Pharmacokinetics and pharmacodynamics of mibavademab (a leptin receptor agonist): Results from a first-in-human phase I study

Mibavademab (previously known as REGN4461), a fully human monoclonal antibody, is being investigated for the treatment of conditions associated with leptin deficiency. Here, we report pharmacokinetics (PKs), pharmacodynamics, and immunogenicity from a phase I study in healthy participants (NCT03530514). In part A, lean or overweight healthy participants were randomized to single-ascending-dose cohorts of 0.3, 1.0, 3.0, 10, and 30 mg/kg intravenous (i.v.), or 300 and 600 mg subcutaneous doses of mibavademab or placebo. In part B, overweight or obese participants were randomized to receive multiple doses of mibavademab (15 mg/kg i.v. loading dose and 10 mg/kg i.v. at weeks 3, 6, and 9) or placebo, stratified by body mass index and baseline leptin levels: low leptin (<5 ng/mL) or relatively low leptin (5-8 ng/mL in men and 5-24 ng/mL in women). Fifty-six and 55 participants completed the single-ascending-dose and multiple-dose parts, respectively. In the single-ascending-dose cohorts, mibavademab PKs were nonlinear with target-mediated elimination, greater than dose-proportional increases in exposure, and there were no dose-dependent differences in total soluble leptin receptor (sLEPR) levels in serum over time. Following multiple-dose administration of mibavademab in participants with leptin <8 ng/mL, lower mean mibavademab concentrations, higher mean total sLEPR concentrations, and larger mean decreases in body weight than in the relatively low leptin cohorts were observed. Baseline leptin was correlated with mibavademab PKs and pharmacodynamics. No treatment-emergent anti-mibavademab antibodies were observed in any mibavademab-treated participant. Results from this study collectively inform further development of mibavademab to treat conditions associated with leptin deficiency.

Garetosmab in Fibrodysplasia Ossificans Progressiva: Clinical Pharmacology Results from the Phase 2 LUMINA-1 Trial

Here, we report the clinical pharmacology data from LUMINA-1 (NCT03188666), a Phase 2 trial that evaluated garetosmab (a monoclonal antibody against activin A) in patients with fibrodysplasia ossificans progressiva. Forty-four patients were randomly assigned to intravenous 10 mg/kg of garetosmab or placebo every 4 weeks in a double-blind 28-week treatment period, followed by a 28-week open-label treatment period with garetosmab, and subsequent open-label extension. Serum samples were obtained to assess pharmacokinetics (PK), immunogenicity, and bone morphogenetic protein 9 (BMP9). Comparative exposure-response analyses for efficacy and safety were performed with trough concentrations (Ctrough ) of garetosmab prior to dosing. Steady-state PK was reached 12-16 weeks after the first dose of garetosmab, with mean (standard deviation) Ctrough of 105 ± 30.8 mg/L. Immunogenicity assessments showed anti-garetosmab antibody formation in 1 patient (1/43; 2.3%); titers were low, and did not affect PK or clinical efficacy. Median concentrations of BMP9 in serum were approximately 40 pg/mL at baseline. There were no meaningful differences in PK or BMP9 concentration-time profiles between patients who did and did not experience epistaxis or death. The comparative exposure-response analyses demonstrated no association between Ctrough and efficacy or safety. PK findings were consistent with prior data in healthy volunteers and were typical for a monoclonal antibody administered at doses sufficient to saturate target-mediated clearance. There were no trends that suggested patients with higher serum exposures to garetosmab were more likely to experience a reduction in heterotopic ossification or adverse events. Garetosmab is being further evaluated in the Phase 3 OPTIMA trial.

Evinacumab for Pediatric Patients With Homozygous Familial Hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder characterized by severely elevated low-density lipoprotein cholesterol (LDL-C) levels due to profoundly defective LDL receptor (LDLR) function. Given that severely elevated LDL-C starts in utero, atherosclerosis often presents during childhood or adolescence, creating a largely unmet need for aggressive LDLR-independent lipid-lowering therapies in young patients with HoFH. Here we present the first evaluation of the efficacy and safety of evinacumab, a novel LDLR-independent lipid-lowering therapy, in pediatric patients with HoFH from parts A and B of a 3-part study.

METHODS

The phase 3, part B, open-label study treated 14 patients 5 to 11 years of age with genetically proven HoFH (true homozygotes and compound heterozygotes) with LDL-C >130 mg/dL, despite optimized lipid-lowering therapy (including LDLR-independent apheresis and lomitapide), with intravenous evinacumab 15 mg/kg every 4 weeks.

RESULTS

Evinacumab treatment rapidly and durably (through week 24) decreased LDL-C with profound reduction in the first week, with a mean (SE) LDL-C reduction of -48.3% (10.4%) from baseline to week 24. ApoB (mean [SE], -41.3% [9.0%]), non-high-density lipoprotein cholesterol (-48.9% [9.8%]), and total cholesterol (-49.1% [8.1%]) were similarly decreased. Treatment-emergent adverse events were reported in 10 (71.4%) patients; however, only 2 (14.3%) reported events that were considered to be treatment-related (nausea and abdominal pain). One serious treatment-emergent adverse event of tonsillitis occurred (n=1), but this was not considered treatment-related.

CONCLUSIONS

Evinacumab constitutes a new treatment for pediatric patients with HoFH and inadequately controlled LDL-C despite optimized lipid-lowering therapy, lowering LDL-C levels by nearly half in these extremely high-risk and difficult-to-treat individuals.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04233918.

Population Pharmacokinetic Analysis of Quizartinib in Healthy Volunteers and Patients With Relapsed/Refractory Acute Myeloid Leukemia

Quizartinib is an FMS‐like tyrosine kinase 3 (FLT3) inhibitor that has shown robust clinical activity in patients with FLT3‐internal tandem duplication–mutated relapsed/refractory acute myeloid leukemia (AML). This analysis evaluated the population pharmacokinetics (PK) of quizartinib and its active metabolite, AC886, in a pooled analysis of data from 649 healthy volunteers or patients with AML from 8 clinical trials including the phase 3 QuANTUM‐R study. Quizartinib was given as a single dose or multiple once‐daily doses of 20, 30, 60, or 90 mg. Nonlinear mixed‐effects modeling was performed using observed concentrations of quizartinib and AC886. Strong CYP3A inhibitor use resulted in an 82% increase in the area under the curve (AUC) and a 72% increase in the maximum concentration (C_max) of quizartinib. Albumin level, age, and body surface area were statistically significant covariates on quizartinib PK. However, their individual effects on quizartinib AUC and C_max were <20%. For AC886, strong CYP3A inhibitor use, body surface area and black/African American race were significant covariates. Except for strong CYP3A inhibitor use, the effects on the overall exposure (AUC of quizartinib + AC886) were <20%. The population PK model provided an adequate description of the observed concentrations of quizartinib and AC886 in both healthy volunteers and patients with AML. Only concomitant use of strong CYP3A inhibitors had a clinically meaningful effect on quizartinib PK exposure.

Randomized, Double-Blind, Single-Dose, Placebo-Controlled Crossover Study to Evaluate the Effects of Esaxerenone on QTc Interval in Healthy Subjects

This phase 1 single-center, single-dose, double-dummy, placebo-controlled, 4-period and 4-sequence crossover study assessed the potential of esaxerenone, a novel nonsteroidal mineralocorticoid receptor blocker used to treat hypertension, to affect cardiac repolarization. In this double-blind study, 55 subjects were randomized to single doses of 10 mg esaxerenone (therapeutic dose), 40 mg esaxerenone (supratherapeutic dose), 400 mg moxifloxacin, or placebo. Serial electrocardiograms and pharmacokinetics (PK) were obtained over 24 and 168 hours, respectively. The primary end point was Fridericia-corrected QT interval (QTcF). Secondary end points included safety and PK. Assay sensitivity was confirmed as the lower limit of 90% confidence interval (90%CIs) for placebo-corrected change from baseline QTcF (∆∆QTcF) for moxifloxacin was >5 milliseconds at the prespecified times; mean ∆∆QTcF was 12.5 milliseconds at 3 and 4 hours postdose. The upper 90%CI limits of ∆∆QTcF were ≤0 milliseconds at all times for both doses of esaxerenone. No concentration-QTc relationship was identified. Therefore, esaxerenone had no potential to inhibit cardiac repolarization. No deaths or serious adverse events (AEs) occurred; 1 subject discontinued the study because of a treatment-emergent AE unrelated to esaxerenone. This clinical evaluation showed that esaxerenone has no QTc prolongation potential.

