Stealth Biotherapeutics
AcquiredStealth Biotherapeutics is a biotech company in Needham, United States, founded in 2007. It has raised $53.5M across 3 rounds, most recently a $25.0M Series B in July 2026.
Stealth BioTherapeutics Inc.
- Headquarters
- Needham, Massachusetts
- Employees
- 51–200
- Founded
- 2007
- Business Model
- B2B
- Website
- stealthbt.com
- Total Funding
- $53.5M
- Last Round
- $25.0M Series BJul 2026
- Rounds
- 3
- Type
- Public
- Acquisition Date
- Nov 2022
Totals include recorded grants and other qualifying funding, not just equity. What counts toward funding.
Indexed holds 3 funding rounds and 3 investors for this company. The full record is or through the API.
About
Stealth BioTherapeutics is an innovative biopharmaceutical company developing therapies to treat mitochondrial dysfunction associated with genetic mitochondrial diseases and common diseases of aging. Founded in 2007 and headquartered in Needham, Massachusetts, the company collaborates with patients, advocacy organizations, and leading academic and medical institutions to advance a platform of late-stage clinical programs targeting rare genetic diseases and aging-related conditions. In 2026, the company rebranded as Mighty Therapeutics to reflect its continued commitment to advancing mitochondrial medicine.
Summary
It lists 51–200 employees. It has raised $53.5M in total across 3 rounds, most recently a $25.0M Series B round in Jul 2026. Investors include Morningside Venture Investments, K2 HealthVentures and Horizon Technology Finance.
Tech & App Stack
1 technology or app tracked
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Funding & Exit History
Jul 2026
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Funding: Venture Round through Series B. Amounts, valuations, and investors where available.
Investors
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