Istesso
Istesso is a London-based clinical-stage biopharmaceutical company developing first-in-class oral Mitochondrial Complex I Modulators (MCMs) for tissue repair, with lead asset leramistat in Phase 2 trials for sarcopenia in rheumatoid arthritis patients.
- Company typePrivate
- Founded2017
- HeadquartersLondon, United Kingdom
- Headcount11–50
- GTM typeB2B
- OfferingServices
What Istesso does
Istesso Limited is a London-based clinical-stage biopharmaceutical company founded in 2017 that develops first-in-class oral regenerative medicines based on Mitochondrial Complex I Modulators (MCMs), a proprietary class of small-molecule drugs designed to activate the body's natural tissue repair mechanisms rather than suppress disease symptoms. The company's lead clinical asset, leramistat (IST-03, formerly MBS2320), is an oral small molecule in Phase 2 development for secondary sarcopenia in rheumatoid arthritis patients, with clinical sites at Newcastle University and Newcastle Hospitals in conjunction with the National Institute for Health and Care Research (NIHR). The pipeline additionally includes development candidate MBS2687 — an orally available MCM with best-in-class potential — and discovery-stage asset IST003.
Leramistat has previously received FDA Fast Track designation and Orphan Drug Designation for idiopathic pulmonary fibrosis, and the company has published peer-reviewed preclinical data in The Journal of Pharmacology and Experimental Therapeutics demonstrating muscle quality restoration in aged mouse models and tissue-protective effects in collagen-induced arthritis models. As of June 2026, the IST-03 Phase 2 sarcopenia trial represents a strategic refocus of the lead asset toward musculoskeletal repair following Phase 2b rheumatoid arthritis results showing muscle-protective effects.
The company is pre-revenue and does not currently commercialize any products; its expected future revenue model centers on pharmaceutical product sales following regulatory approval, supplemented by licensing and co-development agreements with larger partners — exemplified by an Option and Licence Agreement with Janssen Biotech Inc. for MBS2320. Istesso is controlled by FTSE-listed IP Group plc, which holds an undiluted 56.5% stake; approximately £10 million has been disclosed as raised across 2018-2019 financing rounds from IP Group, Parkwalk Advisors, and Puhua Capital. Leadership includes CEO and co-founder Lisa Patel (former GSK), Executive Chairman Sam Williams (Managing Partner, IP Group Life Sciences), and non-executive directors Peter Allen (former CFO of Celltech), Professor Sir Keith Peters (former Regius Professor of Physic at Cambridge) and Dr Michael Owen (former SVP at GSK and Kymab co-founder).
Istesso firmographics
Firmographics- Name
- Istesso
- Legal name
- Istesso Limited
- Website
- https://istesso.co.uk
- Company type
- Private
- Founded year
- 2017
- Operating status
- Operating
- Headcount range
- 11–50 employees
- Short description
- Istesso is a London-based clinical-stage biopharmaceutical company developing first-in-class oral Mitochondrial Complex I Modulators (MCMs) for tissue repair, with lead asset leramistat in Phase 2 trials for sarcopenia in rheumatoid arthritis patients.
- Ownership category
- akta.pro rank
Where Istesso is headquartered
LocationHeadquarters
- HQ city
- London
- HQ country
- United Kingdom
- HQ region
- Europe
Offices1 record
Markets served
Istesso business model
Business model- GTM type
- B2B
- Offering type
- Services
- Cost components
- Technology or R&D, Personnel, Operations, Marketing or Sales
Revenue model
- Pharmaceutical Drug Development: Istesso is a clinical-stage biopharmaceutical company developing novel regenerative medicines. The company is pre-revenue and does not currently commercialize any products. Future revenue is expected to come from pharmaceutical product sales following regulatory approval, potential licensing agreements, and co-development partnerships with larger pharmaceutical companies.
Go-to-market motion2 records
Distribution channels1 record
Marketing channels6 records
Istesso product offering
Product offeringCore offering
Istesso is a clinical-stage biopharmaceutical company developing first-in-class oral regenerative medicines based on mitochondrial Complex I modulators (MCMs), a novel class of small molecule drugs that activate the body's natural repair mechanisms to regenerate damaged tissue. Its lead clinical candidate, leramistat, is in Phase 2 trials for sarcopenia caused by rheumatoid arthritis, with a broader pipeline targeting chronic age-related diseases.
Product overview
Istesso is developing pioneering oral regenerative medicines focused on mitochondrial Complex I modulators (MCMs). The company's lead clinical program is leramistat (formerly MBS2320), a first-in-class oral small molecule drug in Phase 2 trials for musculoskeletal repair in secondary sarcopenia. The pipeline includes MBS2687 (development candidate) and IST003 as additional assets, each targeting chronic age-related diseases with blockbuster potential. The MCM platform enables tissue repair and regeneration across multiple organs by activating the body's own repair mechanisms without immunosuppression.
Differentiator
Problem solved
Functional benefit
Products and services
- Leramistat First-in-class oral regenerative medicine and mitochondrial Complex I modulator (MCM) in Phase 2 development for musculoskeletal repair in secondary sarcopenia. Restores damaged tissue and builds resilience without suppressing the immune system.
- MBS2687 Orally available small-molecule MCM with best-in-class potential. Development candidate nominated for primary adaptive repair in indications to be determined.
- IST003 Pipeline asset in discovery/preclinical stage as part of Istesso's MCM programme targeting chronic age-related conditions.
- MBS2320 Former designation/name for leramistat. First-in-class metabolic reprogramming agent with dual mode-of-action reducing inflammation and supporting tissue remodelling. Previously in clinical development for rheumatoid arthritis and IPF.