Safety and Pharmacokinetics of DS-1040 Drug-Drug Interactions With Aspirin, Clopidogrel, and Enoxaparin

DS-1040, a novel low-molecular-weight inhibitor of activated thrombin-activatable fibrinolysis inhibitor, is under development for the treatment of thromboembolic diseases including venous thromboembolism and acute ischemic stroke. Here we describe the results of 3 studies that evaluated the safety and tolerability of DS-1040 along with the effect on DS-1040 pharmacokinetic (PK) parameters, when dosed alone or when coadministered with aspirin (NCT02071004), clopidogrel (NCT02560688), or enoxaparin in healthy subjects. Concomitant administration of single-dose DS-1040 with multiple-dose aspirin, multiple-dose clopidogrel, or single-dose enoxaparin, consistent with clinically relevant dose regimens, was safe and well tolerated with no serious treatment-emergent adverse events (TEAEs), TEAEs leading to discontinuation, bleeding-related TEAEs, and no significant changes in coagulation parameters. DS-1040 did not prolong bleeding time when administered concomitantly with aspirin or clopidogrel. In the aspirin study, DS-1040 PK was evaluated following the concomitant administration with multiple-dose aspirin, where the plasma DS-1040 exposure (peak plasma concentration [C_max ] and area under the concentration-time curve [AUC_inf ]) was to be similar to the data previously published in the first-in-human study of DS-1040 in healthy subjects. The PK parameters of DS-1040 coadministered with clopidogrel were similar to those of DS-1040 alone, with small increases in geometric means for C_max (7%) and AUC_last (9%). When coadministered with enoxaparin, the PK parameters of DS-1040 were not affected (1.1% and 1.5% decreases in geometric means for C_max and AUC_last , respectively). Therefore, concomitant administration of DS-1040 and clopidogrel or enoxaparin did not demonstrate PK drug-drug interactions.

Effect of Food on the Pharmacokinetics of Quizartinib

Quizartinib is an oral, highly potent, and selective type II FMS‐like tyrosine kinase 3 inhibitor in development for acute myeloid leukemia. This parallel‐group study evaluated potential food effects on quizartinib absorption in healthy subjects who received a single 30‐mg dose after overnight fasting (n = 34) or a high‐fat, high‐calorie meal (n = 30). Blood samples were collected through 504 hours after dosing, and pharmacokinetic parameters calculated were maximum observed concentration (C_max) and area under plasma concentration–time curve from time 0 to last quantifiable concentration (AUC_last) and from time 0 to infinity (AUC_inf). Mean quizartinib pharmacokinetic profiles were similar under fasted and fed conditions. The geometric least squares means ratios (%) for fed/fasted and associated 90% confidence intervals (CIs) for C_max, AUC_last, and AUC_inf were 91.58 (82.15‐102.08), 105.39 (90.79‐122.35), and 108.39 (91.54‐128.34), respectively. The 90%CI for the ratio fell within the 80% to 125% limits for C_max and AUC_last, with 90%CI for AUC_inf slightly outside the limits (ie, 128%). Food delayed quizartinib time to C_max by 2 hours. All adverse events were either mild or moderate; no discontinuations due to adverse events occurred. Based on these results, quizartinib can be administered without regard to food.

A drug-drug interaction study to assess the potential effect of acid-reducing agent, lansoprazole, on quizartinib pharmacokinetics

PURPOSE

Quizartinib, a potent, selective FMS-like tyrosine kinase 3 (FLT3) inhibitor, is currently in phase 3 development for patients with FLT3-internal tandem duplication-mutated acute myeloid leukemia (AML). Acid-reducing agents (ARAs; e.g., proton pump inhibitors) are frequently used during AML treatment. Since quizartinib demonstrates pH-dependent solubility, the effect of lansoprazole coadministration on pharmacokinetics (PK) of quizartinib tablet formulation was assessed.

