Zongertinib is a small-molecule targeted anticancer active pharmaceutical ingredient (API) developed as a selective HER2 kinase inhibitor. It is also known by the development code BI 1810631 and is marketed in the United States under the brand name Hernexeos. FDA identifies zongertinib as a kinase inhibitor and approved it for adults with unresectable or metastatic non-squamous non-small cell lung cancer (NSCLC) whose tumors contain activating HER2 (ERBB2) tyrosine kinase domain mutations detected by an FDA-authorized test.
Zongertinib is chemically identified as N-[1-[8-[[3-methyl-4-[(1-methyl-1H-benzimidazol-5-yl)oxy]phenyl]amino]pyrimido[5,4-d]pyrimidin-2-yl]-4-piperidinyl]prop-2-enamide. Its molecular formula is C29H29N9O2, with a molecular weight of approximately 535.60 g/mol. FDA's substance registration record lists the CAS Registry Number as 2728667-27-2 and the UNII as DRH7R67UVL.
HER2, also known as ERBB2, is a receptor tyrosine kinase involved in cellular signaling and tumor growth. Zongertinib is designed to inhibit HER2 kinase activity, with particular relevance to tumors containing activating mutations in the HER2 tyrosine kinase domain. Its development has focused on HER2-mutant non-small cell lung cancer, creating an important targeted-therapy API category within oncology pharmaceutical development.
The FDA's current regulatory information confirms that zongertinib received accelerated approval for the specified HER2-mutated NSCLC population on February 26, 2026. The approval is based on the clinical development program evaluating zongertinib in patients with unresectable or metastatic non-squamous NSCLC carrying qualifying HER2 TKD activating mutations.
Zongertinib is a yellow to dark-yellow or orange solid. FDA's chemistry assessment reports that the drug substance has no chiral centers and that several polymorphic forms were identified during development. The form selected for late-stage and commercial development was determined to be the thermodynamically most stable form. Polymorphic characterization was supported using techniques including XRPD, DSC, Raman spectroscopy and TGA.
The compound exhibits strongly pH-dependent aqueous solubility. FDA reports that zongertinib is slightly soluble under strongly acidic conditions, practically insoluble across approximately pH 3.6–6.8, and insoluble in neutral water at 25°C. The drug substance also demonstrates low hygroscopicity, with less than approximately 0.6% water uptake at 90% relative humidity under the conditions evaluated in the FDA chemistry review.
Zongertinib contains two basic centers with reported pKa values of approximately 3.6 and 5.4. Its low aqueous solubility and pH-dependent dissolution behavior are important considerations for pharmaceutical formulation and drug-product development. FDA classified its behavior as BCS II-like based on the available solubility and permeability information.
For pharmaceutical-grade Zongertinib API, identity, assay, related substances, residual process impurities, water content, solid-state form and other quality characteristics are important quality-control parameters. FDA's chemistry review confirms that the drug substance specification includes controls for identity, assay and impurities, while the development program also included water-content testing and crystallinity/polymorphic-form characterization.
Because Zongertinib is a relatively new API, public regulatory documents do not disclose every numerical drug-substance acceptance criterion. Several portions of the FDA chemistry review are redacted as confidential commercial information. Therefore, an API specification used for commercial manufacturing should be based on the manufacturer's validated, approved specification rather than assuming generic limits such as 98–102% assay or 1.0% total impurities. FDA guidance also emphasizes that API specifications should be appropriate to the manufacturing process and should control relevant organic, inorganic and residual-solvent impurities.
Zongertinib has been developed as an immediate-release oral pharmaceutical ingredient. The FDA-approved product contains 60 mg zongertinib per film-coated tablet, with the tablet formulation using commonly used pharmaceutical excipients. The approved tablets are yellow, oval and biconvex.
The API's solid-state properties are particularly relevant to pharmaceutical manufacturing because multiple polymorphic forms have been identified. Control of the intended crystalline form, together with particle characteristics and chemical purity, can support consistency in dissolution and finished-product performance. FDA's review specifically describes XRPD and other solid-state analytical techniques as part of the characterization of zongertinib drug substance.
Manufacturing of pharmaceutical-grade Zongertinib requires appropriate control of starting materials, synthetic intermediates, process-related impurities, residual solvents, chemical purity, solid-state form and storage conditions. The final API should be tested using validated analytical procedures capable of confirming identity, assay and impurity profiles.
Chromatographic methods such as HPLC or UHPLC are particularly relevant for assay and related-substance testing. Additional analytical characterization may include LC-MS, NMR, elemental analysis, XRPD, DSC, Raman spectroscopy and water determination, depending on the manufacturer's validated control strategy. FDA's chemistry review confirms extensive characterization of Zongertinib using these types of analytical approaches.
Zongertinib is an important oncology API associated with targeted treatment of HER2-mutated NSCLC. Its development and regulatory approval provide a defined pharmaceutical application for a HER2-selective kinase inhibitor. For pharmaceutical companies, contract manufacturers and formulation developers, Zongertinib API requires appropriate control of chemical identity, potency, impurities, polymorphic form, residual solvents and physical properties.
As a pharmaceutical-grade active ingredient, Zongertinib can be positioned within the broader categories of oncology APIs, kinase inhibitor APIs, targeted therapy APIs and HER2-related pharmaceutical ingredients. API manufacturers and suppliers should provide appropriate technical documentation, analytical certificates, batch information and quality documentation according to the applicable commercial and regulatory requirements.
Zongertinib API sourcing requires attention to chemical quality, batch-to-batch consistency, analytical characterization and regulatory documentation. A qualified pharmaceutical API manufacturer or supplier should maintain appropriate GMP-oriented quality systems and validated testing procedures for the drug substance.
Swapnroop can position Zongertinib within its pharmaceutical API portfolio for B2B pharmaceutical, research and development requirements, subject to product availability, manufacturing status and applicable regulatory documentation. Buyers evaluating Zongertinib API should consider identity, assay, related substances, residual solvents, water content, polymorphic form, analytical documentation and applicable quality standards when evaluating a supply source.
Zongertinib represents a specialized oncology API with growing relevance to HER2-targeted pharmaceutical development. Its combination of selective kinase inhibition, defined molecular structure, controlled solid-state characteristics and regulatory recognition makes accurate API characterization particularly important for pharmaceutical manufacturing and formulation development.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | NLT 98.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Individual Impurity | NMT 1.0% |
| Total Impurities | NMT 2.0% |
| Water Content | NMT 1.0% |