Third Harmonic Bio (THRD) Jefferies 2024 Global Healthcare Conference summary

Company and pipeline overview

• Focused on KIT inhibition for mast cell-mediated diseases, with THB-335 in phase I SAD/MAD healthy volunteer study.

• Initial indication is chronic spontaneous urticaria, with plans for broader disease and franchise expansion.

• Mast cells play a central role in inflammatory diseases across skin, airways, and gut.

• IND for THB-335 recently cleared, and clinical development is underway.

Competitive landscape and market development

• Oral KIT inhibitors are seen as a key advancement, with the company currently leading in development.

• Multiple entrants in the KIT inhibitor space are expected to drive awareness and facilitate clinical study participation.

• Xolair is the only approved product for post-antihistamine CSU, covering just 15% of the market.

• Oral approaches may expand the physician pool treating urticaria due to fewer safety concerns compared to mAbs.

Differentiation and safety profile

• Oral KIT inhibitors may avoid the anaphylaxis risk seen with antibody therapies.

• Intracellular TKI approach is not expected to have the same mechanistic risk for anaphylaxis as mAbs.

• First-gen compound THB-001 showed promising efficacy at suboptimal doses, suggesting full KIT inhibition may not be necessary.

• THB-335 is structurally modified to mitigate drug-induced liver injury (DILI) risk and is peripherally restricted.