Quantifiable outcome
- Phase 2 trial IST-03 initiated June 2026 for sarcopenia in rheumatoid arthritis patients at Newcastle University and Newcastle Hospitals
- +4 more outcomes
Companies that use Istesso
Customer profileSegments3 records
Ideal customer profiles2 records
Istesso technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature3 records
Istesso partnerships and signals
Strategic signalPartnerships
Two partnerships are on record, tiered core.
- Newcastle University and Newcastle HospitalscorePhase 2 clinical trial IST-03 being conducted at Newcastle University and Newcastle Hospitals, working with the National Institute for Health and Care Research (NIHR). Dr Josh Bennett serves as Investigator at Newcastle University. Trial sites feature specialist facilities and biopsy expertise including advanced imaging and analysis techniques.
- Janssen Biotech Inc.coreIstesso has an Option and Licence Agreement with Janssen Biotech Inc. for MBS2320, a first-in-class metabolic reprogramming agent for the treatment of rheumatoid arthritis with dual mode-of-action.
Scale indicators5 records
Recent moves6 records
Expansion highlights6 records
Istesso competitors and assessment
Company assessmentDirect peers
- Stealth BioTherapeutics: Clinical-stage biopharmaceutical company developing mitochondria-targeted therapies (e.g., elamipretide) addressing mitochondrial dysfunction across multiple indications; comparable to Istesso's Mitochondrial Complex I Modulator approach to harnessing mitochondrial biology for disease modification.
- Khondrion: Netherlands-based clinical-stage biotech developing mitochondrial-targeted small molecules to treat mitochondrial diseases; shares Istesso's strategy of modulating mitochondrial bioenergetics with orally bioavailable drugs.
- Abliva (formerly NeuroVive Pharmaceutical): Swedish clinical-stage biotech developing small-molecule modulators of mitochondrial Complex I and related pathways for primary mitochondrial diseases and broader indications; the closest direct mechanistic peer to Istesso's MCM platform.
Emerging players
- BioAge Labs: Clinical-stage biotech using AI and human aging biology to develop therapeutics for metabolic and muscle-related diseases of aging; comparable due to overlapping sarcopenia/metabolic disease focus and emphasis on novel oral small molecules.
- UNITY Biotechnology: Clinical-stage company developing therapeutics that target cellular senescence and aim to restore tissue function in age-related diseases; comparable to Istesso through a shared 'repair rather than suppress' thesis targeting chronic age-related conditions.
- CohBar (now shareholders-led): Previously developed mitochondria-derived peptides (MDPs) for age-related diseases including NASH and obesity-related indications; a thematic peer in mitochondrial-based therapeutics for chronic age-related conditions, though small-molecule delivery differs from Istesso's MCM approach.
- AgeX Therapeutics: Company focused on regenerative medicine and tissue repair technologies targeting age-related degenerative conditions; comparable to Istesso through a shared regenerative-medicine thesis, though operating at the cellular/pluripotent stem cell level rather than small molecules.
- GenSight Biologics: Clinical-stage biotech developing mitochondrial-targeted therapies and gene therapies for neurodegenerative diseases of the eye; shares Istesso's mitochondrial therapeutic focus, though delivery modality differs.
Others
- Mitobridge (acquired by Astellas): Pre-clinical biotech developing small-molecule therapeutics that improve mitochondrial function in Duchenne muscular dystrophy and other indications; acquired by Astellas in 2018, illustrating the established pharma appetite for mitochondrial-targeted assets comparable to Istesso's MCM platform.
Broad incumbents
- Reata Pharmaceuticals: Acquired by Biogen in 2023, Reata developed bardoxolone methyl (Nrf2 activator with mitochondrial effects) approved for Friedreich's ataxia; comparable as an established mitochondrial-mechanism drug developer that validated the space commercially via a major-pharma acquisition.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat3 records
Key risks7 records
Key highlights7 records
Customer concentration
Istesso social profiles
Digital presenceIstesso financial estimates
Financial estimateRevenue estimate
Valuation estimate
Istesso leadership team
Management profileNumber of profiles
Profiles1 record
Istesso funding detail
Funding detailFunding overview
Funding rounds2 records
Investors2 records
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Istesso M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Istesso
What does Istesso do?
Istesso is a clinical-stage biopharmaceutical company developing first-in-class oral regenerative medicines based on mitochondrial Complex I modulators (MCMs), a novel class of small molecule drugs that activate the body's natural repair mechanisms to regenerate damaged tissue. Its lead clinical candidate, leramistat, is in Phase 2 trials for sarcopenia caused by rheumatoid arthritis, with a broader pipeline targeting chronic age-related diseases.
Is Istesso a public or private company?
Istesso is a private company. It is classified as venture growth investor backed and is currently operating.
When was Istesso founded?
Istesso was founded in 2017. It employs 11 to 50 people.
Where is Istesso based?
Istesso is headquartered in London, United Kingdom, in the Europe region.
How does Istesso make money?
One revenue line is on record: pharmaceutical Drug Development.
Who are Istesso's main competitors?
Direct peers on record are Stealth BioTherapeutics, Khondrion and Abliva (formerly NeuroVive Pharmaceutical). Emerging players are BioAge Labs, UNITY Biotechnology, CohBar (now shareholders-led), AgeX Therapeutics and GenSight Biologics. Mitobridge (acquired by Astellas) is listed as an others. Reata Pharmaceuticals is listed as a broad incumbent.
Does Istesso have an API?
No public API is recorded for Istesso.