a targeted approach to mast
cell-driven inflammation

Third Harmonic Bio is a clinical-stage biopharmaceutical company with a singular purpose: To advance a new treatment approach for people living with dermal, respiratory and gastrointestinal inflammatory diseases, which can take a significant toll on health and well-being.

We are currently focused on developing THB335, a highly selective, oral small molecule wild-type KIT inhibitor, for millions of people living with chronic urticaria, severe asthma, and other mast cell-mediated inflammatory diseases.

THB335 is currently being evaluated in a Phase 1 clinical trial, with a planned Phase 2 expansion into chronic spontaneous urticaria (CSU), as well as in other mast cell-mediated diseases. CSU is a severe dermatologic disease affecting up to 1% of the population that is driven by mast cell activation and results in red, itchy, painful welts or hives that significantly impact a patient’s quality of life.

We are also planning to develop THB335 in severe asthma and other mast-cell mediated inflammatory disorders of the skin, airway and gastrointestinal tract.


Third Harmonic Bio is led by an executive team with a proven track record of building great companies, developing impactful medicines, and delivering value to their patients, employees, and shareholders.

Natalie Holles

Chief Executive Officer

Edward R. Conner, M.D.

Chief Medical Officer

Dennis Dean, Ph.D.

Chief Non-Clinical Development Officer

Chris Dinsmore, Ph.D.

Chief Scientific Officer

Jennifer Dittman

Chief Development Operations Officer

Chris Murphy

Chief Financial and Business Officer

Julie Person

Chief Administrative Officer
Board of directors

David Bonita, M.D.

General Partner, Orbimed

Michael Gladstone

Partner, Atlas Venture

Natalie Holles

Chief Executive Officer

Mark Iwicki (Chairman)

CEO, Kala Therapeutics

Geoff McDonough, M.D.

President & CEO, Generation Bio

Rob Perez

Operating Partner, General Atlantic

Martin Seidel, Ph.D.

CEO, IFM Therapeutics

Thomas M. Soloway

CEO, T-knife Therapeutics

(Corporate Headquarters)
1700 Montgomery Street, Suite #210
San Francisco, CA 94111

130 Prospect Street,
Cambridge, MA 02139