CLINICAL PHARMACOLOGY
Mechanism Of Action
Lanadelumab-flyo is a fully human monoclonal antibody (IgG1/κ-light chain) that binds plasma kallikrein and inhibits its proteolytic activity. Plasma kallikrein is a protease that cleaves high-molecular-weight-kininogen (HMWK) to generate cleaved HMWK (cHMWK) and bradykinin, a potent vasodilator that increases vascular permeability resulting in swelling and pain associated with HAE. In patients with HAE due to C1-inhibitor (C1-INH) deficiency or dysfunction, normal regulation of plasma kallikrein activity is not present, which leads to uncontrolled increases in plasma kallikrein activity and results in angioedema attacks. Lanadelumab-flyo decreases plasma kallikrein activity to control excess bradykinin generation in patients with HAE.
Pharmacodynamics
Concentration-dependent inhibition of plasma kallikrein, measured as reduction of cHMWK levels, was demonstrated after subcutaneous administration of TAKHZYRO 150 mg q4wks, 300 mg q4wks or 300 mg q2wks in patients with HAE.
TAKHZYRO did not prolong the QT/QTc interval.
Pharmacokinetics
Following subcutaneous administration, the pharmacokinetics of lanadelumab-flyo was approximately dose-proportional in the therapeutic dose range in patients with HAE (Table 2). The pharmacokinetic properties and exposure (steady state) of lanadelumab-flyo in HAE patients, following subcutaneous administration of 150 mg q4wks, 300 mg q4wks and 300 mg q2wks, are provided in Table 2. Following subcutaneous administration of TAKHZYRO, peak plasma concentrations are reached within 5 days, and terminal elimination half-life is ~2 weeks. The anticipated time to reach steady state concentration was approximately 70 days. At steady-state, the mean accumulation ratio is approximately 1.44, 1.42, and 2.43 for dosing regimen of 150 mg q4wks, 300 mg q4wks and 300 mg q2wks, respectively.
Table 2 Mean (SD) Pharmacokinetic Parameters of Lanadelumab-flyo Following Subcutaneous Administration (Trial 1)
Pharmacokinetic Parameters |
Lanadelumab-flyo |
150 mg q4wks
(N=28) |
300 mg q4wks
(N=29) |
300 mg q2wks
(N=27) |
CL/F (L/day) |
0.667 (0.162) |
0.742 (0.239) |
0.809 (0.370) |
Vc/F (L) |
14.1 (2.93) |
14.9 (4.45) |
16.6 (4.79) |
AUCtau,ss (μg*day/mL) |
233 (56.6) |
441(137) |
408 (138) |
Cmax,ss (μg/mL) |
12.0 (3.01) |
23.3 (7.94) |
34.4 (11.2) |
Cmin,ss (μg/mL) |
4.81 (1.40) |
8.77 (2.80) |
25.4 (9.18) |
tmax (day) |
5.17 (1.09) |
5.17 (1.12) |
4.11 (0.377) |
t1/2 (day) |
14.9 (2.00) |
14.2 (1.89) |
15.0 (2.48) |
CL/F: apparent clearance; Vc/F: apparent volume of distribution; AUCtau,ss: area under the curve over the dosing interval at steady-state; Cmax,ss: maximum
concentration at steady-state; Cmin,ss: minimum concentration at steady state; Tmax: time to maximum concentration; t1/2 terminal elimination half-life. |
Specific Populations
Population pharmacokinetic analyses showed that age, gender and race did not meaningfully influence the pharmacokinetics of lanadelumab-flyo after correcting for body weight. Body weight was identified as an important covariate describing the variability of clearance and volume of distribution, resulting in higher exposure (AUC and Cmax) in lighter patients. However, this difference is not considered to be clinically relevant and no dose adjustments are recommended for any of these demographics.
Pediatric Population
Based on population pharmacokinetics (PK) analyses, the mean lanadelumab-flyo (±SD) AUCss was 629 (204) μg*day/mL following SC administration of TAKHZYRO 300 mg every 2 weeks in pediatric patients 12 to less than 18 years of age. This is approximately 37% higher than the mean AUCss in adult patients (460 μg*day/mL) under the same dosing regimen, due to lower body weight in pediatric patients.
Renal Impairment
No dedicated studies have been conducted to evaluate the PK of lanadelumab-flyo in renal impairment patients. Based on population pharmacokinetic analysis, renal impairment (estimated GFR: 60 to 89 mL/min/1.73m2, [mild, N=98] and 30 to 59 mL/min/1.73m2, [moderate, N=9]) had no effect on the clearance or volume of distribution of lanadelumab-flyo.
Concomitant Medications
The use of analgesic, antibacterial, antihistamine, anti-inflammatory and anti-rheumatic medications had no effect on clearance and volume of distribution of lanadelumab-flyo.
For breakthrough HAE attacks, use of rescue medications such as plasma-derived and recombinant C1-INH, icatibant or ecallantide had no effects on clearance and volume of distribution of lanadelumab-flyo.
Clinical Studies
Trial 1 (NCT02586805)
The efficacy of TAKHZYRO for the prevention of angioedema attacks in patients 12 years of age and older with Type I or II HAE was demonstrated in a multicenter, randomized, double-blind, placebo-controlled parallel-group study (Trial 1).
