Analyses at 6 months showed increases in myelin, white matter and other MRI and MRS measurements as well as functional improvements on validated assessment scales

Encouraging initial efficacy data support further development of rAAV-Olig001-ASPA as a potential therapeutic approach for children with Canavan disease

Trial update to be presented at upcoming 2023 ASGCT Annual Meeting

WAKEFIELD, Mass — Myrtelle Inc. (“Myrtelle” or the “Company”), a gene therapy company focused on developing transformative treatments for neurodegenerative diseases, today announced encouraging initial data and a favorable safety profile at the 6 month post-treatment time point in the 8 patients treated with the Company’s recombinant adeno-associated virus (rAAV) vector-based investigational gene therapy in its open-label Phase 1/2 First-in-Human (FIH) clinical trial for Canavan disease (CD), a fatal genetic brain disorder in children.

Assessments showed statistically significant mean absolute and/or percent increases from baseline measurements in myelin, white matter, grey matter, and total brain volume, and reduction in the volume of cerebrospinal fluid (CSF) by magnetic resonance imaging (MRI) in these patients. Additionally, clinical measurements of motor and cognitive function using the Gross Motor Function Measure (GMFM) and Mullen Scales of Early Learning (MSEL) demonstrated mean absolute and percent improvements across multiple domains. In several domains, the observed improvement in treated patients are in contrast to the observed deterioration in untreated age-matched CD patients within Myrtelle’s natural history data set. No serious drug-related adverse events have been observed to date.

Myrtelle’s FIH trial utilizes the Company’s proprietary rAAV vector to directly target oligodendrocytes, the brain cells affected in CD that are responsible for producing myelin – the insulating material that enables proper neuronal function. In CD, normal brain development is impaired due to a mutation in the ASPA gene that encodes the enzyme Aspartoacylase (ASPA). The deficiency of ASPA enzyme results in multiple biochemical and anatomic changes, including the inability to metabolize N-Acetylaspartate (NAA) which in turn leads to impaired bioenergetics and abnormal brain development. The oligodendrocyte-targeting rAAV vector-based gene therapy is intended to restore ASPA function and hence the metabolism of NAA and brain development in patients with CD.

“The 6-month functional and anatomic data observed in these patients are encouraging in showing positive changes in the patients’ motor, language, cognitive and visual skills.” said Chris Janson, MD, Principal Investigator and Assistant Professor of Neurology and Neuroscience at Wright State University Boonshoft School of Medicine and Director of Human Gene Therapy Center at Wright State Neuroscience Institute in Dayton, OH. “Improvements in functional scores were observed across multiple domains on the GMFM and MSEL assessment tools. In addition, volumetric MRI (magnetic resonance imaging) measurements showed increases in multiple brain tissue compartments and reductions in CSF volume. Reductions in brain NAA, measured by MRS (magnetic resonance spectroscopy) were also seen. These improvements suggest the gene therapy is having its intended effect and encourages advancement of the gene therapy program to bring this potential treatment option to more CD patients.”

An update on the trial at a symposium will be presented by Dr. Janson at the ASGCT 26th Annual Meeting in Los Angeles in May.

ABOUT MYRTELLE

Myrtelle Inc. is a gene therapy company focused on developing transformative treatments for neurodegenerative diseases. The company has a proprietary platform, intellectual property, and portfolio of programs and technologies supporting innovative gene therapy approaches for neurodegenerative diseases. Myrtelle has an exclusive worldwide licensing agreement with Pfizer Inc. for its Canavan disease program. For more information, please visit the Company’s website at: www.myrtellegtx.com.

ABOUT CANAVAN DISEASE

Canavan disease (CD) is a fatal childhood genetic brain disease in which mutations in the Aspartoacylase gene (ASPA) prevent the normal expression of Aspartoacylase (ASPA), a critical enzyme produced in oligodendrocytes that breaks down the neurochemical N-Acetylaspartate (NAA). When not properly metabolized by oligodendrocytes, NAA accumulates in the brain and negatively affects bioenergetics, myelin production, and brain health. Patients with CD are impacted at birth but may appear normal until several months old when symptoms begin to develop. Poor head control, abnormally large head size, difficulty in eye tracking, excessive irritability, severely diminished muscle tone, and delays in reaching motor milestones, such as rolling, sitting, and walking, are the typical initial manifestations of CD. As the disease progresses, seizures, spasticity, difficulties in swallowing, and overall muscle deterioration emerge with most affected children developing life-threatening complications by approximately 10 years of age. Currently, there are no cures for CD, and only palliative treatments are available.

More information on Myrtelle’s clinical trial in Canavan disease can be found on https://clinicaltrials.gov/ under the identifier NCT04833907 or by emailing PatientAdvocacy@MyrtelleGTX.com.

Forward-Looking Statements

This press release contains forward-looking statements. Words such as “may,” “believe,” “will,” “expect,” “plan,” “anticipate,” “estimate,” “intend” and similar expressions (as well as other words or expressions referencing future events, conditions, or circumstances) are intended to identify forward-looking statements. Forward-looking statements are based upon current estimates and assumptions and include statements regarding the improvements suggesting the gene therapy is having its intended effect and encourages advancement of the gene therapy program and the program being a potential treatment option. While Myrtelle believes these forward-looking statements are reasonable, undue reliance should not be placed on any such forward-looking statements, which are based on information available to us on the date of this release. These forward-looking statements are subject to various risks and uncertainties, many of which are difficult to predict, that could cause actual results to differ materially from current expectations and assumptions from those set forth or implied by any forward-looking statements. Important factors that could cause actual results to differ materially from current expectations include, among others, Myrtelle’s program demonstrating safety and efficacy, as well as future results that are consistent with prior results, the ability to generate the data needed for further development of this novel gene therapy in the patients with CD, and the ability to continue its clinical trials and to complete them on time and achieve the desired results. All forward-looking statements are based on Myrtelle’s expectations and assumptions as of the date of this press release. Actual results may differ materially from these forward-looking statements. Except as required by law, Myrtelle expressly disclaims any responsibility to update any forward-looking statement contained herein, whether as a result of new information, future events, or otherwise.

Contacts
Jordana Holovach
Head of Communications and Community
Myrtelle Inc.
781-621-2797 Ext. 102
jholovach@myrtellegtx.com