Tezacaftor API is a small-molecule CFTR corrector used as part of combination therapies for cystic fibrosis. It is designed to improve the cellular processing and trafficking of certain mutant forms of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, including F508del-CFTR. Tezacaftor is used together with ivacaftor in SYMDEKO/Symkevi and with elexacaftor and ivacaftor in TRIKAFTA/KAFTRIO. FDA records document the continued expansion of approved CF indications for tezacaftor-containing regimens.
Tezacaftor is chemically identified as C26H27F3N2O6, with a molecular weight of 520.50 g/mol. FDA GSRS identifies CAS 1152311-62-0 and UNII 8RW88Y506K.
Tezacaftor is also known by the development code VX-661. It contains one defined stereocenter and is supplied as a crystalline solid. PubChem and FDA GSRS identify the absolute stereochemistry of the active substance.
The molecule is structurally distinct from ivacaftor and elexacaftor. In combination therapy, tezacaftor functions primarily as a CFTR corrector, while ivacaftor acts as a CFTR potentiator.
| Property | Value |
|---|---|
| Product Name | Tezacaftor |
| Development Code | VX-661 |
| CAS Number | 1152311-62-0 |
| FDA UNII | 8RW88Y506K |
| Molecular Formula | C26H27F3N2O6 |
| Molecular Weight | 520.50 g/mol |
| Chemical Class | CFTR Corrector |
| Therapeutic Area | Cystic Fibrosis |
| Stereochemistry | One defined stereocenter |
| Physical Form | White to off-white solid |
FDA GSRS and PubChem support the identity, molecular formula, molecular weight and stereochemical information.
Tezacaftor binds to CFTR at a site distinct from the binding site of elexacaftor and facilitates the cellular processing and trafficking of selected mutant CFTR proteins. This increases the amount of functional CFTR protein delivered to the cell surface. When combined with ivacaftor, the corrected CFTR protein can also have improved channel-opening activity.
This complementary mechanism is particularly important for CFTR variants that result in defective protein processing or trafficking.
Tezacaftor is used in combination with other CFTR modulators for the treatment of cystic fibrosis in patients carrying CFTR variants responsive to the respective regimen.
The FDA initially approved SYMDEKO (tezacaftor/ivacaftor) in 2018. Tezacaftor is also an active component of TRIKAFTA, which received expanded FDA approvals, including an approval in March 2026 covering patients aged 2 years and older with a qualifying CFTR variant responsive based on clinical and/or in-vitro evidence or resulting in production of CFTR protein.
Tezacaftor is a chemically synthesized pharmaceutical API with a detailed CMC control strategy. The EMA assessment for ALYFTREK specifically states that the tezacaftor active-substance specification includes controls for:
The EMA also identifies assay, organic impurities, chiral purity, inorganic impurities, residual solvents, palladium and copper as relevant quality attributes considered during active-substance control.
FDA CMC review likewise documents extensive characterization and qualification of tezacaftor-related impurities and analytical procedures.
Tezacaftor is manufactured through controlled chemical synthesis followed by purification and isolation of the crystalline API. Manufacturing controls are particularly important for organic impurities, residual solvents, elemental impurities and stereochemical purity.
A qualified Tezacaftor API Manufacturer in India should maintain validated HPLC and GC analytical methods, appropriate impurity controls and documented batch-to-batch consistency.
Tezacaftor is described by FDA as a white to off-white solid and is practically insoluble in water at less than 5 µg/mL. Its molecular weight is 520.50 g/mol.
For laboratory reference material, Cayman reports solubility of 30 mg/mL in DMSO and 30 mg/mL in DMF, while other laboratory data report substantially different solvent-dependent values. These are solvent-solubility measurements rather than pharmaceutical release specifications.
Tezacaftor should be packaged in a manner that protects the API from moisture, contamination and unsuitable environmental conditions. Commercial reference materials are commonly stored at low temperature and/or under inert conditions, but pharmaceutical API storage should follow the validated stability program and approved specification.
A professional Tezacaftor API supply package may include:
A reliable Tezacaftor API Manufacturer in India should provide pharmaceutical-grade material supported by validated analytical testing, controlled impurity profiles and comprehensive documentation. Regulatory assessments specifically recognize assay, organic impurities, elemental impurities, residual solvents and palladium as important controls for the tezacaftor active substance.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |