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Study on the Effectiveness and Safety of NT 201 (Botulinum Toxin) for Treating Lower Limb Spasticity in Adults After Stroke or Traumatic Brain 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, also known as botulinum toxin, on a condition called lower limb spasticity. Lower limb spasticity is a condition where muscles in the legs become stiff and difficult to move, often occurring after a stroke or traumatic brain injury. The study aims to compare the effectiveness and safety of NT 201 with a placebo in treating this condition.

Participants in the study will receive injections of NT 201 or a placebo into the muscles of the lower limbs. The treatment period will last for up to 92 days. The study will monitor changes in muscle stiffness and any side effects that may occur. The goal is to determine if NT 201 can help reduce muscle stiffness and improve movement in the affected limbs.

The study will also include an open-label extension phase, where all participants may receive NT 201, with or without additional treatment for the upper limbs. This phase will help gather more information on the long-term effects and safety of the treatment. The study is designed to provide valuable insights into the potential benefits of NT 201 for individuals with lower limb spasticity due to stroke or traumatic brain injury.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, the participant is confirmed to meet the eligibility criteria, which include being between 18 and 85 years old and having lower limb spasticity due to stroke or traumatic brain injury.

    The participant must have a specific level of spasticity in the ankle and a certain range of motion.

  2. Step 2

    Initial assessment

    An initial assessment is conducted to establish a baseline for the participant's condition. This includes measuring the spasticity level using the Modified Ashworth Scale and assessing the range of motion in the ankle.

  3. Step 3

    Treatment administration

    The participant receives an intramuscular injection of NT 201 (botulinum toxin) or a placebo. The dosage is 400 Units, specifically targeting the ankle plantar flexors.

    This treatment aims to reduce spasticity in the lower limb.

  4. Step 4

    Follow-up assessments

    Follow-up assessments occur at Weeks 4 and 6. These assessments measure changes in spasticity and overall improvement using the Modified Ashworth Scale and the Goal Attainment Scale.

    The participant's progress is evaluated by both the physician and the participant.

  5. Step 5

    Safety monitoring

    Throughout the study, the participant is monitored for any adverse effects related to the treatment. This includes tracking any new symptoms or changes in health status.

  6. Step 6

    Study completion

    Upon completion of the study period, the participant undergoes a final assessment to evaluate the overall effectiveness and safety of the treatment.

    The results contribute to understanding the treatment's impact on lower limb spasticity.

Who can join the trial?

8 criteria

  • Participants must be **female or male** and between **18 and 85 years old**.
  • Participants must have a **diagnosis of lower limb spasticity**, which means their muscles are stiff or tight, possibly with or without similar issues in the upper limb on the same side of the body. This condition should be caused by a **stroke** or **traumatic brain injury**.
  • Participants must have **disabling ankle flexor spasticity**, which means difficulty in moving the ankle due to muscle stiffness, presenting as **pes equinus** (toe walking) or **pes equinovarus** (toe walking with inward foot turning).
  • Participants must have a **Modified Ashworth Scale-Bohannon (MAS) score** of **2 or 3 points** in the ankle plantar flexor of the affected lower limb. This scale measures muscle stiffness.
  • Participants must have a **minimum passive range of motion** in the ankle of the affected lower limb: **10 degrees dorsiflexion** (upward movement) and **20 degrees plantarflexion** (downward movement).
  • Participants must have had their last **botulinum neurotoxin (BoNT) injection** for treating spasticity or any other condition at least **4 months ago**.
  • For participants on **anticoagulation therapy** (medication to prevent blood clots), the investigator must confirm and document that the participant has:
    • An **activated partial thromboplastin time (aPTT)** of **80 seconds or less** for those on **dabigatran** or other direct thrombin inhibitors.
    • An **international normalized ratio (INR) value** of **2.5 or less** for those on **coumarins** or other anticoagulants monitored by INR.

Who cannot join the trial?

5 criteria

  • Individuals who are not adults cannot participate. This means only people who are 18 years or older can join.
  • People who do not have **lower limb spasticity** cannot take part. **Lower limb spasticity** is a condition where muscles in the legs are too tight, making movement difficult.
  • Participants must have issues specifically with the **ankle plantar flexors**. These are the muscles that help point your toes down.
  • Both men and women can participate, but they must meet all other criteria.
  • People who are considered part of a **vulnerable population** may not be eligible. A **vulnerable population** includes groups who might need special protection, like those with certain health conditions or disabilities.
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Investigated drugs

NT 201 is a medication being studied for its effectiveness and safety in treating lower limb spasticity in adults. This condition can occur after a stroke or traumatic brain injury and involves muscle stiffness, particularly in the ankle area. The trial aims to determine how well this medication works in reducing spasticity and improving movement.

What is already known about the treatment

NT 201 – This medication is administered through injection and is currently being studied in clinical trials for its effectiveness and safety in treating lower limb spasticity in adults, particularly following a stroke or traumatic brain injury. It is primarily indicated for reducing muscle stiffness in the lower limbs. NT 201 works by blocking nerve signals that cause muscles to contract, thereby reducing spasticity. It is classified as a neuromuscular blocking agent.

Investigated diseases

Lower Limb Spasticity – Lower limb spasticity is a condition characterized by increased muscle tone and stiffness in the legs, often resulting from damage to the brain or spinal cord. This condition can lead to difficulty in movement, coordination, and walking, as the muscles may contract involuntarily. It commonly affects the ankle plantar flexors, causing the foot to point downward and making it challenging to place the heel on the ground. Over time, spasticity can lead to muscle shortening and joint deformities if not managed properly. The severity of symptoms can vary, and they may fluctuate depending on factors such as stress, temperature, or fatigue.
Trial detailsLast updated 4 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-505810-12-00Protocol codeM602011014Estimated enrolment600 patientsSponsorMerz Pharmaceuticals GmbH

sourced from the EU Clinical Trials Register and site verification

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