Stealth BioTherapeutics Announces Poster Presentation at American Society of Human Genetics (ASHG) Virtual Annual Meeting

BOSTON, Oct. 19, 2020 /PRNewswire/ -- Stealth BioTherapeutics (Nasdaq: MITO), a clinical-stage biotechnology company focused on the discovery, development and commercialization of novel therapies for diseases involving mitochondrial dysfunction, today announced that the company will have a poster at the upcoming 2020 American Society of Human Genetics (ASHG) Meeting, which is being held online from October 27-30, 2020. Stealth's poster has received a "Reviewers' Choice" award, granted to the top 10% of all poster abstracts, and will be available on-demand to conference attendees via the conference website.

The poster entitled "TAZPOWER Analysis: Elamipretide Significantly Improves Disease Symptomatology versus Natural History Controls in Barth Syndrome," demonstrates the importance of longitudinal natural history data in understanding and validating clinical trial outcomes for ultra-rare diseases like Barth. The natural history control study compared changes over time on functional assessments of exercise endurance and strength for Barth patients receiving elamipretide during the TAZPOWER interventional study and long-term natural history control patients, concluding that patients receiving elamipretide experienced statistically significant functional improvements that are not anticipated by the natural history. In addition, Barth patients receiving elamipretide during the TAZPOWER interventional study experienced statistically significant improvements over time in their left ventricular stroke volume, compared to a decline in stroke volume observed in long-term natural history control patients.  Stroke volume is an important parameter of cardiac function, which is known to be impaired in Barth syndrome.

About the Natural History Control Study

This observational study compared findings on functional assessments collected through weeks 36 and 48 of the open-label extension portion of the TAZPOWER trial with findings on the same assessments for up to 19 prognostically matched natural history control subjects, for whom data was collected longitudinally between 2012 and 2019 by investigators at Johns Hopkins Kennedy-Krieger Institute.  The primary endpoint was the change in distance walked during the 6MWT.  Secondary endpoints included all additional functional assessments for which there was natural history data, which were measurements of muscle strength, balance, and the time to complete an assessment requiring patients to sit and stand five times in succession (5XSST).  A multi-domain responder analysis was also conducted to assess the percentage of patients experiencing at least a 10% clinically meaningful gain (or loss) on these endpoints.  Additionally, this study compared changes in left ventricular stroke volume observed during the open-label extension portions of the TAZPOWER trial with changes observed in the natural history dataset.  All types of heart failure are associated with a deterioration of stroke volume, which is a key component of both cardiac output and ejection fraction. 

About the TAZPOWER Study

TAZPOWER is a Phase 2/3 crossover study evaluating the effects of daily subcutaneous (SC) treatment with elamipretide in 12 patients with genetically confirmed Barth syndrome followed by an open-label treatment extension. Part 1 was a 28-week crossover trial of patients randomized to elamipretide 40 mg SC daily for 12 weeks, followed by SC placebo daily for 12 weeks, or vice versa, separated by a 4-week washout. Part 2 is an open-label assessment for up to 168 weeks of functional assessments, patient-reported outcomes and safety/tolerability.

The primary endpoints included change in distance walked during the 6MWT and change in the BTHS-SA Total Fatigue score. Secondary endpoints included additional functional assessments, patient-reported outcomes, echocardiographic assessments of cardiac structure and function, and safety/tolerability.

About Barth Syndrome

Barth syndrome is an ultra-rare genetic condition characterized by muscle weakness, cardiac abnormalities often leading to heart failure, recurrent infections, delayed growth and reduced life expectancy, typically due to premature cardiac-related death. Barth syndrome occurs almost exclusively in males and is estimated to affect one in 300,000 to 400,000 individuals worldwide at birth. There are currently no FDA-approved therapies for patients with Barth syndrome.

About Stealth

We are a clinical-stage biotechnology company focused on the discovery, development and commercialization of novel therapies for diseases involving mitochondrial dysfunction. Mitochondria, found in nearly every cell in the body, are the body's main source of energy production and are critical for normal organ function. Dysfunctional mitochondria characterize a number of rare genetic diseases and are involved in many common age-related diseases, typically involving organ systems with high energy demands such as the heart, the eye, and the brain. We believe our lead product candidate, elamipretide, has the potential to treat both rare metabolic cardiomyopathies, such as Barth, Duchenne and Becker muscular dystrophies and Friedreich's ataxia, rare mitochondrial diseases entailing nuclear DNA mutations, such as POLG-related disorders, as well as ophthalmic diseases entailing mitochondrial dysfunction, such as dry age-related macular degeneration and Leber's hereditary optic neuropathy. We are evaluating our second-generation clinical stage candidate, SBT-272, for rare neurodegenerative disease indications following promising preclinical data in amyotrophic lateral sclerosis, or ALS. We have optimized our discovery platform to identify novel mitochondria-targeted compounds, including SBT-259, the SBT-550 series of compounds, and other compounds which may be nominated as therapeutic product candidates or utilized as scaffolds to deliver other compounds to mitochondria.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995.  Such forward-looking statements include those regarding Stealth BioTherapeutics' plans, strategies and expectations for its preclinical and clinical advancement of its drug development programs, including its ongoing clinical trials of elamipretide.  Statements that are not historical facts, including statements about Stealth BioTherapeutics' beliefs, plans and expectations, are forward-looking statements.  The words "anticipate," "expect," "hope," "plan," "potential," "possible," "will," "believe," "estimate," "intend," "may," "predict," "project," "would" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.   Stealth BioTherapeutics may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and you should not place undue reliance on these forward-looking statements.  Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements as a result of known and unknown risks, uncertainties and other important factors, including:  Stealth BioTherapeutics' ability to obtain additional funding and to continue as a going concern; the impact of the COVID-19 pandemic; the ability to successfully demonstrate the efficacy and safety of Stealth BioTherapeutics' product candidates and future product candidates;  the preclinical and clinical results for Stealth BioTherapeutics' product candidates, which may not support further development and marketing approval; the potential advantages of Stealth BioTherapeutics' product candidates; the content and timing of decisions made by the U.S. FDA, the EMA or other regulatory authorities, investigational review boards at clinical trial sites and publication review bodies, which may affect the initiation, timing and progress of preclinical studies and clinical trials of Stealth BioTherapeutics product candidates; Stealth BioTherapeutics' ability to obtain and maintain requisite regulatory approvals and to enroll patients in its planned clinical trials; unplanned cash requirements and expenditures; competitive factors; Stealth BioTherapeutics' ability to obtain, maintain and enforce patent and other intellectual property protection for any product candidates it is developing; and general economic and market conditions.  These and other risks are described in greater detail under the caption "Risk Factors" included in the Stealth BioTherapeutics' most recent Annual Report on Form 20-F filed with the Securities and Exchange Commission ("SEC"), as well as in any future filings with the SEC.   Forward-looking statements represent management's current expectations and are inherently uncertain. Except as required by law, Stealth BioTherapeutics does not undertake any obligation to update forward-looking statements made by us to reflect subsequent events or circumstances.

Investor Relations
Stern Investor Relations
Janhavi Mohite, 212-362-1200
IR@StealthBT.com

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SOURCE Stealth BioTherapeutics Inc.