If You Invested in Stealth Biotherapeutics (MITO)

Stealth BioTherapeutics Corp (historically Nasdaq: MITO) is a biotechnology company focused on the discovery, development, and commercialization of novel therapies for diseases involving mitochondrial dysfunction. Mitochondria are the main source of cellular energy and are critical for normal organ function. Stealth’s work centers on conditions in which dysfunctional mitochondria contribute to rare genetic diseases and age-related disorders, particularly in organ systems with high energy demands such as the heart, eye, neuromuscular system, and brain.

According to multiple company announcements, Stealth has described itself as a clinical-stage biotechnology company and, more recently, as a commercial-stage biotechnology company. In a later press release, Stealth BioTherapeutics Inc. stated that its commercial product, FORZINITY (elamipretide) injection, received accelerated approval from the U.S. Food & Drug Administration (FDA) as the first FDA-approved treatment for Barth syndrome and the first FDA-approved mitochondria-targeted therapeutic. The company’s mission, as described in its own materials, is to develop novel therapies to improve the lives of patients living with diseases of mitochondrial dysfunction.

Business focus and therapeutic areas

Stealth’s programs are built around mitochondria-targeted compounds. The company has repeatedly highlighted elamipretide as its lead product candidate in earlier-stage communications, with potential applications in:

• Ophthalmic diseases involving mitochondrial dysfunction, such as dry age-related macular degeneration (dry AMD).
• Rare neuromuscular disorders, including primary mitochondrial myopathy and Duchenne muscular dystrophy.
• Rare cardiomyopathies, including Barth syndrome.

In later communications, Stealth indicated that it is studying elamipretide in additional indications, including dry age-related macular degeneration and primary mitochondrial myopathy, while also advancing development for Barth syndrome. The company has also described a second-generation clinical-stage candidate, SBT-272 (also referred to as bevemipretide (SBT-272) in one release), which targets the cardiolipin-rich inner mitochondrial membrane. Stealth has reported that SBT-272 is being evaluated for rare neurological disease indications, such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia or frontotemporal dementia, based on preclinical and Phase 1 data.

Mitochondrial dysfunction and disease focus

Across its public communications, Stealth emphasizes that dysfunctional mitochondria characterize a number of rare genetic diseases and are involved in many common age-related diseases. The company notes that these conditions often involve organ systems with high energy demands, including:

• The heart, where mitochondrial dysfunction can contribute to cardiomyopathies such as Barth syndrome.
• The eye, in diseases such as dry AMD and other ophthalmic conditions associated with mitochondrial abnormalities.
• The neuromuscular system, in disorders such as primary mitochondrial myopathy and Duchenne muscular dystrophy.
• The brain, in neurological and neurodegenerative diseases, including ALS and frontotemporal lobar dementia.

Stealth has stated that it has optimized a discovery platform to identify novel mitochondria-targeted compounds. These compounds may be advanced as therapeutic product candidates or used as mitochondria-targeted vectors to deliver other agents to mitochondria.

FORZINITY (elamipretide) and Barth syndrome

In a later press release, Stealth BioTherapeutics Inc. announced that FORZINITY (elamipretide) injection was granted accelerated approval by the FDA as a mitochondrial cardiolipin binder indicated to improve muscle strength in adult and pediatric patients with Barth syndrome weighing at least 30 kg. The company described FORZINITY as the first treatment for Barth syndrome and the first FDA-approved mitochondria-targeted therapeutic. This indication was approved under accelerated approval based on improvement in knee extensor muscle strength as an intermediate clinical endpoint, with continued approval potentially contingent upon verification and description of clinical benefit in confirmatory trials.

The same announcement described a patient support initiative, the Mito Assist Patient Support Program, focused on access to FORZINITY. Stealth also reported that it selected AnovoRx Specialty Pharmacy as its exclusive commercial distribution partner for FORZINITY in the United States, with AnovoRx supporting insurance coverage and access processes for patients, caregivers, and healthcare providers.