The study included 125 adult and adolescent patients with Type I or II HAE who experienced at least one investigator-confirmed attack per 4 weeks during the run-in period. Patients were randomized into 1 of 4 parallel treatment arms, stratified by baseline attack rate, in a 3:2:2:2 ratio (placebo, lanadelumab-flyo 150 mg q4wks, lanadelumab-flyo 300 mg q4wks, or lanadelumab-flyo 300 mg q2wks by subcutaneous injection) for the 26-week treatment period. Patients ≥18 years of age were required to discontinue other prophylactic HAE medications prior to entering the study; however, all patients were allowed to use rescue medications for treatment of breakthrough HAE attacks.
Overall, 90% of patients had Type I HAE. A history of laryngeal angioedema attacks was reported in 65% of patients and 56% were on prior long-term prophylaxis. During the study run-in period, attack rates of ≥3 attacks/month were observed in 52% of patients overall.
All TAKHZYRO treatment arms produced clinically meaningful and statistically significant reductions in the mean HAE attack rate compared to placebo across all primary and secondary endpoints in the Intent-to-Treat population (ITT) as shown in Table 3.
Table 3 Results of Primary and Secondary Efficacy Measures-ITT Population
Endpoint Statistics |
Placebo
(N=41) |
TAKHZYRO |
150 mg q4wks
(N=28) |
300 mg q4wks
(N=29) |
300 mg q2wks
(N=27) |
Number of HAE Attacks from Day 0 to 182a |
LS Mean (95% CI) monthly attack rateb |
1.97 (1.64, 2.36) |
0.48 (0.31, 0.73) |
0.53 (0.36, 0.77) |
0.26 (0.14, 0.46) |
% Reduction relative to placebo (95% CI)c |
|
76 (61, 85) |
73 (59, 82) |
87 (76, 93) |
Adjusted p-valuesd |
|
<0.001 |
<0.001 |
<0.001 |
Number of HAE Attacks Requiring Acute Treatment from Day 0 to 182 |
LS Mean (95% CI) monthly attack rateb |
1.64 (1.34, 2.00) |
0.31 (0.18, 0.53) |
0.42 (0.28, 0.65) |
0.21 (0.11, 0.40) |
% Reduction relative to placebo (95% CI)c |
|
81 (66, 89) |
74 (59, 84) |
87 (75, 93) |
Adjusted p-valuesd |
|
<0.001 |
<0.001 |
<0.001 |
Number of Moderate or Severe HAE Attacks from Day 0 to 182 |
LS Mean (95% CI) monthly attack rateb |
1.22 (0.97, 1.52) |
0.36 (0.22, 0.58) |
0.32 (0.20, 0.53) |
0.20 (0.11, 0.39) |
% Reduction relative to placebo (95% CI)c |
|
70 (50, 83) |
73 (54, 84) |
83 (67, 92) |
Adjusted p-valuesd |
|
<0.001 |
<0.001 |
<0.001 |
CI=confidence interval; SD=standard deviation; LS=least squares.
Note: Results are from a Poisson regression model accounting for over dispersion with fixed effects for treatment group (categorical) and normalized baseline attack rate (continuous), and the logarithm of time in days each patient was observed during the treatment period as an offset variable in the model.
a Primary efficacy endpoint.
b Model-based treatment period HAE attack rate (attacks/4 weeks).
c Calculated as the ratio of the model-based treatment period HAE attack rates (lanadelumab/placebo) minus 1 multiplied by 100.
d Adjusted p-values for multiple testing. |
The mean reduction in HAE attack rate was consistently higher across the TAKHZYRO treatment arms compared to placebo regardless of the baseline history of prior long-term prophylaxis, laryngeal attacks, or attack rate during the run-in period.
Additional pre-defined exploratory endpoints included the percentage of patients who were attack free for the entire 26-week treatment period and the percentage of patients achieving threshold (≥50%, ≥70%, ≥90%) reductions in HAE attack rates compared to run-in during the 26-week treatment period. A ≥50% reduction in HAE attack rate was observed in 100% of patients on 300 mg q2wks or q4wks and 89% on 150 mg q4wks compared to 32% of placebo patients. A ≥70% reduction in HAE attack rates was observed in 89%, 76%, and 79% of patients on 300 mg q2wks, 300 mg q4wks, and 150 mg q4wks, respectively, compared to 10% of placebo patients. A ≥90% reduction in HAE attack rates was observed 67%, 55%, and 64% of patients on 300 mg q2wks, 300 mg q4wks, and 150 mg q4wks, respectively, compared to 5% of placebo patients.
The percentage of attack-free patients for the entire 26-week treatment period was 44%, 31%, and 39% in the TAKHZYRO 300 mg q2wks, 300 mg q4wks, and 150 mg q4wks groups respectively, compared to 2% of placebo patients.
Trial 2 (NCT02741596)
Patients who completed Trial 1 were eligible to rollover into an open-label extension study. Rollover patients, regardless of randomization group in Trial 1, received a single dose of TAKHZYRO 300 mg at study entry and were followed until the first HAE attack occurred. All efficacy endpoints were exploratory in this uncontrolled, unblinded study. At week 4 post-dose, approximately 80% of patients who had been in the 300 mg q2wks
treatment group (N=25) in Trial 1 remained attack-free. After the first HAE attack, all patients received open-label treatment with TAKHYZRO 300 mg q2wks.