Maxacalcitol Pharmacokinetic-Pharmacodynamic Modeling and Simulation for Secondary Hyperparathyroidism in Patients Receiving Maintenance Hemodialysis.

BACKGROUND: Maxacalcitol was approved in Taiwan in 2018 as the first active vitamin D3 injection for secondary hyperparathyroidism (SHPT) in patients on maintenance hemodialysis. However, no data from any clinical study with maxacalcitol in Taiwanese patients is available. OBJECTIVES: This analysis aimed to evaluate the profiles of parathyroid hormone (PTH) and calcium (Ca) concentrations in Taiwanese SHPT patients on hemodialysis and maxacalcitol. METHODS: We developed population pharmacokinetic (PK) and pharmacodynamic (PD) models using a modeling and simulation approach. The data for these analyses were obtained from two studies: a clinical pharmacology study in Japanese patients and an ethnic comparison study in healthy Japanese and -Taiwanese volunteers. We then conducted a simulation study with a PK-PD model comprising the PK and PD models developed here. RESULTS: Serum maxacalcitol concentration profile was modeled using a two-compartment model that took into consideration the distribution of concentrations below the lower limit of quantification. An ethnic difference in clearance was included in the PK model as a covariate. A PD model that used a PTH/Ca feedback loop best described the observed data. There were no significant differences in Ca or PTH concentrations between Taiwanese and Japanese based on the simulation results from our PK-PD model, even though maxacalcitol exposure was approximately 40% higher in Taiwanese than in Japanese. CONCLUSIONS: On the basis of these population PK and PD analyses and the clinical study conducted in Japan, there is no clinically relevant difference between Taiwanese and Japanese in terms of serum Ca or PTH levels.

Comparative pharmacokinetics of maxacalcitol in healthy Taiwanese and Japanese subjects.

Pharmacokinetic studies of maxacalcitol in healthy Taiwanese subjects have been conducted. This study to compare the pharmacokinetic properties of maxacalcitol in healthy Taiwanese and Japanese subjects. Healthy male Taiwanese subjects (n = 24) and healthy male Japanese subjects (n = 24) were enrolled in separate single-center and received a single intravenous dose of 1.25, 2.5 and 5 µg maxacalcitol. Male subjects were exclusively employed in the study due to the first administration of maxacalcitol to Taiwanese. Serum samples were collected for up to 72 h for pharmacokinetic analysis, and safety was assessed. Exposures to maxacalcitol as mean C5 and AUCinf appeared to increase with increase of doses in Taiwanese subjects (C5: 74.0, 159, and 321 pg/mL; AUCinf: 473, 763, and 1460 hï½¥pg/mL) and Japanese subjects (C5: 92.9, 174, and 346 pg/mL; AUCinf: 312, 588, and 1040 hï½¥pg/mL). After single bolus IV administration, linearity in maxacalcitol exposure was shown over the dose range of 1.25-5 µg in both Taiwanese and Japanese male healthy subjects. C5 of maxacalcitol was slightly lower (85%) in Taiwanese compared with that in Japanese and AUCinf of maxacalcitol in Taiwanese subjects was contrarily 15.0 (41.6%) higher than that in Japanese subjects, resulted in not much difference in pharmacokinetics of maxacalcitol between Taiwanese and Japanese. Moreover, maxacalcitol was well tolerated in both healthy Taiwanese and Japanese subjects.

Non-Compartmental Pharmacokinetics and Safety of Single-Dose Eldecalcitol (ED-71) in Healthy Chinese Adult Males.

