Stealth BioTherapeutics Provides Update On Clinical Stage Rare Disease Programs

BOSTON, Dec. 13, 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 reported an update on its clinical-stage rare disease programs.

Duchenne muscular dystrophy (DMD).  Early data from a study of elamipretide and an exon-skipping phosphorodiamidate morpholino oligomer (PMO), a therapeutic class that has already garnered regulatory approval and commercialization, in the X-linked muscular dystrophy (mdx) mouse model, demonstrated that elamipretide in combination with the PMO significantly increased dystrophin expression in muscle to almost twice the levels observed following stand-alone treatment with the PMO.  This may be due to improved mitochondrial bioenergetics augmenting the retainment/efficacy of the PMO.  Additional studies are ongoing, and the Company hopes to present the data from these studies at a scientific conference next year.  The Company is scheduled to meet with DCN to discuss its development plan for DMD later this month.

Barth syndrome. During a constructive Type A meeting to discuss next steps in the Barth syndrome development program, DCN signaled alignment with various design elements of a proposed new clinical trial. At DCN's recommendation, the Company will submit a Request for Advice on the protocol synopsis and expects written feedback from the Division within 45 days.  DCN also expressed its willingness to consider other means of generating data supportive of potential approval under alternate pathways, which may require additional animal studies.  The Company expects additional interactions with the Division early next year to explore the feasibility of DCN's suggestion. 

nPMM.  The Company remains on track to initiate NuPOWER, its Phase 3 clinical trial enrolling patients with pathogenic nuclear DNA mutations leading to mitochondrial myopathy (nPMM) with site initiation currently underway.  This trial is enriched for the subgroup of patients who responded to elamipretide therapy in prior clinical trials.

"Our new preclinical data increases our optimism that elamipretide may help address the unmet need for therapies in DMD, and we look forward to discussing our development plan with DCN later this month following our recent constructive meeting on our Barth program," said Reenie McCarthy, Chief Executive Officer at Stealth. "We are also thrilled to be getting back into the clinic with our Phase 3 NuPOWER study, which we hope will offer therapeutic benefit to patients suffering from the severe exercise intolerance, visual dysfunction, and peripheral neuropathy associated with primary mitochondrial myopathy due to nuclear pathogenic mutations.  Several patients affected by this disease are already participating  in our expanded access program, and we hope to generate data to support an approval that will make elamipretide more broadly available for those suffering from this devastating disease."

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 syndrome, DMD and Friedreich's ataxia, primary mitochondrial myopathy caused by 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 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; its expectations regarding regulatory interactions; the potential benefits of Stealth BioTherapeutics' product candidates; and its plans regarding future data presentations. 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 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;  the possibility that the FDA will not file the Barth NDA;  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.