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Absorption, Metabolism, Distribution and Excretion (ADME) and Absolute Bioavailability Assessment of Zongertinib in Healthy Male Volunteers

Year: 2025

Type: article

Abstract: BACKGROUND AND OBJECTIVES: Zongertinib is an irreversible tyrosine kinase inhibitor that selectively inhibits human epidermal growth factor receptor 2 (HER2) while sparing epidermal growth factor receptor (EGFR), minimizing related toxicities. This non-randomized, open-label, Phase I study evaluated the absorption, distribution, metabolism and excretion (ADME) of zongertinib (Part A) and its absolute bioavailability (F) (Part B) in healthy male volunteers. METHODS: C]zongertinib [~ 0.03 MBq] and 90 μg unlabeled drug. Plasma pharmacokinetics, excretion pathways, metabolism, and bioavailability were assessed. Safety was evaluated in both study parts. RESULTS: After oral dosing in Part A, peak plasma concentration occurred at a median of 1-h post-dose (range 0.5‒2.0 h). Mean recovery of the radioactive dose was 93.8%, primarily in feces (92.5%) and minimally in urine (1.30%). Unchanged zongertinib accounted for most circulating radioactivity (74.6%) in plasma and was the most abundant component in feces (31.4% of the dose) and urine (0.18% of dose). In vitro metabolism involved oxidation (48-62%), glucuronidation (13-25%), and glutathione conjugation (13-25%). In part B, the mean F of the oral tablet was 76.2%. Following IV administration, zongertinib showed low plasma clearance (106 mL/min) and a moderate volume of distribution of 138 L. Zongertinib had a manageable safety profile in both study parts. CONCLUSIONS: Zongertinib was rapidly absorbed with high absolute bioavailability. The unchanged zongertinib was the predominant form in plasma and excreta, with fecal excretion as the main elimination pathway. Metabolism occurred primarily through oxidation, with minor contributions from glucuronidation and glutathione conjugation. CLINICAL TRIAL REGISTRATION: Registered under identifier NCT05879991 (25 May 2023).

Source: Clinical Drug Investigation

DOI: 10.1007/s40261-025-01509-9