Factor XII (FXII) is a serine protease involved in multiple cascades, including the kallikrein-kinin system. It may play a role in diseases in which the downstream cascades are dysregulated, such as hereditary angioedema. Garadacimab (CSL312) is a first-in-class, fully human, monoclonal antibody targeting activated FXII (FXIIa). We describe how translational pharmacokinetic (PK) and pharmacodynamic (PD) modeling enabled dose selection for the phase I, first-in-human trial of garadacimab. The PK/PD data used for modeling were derived from preclinical PK/PD and safety studies. Garadacimab plasma concentrations rose with increasing dose, and clear dose-related PD effects were observed (e.g., a mechanism-based prolongation of activated partial thromboplastin time). The PK/PD profile from cynomolgus monkeys was used to generate minimal physiologically-based pharmacokinetic (mPBPK) models with target-mediated drug disposition (TMDD) for data prediction in cynomolgus monkeys. These models were later adapted for prediction of human data to establish dose selection. Based on the final mPBPK model with TMDD and assuming a weight of 70 kg for an adult human, a minimal inhibition (<10%) of FXIIa with a starting dose of 0.1 mg/kg garadacimab and a near maximal inhibition (>95%) at 10 mg/kg garadacimab were predicted. The phase I study is complete, and data on exposure profiles and inhibition of FXIIa-mediated kallikrein activity observed in the trial support and validate these simulations. This emphasizes the utility and relevance of translational modeling and simulation in drug development.
BackgroundFor the prevention of attacks of hereditary angioedema (HAE), the efficacy and safety of subcutaneous human C1-esterase inhibitor (C1-INH[SC]; HAEGARDA, CSL Behring) was established in the 16-week Clinical Study for Optimal Management of Preventing Angioedema with Low-Volume Subcutaneous C1-Inhibitor Replacement Therapy (COMPACT).ObjectiveTo assess the long-term safety, occurrence of angioedema attacks, and use of rescue medication with C1-INH(SC).MethodsOpen-label, randomized, parallel-arm extension of COMPACT across 11 countries. Patients with frequent angioedema attacks, either study treatment-naive or who had completed COMPACT, were randomly assigned (1:1) to 40 IU/kg or 60 IU/kg C1-INH(SC) twice per week, with conditional uptitration to optimize prophylaxis (ClinicalTrials.gov registration no. NCT02316353).ResultsA total of 126 patients with a monthly attack rate of 4.3 in 3 months before entry in COMPACT were enrolled and treated for a mean of 1.5 years; 44 patients (34.9%) had more than 2 years of exposure. Mean steady-state C1-INH functional activity increased to 66.6% with 60 IU/kg. Incidence of adverse events was low and similar in both dose groups (11.3 and 8.5 events per patient-year for 40 IU/kg and 60 IU/kg, respectively). For 40 IU/kg and 60 IU/kg, median annualized attack rates were 1.3 and 1.0, respectively, and median rescue medication use was 0.2 and 0.0 times per year, respectively. Of 23 patients receiving 60 IU/kg for more than 2 years, 19 (83%) were attack-free during months 25 to 30 of treatment.ConclusionsIn patients with frequent HAE attacks, long-term replacement therapy with C1-INH(SC) is safe and exhibits a substantial and sustained prophylactic effect, with the vast majority of patients becoming free from debilitating disease symptoms. For the prevention of attacks of hereditary angioedema (HAE), the efficacy and safety of subcutaneous human C1-esterase inhibitor (C1-INH[SC]; HAEGARDA, CSL Behring) was established in the 16-week Clinical Study for Optimal Management of Preventing Angioedema with Low-Volume Subcutaneous C1-Inhibitor Replacement Therapy (COMPACT). To assess the long-term safety, occurrence of angioedema attacks, and use of rescue medication with C1-INH(SC). Open-label, randomized, parallel-arm extension of COMPACT across 11 countries. Patients with frequent angioedema attacks, either study treatment-naive or who had completed COMPACT, were randomly assigned (1:1) to 40 IU/kg or 60 IU/kg C1-INH(SC) twice per week, with conditional uptitration to optimize prophylaxis (ClinicalTrials.gov registration no. NCT02316353). A total of 126 patients with a monthly attack rate of 4.3 in 3 months before entry in COMPACT were enrolled and treated for a mean of 1.5 years; 44 patients (34.9%) had more than 2 years of exposure. Mean steady-state C1-INH functional activity increased to 66.6% with 60 IU/kg. Incidence of adverse events was low and similar in both dose groups (11.3 and 8.5 events per patient-year for 40 IU/kg and 60 IU/kg, respectively). For 40 IU/kg and 60 IU/kg, median annualized attack rates were 1.3 and 1.0, respectively, and median rescue medication use was 0.2 and 0.0 times per year, respectively. Of 23 patients receiving 60 IU/kg for more than 2 years, 19 (83%) were attack-free during months 25 to 30 of treatment. In patients with frequent HAE attacks, long-term replacement therapy with C1-INH(SC) is safe and exhibits a substantial and sustained prophylactic effect, with the vast majority of patients becoming free from debilitating disease symptoms.
