Third Harmonic Bio Reports $45.5 Million Net Loss for 2024, Announces Restructuring and THB335 Clinical Trial Results

Third Harmonic Bio, Inc. (THRD) reported a net loss of $45.5 million for the year ended December 31, 2024, a 48% increase from the $30.8 million net loss in 2023. This increase stemmed primarily from a $12.5 million rise in research and development expenses, largely due to the clinical development of THB335, their next-generation oral KIT inhibitor. General and administrative expenses also increased by $2.4 million, primarily due to higher employee-related costs. The company had $285.1 million in cash and cash equivalents at the end of 2024.

Significant changes occurred during the fiscal year. In February 2025, THRD announced Phase 1 single and multiple ascending dose (SAD/MAD) clinical trial results for THB335 in healthy volunteers, showing a half-life of approximately 40 hours and dose-dependent reductions in serum tryptase, a biomarker of mast cell activation. The company also announced a restructuring, halting all non-THB335-related research and reducing its workforce by approximately 50%. This restructuring was intended to strengthen the balance sheet and streamline operations. THRD also engaged TD Cowen to advise on a strategic review process aimed at maximizing shareholder value.

Operational developments included the advancement of THB335 towards a Phase 2 clinical trial in chronic spontaneous urticaria (CSU). Near-term activities involve completing subchronic toxicology studies and submitting regulatory filings. The company's strategy focuses on developing oral KIT inhibitors for mast cell-driven inflammatory diseases, initially targeting CSU, with potential expansion into other skin, respiratory, and gastrointestinal conditions. As of December 31, 2024, THRD employed 53 full-time employees, 35 of whom were in research and development.

The company's financial performance is heavily reliant on the success of THB335 and its ability to identify and develop future product candidates. The 10-K filing highlights numerous risks, including the inherent uncertainties of drug development, competition from larger pharmaceutical companies, the need for substantial additional funding, and the complexities of regulatory approval processes in the U.S. and other jurisdictions. The company's outlook anticipates continued losses for the foreseeable future, with expenses expected to increase as THB335 development progresses. The company's financial projections extend to at least 2026, based on current cash reserves and operating plans, subject to the outcome of the strategic review.