Third Harmonic Bio (THRD) Stifel 2024 Healthcare Conference summary

Strategic focus and clinical development

• Aims to introduce a new oral therapy targeting KIT for mast cell inflammatory diseases, with urticaria as the lead indication and asthma as a secondary focus.

• Clinical data for the new oral KIT inhibitor is expected in the first quarter, with a phase two study in chronic urticaria planned to follow.

• The second-generation molecule, THB-335, was developed to address liver toxicity seen in the first-generation compound, while improving potency, selectivity, and pharmacokinetics.

• The phase one study will provide comprehensive data on safety, PK/PD, and metabolite profiles to inform dose selection for phase two.

• The company is operationally preparing for rapid phase two initiation, including regulatory submissions and site selection.

Market opportunity and competitive landscape

• Urticaria is underappreciated in severity and has significant unmet need, with only one approved post-antihistamine therapy that has safety limitations.

• Oral KIT inhibitors may offer efficacy and safety advantages over antibody approaches, notably by avoiding the risk of anaphylaxis.

• The clinical trial landscape in urticaria is expanding, increasing physician engagement and awareness, which is expected to benefit patient care.

• The company is leveraging its position as a later entrant to optimize efficiency and dose selection in clinical development.

Scientific rationale and future directions

• KIT inhibition has shown high efficacy in urticaria and promising results in severe asthma, supported by both clinical and preclinical data.

• The company is exploring the optimal degree of KIT inhibition needed for efficacy, with phase two designed to test multiple doses.

• Plans to expand into other mast cell-mediated inflammatory diseases, aiming for a pipeline-in-a-target strategy.

• The new molecule is designed for once-daily dosing, improved drug properties, and extended patent protection through 2043.