Background: Hereditary angioedema (HAE) types I and II are genetic disorders due to low levels or improper function of a protein called C1-esterase inhibitor (C1-INH) and are characterized by recurrent, disfiguring, and potentially life-threatening attacks of subcutaneous and submucosal edema. HAE typically manifests in childhood or adolescence, with onset of symptoms occurring at a mean age of 10 to 11 years. Symptoms and attacks may become more severe at puberty due to hormonal factors. Subcutaneous C1-INH (C1-INH [SC], HAEGARDA®, CSL Behring, Marburg, Germany) at 60 IU/kg twice weekly was …
Subcutaneous C1‐inhibitor (HAEGARDA, CSL Behring), is a US Food and Drug Administration (FDA)‐approved, highly concentrated formulation of a plasma‐derived C1‐esterase inhibitor (C1‐INH), which, in the phase III Clinical Studies for Optimal Management in Preventing Angioedema with Low‐Volume Subcutaneous C1‐inhibitor Replacement Therapy (COMPACT) trial, reduced the incidence of hereditary angioedema (HAE) attacks when given prophylactically. Data from the COMPACT trial were used to develop a repeated time‐to‐event model to characterize the timing and frequency of HAE attacks as a function of C1‐INH activity, and then develop an exposure–response model to assess the relationship between C1‐INH functional activity levels (C1‐INH(f)) and the risk of an attack. The C1‐INH(f) values of 33.1%, 40.3%, and 63.1% were predicted to correspond with 50%, 70%, and 90% reductions in the HAE attack risk, respectively, relative to no therapy. Based on trough C1‐INH(f) values for the 40 IU/kg (40.2%) and 60 IU/kg (48.0%) C1‐INH (SC) doses, the model predicted that 50% and 67% of the population, respectively, would see at least a 70% decrease in the risk of an attack.
Long-term prophylaxis with subcutaneous (SC) administration of a highly concentrated plasma-derived C1-esterase inhibitor (C1-INH) formulation was recently approved by the Food and Drug Administration for hereditary angioedema (HAE) attack prevention.To characterize the population pharmacokinetics of C1-INH (SC) (HAEGARDA® ; CSL Behring) in healthy volunteers and HAE patients, and assess the variability and influence of covariates on pharmacokinetics.C1-INH functional activity data obtained after administration of various C1-INH (intravenous; IV) and C1-INH (SC) doses from 1 study in healthy volunteers (n = 16) and 2 studies in subjects with HAE (n = 108) were pooled to develop a population pharmacokinetic model (NONMEM v7.2). Pharmacokinetic parameters derived from steady-state simulations based on the final model were also evaluated.C1-INH functional activity following C1-INH (SC) administration was described by a linear one-compartment model with first-order absorption and elimination, with inter-individual variability in all parameters tested. The mean population bioavailability of C1-INH (SC), and pharmacokinetic parameters for clearance (CL), volume of distribution, and absorption rate were estimated to be ~43%, 1.03 mL/hour/kg, 0.05 L/kg and 0.0146 hour-1 , respectively. The effect of bodyweight on CL of C1-INH functional activity was included in the final model, estimated to be 0.74. Steady-state simulations of C1-INH functional activity vs time profiles in 1000 virtual HAE patients revealed higher minimum functional activity (Ctrough ) levels after twice-weekly dosing with 40 IU/kg (~40%) and 60 IU/kg (~48%) compared with 1000 IU IV (~30%). Based on the population pharmacokinetic model, the median time to peak concentration was ~59 hours and the median apparent plasma half-life was ~69 hours.Twice-weekly bodyweight-adjusted dosing of C1-INH (SC) exhibits linear pharmacokinetics and dose-dependent increases in Ctrough levels at each dosing interval. In this analysis, SC dosing led to maintenance of higher Ctrough levels than IV dosing.
