A Phase 1/2 interventional study of PM577a in Wilson Disease, Wilson's Disease and Wilsons Disease, sponsored by Prime Medicine, Inc.. Recruiting at 4 sites in 2 countries. Open to participants aged 12 Years and older. Per ClinicalTrials.gov, last updated 2026-10-01.
Sponsored by Prime Medicine, Inc. · Phase 1/2, Interventional, and Treatment
The purpose of this study is to evaluate the safety, tolerability, biological activity, and initial efficacy of PM577a, an investigational Prime Editing therapy, in adults and adolescents with Wilson disease (WD).
Wilson disease is caused by changes (mutations) in the ATP7B gene that prevent the body from removing excess copper normally. PM577a is designed to precisely correct one of the most common disease-causing ATP7B mutations (p.H1069Q) in liver cells with the goal of restoring normal copper metabolism.
This is the first study of PM577a in people. Participants will receive a single intravenous (IV) infusion of PM577a and will be monitored closely to evaluate safety, how the body responds to treatment, whether copper metabolism improves, and whether treatment may improve signs and symptoms of Wilson disease.
This is a Phase 1/2, open-label study evaluating PM577a in adults and adolescents with Wilson disease who have specific disease-causing changes in the ATP7B gene, including at least one p.H1069Q mutation.
The study will evaluate the safety of PM577a, determine an appropriate dose for future studies, and assess whether treatment restores copper metabolism and improves clinical measures of Wilson disease. Participants will receive a single IV infusion of PM577a and will undergo regular safety evaluations, laboratory testing, imaging, and clinical assessments for approximately 48 weeks after treatment. Participants will then be asked to enroll in a separate long-term follow-up study to continue monitoring safety and treatment effects.
80 studies on the registry are indexed under Hepatolenticular Degeneration; 31 are open to participants now.
This study's planned enrollment of 42 is above the median of 30 across 44 interventional studies indexed under Hepatolenticular Degeneration.
Browse Hepatolenticular Degeneration studies →Prime Medicine, Inc. is the lead sponsor of 4 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Active infectious disease including:
Any condition, laboratory abnormality, or reason that could adversely affect participant safety or study results, as determined by the Investigator, including, but not limited to:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
PM577a is a sterile suspension of lipid nanoparticle (LNP)-formulated Prime Editors (PEs) intended for single dose intravenous (IV) infusion for the treatment of Wilson disease (WD).
Drug: PM577a
PM577a is being evaluated in participants with Wilson disease caused by biallelic pathogenic, likely pathogenic, or suspected pathogenic ATP7B variants, including at least one p.H1069Q allele.
Safety and tolerability of PM577a. Quantified by frequency and severity of treatment emergent adverse events (TEAEs).
Time frame: Post-infusion through Week 48
Frequency and severity of Dose Limiting Toxicities (DLTs)
Time frame: Infusion through the 14-day post infusion DLT observation period
Evidence of improved copper metabolism based on meeting the criteria to stop standard of care (SOC) therapy (chelation or zinc), including stable or improving non-ceruloplasmin bound copper levels and liver function tests.
Time frame: Infusion through Week 48
Percent of participants with non-ceruloplasmin bound copper (NCC)
Time frame: Weeks 12, 24, and 48 post-infusion
Percent change from baseline in ceruloplasmin levels
Time frame: From PM577a infusion to Weeks 4, 6, 9, 12, 24, and 48 post-infusion
Percent of participants with ceruloplasmin within the normal range
Time frame: Weeks 4, 6, 9, 12, 24, and 48 post-infusion
Percent of participants with improved non-ceruloplasmin bound copper measured by protein speciation (NCC-Sp)
Time frame: Weeks 12, 24, and 48 post-infusion of PM577a
Change in serum radiocopper ratio
Time frame: 24 hours/2 hours post-64Cu injection from baseline to Week 6 or later post-infusion of PM577a
Percent change in liver copper efflux
Measured by hepatic 64Cu PET standard uptake value (SUV)
Time frame: 1.5 hours and 20 hours post 64Cu injection from baseline to Week 6 or later post-infusion of PM577a
Percentage of participants off of standard of care
Time frame: Weeks 12 and 48 post-infusion of PM577a
On-target editing
Measured by liver biopsy specimen
Time frame: Weeks 24 and 48 post-infusion
Percent change in Liver Copper Concentration
Assessed by liver biopsy
Time frame: From baseline to Week 24, and to Week 48 post PM577a infusion
Change in Liver Stiffness
Measured using transient or shear wave elastography
Time frame: from baseline to Week 48 post PM577a infusion
Evaluation of health-related quality of life (HRQoL) as compared to baseline
Measured using the age-appropriate EuroQol 5 Dimension 5-Level instrument (EQ-5D-5L)
Time frame: From baseline through study completion (Week 48)
Percent of participants with stable or improved modified Unified Wilson's Disease Rating Scale (mUWDRS) score
Test is divided into 3 parts to assess for neurological and functional status in Wilson disease and divided into 3 parts. Part 1 (range 0-3), Part 2a (range 0-40), Part 2b (range 0-20) and Part 3 (range 0-147). Total cumulative range is 0-210. Higher scores indicate greater disease severity.
Time frame: Week 48 post PM577a infusion compared to baseline
Percent of participants with stable or improved score on the Clinical Global Impression Improvement Scale (CGI-I)
Scores range from 1-7. Lower scores indicate a better outcome.
Time frame: Measured over the course of the study (through Week 48) compared to baseline
Percent of participants with stable or improved score on the Clinical Global Impression Severity Scale (CGI-S)
Scores range from 1-7. Lower scores indicate a better outcome.
Time frame: Measured over the course of the study (through Week 48) compared to baseline
Percent of participants with stable or improved Model for End-Stage Liver Disease (MELD) score
Scores range from 6 and upward, with higher scores indicating a more severe liver disease and a worse prognosis.
Time frame: Measured at Week 48 post PM577a infusion compared to baseline
Percent of participants with stable or improved modified Nazer score
This score assesses prognosis in Wilson disease using total bilirubin, international normalized ratio (INR), aspartate aminotransferase (AST), white blood cell count (WBC), and serum albumin. Each component is scored from 0 to 4, producing a total score ranging from 0 to 20. Higher scores indicate a worse prognosis.
Time frame: Measured at Week 48 post PM577a infusion compared to baseline
Percent change in 24-hour urinary copper excretion (UCE)
For participants who are not on standard of care at the specified timepoint
Time frame: From baseline to Weeks 12, 24, and 48 post PM577a infusion
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
No contact was published for this record. The registry link below has the sponsor’s details.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Hepatolenticular Degeneration →
Prime Medicine, Inc.