Pharmacokinetics and Pharmacodynamics of the BACE1 Inhibitor Verubecestat (MK-8931) in Healthy Japanese Adults: A Randomized, Placebo-Controlled Study

β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is required for the production of β-amyloid (Aβ) peptides and is considered a potential treatment target for Alzheimer's disease (AD). To support Japan's participation in the global clinical development program, we characterized the safety, pharmacokinetics (PKs), and pharmacodynamics of the BACE1 inhibitor verubecestat (MK-8931) in 24 healthy Japanese adults in a two-part, single-center, randomized, placebo-controlled phase I trial (protocol MK-8931-007) and compared the results with historical data from non-Japanese subjects. Both single (20, 100, and 450 mg) and multiple (80 and 150 mg once daily for 14 days) doses of verubecestat were well tolerated. Verubecestat's PK profile was similar in Japanese and non-Japanese subjects. Verubecestat also reduced mean cerebrospinal fluid concentrations of the Aβ proteins Aβ40, Aβ42, and soluble β fragment of amyloid precursor protein; the level of reduction was comparable between Japanese and non-Japanese subjects. These results support the continued global development of verubecestat as a potential disease-modifying agent for Japanese and non-Japanese subjects who are at risk for developing AD.

Pharmacokinetics of Tildrakizumab (MK-3222), an Anti-IL-23 Monoclonal Antibody, After Intravenous or Subcutaneous Administration in Healthy Subjects

Tildrakizumab, a high-affinity humanized IgG1k antibody that selectively binds interleukin (IL)-23 p19 subunit of cytokine IL-23 and neutralizes its function, is under investigation for treatment of moderate-to-severe chronic plaque psoriasis. The objective of this analysis was to assess the pharmacokinetics, bioavailability and safety/tolerability of single ascending doses of tildrakizumab after intravenous (IV) and subcutaneous (SC) dosing in healthy subjects. P05661 was a phase 1, single-dose, randomized, placebo-controlled study of tildrakizumab IV doses of 0.1, 0.5, 3 and 10 mg/kg, or placebo. P05776 was a phase 1, single-dose, randomized, placebo-controlled study of tildrakizumab SC doses of 50 or 200 mg, or placebo. After either single IV or SC dosing, tildrakizumab exhibited slow systemic clearance (CL), limited volume of distribution and a long t_1/2 . Both the C_max and the area under the curve (AUC) increased proportionally with doses from 0.1 to 10 mg/kg, or 50-200 mg. The bioavailability of SC dosing was ~80% (90% CI: 62-103%) for 50 mg and ~73% (90% CI: 46-115%) for 200 mg, respectively, versus 0.5 and 3 mg/kg IV. Across both studies, six of 43 evaluable subjects were positive for post-dose antidrug antibodies; two of these were positive for neutralizing antibodies. Most adverse events (AEs) were mild; the most frequent AEs included upper respiratory tract infection and headache. Single doses of tildrakizumab 0.1, 0.5, 3 and 10 mg/kg administered IV or single doses of 50 and 200 mg administered SC were safe and well tolerated in healthy adult subjects.

Intravenous Pharmacokinetics, Local Tolerability, and Hemolysis of an SBE7-β-Cyclodextrin Formulation of the Neurokinin-1 Receptor Antagonist Vestipitant

Vestipitant is a potent and selective neurokinin 1 (NK-1) receptor antagonist that was investigated as a potential treatment for post-operative nausea and vomiting (PONV). A previous mannitol-based formulation of vestipitant was associated with hemolytic activity in preclinical studies. In an effort to reduce the hemolytic potential and develop an IV formulation of vestipitant that could be administered more rapidly, an IV formulation containing sulfobutylether-7-beta-cyclodextrin (SBE7-β-CD, Captisol™) was developed and tested in a phase 1 clinical study. This was a randomized, single-blind (subjects and investigator—blinded, sponsor-unblinded), placebo controlled, dose escalation study in healthy subjects in which 7 cohorts of 8 subjects per cohort received SBE7-β-CD -based vestipitant (2 mg/mL) or placebo (saline) in a 3:1 ratio (active:placebo) at different doses and infusion rates. The results demonstrated the ability to infuse up to 48 mg vestipitant in a 2 mg/mL formulation over 30 seconds with no evidence of hemolytic effects. Cohorts of subjects at lower doses and longer infusion duration (>1 minute) reported more AEs related to the infusion site than those at the higher doses and faster infusion rates.