METHODS

An open-label, parallel-group study randomized 64 healthy adults to single-dose quizartinib 30 mg alone (reference) or lansoprazole (60 mg once daily, days 1-5) + single-dose quizartinib 30 mg (day 5) (test). Plasma concentrations of quizartinib and its active metabolite, AC886, were measured to 504 h postdose; the effect of lansoprazole on quizartinib PK was assessed by analysis of variance.

RESULTS

Quizartinib geometric mean ratios (test/reference) and 90% confidence intervals for maximum observed plasma concentration (Cmax), area under the concentration-time curve to last measurable drug concentration (AUClast), and AUC to infinity were 86.11% (78.4%, 94.6%), 93.96% (79.6%, 110.9%), and 95.30% (80.2%, 113.3%), respectively. Comparisons showed a modest decrease in quizartinib absorption when co-administered with lansoprazole, with lower limits for Cmax and AUClast just below 80-125% limits. Treatment-emergent adverse events were mild or moderate; the most frequent in either treatment group were headache [quizartinib alone: (n = 3) 10%], upper respiratory tract infection [quizartinib alone: (n = 2) 6.7%; lansoprazole + quizartinib: (n = 3) 9.1%], and muscle tightness [quizartinib alone: (n = 2) 6.7%].

CONCLUSIONS

Concomitant lansoprazole had minimal effect on quizartinib PK as a formulated tablet, indicating that quizartinib can be administered with ARAs.

Abuse potential of mirogabalin in recreational polydrug users

Mirogabalin is a selective calcium channel α₂δ subunit ligand being developed to treat neuropathic pain. In accordance with US Food and Drug Administration (FDA) guidance, the human abuse potential of mirogabalin (15–105 mg) was examined, relative to placebo, diazepam (15 or 30 mg), and pregabalin (200 or 450 mg), in two single-dose, randomized, double-blind, placebo- and active-controlled crossover studies in recreational polydrug users who could discern between positive comparator and placebo. The primary endpoint was maximum observed effect (E_max) for Drug Liking Visual Analog Scale. At therapeutic doses, mirogabalin Drug Liking E_max did not differ significantly from placebo and was significantly lower than diazepam and pregabalin. This indicates therapeutic doses mirogabalin may have less abuse potential versus diazepam or pregabalin. At supratherapeutic doses (⩾4× therapeutic dose), mirogabalin had significantly higher Drug Liking E_max than placebo, but lower E_max than pregabalin. In both studies, therapeutic doses of mirogabalin demonstrated limited evidence of abuse potential.

Pharmacokinetics, Metabolism, and Excretion of [14C]Esaxerenone, a Novel Mineralocorticoid Receptor Blocker in Humans

Esaxerenone (CS-3150) is a novel, nonsteroidal, selective mineralocorticoid receptor blocker. The absorption, metabolism, distribution, and excretion of esaxerenone were assessed in in vitro studies and in a clinical study, where [¹⁴C]esaxerenone (150 μCi/20 mg) was administered orally to six healthy male subjects. The plasma concentrations of esaxerenone and its metabolites (M4, M11, and M1) were measured using liquid chromatography-tandem mass spectrometry. The recovery of radioactivity was 92.5%, with 38.5% and 54.0% excreted in the urine and feces, respectively. The half-life of radioactivity in blood and plasma was approximately 30 hours, similar to that of the unchanged form in plasma. The blood-to-plasma ratio was 0.628, demonstrating low partitioning to blood components. In plasma, esaxerenone was the most abundant moiety (40.8%), followed by O-glucuronide (21.4%; M4), acyl-glucuronide of amide-bond hydrolysate (8.0%; M11), and the deshydroxyethyl form (1.7%; M1). In vitro studies showed that esaxerenone was a substrate of CYP3A and multiple UDP-glucuronosyltransferase isoforms. Oxidation contributed approximately 30% to its clearance, as indicated by the excretion ratio of oxidized metabolites into urine and feces. Caco-2 studies showed that esaxerenone was a substrate of P-glycoprotein and breast cancer resistance protein; however, the excretion ratios of the unchanged form in the feces and urine were 18.7% and 1.6%, respectively, indicating that these transporters were not important for the absorption and elimination of esaxerenone. Low urinary excretion of esaxerenone suggested that the plasma exposure of esaxerenone was not affected by renal dysfunction. Multiple elimination pathways including oxidation, glucuronidation, and hydrolysis, and the low contribution of transporters, indicated limited drug-drug interaction potential.

