Myrtelle Announces Positive Interim Data in Phase 1/2 Clinical Trial of Its Proprietary Investigational Gene Therapy rAAV-Olig001-ASPA in Canavan Disease

Phase 1/2 clinical study is evaluating Myrtelle’s first-of-its-kind proprietary adeno-associated virus (rAAV) vector designed to enable targeting of oligodendrocytes

Eight patients have been treated in the ongoing Phase 1/2 First-in-Human clinical trial with favorable findings observed to date

Assessments of all treated patients through three-months of follow-up show improvements in neuroimaging and functional scales

WAKEFIELD, Mass.–(BUSINESS WIRE)–#Canavan—Myrtelle Inc. (“Myrtelle” or the “Company”), a gene therapy company focused on developing transformative treatments for neurodegenerative diseases, today announced updated initial findings of the 8 patients treated with the Company’s recombinant adeno-associated virus (rAAV) vector-based investigational gene therapy for open-label Phase 1/2 First-in-Human (FIH) clinical trial for Canavan disease (CD), a fatal genetic disorder in children. Early data from the study, being conducted at Dayton Children’s Hospital (Dayton, Ohio), at three months following gene therapy treatment have shown encouraging results to date.

Assessments for all 8 patients through their three-month follow-up visits have shown increases in white matter, grey matter, and total brain volumes within three months and reduction in the volume of cerebrospinal fluid (CSF) in most patients by magnetic resonance imaging (MRI). Additionally, clinical measurements of motor and cognitive function using the Gross Motor Function Measure (GMFM) and Mullen Scales of Early Learning (MSEL) tools have demonstrated improvements across several domains. The observed improvements following gene therapy are in contrast to the continuous clinical decline expected for untreated CD patients. The first three patients treated with the gene therapy in cohort one are now at least 18 months post therapy. As announced previously, assessments of these initial three patients at later time points also showed improvements on imaging and validated functional scale measurements. No serious drug-related adverse events have been observed in treated patients to date.

Myrtelle’s FIH trial utilizes the Company’s proprietary rAAV vector to directly target oligodendrocytes, the brain cells affected in CD which 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 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 causes abnormal accumulation of NAA and deficiency of downstream metabolites, leading 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 early results to date in patients treated in Myrtelle’s Phase 1/2 clinical trial are encouraging. The available evidence suggests the delivered gene therapy is, within three months, rapidly eliciting its intended effect. Given these data, we are encouraged to continue tracking these treated patients and to advance development of the candidate gene therapy to bring this potential treatment options to CD patients,” commented Rob Lober, MD, Principal Investigator on the Phase 1/2 study and Attending Neurosurgeon at Dayton Children’s Hospital and Associate Professor of Pediatrics at Wright State University Boonshoft School of Medicine.

Myrtelle has previously announced that rAAV-Olig001-ASPA has received Orphan Drug, Rare Pediatric Disease, and Fast Track designations from the US Food and Drug Administration as well as Orphan Drug Designation and Advanced Therapeutic Medicinal Product classification from the European Medicines Agency.

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 [email protected].

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 delivered gene therapy is, within three months, rapidly eliciting its intended effect. 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

Media:

Jordana Holovach

Head of Communications and Community

Myrtelle Inc.

781-621-2797 Ext. 102

[email protected]