Velcalcetide (AMG 416), a novel peptide agonist of the calcium-sensing receptor, reduces serum parathyroid hormone and FGF23 levels in healthy male subjects

CONTEXT

Velcalcetide, also known as AMG 416, is a novel, long-acting selective peptide agonist of the calcium sensing receptor. It is being developed as an intravenous treatment of secondary hyperparathyroidism (SHPT) in hemodialysis patients with chronic kidney disease-mineral and bone disorder.

OBJECTIVE

To assess the safety, tolerability, pharmacokinetics and pharmacodynamics of velcalcetide in healthy male volunteers.

METHODS

The study was a double-blind, randomized, placebo-controlled, single-dose, dose-escalation study in healthy males aged 18-45 years conducted at a single center. Each cohort included eight subjects randomized 6:2 to velcalcetide or placebo.

INTERVENTION

Velcalcetide at 0.5, 2, 5 and 10 mg or placebo was administered intravenously.

OUTCOMES

Measurements included plasma ionized calcium (iCa), serum total calcium, intact parathyroid hormone (iPTH), phosphorus and fibroblast growth factor-23 (FGF23), 1,25-dihydroxyvitamin D, calcitonin and urine creatinine, calcium and phosphorus and plasma pharmacokinetics for velcalcetide. Vital signs, safety biochemical and hematological indices, and adverse events were monitored throughout the study.

RESULTS

Intravenous administration of velcalcetide was well tolerated with no adverse reaction of nausea, vomiting or diarrhea reported. Velcalcetide mediated dose-dependent decreases in serum iPTH at 30 min, FGF23 at 24 h and iCa at 12 h post dose (P<0.05) and in urine fractional excretion of phosphorus and increases in tubular reabsorption of phosphorus. Velcalcetide plasma exposure increased in a dose-related manner and the terminal elimination of half-life was comparable across the dose range evaluated and ranged from 18.4 to 20.0 h.

CONCLUSION

Single IV doses of velcalcetide were well tolerated and associated with rapid, sustained, dose-dependent reductions in serum PTH. The results support further evaluation of velcalcetide as a treatment for SHPT in hemodialysis patients.

A phase 1, randomized, placebo-controlled, dose-escalation study of an anti-IL-13 monoclonal antibody in healthy subjects and mild asthmatics

AIMS

IL-13 is implicated as an important mediator of the pathology of asthma. This first clinical study with GSK679586, a novel humanized anti-IL-13 IgG1 monoclonal antibody, evaluated the safety, pharmacokinetics and pharmacodynamics of escalating single and repeat doses of GSK679586.

METHODS

In this randomized, double-blind study, healthy subjects received single intravenous infusions of GSK679586 (0.005, 0.05, 0.5, 2.5, 10 mg kg(-1)) or placebo and mild intermittent asthmatics received two once monthly intravenous infusions of GSK679586 (2.5, 10, 20 mg kg(-1)) or placebo.

RESULTS

GSK679586 displayed approximately linear pharmacokinetics (based on AUC and C(max)) with limited accumulation upon repeat administration. In mild intermittent asthmatics, treatment with GSK679586 produced an increase in serum total IL-13 concentrations, indicative of GSK679586-IL-13 complex formation. Additionally, mean levels of exhaled nitric oxide (FeNO), a marker of pulmonary inflammation, were reduced relative to baseline at 2.5, 10 and 20 mg kg(-1) doses of GSK679586 at both 2 weeks (19%, 44% and 52% decreases) and 8 weeks (29%, 55% and 42% decreases) after the second infusion. GSK679586 was well tolerated; the incidence of AEs was comparable across all presumed biologically active doses and there were no treatment-related SAEs.

