Amivantamab is a low-fucose, fully-human IgG1-based EGFR-MET bispecific antibody with immune cell-directing activity that targets tumours with activating EGFR Exon 20 insertion mutations. Amivantamab binds to the extracellular domains of EGFR and MET.
Amivantamab disrupts EGFR and MET signalling functions through blocking ligand binding and enhancing degradation of EGFR and MET, thereby preventing tumour growth and progression. The presence of EGFR and MET on the surface of tumour cells also allows for targeting of these cells for destruction by immune effector cells, such as natural killer cells and macrophages, through antibody-dependent cellular cytotoxicity (ADCC) and trogocytosis mechanisms, respectively.
Amivantamab decreased serum albumin concentration, a pharmacodynamic effect of MET inhibition, typically during the first 8 weeks; thereafter, albumin concentration stabilised for the remainder of amivantamab treatment.
Amivantamab area under the concentration-time curve (AUC1week) increases proportionally over a dose range from 350 to 1,750 mg.
Following administration of amivantamab at the recommended dose and schedule, the mean serum AUC1week was approximately 2.9-fold higher after the fifth dose, following the weekly dosing, compared to the first dose.
Steady state was achieved approximately 2 months into the every 2-week dosing period (by the ninth infusion) at 1,050 mg, and the mean serum AUC1week was approximately 2.4 fold higher at steady state compared to the first dose.
Amivantamab geometric mean (CV%) total volume of distribution, based on population PK parameter estimates, was 5.37 (21%) L following administration of the recommended dose of amivantamab.
Amivantamab clearance is higher with low doses (<350 mg) but linear within the clinical dose range. The geometric mean (CV%) linear clearance was estimated to be 225 (25%) mL/day, based on population PK modelling. The geometric mean (CV%) terminal half-life associated with linear clearance, derived based on population PK parameter estimates, was 15.7 (26%) days, following administration of the recommended dose of amivantamab as monotherapy.
No clinically meaningful differences in the pharmacokinetics of amivantamab were observed based on age (32-87 years).
No clinically meaningful effect on the pharmacokinetics of amivantamab was observed in patients with mild (60 ≤ creatinine clearance [CrCl] < 90 mL/min) and moderate (29 ≤ CrCl < 60 mL/min) renal impairment. The effect of severe renal impairment (15 ≤ CrCl < 29 mL/min) on amivantamab pharmacokinetics is unknown.
Changes in hepatic function are unlikely to have any effect on the elimination of amivantamab since IgG1-based molecules such as amivantamab are not metabolised through hepatic pathways.
No clinically meaningful effect in the pharmacokinetics of amivantamab was observed based on mild hepatic impairment [(total bilirubin ≤ ULN and AST > ULN) or (ULN < total bilirubin ≤ 1.5 x ULN)]. The effect of moderate (total bilirubin 1.5 to 3 times ULN) and severe (total bilirubin > 3 times ULN) hepatic impairment on amivantamab pharmacokinetics is unknown.
The pharmacokinetics of amivantamab in paediatric patients have not been investigated.
Non-clinical data reveal no special hazard for humans based on conventional studies of repeated dose toxicity.
No animal studies have been performed to establish the carcinogenic potential of amivantamab. Routine genotoxicity and carcinogenicity studies are generally not applicable to biologic pharmaceuticals as large proteins cannot diffuse into cells and cannot interact with DNA or chromosomal material.
No animal studies have been conducted to evaluate the effects on reproduction and foetal development; however, based on its mechanism of action, amivantamab can cause foetal harm or developmental anomalies. As reported in the literature, reduction, elimination, or disruption of embryo foetal or maternal EGFR signaling can prevent implantation, cause embryo foetal loss during various stages of gestation (through effects on placental development), cause developmental anomalies in multiple organs or early death in surviving foetuses. Similarly, knock out of MET or its ligand hepatocyte growth factor (HGF) was embryonic lethal due to severe defects in placental development, and foetuses displayed defects in muscle development in multiple organs. Human IgG1 is known to cross the placenta; therefore, amivantamab has the potential to be transmitted from the mother to the developing foetus.
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