Perineural Injections of Incobotulinumtoxin-A for Diabetic Neuropathic Pain of the Lower Extremities (PINBOT)

Perineural Injections of Incobotulinumtoxin-A for Diabetic Neuropathic Pain of the Lower Extremities: A Double-blind, Randomized, Placebo-controlled Study

The goal of this clinical trial is to test perineural injections (injections around a nerve) of incobotulinumtoxin-A in participants with diabetic nerve pain of the feet and lower legs.

The main questions it aims to answer are:

• Is the treatment safe and effective?
• Does the treatment affect participants quality of life, depression, physical activity, daily life, and sensation?

Participants will be treated every 12 weeks, for a total of 24 weeks, with either incobotulinumtoxin-A or a placebo.

Study Overview

• Status: Recruiting
• Conditions: Diabetic Neuropathy, Painful
• Intervention / Treatment: Drug: Saline; Drug: Incobotulinumtoxin-A 100 UNIT Injection

Detailed Description

This study is a randomized, double-blind, placebo-controlled trial, investigating the safety, efficacy, use of rescue medication, and impact on NPSI scores, health-related QoL, activities of daily living (ADLs) and levels of physical activity of perineural incobotulinumtoxin-A (iBonT-A) or placebo injections, in persons with DNP of the lower extremities.

Participants will be randomly assigned via simple block randomization to receive either 100 units of iBonT-A in each leg (total of 200 units), or a placebo in each leg, injected perineurally around both distal sciatic nerves once every 12 weeks, for a total of 24 weeks.

Injections are performed with sonographic guidance by an experienced operator. Contents of the blinded vials, containing either 100 U of iBonT-A or a placebo consisting of small amounts of sucrose and albumin are diluted in 5 ml of sterile saline. The injection point is just distal to the sciatic nerve bifurcation. The skin is penetrated from the lateral side using a non-cutting needle (Pajunk, SonoBlock, 22G x 80 mm, Facet S Tip). With the needle in plane in relation to the ultrasound probe, the nerves are visualized in short axis. The needle tip is placed inside the common sheath surrounding the tibial and peroneus communis nerves. The location of the needle tip is verified with small boli of sterile saline solution in combination with ultrasound. Correct distribution of the injectant is confirmed with dynamic scanning. Fluid distention must be seen around both components. When confirmation of optimal needle placement the 100 units iBonT-A or placebo is injected. The procedure is repeated for both legs.

Participants will be asked to rate their neuropathic pain once a day, as well as register their daily use of rescue medication. Secondary outcome measures will be rated at baseline and at 4, 12, 16 and 24 weeks.

Safety information consists of adverse events recording, as well as motorfunction and sensory changes over time.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Marc Klee Olsen, MD; Phone Number: +4538633030; Email: marc.klee.olsen@regionh.dk
• Study Contact Backup: Name: Trine Thomsen, MsC; Phone Number: +4538632712; Email: trine.hoermann.thomsen@regionh.dk

Study Locations

• Denmark
  • Glostrup Municipality, Denmark, 2600
    • Recruiting
    • Rigshospitalet Glostrup
    • Contact: Marc K Olsen, MD; Email: marc.klee.olsen@regionh.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Are 18 years or older
• Are diagnosed with diabetes type I or II
• Score 3 or above on the Doleur Neuropathique 4 interview section

• Suffer from pain of the lower extremities which

  • is considered by the participant as their dominant overall dominant pain
  • is rated at least 4 out of 10 of the NRS pain scale in both legs (on average over the past 7 days)
  • is present in both feet, roughly symmetrically.
  • has been present for at least 6 months
• Show sensory deficits and/or allodynia or hyperalgesia in the painful area, consistent with the IASP definition of probable chronic neuropathic pain40.
• Are in a stable analgesic treatment regime for at least 1 month prior to inclusion and for the duration of the study
• Are using an approved, safe contraceptive (for premenopausal women)
• Speak, read, and understand Danish

Exclusion Criteria:

• • Have a known allergy or hypersensitivity to BonT-A

  • Have been treated with BonT in the last 6 months.
  • Are diagnosed with myasthenia, Eaton-Lambert syndrome, or amyotrophic lateral sclerosis
  • Have a known malignant condition
  • Have an ongoing infection in the area of injection
  • Are expecting to change their pain medication during the study period
  • Have been treated with topical agents such as capsaicin or lidocaine products in the affected areas for at least 3 months prior to inclusion

  • Are diagnosed with a competing cause of central or peripheral neuropathic pain, or other painful chronic conditions of the lower extremities, such as:

