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Study on the Effectiveness and Safety of NT 201 Injections for Adults with Chronic Neuropathic Pain from Postherpetic Neuralgia or Nerve Injury

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the effects of a treatment called NT 201 on individuals experiencing chronic neuropathic pain. This type of pain can occur due to conditions like postherpetic neuralgia, which is pain following a shingles infection, or from a peripheral nerve injury, which might happen after surgery or an accident. The trial aims to see if NT 201 can effectively reduce pain intensity compared to a placebo. NT 201 is a form of Clostridium botulinum neurotoxin type A, which is administered through injections.

Participants in the study will receive either the NT 201 injections or placebo injections. The study will monitor changes in pain levels over several weeks to determine the effectiveness of the treatment. The trial is designed to be double-blind, meaning neither the participants nor the researchers will know who is receiving the actual treatment or the placebo, ensuring unbiased results. The study will also track any side effects that may arise during the treatment period.

The purpose of this trial is to gather evidence on whether NT 201 can provide relief for those suffering from moderate to severe chronic neuropathic pain. By comparing the effects of NT 201 to a placebo, researchers hope to establish its potential as a treatment option for managing this type of pain. Participants will be closely monitored throughout the study to ensure their safety and to collect accurate data on the treatment's impact on their pain levels.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial visit

    Upon joining the clinical trial, you will attend an initial visit. During this visit, your eligibility for the study will be confirmed based on specific criteria, such as having chronic neuropathic pain for at least 6 months.

    You will be asked to complete a questionnaire to assess your pain level. This will help determine your baseline pain intensity.

  2. Step 2

    Randomization

    After the initial visit, you will be randomly assigned to one of two groups. One group will receive the active treatment, NT 201, and the other group will receive a placebo.

    This process is double-blind, meaning neither you nor the study staff will know which group you are in.

  3. Step 3

    Treatment administration

    If you are in the active treatment group, you will receive NT 201 through a subcutaneous injection. This means the medication is injected under the skin.

    The dosage and frequency of the injections will be determined by the study protocol and administered by qualified medical personnel.

  4. Step 4

    Follow-up visits

    You will attend regular follow-up visits to monitor your progress and any changes in your pain levels. These visits will occur at specified intervals, such as every two weeks.

    During these visits, you may be asked to complete additional questionnaires and undergo medical assessments to evaluate the effectiveness and safety of the treatment.

  5. Step 5

    End of study

    At the end of the study period, which is estimated to be around 12 weeks, you will have a final visit.

    During this visit, your overall experience and any side effects will be reviewed. You will also receive information about the next steps, if applicable.

Who can join the trial?

5 criteria

  • The patient must have chronic peripheral neuropathic pain (PNP) that has lasted for at least 6 months. This pain should be related to either a past episode of herpes zoster (also known as shingles) or a peripheral nerve injury (caused by surgery or an accident).
  • The patient must have a documented diagnosis of either chronic neuropathic pain after a peripheral nerve injury (such as pain after surgery or an accident) or postherpetic neuralgia (PHN), which is pain following shingles. This diagnosis should be at least probably certain according to a specific grading system used by experts.
  • The patient must score at least 4 out of 10 points on the Neuropathic Pain 4 Questions (DN4) questionnaire, which is a tool used to assess the type of pain.
  • The study is open to both male and female participants.
  • The study includes participants from vulnerable populations, which means it considers people who might need special attention or care.

Who cannot join the trial?

8 criteria

  • Patients with any other type of chronic pain that is not related to postherpetic neuralgia (pain following shingles) or peripheral nerve injury (damage to the nerves outside the brain and spinal cord).
  • Patients who have a history of allergic reactions to the study medication or similar treatments.
  • Patients who are currently participating in another clinical trial.
  • Patients with any medical condition that the study doctors believe would make it unsafe for them to participate.
  • Patients who are pregnant or breastfeeding.
  • Patients who have a history of drug or alcohol abuse within the past year.
  • Patients who have had major surgery within the past three months.
  • Patients with severe mental health conditions that are not well controlled.
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Investigated drugs

NT 201 is a medication being tested in this clinical trial to see if it can help reduce pain for people who have chronic neuropathic pain. This type of pain can happen after conditions like postherpetic neuralgia, which is pain following shingles, or after an injury to the nerves. The trial is looking at how well NT 201 works in decreasing the intensity of this pain when given as an injection under the skin. The goal is to find out if NT 201 can make a significant difference in reducing daily pain levels compared to not using the medication.

What is already known about the treatment

NT 201 – NT 201 is administered through subcutaneous injections, meaning it is injected under the skin. It is currently being studied in clinical trials to assess its effectiveness and safety for treating moderate to severe chronic peripheral neuropathic pain, specifically due to postherpetic neuralgia or peripheral nerve injury. The main goal of this medication is to reduce the intensity of daily pain experienced by patients. At the molecular level, NT 201 works by targeting specific pathways involved in pain signaling, although the exact mechanism is still under investigation. It is classified pharmacologically as a treatment for neuropathic pain.

Investigated diseases

  • Postherpetic Neuralgia

    Postherpetic neuralgia is a condition characterized by persistent nerve pain following an outbreak of shingles, which is caused by the varicella-zoster virus. The pain is typically localized to the area where the shingles rash appeared and can be severe and debilitating. It is a type of neuropathic pain, meaning it results from nerve damage or dysfunction. The pain can be described as burning, stabbing, or aching, and may be accompanied by increased sensitivity to touch or temperature changes. Over time, the intensity of the pain may fluctuate, but it often persists for months or even years after the initial shingles infection has resolved.

  • Peripheral Neuropathic Pain

    Peripheral neuropathic pain arises from damage or dysfunction of the peripheral nerves, which are the nerves outside the brain and spinal cord. This type of pain can result from various causes, including physical injury, infections, or systemic diseases like diabetes. The pain is often described as burning, tingling, or shooting, and it may be accompanied by numbness or weakness in the affected area. It can affect any part of the body but is most commonly experienced in the hands and feet. The progression of peripheral neuropathic pain can vary, with some individuals experiencing a gradual increase in symptoms, while others may have sudden and severe episodes.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2022-501461-52-00Protocol codeM602011079Estimated enrolment120 patientsSponsorMerz Therapeutics GmbH

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