Third Harmonic Bio (THRD) TD Cowen Chronic Urticaria Summit summary

Strategic focus and pipeline progress

• Advancing oral wild-type KIT inhibitors for mast cell-mediated diseases, targeting large markets with unmet needs.

• Lead candidate THB335 is in phase I, with data expected in Q1 next year and rapid transition planned to phase II in chronic spontaneous urticaria (CSU).

• Phase II will be a multi-dose, efficacy-powered study aiming for direct progression to registration studies.

• Ongoing preclinical work supports potential expansion into severe asthma and other inflammatory diseases.

• Active medicinal chemistry efforts continue to optimize and expand the KIT inhibitor pipeline.

Differentiation and clinical rationale

• KIT is a validated, upstream target for mast cell function, offering broad utility across heterogeneous CSU populations.

• Oral small molecule approach offers patient and physician preference, dose titration flexibility, and avoids antibody-related anaphylaxis risk.

• Once-daily dosing is a potential advantage over other oral competitors, pending confirmation in ongoing studies.

• Safety profile improvements in THB335 address prior hepatotoxicity seen with THB001, with metabolic liabilities structurally resolved.

• Selectivity against KIT and related kinases is maintained or improved in THB335, with no off-target toxicity observed in preclinical studies.

Market landscape and commercial strategy

• Current market for CSU is underpenetrated due to limitations of existing therapies, notably Xolair's anaphylaxis risk and in-office monitoring requirements.

• Market development is prioritized over market share, with increased awareness and diagnosis expected as more oral agents enter the field.

• KIT inhibitors are positioned as potentially best-in-disease for efficacy and durability, with robust biomarker (serum tryptase) correlation.

• Pipeline strategy balances rapid advancement of THB335 with ongoing development of next-generation molecules for broader indications.

• Strong cash position ($255M) ensures funding through phase II CSU readout and continued execution.