Evaluation of Botulinum Toxin Type A Efficacy and Safety in Cervical Dystonia Patients with Abnormal Back Muscle Activity: A Double-Blind, Placebo-Controlled Study

The primary objective of this study is to investigate the presence of abnormal **muscle activity** in the thoracic and lumbar regions in individuals with cervical dystonia. This condition is characterized by atypical muscle activity in the neck muscles, leading to abnormal postures such as head rotation, tilting, and tremor. The study aims to assess the efficacy and potential side effects of **botulinum toxin type A** injections in the back muscles of participants exhibiting abnormal activity in these regions. This is clinically relevant as cervical dystonia is primarily treated with localized botulinum toxin injections to reduce abnormal muscle activity by paralyzing the target muscles, potentially improving patient outcomes and quality of life.

The clinical trial involves participants diagnosed with **cervical dystonia**, characterized by abnormal muscle activity in the neck region, leading to typical postural abnormalities such as head rotation, tilting, and tremors. The study population includes both male and female subjects aged 18 years and older. Participants are required to have a history of regular botulinum toxin treatment for cervical dystonia. The trial does not involve a vulnerable population. The sponsor has not provided information regarding the total number of participants. Selection criteria include individuals with abnormal muscle activity in the neck and shoulder area, resulting in prolonged abnormal head movements and postures. Participants must provide informed consent to partake in the study. Lifestyle factors such as diet and physical activity are not specified as part of the selection criteria.

The clinical trial is designed to evaluate the efficacy and safety of **botulinum toxin type A** in treating cervical dystonia, characterized by abnormal muscle activity in the neck region. This study is a randomized, double-blind, controlled trial, conducted in two phases. The first phase aims to assess the presence of abnormal muscle activity in the thoracic and lumbar regions in individuals with cervical dystonia. The second phase investigates the therapeutic effects and potential side effects of botulinum toxin injections in the back muscles of participants exhibiting abnormal activity. The trial is expected to conclude by June 30, 2026, with recruitment having commenced on December 1, 2022.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as being over 18 years of age, having a diagnosis of cervical dystonia, and receiving regular botulinum toxin treatment. Following the screening, eligible participants will be randomized to receive either the active treatment or placebo. The study includes multiple follow-up visits to monitor the treatment's effects and any adverse events. The primary endpoint is the change in dystonia severity, measured using the Unified Dystonia Rating Scale (UDRS). The end-of-study visit will assess the overall outcomes and gather final data.

The expected duration of participant involvement is approximately four months, aligning with the maximum treatment period. Conditions that may lead to early termination from the study include withdrawal of consent, significant adverse events, or non-compliance with study procedures. The trial's methodology ensures rigorous assessment of the treatment's impact on cervical dystonia, contributing valuable data to the understanding and management of this condition.

The clinical trial involves the administration of several **experimental medications** and a non-experimental treatment. The first experimental medication is **Botox 50 Allergan-yksikköä**, which is a **solution for injection** containing **botulinum toxin type A**. This medication is administered via **intramuscular injection**. The dosage is measured in **international units (IU)**, with a maximum daily dose of 400 IU and a total maximum dose of 1600 IU over a treatment period of 4 weeks. The administration schedule is designed to ensure participant compliance and monitor any adverse effects.

The second experimental medication is **Botox 100 Allergan-yksikköä**, also a **solution for injection** containing **botulinum toxin type A**. Similar to the first medication, it is administered through **intramuscular injection**. The dosage parameters are consistent with the first medication, with a maximum daily dose of 400 IU and a total maximum dose of 1600 IU over a 4-week period. The administration and monitoring procedures are identical to those of the first medication.

The third experimental medication is **XEOMIN 50 yksikköä**, which is a **solution for injection** containing **clostridium botulinum neurotoxin type A (150KD), free of complexing proteins**. This medication is also administered via **intramuscular injection**. The dosage is set at a maximum of 400 IU per day, with a total maximum dose of 1600 IU over a 4-week treatment period. Compliance and adverse effects are closely monitored throughout the trial.

The fourth experimental medication is **XEOMIN 100 yksikköä**, another **solution for injection** containing **clostridium botulinum neurotoxin type A (150KD), free of complexing proteins**. It is administered through **intramuscular injection**. The dosage limits are the same as the previous medications, with a maximum daily dose of 400 IU and a total maximum dose of 1600 IU over 4 weeks. Participant compliance and safety are prioritized during the administration.

The non-experimental treatment used in the study is **NaCl 0.9% B. Braun, Infusionslösung**, a **solution for infusion** containing **sodium chloride**. This treatment serves as a comparator and is administered via **intramuscular route**. The dosage is measured in **milliliters (ml)**, with a maximum daily dose of 4 ml and a total maximum dose of 16 ml over a 4-week period. The administration of this treatment is carefully monitored to ensure consistency and participant safety.

Efficacy in this clinical trial will be assessed by evaluating changes in the severity of **dystonia** using the Unified Dystonia Rating Scale (UDRS). This scale is a validated tool designed to measure the severity and impact of dystonia symptoms. The primary endpoint of the trial is the change in dystonia severity as measured by the UDRS. The trial will involve a double-blind phase to investigate the efficacy and potential side effects of botulinum toxin treatment in participants with abnormal back muscle activity associated with cervical dystonia. The trial is structured to ensure objective and reliable assessment of treatment outcomes, with data collection scheduled at specific intervals throughout the study period. The trial is expected to conclude by June 30, 2026, with recruitment having started on December 1, 2022.