Each single-use PushtronexTM system (on-body infusor with prefilled cartridge) delivers a 3.5 mL solution containing 420 mg evolocumab, acetate (4.2 mg), polysorbate 80 (0.35 mg), proline (89 mg) in Water for Injection, USP. Sodium hydroxide may be used to adjust to a pH of 5.0.
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
Evolocumab is a human monoclonal IgG2 directed against human proprotein convertase subtilisin kexin 9 (PCSK9). Evolocumab binds to PCSK9 and inhibits circulating PCSK9 from binding to the low density lipoprotein (LDL) receptor (LDLR), preventing PCSK9-mediated LDLR degradation and permitting LDLR to recycle back to the liver cell surface. By inhibiting the binding of PCSK9 to LDLR, evolocumab increases the number of LDLRs available to clear LDL from the blood, thereby lowering LDL-C levels.
12.2 Pharmacodynamics
Following single subcutaneous administration of 140 mg or 420 mg of evolocumab, maximum suppression of circulating unbound PCSK9 occurred by 4 hours. Unbound PCSK9 concentrations returned toward baseline when evolocumab concentrations decreased below the limit of quantitation.
12.3 Pharmacokinetics
Evolocumab exhibits non-linear kinetics as a result of binding to PCSK9. Administration of the 140 mg dose in healthy volunteers resulted in a Cmax mean (standard deviation [SD]) of 18.6 (7.3) μg/mL and AUClast mean (SD) of 188 (98.6) day•μg/mL. Administration of the 420 mg dose in healthy volunteers resulted in a Cmax mean (SD) of 59.0 (17.2) μg/mL and AUClast mean (SD) of 924 (346) day•μg/mL. Following a single 420 mg intravenous dose, the mean (SD) systemic clearance was estimated to be 12 (2) mL/hr. An approximate 2- to 3-fold accumulation was observed in trough serum concentrations (Cmin [SD] 7.21 [6.6]) following 140 mg doses administered subcutaneously every 2 weeks or following 420 mg doses administered subcutaneously monthly (Cmin [SD] 11.2 [10.8]), and serum trough concentrations approached steady state by 12 weeks of dosing.
Absorption
Following a single subcutaneous dose of 140 mg or 420 mg evolocumab administered to healthy adults, median peak serum concentrations were attained in 3 to 4 days, and estimated absolute bioavailability was 72%.
Distribution
Following a single 420 mg intravenous dose, the mean (SD) steady-state volume of distribution was estimated to be 3.3 (0.5) L.
Metabolism and Elimination
Two elimination phases were observed for REPATHA. At low concentrations, the elimination is predominately through saturable binding to target (PCSK9), while at higher concentrations the elimination of REPATHA is largely through a non-saturable proteolytic pathway. REPATHA was estimated to have an effective half-life of 11 to 17 days.
Specific Populations
The pharmacokinetics of evolocumab were not affected by age, gender, race, or creatinine clearance, across all approved populations [see Use in Specific Populations (8.5)].
The exposure of evolocumab decreased with increasing body weight. These differences are not clinically meaningful.
Renal Impairment
Since monoclonal antibodies are not known to be eliminated via renal pathways, renal function is not expected to impact the pharmacokinetics of evolocumab. Patients with severe renal impairment (estimated glomerular filtration rate [eGFR] < 30 mL/min/1.73 m2) have not been studied.
Hepatic Impairment
Following a single 140 mg subcutaneous dose of evolocumab in pat |
