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Study on the Safety and Effects of ALN-APP for Patients with Cerebral Amyloid Angiopathy

Fast replyInvestigationalNo placebo
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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 a neurological condition called Cerebral Amyloid Angiopathy (CAA). CAA occurs when amyloid proteins build up in the walls of blood vessels in the brain, which can lead to problems such as bleeding into the brain. The study will evaluate a treatment called Mivelsiran, which is administered as a solution for injection. Mivelsiran is also known by its code name ALN-APP. The purpose of the study is to assess the effect of Mivelsiran on the occurrence of new small brain bleeds, known as Cerebral Microbleeds (CMBs), in patients with CAA.

Participants in the study will receive either Mivelsiran or a placebo, which is a substance with no active medication. The study is designed to be double-blind, meaning neither the participants nor the researchers will know who is receiving the actual treatment or the placebo. This helps ensure that the results are not influenced by expectations. The treatment will be given through a method called intrathecal use, which involves injecting the solution into the space around the spinal cord. The study will monitor participants over a period of time to observe any changes in the incidence of new CMBs and other related outcomes.

The study will also use MRI scans to detect changes in the brain and assess the safety and tolerability of Mivelsiran. MRI, or Magnetic Resonance Imaging, is a technique that uses magnetic fields and radio waves to create detailed images of the organs and tissues in the body. The trial aims to provide valuable information on the potential benefits and risks of using Mivelsiran for treating CAA, contributing to a better understanding of how to manage this condition effectively.

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 study, an initial visit is conducted to confirm eligibility. This involves a review of medical history and a physical examination.

    An MRI scan is performed to assess the brain's condition. This scan helps in identifying any existing issues related to cerebral amyloid angiopathy (CAA).

  2. Step 2

    Treatment assignment

    Participants are randomly assigned to receive either the investigational medication Mivelsiran or a placebo. A placebo is a substance with no active medication, used for comparison.

    The medication is administered through intrathecal use, which means it is injected into the space around the spinal cord.

  3. Step 3

    Medication administration

    The medication or placebo is given as a solution for injection. The frequency and dosage are determined by the study protocol and are administered by healthcare professionals.

    Participants will receive the treatment over a specified period, with regular monitoring to ensure safety and effectiveness.

  4. Step 4

    Regular follow-up visits

    Regular follow-up visits are scheduled to monitor health and response to the treatment. These visits include physical examinations and additional MRI scans.

    Participants are required to report any side effects or changes in health during these visits.

  5. Step 5

    Final assessment

    At the end of the study period, a final assessment is conducted. This includes a comprehensive review of health status and any changes observed during the trial.

    The final MRI scan is performed to evaluate the effect of the treatment on cerebral microbleeds and other related conditions.

Who can join the trial?

12 criteria

  • Must be a male or female aged 50 years or older for Sporadic Cerebral Amyloid Angiopathy (sCAA) patients.
  • Must be a male or female aged 30 years or older for Dutch-type Cerebral Amyloid Angiopathy (D-CAA) patients.
  • Must have a probable diagnosis of Cerebral Amyloid Angiopathy (CAA) based on specific criteria, including medical history and MRI findings.
  • For D-CAA patients, must have a known E693Q APP gene mutation.
  • Must have corrected vision of 20/50 or better for those undergoing specific brain imaging tests.
  • Must be able and willing to meet all study requirements, including travel, procedures, and visits.
  • Must have a supportive study partner who can provide accurate information about the patient's abilities and attend certain study visits.
  • Must be able to undergo and tolerate MRI scans (no metal implants or conditions that make MRI intolerable).
  • Must have a Body Mass Index (BMI) between 18 and 34 kg/m².
  • Must be able to tolerate a lumbar puncture (LP), a procedure to collect fluid from the spine.
  • Must have evaluable brain MRI imaging at the screening visit.
  • Must be able to understand, willing and able to comply with study requirements, and provide written informed consent. If unable to provide consent, a legally authorized representative may do so if allowed by local regulations.

Who cannot join the trial?

4 criteria

  • Patients with a condition called Cerebral Amyloid Angiopathy (CAA), where certain proteins build up in the brain's blood vessels, cannot participate.
  • Patients who have experienced bleeding in the brain are not eligible.
  • Patients with new lobar Cerebral Microbleeds (CMBs), which are small areas of bleeding in the brain, cannot join the study.
  • Individuals who are part of a vulnerable population, meaning they may have additional risks or need special protection, are not allowed to participate.
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Investigated drugs

ALN-APP is a medication being studied for its potential to help patients with a condition called Cerebral Amyloid Angiopathy (CAA). This condition involves the buildup of a protein called amyloid in the walls of the blood vessels in the brain, which can lead to problems like bleeding. ALN-APP is administered directly into the spinal fluid, a method known as intrathecal administration, to see if it can reduce the occurrence of new small brain bleeds, known as cerebral microbleeds. The study aims to understand how effective and safe ALN-APP is for patients with this condition.

What is already known about the treatment

ALN-APP – ALN-APP is administered through a method called intrathecal injection, which involves delivering the medication directly into the spinal fluid. This medication is currently being studied in clinical trials, specifically in a Phase 2 study, to assess its effectiveness and safety for treating Cerebral Amyloid Angiopathy (CAA), a condition where amyloid proteins accumulate in the brain's blood vessels, leading to potential bleeding. The main goal of ALN-APP is to reduce the occurrence of new small brain bleeds, known as cerebral microbleeds. At the molecular level, ALN-APP works by targeting and reducing the production of amyloid proteins, which are believed to contribute to the disease. It falls under the pharmacological classification of RNA interference therapeutics, which are designed to silence specific genes involved in disease processes.

Investigated diseases

Cerebral Amyloid Angiopathy – Cerebral Amyloid Angiopathy is a neurological condition characterized by the accumulation of amyloid proteins in the walls of blood vessels in the brain. This buildup can lead to structural changes in the blood vessels, making them more prone to rupture. As the disease progresses, it can cause bleeding into the brain, known as cerebral hemorrhages. These hemorrhages are often recurrent and can vary in size and location within the brain. The condition is associated with the development of cerebral microbleeds, which are small areas of bleeding that can be detected using imaging techniques like MRI. Over time, the disease may also lead to changes in brain tissue and function due to repeated bleeding events.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-510137-29-01Protocol codeALN-APP-002Estimated enrolment200 patientsSponsorAlnylam Pharmaceuticals Inc.

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).