BACKGROUND AND OBJECTIVES: Eldecalcitol (ED-71) is a novel active vitamin D3 derivative, used for the treatment of osteoporosis. This is the first clinical study to investigate the pharmacokinetics and safety of eldecalcitol in Chinese subjects. METHODS: This was an open, single-center, randomized, two-dose level, two-period crossover phase I study in 24 healthy Chinese adult males. Eligible subjects received a single oral dose of eldecalcitol capsule 0.5 or 0.75 µg at period 1 or period 2, monitored over a 144-h observation period for pharmacokinetics and a 14-day observation period for safety. The wash-out time was 14 days. The data observed in this study were compared with historical data in Japanese subjects to evaluate the inter-ethnic differences in pharmacokinetics. RESULTS: After single doses of 0.5 and 0.75 µg eldecalcitol, the maximum serum concentration (Cmax) of eldecalcitol was reached within 3.0-4.0 h (Cmax was 0.0638 ± 0.0076 ng/ml in the 0.5-µg group and 0.0944 ± 0.0126 ng/ml in the 0.75-µg group, area under the concentration-time curve from 0 to 24 h (AUC(0-24h)) was 1.02 ± 0.15 ng·h/mL in the 0.5-µg group and 1.57 ± 0.26 ng·h/mL in the 0.75-µg group). The pharmacokinetic parameters was similar between the Chinese and Japanese subjects; both Cmax and partial AUCs could be considered to be dose-proportional over the tested dose range of 0.5-0.75 µg in Chinese subjects, which was in line with previously published results on eldecalcitol linear pharmacokinetics (range 0.1-1.0 µg) in Japanese subjects. Alanine aminotransferase increase was the most common adverse event (AE). No drug-related serious AEs were reported. All of the drug-related AEs of eldecalcitol were mild in severity. CONCLUSION: Pharmacokinetic exposure (Cmax and partial AUCs) was dose-proportional over the tested dose range of 0.5-0.75 µg in healthy Chinese adult males. The pharmacokinetic character of eldecalcitol in Chinese subjects was similar to historical data from Japanese subjects. Eldecalcitol was well tolerated at doses ranging from 0.5 to 0.75 µg, with no new safety signals identified. CLINICAL TRIAL REGISTRATION: This study was registered at the China Food and Drug Administration (Registration number: 2014L02212 and 2014L02213), and also registered at http://www.chinadrugtrials.org.cn (No. CTR20160430).

Phase II study of TP300 in patients with advanced gastric or gastro-oesophageal junction adenocarcinoma.

BACKGROUND: TP300, a recently developed synthetic camptothecin analogue, is a highly selective topoisomerase I inhibitor. A phase I study showed good safety and tolerability. As camptothecins have proven active in oesophago-gastric adenocarcinomas, in this phase II study we assessed the efficacy and safety of TP300 in patients with gastric or gastro-oesophageal junction (GOJ) adenocarcinomas. METHODS: Eligible patients had metastatic or locally advanced gastric or Siewert Types II or III GOJ inoperable adenocarcinoma. Patients were chemotherapy naïve unless this had been administered in the perioperative setting. TP300 was administered as a 1-h intravenous infusion every 3 weeks (a cycle) for up to 6 cycles at a starting dose of 8 mg/m2 with intra-patient escalation to 10 mg/m2 from cycle 2 in the absence of dose-limiting toxicity. Tumour responses (RECIST 1.1) were assessed every 6 weeks. Toxicity was recorded by NCI-CTCAE version 3.0. Using a modified two-stage Simon design (Stage I and II), a total of 43 patients were to be included providing there were 3 of 18 patients with objective response in Stage I of the study. RESULTS: In Stage I of the study 20 patients (14 males, 6 females), median age 67 years (range 40 - 82), performance status ECOG 0/1, with GC [14] or GOJ carcinoma [6] were enrolled. Of the 16 evaluable patients, 11 received the planned dose increase to 10 mg/m2 at cycle 2, 2 decreased to 6 mg/m2, and 3 continued on 8 mg/m2. There were no objective responses after 2 cycles of treatment. Twelve patients had stable disease for 1 - 5 months and 4 had progressive disease. Median progression free survival (PFS) was 4.1 months (CI [1.6 - 4.9]), median time to progression (TTP) was 2.9 months (CI [1.4 - 4.2]). Grade 3/4 toxicities (worst grade all cycles) included 7 patients (35 %) with neutropenia, 4 patients (20 %) with anaemia, 2 patients (10 %) with thrombocytopenia, and 3 patients (15 %) with fatigue. This study was terminated at the end of Stage I due to a lack of the required (3/18) responders. CONCLUSIONS: This study of TP300 showed good drug tolerability but it failed to demonstrate sufficient efficacy as measured by radiological response. TRIAL REGISTRATION: EU-CTR 2009-012097-12 2009-09-03.

Phase I study of the anti-MET antibody onartuzumab in patients with solid tumors and MET-positive lung cancer.

