Stealth BioTherapeutics Announces Poster Presentation at American College of Cardiology (ACC) Annual Meeting

BOSTON, May 17, 2021 /PRNewswire/ -- Stealth BioTherapeutics Corp (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 is presenting a poster at the 2021 American College of Cardiology (ACC) meeting being held virtually from May 15-17, 2021.

The poster entitled "Elamipretide Improves Functional Assessments when Compared to the Natural History Progression of Cardiomyopathy-related Disease Symptomatology in Patients with Barth Syndrome: A TAZPOWER Analysis" presents data from a Phase 3 retrospective natural history control trial comparing the cardiac and functional effects of elamipretide on Barth syndrome patients at week 72 of the open label extension portion to a natural history control (NHC) cohort derived from a 9-year long NHC study and matched using propensity scoring. The cardiac findings show that long-term treatment with elamipretide results in significant improvements in left ventricular stroke volume, which continue to strengthen over time with elamipretide, and which would otherwise be expected to decline during the natural course of the disease.  Significant improvements were also observed in distance walked on the six-minute walk test and other functional endpoints, which also strengthen over time with elamipretide and would not be expected to improve during the natural course of the disease.

About the Phase 3 Natural History Control Study

The Phase 3 retrospective natural history control study compared findings on functional assessments collected through weeks 36 and 48 and, as an FDA-requested post hoc analysis, week 72 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 were 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 were natural history data, including measurements of muscle strength, balance, and the time to complete an assessment requiring patients to sit and stand five times in succession.  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 192 weeks of functional and cardiac assessments, patient-reported outcomes and safety/tolerability.

The primary endpoints included change in distance walked during the 6MWT and change in patient-reported outcomes. 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 cardiac abnormalities often leading to heart failure, muscle weakness, 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 muscular dystrophy and Friedreich's ataxia, rare mitochondrial diseases entailing nuclear DNA mutations, 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, and our new series of small molecules, SBT-550, for rare neurological disease indications following promising preclinical data. We have optimized our discovery platform to identify novel mitochondria-targeted compounds which may be nominated as therapeutic product candidates or utilized as mitochondria-targeted vectors 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, but are not limited to, statements relating to preliminary clinical data. 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: 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; whether the company's clinical trials will be fully enrolled and completed when anticipated; whether results obtained in preclinical studies and clinical trials will be indicative of results that will be generated in future clinical trials; whether elamipretide will successfully advance through the clinical trial process on a timely basis, or at all; whether the results of the company's clinical trials will warrant regulatory submissions and whether elamipretide will receive approval from the FDA or equivalent foreign regulatory agencies for GA, AMD, Barth syndrome or any other indication when expected or at all; whether, if Stealth BioTherapeutics' products receive approval, they will be successfully distributed and marketed; its expectations regarding regulatory interactions; the potential benefits of Stealth BioTherapeutics' product candidates; its key milestones for 2021 and 2022; and its plans regarding future data presentations; 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 potential advantages of Stealth BioTherapeutics' product candidates; the content and timing of decisions made by the 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") on April 6, 2021, 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
[email protected] 

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SOURCE Stealth BioTherapeutics Inc.