CONCLUSIONS

GSK679586 demonstrated dose-dependent pharmacological activity in the lungs of mild intermittent asthmatics. These findings, together with the favourable safety profile and advantageous PK characteristics of a monoclonal antibody (e.g. a long half-life supporting less frequent dosing), warrant further investigation of GSK679586 in a broader asthma patient population.

Acute hyperkalemia associated with inhalation of a potent ENaC antagonist: Phase 1 trial of GS-9411

BACKGROUND

Inhaled epithelial sodium channel (ENaC) blockers are designed to increase airway surface liquid volume, thereby benefiting cystic fibrosis patients. This study evaluated the safety, tolerability, and pharmacokinetics of multiple doses of ENaC blocker GS-9411, in healthy participants.

METHODS

This randomized, double-blind, placebo-controlled, parallel-group, residential, Phase 1 study evaluated inhaled GS-9411 (2.4, 4.8, and 9.6 mg) or placebo, dosed twice daily for 14 days.

RESULTS AND CONCLUSIONS

GS-9411 was well tolerated; 86.1% of treated participants completed dosing (n=31/36). Cough and dizziness (27.8% participants each; most of mild severity) were the most commonly reported adverse events and occurred in both placebo and GS-9411 treatment groups. Arrhythmias were not observed for GS-9411-treated participants, and electrocardiographic changes were not considered clinically significant. Serum potassium levels exceeded the upper limit of normal (>5 mmol/L), 4 hr after the morning dose in GS-9411 (n=16/24) and placebo (n=4/12) treatment groups (38 incidences total). Retesting revealed levels had returned to normal within 2-3 hr. In urine electrolyte analyses, obtained 0-6 hr after the Day 1 morning dose, mean sodium/potassium ratios significantly increased from values 0-6 hr before dosing. Increased urine sodium/potassium ratios corresponded with high urine concentrations of active GS-9411 metabolites, which inhibited sodium reabsorption in the kidney, leading to the observed transient hyperkalemia in these participants. Inhaled GS-9411 was well tolerated except for the emergence of transient clinically significant hyperkalemia; this finding resulted in termination of further clinical development of this drug and will necessitate development of a new generation of ENaC blockers, which provide a sustained improvement in mucociliary clearance, while reducing renal exposure to ENaC blockade. Transient increases in mean urine sodium/potassium ratios appeared to be the first signal of electrolyte imbalances resulting from drug-induced block of ENaC in the kidney. The results of this study strongly suggest that clinical trials of novel ENaC blockers will require intensive measurement of plasma and urine electrolyte levels.

The effects of ALV003 pre-digestion of gluten on immune response and symptoms in celiac disease in vivo

Effective treatment of celiac disease is an unmet medical need. A glutenase that destroys immunogenic gluten peptides may be clinically valuable. Twenty patients with celiac disease were randomly assigned to ingest a large gluten meal (16 g daily for 3 days) pre-treated with ALV003, a mixture of highly specific glutenases (n=10), or pre-treated with placebo (n=10). Peripheral blood T-cell IFN-gamma ELISpot responses to gliadin and an immunogenic 33mer and symptoms were assessed. While baseline IFN-gamma ELISpot responses to gliadin and the 33mer were negative in all patients, a significant ELISpot response to gliadin or the 33mer was observed in 6 of 10 patients consuming placebo-treated gluten and 0 of 10 consuming ALV003 pre-treated gluten (p=0.011). Symptoms typically associated with gluten ingestion occurred in both groups and were not significantly reduced by ALV003 pre-treatment. ALV003 pre-treatment can abolish immune responses induced by gluten in patients with celiac disease.

