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News Release

News Release

News Release

Homology Medicines Announces First Presentation of Data with HMI-203 In Vivo Gene Therapy Development Candidate for Hunter Syndrome

February 8, 2021 at 2:50 PM EST

- IND-Enabling Studies Demonstrated Potential of a Single I.V. Administration of HMI-203 to Address Peripheral and CNS Components of Disease -

- Data at WORLDSymposium™ Support Plans to Initiate a HMI-203 Phase 1/2 Clinical Trial
This Year -

BEDFORD, Mass., Feb. 08, 2021 (GLOBE NEWSWIRE) -- Homology Medicines, Inc. (Nasdaq: FIXX), a clinical-stage genetic medicines company, announced today the first scientific presentation of data from IND-enabling studies with its HMI-203 gene therapy development candidate for Hunter syndrome (MPS II). The results from Homology’s in vivo approach demonstrated the potential of HMI-203 to address peripheral manifestations in the murine disease model and showed that HMI-203 crossed the blood-brain-barrier following a single I.V. administration. These data will be presented during a poster presentation at the 17th Annual WORLDSymposium™ Meeting, where Homology will also present long-term data from its HMI-202 in vivo gene therapy program for metachromatic leukodystrophy (MLD).

“By leveraging our family of AAVHSC vectors to target both peripheral organs and the central and peripheral nervous systems in preclinical models of Hunter syndrome and MLD, debilitating diseases that have high unmet medical need, we also demonstrated the continued expansion of our CNS platform,” stated Albert Seymour, Ph.D., Chief Scientific Officer of Homology Medicines. “This is our first presentation of preclinical data from our Hunter syndrome gene therapy program, and these IND-enabling studies showed that a single I.V. administration produced high levels of enzymatic expression across disease-relevant tissues and achieved phenotypic correction of skeletal deformities. These results support our plans to move this program forward into a Phase 1/2 clinical trial this year.”

In the poster titled, “HMI-203: Investigational Gene Therapy for Mucopolysaccharidosis Type II (MPS II), or Hunter Syndrome,” a single I.V. administration of HMI-203 in the adult murine model:

  • Led to robust biodistribution and sustained human I2S (hI2S) enzyme expression, which resulted in:
    • Significant reductions in key Hunter syndrome biomarkers of heparin sulfate glycosaminoglycans (GAGs) and lysosomal-associated membrane protein 1 (LAMP-1) in the brain, liver, heart, spleen, lung and kidneys compared with vehicle.   
    • Significant reductions in heparan sulfate GAGs in the cerebrospinal fluid (CSF) compared with vehicle.
  • Ameliorated paw deformities, as shown by significant changes in measurements of ankle depth, paw width, paw depth and ankle width compared with vehicle.
  • Led to uptake of hI2S from the serum of the HMI-203-treated model in human cell lines, demonstrating potential for cell cross-correction.

In an additional poster titled, “HMI-202: Gene Therapy Development Candidate for Metachromatic Leukodystrophy (MLD),” a single I.V. administration of HMI-202:

  • Crossed the blood-brain-barrier and blood-nerve-barrier in the murine MLD disease model and in non-human primates (NHPs), with human ARSA (hARSA) detected in neuronal and glial cells.
  • Showed durable hARSA activity in the central nervous system of the disease model, with distribution levels resembling those of Arsa in normal age-matched controls.
  • Demonstrated significant changes in key MLD biomarkers of LAMP-1, glial fibrillary acidic protein (GFAP), MAL transcript and neuronal sulfatides in the disease model compared with vehicle, similar to age-matched wild type controls.

Homology’s e-poster presentations will take place on February 11, 2021 at 2:30 p.m. ET. For more information, visit

About Mucopolysaccharidosis Type II (MPS II), Hunter Syndrome
MPS II, or Hunter syndrome, is a rare, X-linked lysosomal storage disorder caused by mutations in the iduronate-2-sulfatase (IDS) gene, which is responsible for producing the I2S enzyme that breaks down large sugar molecules, or cellular waste, called glycosaminoglycans (GAGs). Severe Hunter syndrome results in toxic lysosomal accumulation of GAGs that causes progressive debilitation and decline in intellectual function. Hunter syndrome occurs in approximately 1 in 100,000 to 1 in 170,000 males, and the severe form leads to life expectancy of 10 to 20 years.

About Metachromatic Leukodystrophy (MLD)
MLD is a rare lysosomal storage disorder caused by mutations in the ARSA gene. ARSA is responsible for the creation of the arylsulfatase A (ARSA) protein, which is required for the breakdown of cellular components. In MLD, these cellular components accumulate and destroy myelin-producing cells in the peripheral and central nervous system leading to progressive and serious neurological deterioration. The late infantile form of the disorder is estimated to affect 1 in 40,000 people, and it is fatal within five to ten years after onset.

About Homology Medicines, Inc.
Homology Medicines, Inc. is a clinical-stage genetic medicines company dedicated to transforming the lives of patients suffering from rare genetic diseases with significant unmet medical needs by curing the underlying cause of the disease. Homology’s proprietary platform is designed to utilize its human hematopoietic stem cell-derived adeno-associated virus vectors (AAVHSCs) to precisely and efficiently deliver genetic medicines in vivo either through a gene therapy or nuclease-free gene editing modality across a broad range of genetic disorders. Homology has a management team with a successful track record of discovering, developing and commercializing therapeutics with a particular focus on rare diseases, and intellectual property covering its suite of 15 AAVHSCs. Homology believes that its compelling preclinical data, scientific expertise, product development strategy, manufacturing capabilities and intellectual property position it as a leader in the development of genetic medicines. For more information, please visit

Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation statements regarding our expectations surrounding the potential, safety, efficacy, and regulatory and clinical progress of our product candidates; our plans to move forward into a Phase 1/2 clinical trial for HMI-203 this year; our position as a leader in the development of genetic medicines; and our participation in upcoming presentations and conferences. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: the impact of the COVID-19 pandemic on our business and operations, including our preclinical studies and clinical trials, and on general economic conditions; we have and expect to continue to incur significant losses; our need for additional funding, which may not be available; failure to identify additional product candidates and develop or commercialize marketable products; the early stage of our development efforts; potential unforeseen events during clinical trials could cause delays or other adverse consequences; risks relating to the capabilities of our manufacturing facility; risks relating to the regulatory approval process; interim, topline and preliminary data may change as more patient data become available, and are subject to audit and verification procedures that could result in material changes in the final data; our product candidates may cause serious adverse side effects; inability to maintain our collaborations, or the failure of these collaborations; our reliance on third parties; failure to obtain U.S. or international marketing approval; ongoing regulatory obligations; effects of significant competition; unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives; product liability lawsuits; failure to attract, retain and motivate qualified personnel; the possibility of system failures or security breaches; risks relating to intellectual property and significant costs as a result of operating as a public company. These and other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2020 and our other filings with the SEC could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management’s estimates as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change.

Company Contacts:
Theresa McNeely
Chief Communications Officer
and Patient Advocate

Media Contact:
Cara Mayfield
Senior Director, Patient Advocacy
and Corporate Communications

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Source: Homology Medicines, Inc.