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Homology Medicines Announces Presentations on HMI-203 Investigational Gene Therapy for Hunter Syndrome and Broad Applicability of AAVHSC Platform for Lysosomal Storage Disorders at the 18th Annual WORLDSymposium™ Meeting

- Data Supported juMPStart Trial Evaluating One-Time, Systemic Administration of HMI-203 in ERT-Treated Adults -

- Details of HMI-203 Clinical Trial Design and Encouraging Preclinical Data Featured in Platform Presentations -

BEDFORD, Mass., Feb. 10, 2022 (GLOBE NEWSWIRE) -- Homology Medicines, Inc. (Nasdaq: FIXX), a genetic medicines company, announced today multiple presentations on HMI-203 gene therapy candidate for the treatment of Hunter syndrome (MPS II), which is being evaluated in juMPStart, a Phase 1 open-label, dose-escalation clinical trial in adults with Hunter syndrome. In oral platform presentations, key eligibility criteria and planned endpoints for the juMPStart trial were discussed and data from the HMI-203 IND-enabling studies were presented. Homology also shared patient, caregiver and key opinion leader (KOL) feedback on the unmet medical need in Hunter syndrome, despite the availability of enzyme replacement therapy (ERT), and the potential for a one-time gene therapy for patients that could impact peripheral and central nervous system (CNS) manifestations. These presentations at the 18th Annual WORLDSymposium™ Meeting also included data on Homology’s AAVHSC platform and potential to treat additional lysosomal storage disorders, including metachromatic leukodystrophy (MLD), based on CNS transduction in non-human primates (NHPs).

“These presentations highlight how Homology’s gene therapy approach to Hunter syndrome and other lysosomal storage diseases is developed to target both the peripheral as well as the CNS manifestations of these multi-organ disorders,” stated Albert Seymour, Ph.D., Chief Scientific Officer of Homology Medicines. “We designed the juMPStart clinical trial with our one-time, systemic gene therapy candidate by incorporating data and feedback we generated from our IND-enabling studies, as well as patient, caregiver and physician feedback. We believe that HMI-203 has the potential to address the peripheral and CNS challenges of Hunter syndrome that are not addressed by standard of care ERT, and that a one-time I.V. administration would be a major advance for patients and their families.”

In the platform presentation titled, “Clinical Trial Design for HMI-203 Investigational Gene Therapy for Mucopolysaccharidosis Type II (MPS II) Informed by Cross-Correction Potential and Key Opinion Leader Input,” new details about the juMPStart trial were presented along with data from IND-enabling studies, including:

  • juMPStart clinical trial design, which includes three sequential dose cohorts with up to three adults with Hunter syndrome currently on ERT in each cohort;
  • Select eligibility criteria and planned endpoints for juMPStart; and
  • Evidence of cellular cross-correction indicating that I2S enzyme can be produced from transduced cells, secreted into the bloodstream and then taken up by nearby un-transduced cells following a single intravenous (I.V.) administration of HMI-203 in the Hunter syndrome murine model.

Related, in the platform presentation and accompanying poster titled, “Summary of Nonclinical Data for a Gene Therapy Developmental Candidate HMI-203 for Mucopolysaccharidosis Type II, or Hunter Syndrome,” additional data from IND-enabling studies with HMI-203 were presented. A single I.V. administration of HMI-203 in the Hunter syndrome murine model resulted in long-term:

  • Transduction and therapeutically relevant I2S expression in key peripheral tissues and CNS;
  • Reduction of LAMP1 accumulation in peripheral tissues and the CNS, which indicates normal lysosome function;
  • Reduction in additional Hunter syndrome biomarkers; and
  • Direct skeletal benefit by preventing progression of craniofacial and hindlimb deformities.

In a poster co-authored with the National MPS Society, “Patient and Physician Perspectives Inform Clinical Trial Design for a Single Intravenous Dose of HMI-203, a Gene Therapy Candidate for Adults with Mucopolysaccharidosis Type II (MPS II), or Hunter Syndrome,” data on unmet medical need in adult patients with Hunter syndrome were highlighted alongside KOL feedback on the proposed juMPStart clinical trial design. Feedback from patients, caregivers and KOLs demonstrated that:

  • While ERT is currently the most beneficial therapy for Hunter syndrome, the unmet medical needs remain high and most burdensome, including: limited range of motion and mobility, pain and hearing loss;
  • Patient expectations for a one-time gene therapy, include disease maintenance with ERT-independence; and
  • KOLs supported planned design for juMPStart, including ERT-discontinuation plan.

Lastly, in the poster titled, “AAVHSCs and CNS-Targeting Gene Therapy for Lysosomal Storage Disorders,” the potential of utilizing AAVHSCs for lysosomal storage disorders was presented. Following a single I.V. administration of AAVHSCs in NHPs, data demonstrated:

  • Broad peripheral microglia tropism to cells that are important for maintaining CNS health;
  • Crossing of the blood-brain and -retina barriers, allowing access to the CNS; and
  • Cross-correction potential of lysosomal enzymes in nearby cells.

For more information, please visit www.homologymedicines.com/publications.

About Mucopolysaccharidosis Type II (MPS II), or 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 Homology Medicines, Inc.
Homology Medicines, Inc. is a clinical-stage genetic medicines company dedicated to transforming the lives of patients suffering from rare diseases by addressing the underlying cause of the disease. Homology’s clinical programs include HMI-102, an investigational gene therapy for adults with phenylketonuria (PKU); HMI-103, a gene editing candidate for PKU; and HMI-203, an investigational gene therapy for Hunter syndrome. Additional programs focus on metachromatic leukodystrophy (MLD), paroxysmal nocturnal hemoglobinuria (PNH) and other diseases. Homology’s proprietary platform is designed to utilize its family of 15 human hematopoietic stem cell-derived adeno-associated virus vectors (AAVHSCs) to precisely and efficiently deliver genetic medicines in vivo through a gene therapy or nuclease-free gene editing modality, as well as to deliver one-time gene therapy to produce antibodies throughout the body through the GTx-mAb platform. Homology has a management team with a successful track record of discovering, developing and commercializing therapeutics with a focus on rare diseases. Homology believes its initial clinical data and compelling preclinical data, scientific and product development expertise, internal manufacturing capabilities and broad intellectual property position Homology as a leader in genetic medicines. For more information, visit www.homologymedicines.com.

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; the potential of our gene therapy and gene editing platforms, including our GTx-mAb platform; our plans and timing for the release of additional preclinical and clinical data; our beliefs regarding our manufacturing capabilities; 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 quarter ended September 30, 2021 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
tmcneely@homologymedicines.com
781-301-7277

Media Contact:
Cara Mayfield
Vice President, Patient Advocacy
and Corporate Communications
cmayfield@homologymedicines.com
781-691-3510

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