Comparison of a once-a-day sustained-release morphine formulation with standard oral morphine treatment for cancer pain

Kadian/Kapanol (K) is a capsule formulation of morphine designed for 12- or 24-hourly dosing. This double-blind study compared the efficacy and safety of K every 24 hr to K every 12 hr and MS Contin tablets (MSC) every 12 hr. One hundred fifty-two patients with cancer pain were titrated to adequate analgesia with immediate-release morphine (IRM) solution. Stabilized patients were randonized to one of the three treatments for 7 +/- 1 days. Rescue medication was IRM tablets. Efficacy and safety were assessed by time to first remedication and total dose of rescue medication, pain scores, global assessments, and incidence of morphine-related side effects. Fifty-four patients were treated with K every 24 hr. 45 with K every 12 hr. and 53 with MSC every 12 hr. Mean age was 61 years and mean total daily dose of morphine was 138 mg. Forty-six percent of the K every 24 hr patients, 51% of the K every 12 hr patients, and 55% of the MSC every 12 hr patients required rescue medication on the final day. Time to remedication was 16.0 hr for K every 24 hr, 9.1 hr for K every 12 hr and 8.7 hr for MSC every 12 hr (P = 0.0010). Patient global assessment significantly favored K every 24 hr over MSC every 12 hr (P = 0.018). There were no statistically significant differences among the treatments for any morphine-related side effects when adjusted for baseline. K had efficacy and safety profiles similar to MSC every 12 hr but had the advantage of 12- or 24-hourly administration.

Changes in the renin-angiotensin system, exchangeable body sodium, and plasma and atrial content of atrial natriuretic factor during evolution of chronic renal failure in the rat

The remnant kidney model of progressive renal failure in the rat was used to assess the relationships between the renin-angiotensin system, exchangeable body sodium, and both plasma concentration and atrial content of atrial natriuretic factor (ANF) measured sequentially over 4 weeks. Following subtotal nephrectomy plasma creatinine (mumol/L) rose from 40 +/- 6 (sham) to 107 +/- 24 (P less than 0.05) at 1 week, and rose further to 124 +/- 20 (P less than 0.05) by 4 weeks. Plasma renin activity (nanograms of angiotensin I/mL/min) rose from 4.5 +/- 0.5 to 11.8 +/- 2.8 (P less than 0.05) at 1 week, but was suppressed by 4 weeks to 2.2 +/- 0.3 (P less than 0.001). Plasma angiotensin II (pg/mL) was 52 +/- 2 (sham), 117 +/- 20 at 1 week (P less than 0.05) and 51.3 at 4 weeks. Exchangeable sodium (mmol/kg) rose progressively from 43.2 +/- 5 (before surgery) to 48.6 +/- 0.9 at 1 week and 50.8 +/- 2.2 at 4 weeks. Plasma atrial natriuretic factor (ANF) (pg/mL) rose progressively from 114 +/- 6 (sham) to 248 +/- 31 (P less than 0.01) at 1 week and 456 +/- 78 at 4 weeks (P less than 0.01). Atrial ANF content fell as the plasma concentration rose. In the remnant kidney model of progressive renal failure there was a progressive increase in exchangeable body sodium and plasma atrial natriuretic factor, with reciprocal changes in atrial ANF content suggesting that ANF secretion rate was increased. Initially the renin-angiotensin system was stimulated, but later it was suppressed.

Angiotensin II levels, hemodynamics, and sympathoadrenal function after low-dose captopril in heart failure

The angiotensin converting enzyme inhibitor captopril improves the altered hemodynamics in many patients with chronic heart failure, but the first dose may precipitate hypotension. Ten patients with chronic heart failure were studied, nine with high plasma concentrations of renin and one with a low concentration. Frequent measurements of plasma concentrations of angiotensin II, renin, and catecholamines were made over 60 minutes after a small dose (6.25 mg) of captopril and related to concurrently measured hemodynamic variables. Captopril caused a decrease in systemic and pulmonary artery pressure and an increase in cardiac index, and these changes coincided with reductions in the plasma concentrations of angiotensin II and increases in plasma concentrations of renin. The hemodynamic changes were accompanied by reductions in the plasma concentrations of norepinephrine but transient increases in plasma concentrations of epinephrine in patients in whom vasomotor syncope developed. The patient with a low plasma renin concentration showed little hemodynamic response to the drug. It is concluded that vasomotor syncope occurs quite frequently in patients with severe chronic heart failure after captopril in a small dose and is associated with a selective increase in epinephrine secretion from the adrenal medulla.