Patritumab with Cetuximab plus Platinum-Containing Therapy in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck: An Open-Label, Phase Ib Study

PURPOSE

Patritumab plus cetuximab with platinum as first-line therapy for patients with recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) was evaluated for safety and to determine the recommended phase II combination dose.

PATIENTS AND METHODS

Patients aged ≥18 years with confirmed R/M SCCHN received intravenous patritumab (18 mg/kg loading dose; 9 mg/kg maintenance dose every 3 weeks) + cetuximab (400 mg/m² loading dose; 250 mg/m² maintenance dose weekly) + cisplatin (100 mg/m² every 3 weeks) or carboplatin (AUC of 5) for six cycles or until toxicity, disease progression, or withdrawal. Primary endpoints were dose-limiting toxicities [DLT; grade ≥3 (21-day observation period)] and treatment-emergent adverse events (TEAE). Pharmacokinetics, human antihuman antibodies (HAHA), tumor response, progression-free survival (PFS), and overall survival (OS) were assessed.

RESULTS

Fifteen patients completed a median (range) of 8.7 (2.0-20.7) patritumab cycles. No DLTs were reported. Serious adverse events were reported in 9 patients (patritumab-related n = 4). TEAEs (N = 15 patients) led to patritumab interruption in 7 patients. Patritumab-related dose reductions were reported in 1 patient. Patritumab (18 mg/kg) pharmacokinetics (N = 15) showed mean (SD) AUC_0-21d of 2,619 (560) μg/day/mL and maximum concentration of 499.9 (90.4) μg/mL. All patients were HAHA-negative at study end (single, transient low titer in 1 patient). Tumor response rate (complete plus partial response; N = 15) was 47%. Median (95% confidence interval) PFS and OS (N = 15) were 7.9 (3.7-9.7) and 13.5 (6.6-17.5) months, respectively.

CONCLUSIONS

Patritumab (18 mg/kg loading dose, 9 mg/kg maintenance dose) plus cetuximab/platinum was tolerable, active in SCCHN, and selected as the phase II dose regimen.

Tolerability, pharmacokinetics, and pharmacodynamics of mirogabalin in healthy subjects: Results from phase 1 studies

Three phase 1 pharmacokinetic (PK)/pharmacodynamics (PD) studies were conducted in healthy men and women to further characterize the safety, tolerability, and PK/PD of mirogabalin administration with or without food and to guide the dose selection and regimen for phase 2 and 3 clinical development. The 3 studies included 2 randomized, double-blind, placebo-controlled, single- and multiple-ascending-dose studies, and 1 open-label, crossover study to evaluate the PK of mirogabalin administered under fasting and fed (high-fat meal) conditions. Forty-eight and 47 healthy volunteers completed the single- and multiple-dose studies, respectively. Thirty subjects were enrolled and completed the food effect study. Mirogabalin was well tolerated in the fed and fasted states. The most frequent treatment-emergent adverse events (TEAEs)-dizziness and somnolence-were expected based on mirogabalin's mechanism of action. Subjects receiving the highest mirogabalin doses (50 and 75 mg single dose) showed greater dizziness and sedation and higher rates of TEAEs than subjects receiving 3-30 mg. After oral administration, mirogabalin was rapidly absorbed (time to maximum concentration, ∼1 hour) and eliminated through urine unchanged (61%-72% urinary excretion). Exposure increased in a dose-proportional manner after single or multiple mirogabalin doses. No significant accumulation occurred with multiple doses over 14 days. After single doses of mirogabalin (15 mg), the bioavailability was considered equivalent in the fed and fasted states, indicating that mirogabalin can be taken without food restrictions. Based on these data, mirogabalin 15 mg twice daily was selected as the highest target dose for further clinical development.