Evaluation of Vutrisiran Efficacy and Safety in Transthyretin Amyloidosis with Cardiomyopathy: A Phase 3 Randomized, Double-Blind, Placebo-Controlled Study

The primary objective of this study is to evaluate the **efficacy** of vutrisiran compared to placebo in reducing all-cause mortality and cardiovascular events in patients with Transthyretin Amyloidosis with Cardiomyopathy (ATTR Amyloidosis with Cardiomyopathy). This is clinically relevant as it aims to address the high mortality and morbidity associated with this condition by potentially offering a therapeutic option that can improve survival and reduce cardiovascular complications.

Secondary objectives include evaluating the efficacy of vutrisiran compared with placebo treatment on:

• Functional capacity
• Patient-reported health status and health-related quality of life
• All-cause mortality
• Severity of clinical heart failure symptoms

The clinical trial involves a total of **250 participants** diagnosed with **Transthyretin Amyloidosis with Cardiomyopathy (ATTR Amyloidosis with Cardiomyopathy)**. The study population includes both male and female subjects, aged between **18 to 85 years**, who are clinically stable and have not experienced cardiovascular-related hospitalizations within six weeks prior to randomization. Participants were selected based on specific inclusion criteria, including a documented diagnosis of ATTR amyloidosis with cardiomyopathy and a medical history of heart failure. The trial population is characterized by a Karnofsky performance status of at least 60% and the ability to complete a minimum of 150 meters on the 6-minute walk test at screening. Lifestyle considerations such as diet and physical activity are not specified, but participants must be able to comply with study requirements and provide written informed consent. The trial includes a vulnerable population, and both tafamidis-naïve patients and those on tafamidis are eligible, provided the use is on-label for cardiomyopathy. The sponsor has not provided additional information regarding specific lifestyle factors or habits of the participants.

The clinical trial is a **Phase 3**, randomized, double-blind, placebo-controlled, multicenter study designed to evaluate the efficacy and safety of **vutrisiran** in patients with **Transthyretin Amyloidosis with Cardiomyopathy**. The primary objective is to assess the impact of vutrisiran compared to placebo on reducing all-cause mortality and cardiovascular events. The trial is expected to run from November 21, 2019, to November 21, 2025, with participant involvement lasting up to 60 months.

Participants will be randomly assigned to receive either vutrisiran, administered as a **solution for injection** in a pre-filled syringe, or a placebo, which is 0.9% sodium chloride. The administration route for vutrisiran is **subcutaneous use**. The study includes several key visits: an initial screening visit to confirm eligibility, regular follow-up visits to monitor safety and efficacy, and an end-of-study visit to collect final data. The inclusion criteria require participants to be aged 18 to 85 years, have a documented diagnosis of ATTR amyloidosis with cardiomyopathy, and meet specific clinical stability and performance status requirements.

Participants are expected to complete a 6-minute walk test and have a Karnofsky performance status of at least 60%. The primary endpoint is a composite outcome of all-cause mortality and recurrent cardiovascular events, including hospitalizations and urgent heart failure visits. Secondary endpoints include changes from baseline in the 6-minute walk test, Kansas City Cardiomyopathy Questionnaire-Overall Summary, all-cause mortality, and New York Heart Association Class.

Conditions that may lead to early termination from the study include significant adverse events, withdrawal of consent, or non-compliance with study procedures. The trial is not classified as low intervention, and the study design ensures rigorous assessment of the investigational product's efficacy and safety in the target population.

The clinical trial involves the administration of **Amvuttra**, a 25 mg solution for injection in a pre-filled syringe, containing the active substance **vutrisiran**. Vutrisiran is a chemically synthesized double-stranded oligonucleotide linked to a ligand with three GalNAc residues, classified under the ATC code N07XX as an "Other Nervous System Drug." The pharmaceutical form is a solution for injection, and the route of administration is subcutaneous. The maximum daily dose is 25 mg, with a total maximum dose of 550 mg over a treatment period of 60 days. The medication is not a pediatric formulation and is designated as an orphan drug. The product is manufactured by Alnylam Netherlands B.V. and is authorized for use in the European Union under the marketing authorization number EU/1/22/1681/001.

The study also utilizes a non-experimental treatment, 0.9% **sodium chloride**, which serves as a placebo comparator. The sodium chloride solution is used to maintain the double-blind nature of the trial, ensuring that neither the participants nor the investigators are aware of the treatment assignments. The pharmaceutical form and route of administration for the sodium chloride solution are not specified in the trial data. The use of sodium chloride as a placebo is standard practice in clinical trials to evaluate the efficacy and safety of the experimental medication, in this case, vutrisiran, in patients with transthyretin amyloidosis with cardiomyopathy.

The efficacy of vutrisiran in the treatment of **Transthyretin Amyloidosis with Cardiomyopathy** will be assessed through a Phase 3, randomized, double-blind, placebo-controlled, multicenter study. The primary endpoint for evaluating efficacy is a composite outcome of all-cause mortality and recurrent cardiovascular (CV) events, including CV hospitalizations and urgent heart failure (HF) visits. This will be measured in both the overall population and the vutrisiran monotherapy subgroup, which consists of patients not on tafamidis at the study baseline.

Secondary endpoints include changes from baseline in the 6-minute walk test (6-MWT), the Kansas City Cardiomyopathy Questionnaire-Overall Summary (KCCQ-OS), all-cause mortality, and changes from baseline in the New York Heart Association (NYHA) Class. These parameters will also be evaluated in both the overall population and the vutrisiran monotherapy subgroup. The study will utilize validated scales and patient-reported outcomes to measure these endpoints. The schedule for measuring and collecting data on these efficacy parameters will be aligned with the study's protocol, ensuring systematic and consistent data collection throughout the trial duration.