MYR-101
An investigational treatment for Canavan Disease.
Drug facts
The same compound appears under different names depending on the context. Here is how to identify MYR-101 wherever you encounter it, plus the key facts at a glance.
- Generic name
- MYR-101
- Development codes
- MYR-101, rAAV-Olig001-ASPA
- Drug class
- AAV gene therapy (oligodendrocyte-targeted)
- Manufacturer
- Myrtelle
- How it's taken
- One-time injection into the brain during surgery, in a trial only
An investigational one-time gene therapy for Canavan disease from Myrtelle, given into the fluid spaces of the brain during surgery, that delivers a working ASPA gene to the brain's myelin-making cells [5].
Interim results from 8 children in its Phase 1/2 trial were published in Nature Medicine in 2025, from a study without a control group [1]. It is not FDA approved.
We'll email you when the FDA acts on MYR-101 and when new trials for Canavan Disease open. Unsubscribe anytime.
- Trial Alerts, when a new trial opens or a trial changes
- Disease Updates, FDA decisions and condition news, usually 1 or 2 emails a month
We never share your email. Unsubscribe anytime. Privacy policy · Check any health site
How MYR-101 works
Canavan disease leaves the brain without aspartoacylase, the enzyme made from the ASPA gene that breaks down N-acetylaspartate (NAA). The enzyme normally works in oligodendrocytes, the cells that build myelin, the coating on nerve fibers. MYR-101 uses a virus shell called Olig001 that is designed to reach oligodendrocytes and carries a working ASPA gene into them [5] [1]. The goal is to lower NAA and let myelin form. The EU clinical trial register lists the name ciracigene golparvovec [4].
Clinical trial results
The US trial, CAN-GT (NCT04833907), is an open-label Phase 1/2 study for about 24 children aged 3 to 60 months, with safety at 12 months as its main measure. ClinicalTrials.gov lists it as enrolling by invitation at Dayton Children's Hospital in Ohio; the record was last updated in November 2025, and its estimated primary completion date of August 2026 has passed without an update [5].
A European version of the trial at Bicêtre Hospital near Paris was authorised in France in February 2026, measuring the change in spinal fluid NAA at 6 months; the EU register lists a start date of September 2, 2026 and shows recruitment as not yet started [4].
Leone and colleagues reported 12-month interim results for 8 children in Nature Medicine in September 2025. Treatment lowered NAA in the spinal fluid, increased myelination on MRI and improved scores on the Mullen Scales of Early Learning, a test of early development and language, and the report also measured gross motor function. The study had no control group, the authors call the findings preliminary, and several authors are paid consultants, shareholders or officers of Myrtelle [1].
Main registered trial: NCT04833907 on ClinicalTrials.gov. Check it for the current status, sites and contacts before asking about enrollment.
Side effects and safety
In the Nature Medicine report on 8 children, every child had at least 1 side effect and 7 of 8 had at least 1 serious side effect, none of which were considered related to MYR-101, and all side effects and serious side effects resolved fully [1]. Because it is given during brain surgery, the procedure carries its own risks, and the trial gives seizure-preventing medicine for 3 months afterward [5]. No clinical hold has been reported.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking MYR-101
Given once by neurosurgery, as injections into 2 of the brain's fluid-filled ventricles [5]. Children receive a 3-month prednisone taper to calm the immune response, which can be extended if MRI shows new inflammation, and levetiracetam for 3 months after surgery to help prevent seizures [5].
Development history
Myrtelle announced FDA Fast Track, rare pediatric disease and orphan drug designations on March 15, 2022, and RMAT designation, an FDA program for cell and gene therapies that brings more frequent FDA advice, on April 2, 2024. It announced in June 2024 that the FDA selected the program for its START pilot, and in December 2022 that the European Medicines Agency granted orphan designation [2].
Myrtelle has an exclusive worldwide licensing agreement with Pfizer covering AAV vectors that target oligodendrocytes [2]. Myrtelle has described its regulatory path toward a BLA submission, the filing that asks the FDA for approval, but has not given a date [3].
