Safety, Tolerability and Efficacy of NPI-001 in Patients With Hereditary Cystatin C Amyloid Angiopathy (HCCAA) (HCCAA)

July 16, 2026 updated by: Arctic Therapeutics
The study aims to measure safety, tolerability and biomarker-based efficacy of NPI-001 (AT-001) in Subjects with Hereditary Cystatin C Amyloid Angiopathy (HCCAA). In the study participants receive increasing dose or active treatment (250 mg vs 500mg vs 750 mg) or matched placebo in the form of tablets BID.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
15

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Iceland
      • Reykjavik, Iceland, 108
        • Landspitali University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Patient is male or female, aged 12 or older, and of Icelandic ancestry (see section 5.1 Selection of Trial Population). Subjects 12-17 years old will only qualify for inclusion if the DSMB approves lowering the minimum age following review of at least 3 months of safety in adults.
  2. Patient has been genotyped/sequenced and confirmed to carry the L68Q mutation in the cystatin C gene.
  3. Patients with previously established cystatin C/amyloid protein complexes in the skin
  4. Patients with mild cognitive impairment with cognitive function to follow the study protocol.
  5. Patient is willing to have a baseline and follow up skin biopsies according to the schedule of assessments, for up to 12 months, and up to 24 months if participating in the extension phase.*
  6. Patient is willing to have a baseline and follow up blood tests according to the schedule of assessments, for up to 12 months, and up to 24 months if participating in the extension phase.*
  7. Patient is willing to undergo MRI evaluations of the brain.*
  8. Patient has provided informed consent for participation in trial.
  9. Patient is willing and able to use contraception consistent with local regulations regarding the methods for participants in the clinical trial.

Both female participants of childbearing potential and male participants able to father children must have (or have a partner who has) had a bilateral oophorectomy, hysterectomy or bilateral salpingectomy; must abstain from intercourse; or must agree to practice 2 acceptable methods of contraception throughout the course of the study and 4 weeks after the last visit. Acceptable methods of contraception include hormonal contraception (i.e., birth control pills, injected hormones, dermal patch or vaginal ring), intrauterine device, barrier methods (diaphragm, condom), tubal ligation, and vasectomy.

Exclusion Criteria:

  1. Patient does not have L68Q mutation.
  2. Patients with moderate to severe cognitive impairment.
  3. Patient has clinically significant illness, mental or physical, that, in the opinion of the investigator, might confound the results of the study, pose additional risk to the patient by their participation, or prevent/impede the patient from completing the study.
  4. Patient has known sensitivity to NAC
  5. Coagulation/clotting parameters clinically significant outside the normal range (platelet counts, aPTT, PT)
  6. Subject is not willing to cease NAC supplementation at least 2 weeks prior to study participation.
  7. Patient is pregnant or breastfeeding.
  8. Known or suspected excessive alcohol or drug abuse.
  9. There is any concern by the investigator regarding the patient's safety, compliance, or suitability with respect to his/her participation in the study.
  10. Use of other investigational drugs at the time of enrollment, or within 5 half-lives of enrollment, or within 14 days, whichever is longer.
  11. Patient is taking medications known to affect or be affected by CYP enzymes or transporters will be excluded to avoid any inference.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Landspitali University Hospital
All participants receive active treatment in the form of tablets administered twice per day.
Drug: NACA
250 mg tablets BID, increasing dosage from 250 mg BID to 750 mg BID
Other Names:
  • AT-001
  • NAC-amid

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Incidence of Treatment-Emergent Adverse Events
Time Frame: Through study completion, up to 24 months
Incidence of Treatment-Emergent Adverse Events in response to NPI-001 (AT-001) administered orally in subjects with HCCAA. Assessment of the number of participants with treatment-related adverse events. Assessment of the amount of mild and severe adverse events related to the treatment.
Through study completion, up to 24 months
Frequency of cerebral bleeding events
Time Frame: Through study completion, up to 24 months
Assessment of frequency of clinical cerebral bleedings events, defined as any bleed that causes stroke, hemorrhagic or ischemic after 12 months of treatment (main study) and after 24 months of treatment (12 - months study extension phase)
Through study completion, up to 24 months
Safety labs results within normal range
Time Frame: Through study completion, up to 24 months
Safety labs result not being outside of normal ranges and/or not clinically significant as assessed by the PI.
Through study completion, up to 24 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Biomarker - cystatin C aggregation in the skin
Time Frame: Through study completion, up to 24 months
Reduction in amyloid-cystatin C complexes in skin biopsies compared with baseline levels based on % of area stained using Immunohistochemistry
Through study completion, up to 24 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Arctic Therapeutics

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 3, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 29, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 18, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 21, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 21, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 16, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • AT-23-01
  • 2023-503969-36-01 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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