatment of peripheral neuropathic pain with Botulinum Toxin (BoNT) has showed promising results since the first study was released in 2001. Further research, however, is needed in order to strengthen the treatment, and a number of questions are unanswered. This includes which indication is the treatment the most effective, how should the treatment be administered, what is the duration of the effect? This study is a prospective interventional open label study, designed to assess the efficacy and safety of Botolinum toxin in the treatment of chronic neuropathic pain.

Detailed Description: Background:

There are eight randomized controlled trials investigating the effectiveness of BoNT for peripheral neuropathic pain. The indications in the studies include diabetic neuropathy, post-herpetic neuropathy, and peripheral nerve injury. Overall, the studies indicate a treatment effect that is significantly better than placebo. However, the studies are relatively small, their outcome measures vary, making comparison difficult, and there is considerable variation in the degree of pain reduction. The duration of the effect of BoNT treatment varies greatly and has not been systematically studied. The current evidence provides a promising background in the treatment of BoNT og neuropathic pain, but further research and documentation are needed.

At the Interdisciplinary Pain Center, Zealand University Hospital, BoNT treatment is already used for patients with neuropathic pain, who do not respond to 1. and 2. line treatments. This study will evaluate the efficacy of the treatment.

Method:

The objective of this study is to prospectively follow a one-year cohort and subsequently conduct a follow-up of 7 months (three treatments) for patients initiating BoNT treatment. The follow-up includes monitoring the treatment's effectiveness, duration, and recording adverse reactions.

Recruitment & Eligibility

Inclusion Criteria

Condition of neuropathic pain verified by paraclinical examination or supported by underlying diseases (e.g., diabetes or herpes zoster).
The condition is characterized by allodynia, hyperalgesia, and/or neuralgiform symptoms such as burning and stabbing pain.
The affected area can be identified through objective examination with detection of disturbances in touch using cotton swabs, pin-prick, and/or vibration

Exclusion Criteria

Mixed etiology of pain not solely attributable to neuropathy (e.g., fibromyalgia and neuropathy or nociceptive pain and neuropathy).
Contraindication to BoNT treatment (allergy to the toxin).
Pregnancy.
Diseases where BoNT treatment is contraindicated, such as motor neuron diseases and muscular dystrophy.
Severe psychiatric disorder.

Arm && Interventions

Group	Intervention	Description
Intervention group	Botulinum toxin type A	Patients treated with Botulinum Toxin

Primary Outcome Measures

Name	Time	Method
Maximal pain intensity	At 28 days, 4 months, and 7 months after initiating treatment with BoNT type A (Xeomin®).	Proportion of patients with clinically relevant reduction in maximum pain (last 24 hours) compared to baseline, assessed using the Numerical Rating Scale (NRS 0-10; Zero represents 'no pain at all' and the upper limit represents 'the worst pain ever possible'). A minimal important difference (MID) of NRS 1 is considered as clinically relevant.
pain intensity at rest	At 28 days, 4 months, and 7 months after initiating treatment with BoNT type A (Xeomin®)	Proportion of patients with clinically relevant reduction in average pain at rest (last 24 hours) compared to baseline, assessed using the Numerical Rating Scale (NRS 0-10). A MID of NRS 1 is considered as clinically relevant.
Frequency of serious adverse reactions	Up to 7 months after initiating treatment	Frequency of serious adverse reactions (according to ICH-GCP definition).
Frequency of serious adverse events	Up to 7 months after initiating treatment	Frequency of serious adverse events (according to ICH-GCP definition).

Secondary Outcome Measures

Name	Time	Method
EuroQol-5 Dimension (EQ-5D)	At 28 days, 4 months, and 7 months after initiating treatment with BoNT type A (Xeomin®).	Change in health-related quality of life (EQ-5D) compared to baseline. EQ-5D includes pain evaluation using the visual analogue scale (VAS 0-100; Zero represents 'no pain at all' and the upper limit represents 'the worst pain ever possible')
Neuropathic Pain Symptom Inventory (NPSI)	At 28 days, 4 months, and 7 months after initiating treatment with BoNT type A (Xeomin®).	Change in neuropathic pain compared to baseline using the NPSI that evaluates 12 different symptoms according to a numerical rating scale from 0 to 10 (Zero represents 'no pain at all' and the upper limit represents 'the worst pain ever possible')
Onset and duration	At 28 days	Time from treatment before onset of effect and duration of effect