Explore Canavan Disease trials
Other Canavan Disease treatments
Common questions about MYR-101
▸What is MYR-101?
An investigational one-time gene therapy for Canavan disease from Myrtelle, given into the fluid spaces of the brain during surgery, that delivers a working ASPA gene to the brain's myelin-making cells [5]. Interim results from 8 children in its Phase 1/2 trial were published in Nature Medicine in 2025, from a study without a control group [1]. It is not FDA approved.
▸How does MYR-101 work?
Canavan disease leaves the brain without aspartoacylase, the enzyme made from the ASPA gene that breaks down N-acetylaspartate (NAA). The enzyme normally works in oligodendrocytes, the cells that build myelin, the coating on nerve fibers. MYR-101 uses a virus shell called Olig001 that is designed to reach oligodendrocytes and carries a working ASPA gene into them [5] [1]. The goal is to lower NAA and let myelin form. The EU clinical trial register lists the name ciracigene golparvovec [4].
▸What are the side effects of MYR-101?
In the Nature Medicine report on 8 children, every child had at least 1 side effect and 7 of 8 had at least 1 serious side effect, none of which were considered related to MYR-101, and all side effects and serious side effects resolved fully [1]. Because it is given during brain surgery, the procedure carries its own risks, and the trial gives seizure-preventing medicine for 3 months afterward [5]. No clinical hold has been reported.
▸How is MYR-101 taken?
▸Is MYR-101 FDA approved?
MYR-101 is currently in phase 2 clinical trials for Canavan Disease. It has not yet received FDA approval.
▸How is the Myrtelle Canavan gene therapy given?
Once, during neurosurgery, as injections into the fluid-filled spaces of the brain.
Around treatment: a 3-month prednisone taper and 3 months of levetiracetam to help prevent seizures.
Why surgery: it places the gene therapy close to the brain cells that make myelin.
Source: ClinicalTrials.gov NCT04833907.
▸What did the Nature Medicine Canavan gene therapy trial show?
In 8 children at 12 months, treatment lowered NAA in the spinal fluid, increased myelination on MRI and improved Mullen Scales scores, a test of early development.
Safety: 7 of 8 had a serious side effect, none considered related to the gene therapy, and all side effects resolved fully.
Caution: no control group; the authors call the findings preliminary.
Source: Leone et al., Nature Medicine, September 2025.
▸When could MYR-101 be FDA approved?
No date has been set. Myrtelle has described its path toward a BLA, the filing that asks the FDA for approval, but has not announced one.
Designations: Fast Track, RMAT, rare pediatric disease and orphan drug.
Source: Myrtelle release, May 11, 2026; Myrtelle news page.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- Nature Medicine 31(11):3772-3779 · 2025-09-16. Oligodendrocyte-targeted adeno-associated virus gene therapy for Canavan disease in children: a phase 1/2 trial. https://pubmed.ncbi.nlm.nih.gov/40957959/
- Myrtelle. Myrtelle news and announcements. https://myrtellegtx.com/news/
- Myrtelle (PR Newswire, BioSpace copy) · 2026-05-11. Myrtelle to present clinical data and regulatory progress for MYR-101 gene therapy program at ASGCT 2026. https://www.biospace.com/press-releases/myrtelle-to-present-clinical-data-and-regulatory-progress-for-myr-101-gene-therapy-program-at-asgct-2026
- EU Clinical Trials Information System. Phase 1/2, Open Label, Sequential Cohort Study of a Single Intracranial Dose of rAAVOlig001-ASPA Gene Therapy (CAN-GT, CD Olig001-101). https://euclinicaltrials.eu/ctis-public-api/retrieve/2024-519412-13-00
- ClinicalTrials.gov. rAAV-Olig001-ASPA Gene Therapy for Treatment of Children With Typical Canavan Disease. https://clinicaltrials.gov/study/NCT04833907