    • spinal stenosis
    • claudication
    • previous trauma or nerve injury
    • cancer related pain
  • Have a psychiatric condition that affects their completion of the study, as assessed by the investigator.
  • Are active abusers of alcohol or illegal substances
  • Are using or receiving treatment with cannabis products of any kind
  • Are pregnant or planning pregnancy during the study period
  • Score more than 12 on the Charlson Comorbidity Index

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Incobotulinumtoxin-A; 100 units of incobotulinumtoxin-A in 5ml of sterile saline around both distal ischial nerves.	Drug: Incobotulinumtoxin-A 100 UNIT Injection; Perineural injection
Placebo Comparator: Placebo; 5ml sterile saline with small amounts of human albumin and sucrose (identical to binding agents in active vials)	Drug: Saline; Placebo containing trace amounts of human albumin and sucrose, diluted with 5ml of sterile saline.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in daily neuropathic pain scores	Differences in pain scores, as measured by the Numeric Rating Scale (0-11), between groups.	Recorded once daily for 1 week prior to first injection and daily for the duration of the study. Outcome is defined as differences in change from baseline of average daily and weekly pain scores between groups.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Use of rescue medication	Recorded using pain diary with simple Yes/No for use of any rescue medication. Changes in use of rescue medication over time and between groups.	Recorded once daily for 1 week prior to first injection and daily for the duration of the study. Defined as differences in change from baseline of average days per week of rescue medication usage across the study period.
Neuropathic Pain Symptom Inventory	Changes in NPSI total and sub-scores over time and between groups.	Baseline, 4 weeks, 12 weeks, 16 weeks, 24 weeks.
Health-related quality of life	EQ-5D-5L	Baseline, 4 weeks, 12 weeks, 16 weeks, 24 weeks.
Activities of daily living	Canadian Occupational Outcome Measure (COPM)	Baseline, 4 weeks, 12 weeks, 16 weeks, 24 weeks.
Physical activity	Grimby-Saltin Physical Activity Scale, Danish Version (PAS-2-DK)	Baseline, 4 weeks, 12 weeks, 16 weeks, 24 weeks.
Depression symptoms	Beck Depression Inventory II (BDI-II)	Baseline, 4 weeks, 12 weeks, 16 weeks, 24 weeks.
Adverse events	Incidence, severity and character of adverse, compared between active and placebo groups	Number and nature of adverse events compared between groups at 24 weeks.
Motorfunction of the lower legs.	Oxford MRC Muscle Power Assessment	Baseline, 4 weeks, 12 weeks, 16 weeks, 24 weeks.
Sensory function	Sensation of the lower legs and feet, as measured by Quantitative Sensory Testing, according to the DFNS protocol.	Baseline, 4 weeks, 12 weeks, 16 weeks, 24 weeks.

Collaborators and Investigators

• Sponsor: Rigshospitalet, Denmark
• Collaborators: Merz Pharmaceuticals GmbH; Capital Region Pharmacy, Denmark; The GCP unit at Copenhagen University Hospital; Toyota Foundation Denmark; Steno Diabetes Center Zealand Region; Shipwright Per Henriksen, R., and wife Foundation
• Investigators: Study Director: Bo Biering-Sørensen, MD, Neurological Pain Clinic, Rigshospitalet

Publications and helpful links

General Publications

• Klee M, Hormann Thomsen T, Enggaard TP, Bitsch MS, Simonsen L, Jensen RH, Biering-Sorensen B. Perineural injections of incobotulinumtoxin-A for diabetic neuropathic pain of the lower extremities: protocol for a phase II, single-centre, double-blind, randomised, placebo-controlled trial (the PINBOT study). BMJ Open. 2024 Jan 22;14(1):e074372. doi: 10.1136/bmjopen-2023-074372.

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2023
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: October 31, 2022
• First Submitted That Met QC Criteria: November 14, 2022
• First Posted (Actual): November 21, 2022

Study Record Updates

• Last Update Posted (Actual): December 10, 2025
• Last Update Submitted That Met QC Criteria: December 3, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Endocrine System Diseases; Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Diabetes Mellitus; Diabetes Complications; Diabetic Neuropathies; Inorganic Chemicals; Chlorine Compounds; Sodium Compounds; Chlorides; Hydrochloric Acid; Sodium Chloride
• Other Study ID Numbers: PINBOT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Study data will be published in anonymised format as supplementary material to publications. Study protocol, SAP, ICH And analytic code available upon request.
• IPD Sharing Time Frame: Data will be published as supplementary material to publications.
• IPD Sharing Access Criteria: Open Access
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No