Management team

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


Natalie Holles

Chief Executive Officer

Edward R. Conner, M.D.

Chief Medical Officer

Robert Ho

Chief Financial Officer

Gregg Keaney, Ph.D.

Senior Vice President, Drug Discovery and Product Development

Julie Person

Chief Administrative Officer

Adrian S. Ray

Chief Scientific Officer

Steve Sweeney

Senior Vice President, Development Operations
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

Shao-Lee Lin, M.D., Ph.D.

CEO, Acelyrin, Inc.

Rob Perez

Operating Partner, General Atlantic

Martin Seidel, Ph.D.

CEO, IFM Therapeutics

Thomas M. Soloway

Chief Executive Officer, T-knife Therapeutics
Our Science
The opportunity

Mast cells are the primary effector cells of allergic-inflammatory diseases of the skin, airway, and gastrointestinal tract, which collectively affect millions of people worldwide. In their most severe forms, these diseases are associated with significant morbidity. Despite significant investment in the field and the availability of several approved therapies, there remains a significant unmet need in the treatment of these diseases.

Targeting mast cells directly through highly selective inhibition of KIT represents a novel therapeutic approach and may be key to achieving the clinical efficacy needed for broad symptomatic relief across a range of allergic and other inflammatory disorders. The ideal therapeutic profile would combine the target selectivity and potency of a biologic with the ease of administration that an oral small molecule affords.

Our Science
THB-001 for urticaria and beyond

THB001 is a highly selective, oral small-molecule inhibitor of KIT in clinical development for the treatment of severe allergic and mast cell-driven inflammatory diseases. The initial target indication for THB001 is for the treatment of chronic urticaria, a dermatologic disease driven by mast cell activation that results in red, itchy, painful welts or hives. Chronic urticaria carries significant disease burden for patients, including decreased quality of life, impaired social and work function, depression and sleep disruption. Up to one percent of the U.S. population is believed to be affected by urticaria at some point in their lives.

In preclinical studies, THB001 demonstrated evidence of highly selective KIT inhibition and mast cell depletion in multiple tissue types. In early clinical studies, THB001 demonstrated dose-dependent reductions in serum tryptase, an established marker of mast cell activity and survival.

Beyond chronic urticaria, we plan to pursue development of THB001 in additional skin, airway and gastrointestinal tract indications in which mast cells play a known role in the pathophysiology and symptomatology of the disease.

Pipeline-in-a-product potential

We’re advancing THB001 for the treatment of multiple mast cell-driven inflammatory conditions that share similar pathophysiology, including dermal, respiratory and gastrointestinal diseases. THB001 is currently in clinical development for chronic urticaria, and we anticipate initiating a Phase 1b proof-of-concept study in cold-inducible urticaria in the second half of 2022.


Therapeutic area


Phase 1

Phase 2

Phase 3


(KIT inhibitor)

Therapeutic Area



Phase 1


Phase 1
Therapeutic Area



Phase 1
Clinical Trials
Chronic urticaria

THB001 is in clinical development for chronic urticaria (also known as chronic hives), a dermatologic disease driven by mast cell activation that results in red, itchy, painful welts or hives that develop in response to a specific stimulus (inducible urticaria) or with no known cause (spontaneous or idiopathic urticaria).