Pipeline: elamipretide and SBT-272

Across multiple news releases, Stealth has outlined a pipeline centered on mitochondria-targeted small molecules:

• Elamipretide: Described as the company’s lead product candidate and, in a later release, as the active ingredient in FORZINITY. Stealth has indicated potential applications in rare cardiomyopathies (including Barth syndrome), rare neuromuscular disorders (such as primary mitochondrial myopathy and Duchenne muscular dystrophy), and ophthalmic diseases involving mitochondrial dysfunction (including dry AMD and, in some descriptions, Leber’s hereditary optic neuropathy). Earlier communications also referenced potential use in rare metabolic cardiomyopathies and mitochondrial diseases involving nuclear DNA mutations, such as POLG-related disorders.
• SBT-272: Described as a second-generation clinical-stage candidate and a novel small molecule targeting the cardiolipin-rich inner mitochondrial membrane. Stealth has reported Phase 1 safety and tolerability data in healthy volunteers and preclinical data suggesting mitochondria-protective and neuroprotective effects in models of ALS and other neurodegenerative conditions. The company has stated that SBT-272 is being evaluated for rare neurological disease indications, including ALS and frontotemporal lobar dementia.
• SBT-550 series: In some disclosures, Stealth has mentioned a new series of small molecules, SBT-550, which it is evaluating for rare neurological disease indications following promising preclinical data.

Stealth has also reported that SBT-272 received Orphan Drug Designation from the FDA Office of Orphan Products Development for the treatment of ALS.

Corporate status and listing history

Stealth BioTherapeutics Corp was previously listed on the Nasdaq Global Market under the ticker symbol MITO. In a press release dated November 16, 2022, the company announced the completion of a merger with Stealth Merger Sub Limited, a wholly owned subsidiary of Stealth Parent Limited. In this transaction, Merger Sub merged with and into Stealth BioTherapeutics Corp, with the company continuing as the surviving entity and becoming a privately held company.

As part of the merger announcement, Stealth stated that its American Depositary Shares (ADSs) would no longer be listed on the Nasdaq Global Market. The company also indicated that it requested Nasdaq to file a Form 25 with the U.S. Securities and Exchange Commission to notify the SEC of the delisting of its ADSs and the Section 12(b) deregistration of its registered securities. The company further stated its intention to suspend reporting obligations and terminate registration under Sections 12(g) and 15(d) of the Securities Exchange Act of 1934 by filing a Form 15. Following this process, Stealth’s obligations to file certain reports and forms with the SEC, including Form 20-F and Form 6-K, would be suspended and then cease once deregistration became effective.

Earlier in 2022, Stealth disclosed that it had received a non-compliance notice from Nasdaq regarding minimum bid price and market value of listed securities requirements, and later announced a definitive agreement for a going-private transaction led by a consortium of investors. These communications provide context for the subsequent merger and delisting.

Barth syndrome and rare disease engagement

Stealth has repeatedly highlighted Barth syndrome as a key focus area. In its communications, the company describes Barth syndrome as an ultra-rare genetic condition characterized by mitochondrial abnormalities leading to exercise intolerance, muscle weakness, debilitating fatigue, heart failure, recurrent infections, delayed growth, and reduced life expectancy. The company has noted that Barth syndrome occurs primarily in males and is estimated to affect a very small number of individuals in the United States.

Stealth has also reported participation in events discussing challenges and opportunities in ultra-rare disease drug development, and has referenced its clinical and regulatory development experience with Barth syndrome, including long-term elamipretide therapy data from clinical studies.

Research and development platform

In multiple releases, Stealth states that it has optimized its discovery platform to identify novel mitochondria-targeted compounds. These compounds may be nominated as therapeutic product candidates or used as mitochondria-targeted vectors to deliver other compounds to mitochondria. This platform underpins the company’s work on elamipretide, SBT-272, SBT-550, and other potential candidates aimed at diseases of mitochondrial dysfunction.

Company status for investors and researchers

For purposes of the MITO ticker, Stealth BioTherapeutics Corp should be understood as a former Nasdaq-listed company that completed a going-private merger and delisted its ADSs. Subsequent communications from Stealth BioTherapeutics Inc. describe ongoing development and commercialization activities, including the FDA’s accelerated approval of FORZINITY for Barth syndrome and continued research on elamipretide and SBT-272. Users researching the historical MITO symbol are typically examining Stealth’s prior public-company period, its mitochondria-focused pipeline, and the corporate actions that resulted in its transition to a privately held company.