Onartuzumab is a monovalent, humanized, monoclonal antibody that showed significant survival benefits in combination with erlotinib in MET-positive non-small-cell lung cancer (NSCLC) in pre-specified subgroup analyses of a randomized phase II study. We conducted a two-stage, open-label, multicenter, phase I study of onartuzumab in Japanese patients. Stage 1 investigated the safety, tolerability, pharmacokinetics (PK), and recommended dose of onartuzumab in patients with solid tumors, and Stage 2 determined the safety, tolerability, and PK of onartuzumab plus erlotinib in patients with MET-positive NSCLC. Nine patients received onartuzumab monotherapy (4, 15, or 30 mg/kg on Day 1 of each 21-day cycle) in Stage 1, and six patients received onartuzumab (15 mg/kg) plus erlotinib (150 mg/day) in Stage 2. There were no dose-limiting toxicities in either stage. Serious adverse events (AEs) occurred in one patient in Stage 1 (convulsion), and two patients in Stage 2 (once case each of diarrhea, vomiting, and pulmonary embolism), but there were no grade 4 AEs or AEs leading to death. Onartuzumab PKs were linear in the dose range of 4 to 30 mg/kg, and were not affected by co-administration with erlotinib. PK parameters of onartuzumab were similar to those reported in non-Japanese patients. A partial response was observed in a patient with MET immunohistochemistry 3+ NSCLC without MET gene amplification. Based on these results, the recommended dose of onartuzumab in Japanese patients with solid tumors is 15 mg/kg every 21 days. The combination of onartuzumab with erlotinib is feasible in Japanese patients with MET-positive lung cancer.

Combining onartuzumab with erlotinib inhibits growth of non-small cell lung cancer with activating EGFR mutations and HGF overexpression.

Erlotinib, a tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR-TKI), benefits survival of patients with non-small cell lung cancer (NSCLC) who harbor activating EGFR mutations. However, elevated expression of hepatocyte growth factor (HGF), a ligand of the MET receptor tyrosine kinase, causes erlotinib resistance. Because onartuzumab, a monovalent antibody to MET, blocks HGF-induced MET activation, the addition of onartuzumab to erlotinib may improve therapeutic efficacy. We engineered the human NSCLC cell line PC-9 (MET-positive cells harboring an exon 19 deletion of EGFR) to overexpress hHGF and evaluated the effects of an onartuzumab and erlotinib combination in vitro and in vivo in xenograft models. A stable clone of PC-9/hHGF was less sensitive to erlotinib than the parental PC-9, and the addition of onartuzumab to erlotinib suppressed the proliferation of these cells in vitro. In PC-9/hHGF xenograft tumors, onartuzumab or erlotinib alone minimally inhibited tumor growth; however, combining onartuzumab and erlotinib markedly suppressed tumor growth. The total MET protein level was decreased in PC-9/hHGF cells, because MET is constitutively phosphorylated by autocrine HGF, leading to its ubiquitination and degradation. Onartuzumab reduced phospho-MET levels, inhibited MET ubiquitination, and consequently restored MET protein levels. Moreover, in NSCLC clinical specimens harboring activating EGFR mutations, more than 30% of patients expressed high levels of HGF. Our findings raised the possibility that patients with NSCLC with EGFR mutations who express high levels of HGF may benefit from onartuzumab and erlotinib combination therapy, and that HGF can be a novel biomarker for selecting such patients.

Population pharmacokinetic-pharmacodynamic modelling and simulation of neutropenia induced by TP300, a novel topoisomerase I inhibitor.

OBJECTIVES: TP300 is a novel topoisomerase I inhibitor with neutropenia as a significant toxicity. We developed and evaluated a pharmacokinetic-pharmacodynamic (PK-PD) model, using data from Phase I and II trials to predict neutrophil decrease in patients treated with TP300. METHODS: Plasma drug concentrations of TP300, its active form TP3076 and active metabolite TP3011 and absolute neutrophil counts (ANCs) from a Phase I trial were analysed as a training dataset. A two-plus-two-compartment model was applied to the pharmacokinetics of TP3076 and TP3011. A semi-mechanistic model was used to describe the PK-PD relationship between the plasma concentration of TP3076 and TP3011, and changes in ANC. KEY FINDINGS: The model fitted well to plasma concentrations of TP3076 and TP3011. Model appropriateness was confirmed in a Phase II trial validation dataset. Body weight and liver biochemistry values were identified as covariates. A semi-mechanistic PK-PD model was applied and the longitudinal decrease in ANC was simulated. Neutrophil counts reached their nadir approximately 2 weeks after administration of TP300, and the proportion of subjects affected increased with dose. CONCLUSIONS: This PK-PD model to predict neutropenia following treatment with TP300 fitted well the decrease in ANC with total concentration of TP3076 and TP3011.

Phase I study of TP300 in patients with advanced solid tumors with pharmacokinetic, pharmacogenetic and pharmacodynamic analyses.

BACKGROUND: A Phase I dose escalation first in man study assessed maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and recommended Phase II dose of TP300, a water soluble prodrug of the Topo-1 inhibitor TP3076, and active metabolite, TP3011. METHODS: Eligible patients with refractory advanced solid tumors, adequate performance status, haematologic, renal, and hepatic function. TP300 was given as a 1-hour i.v. infusion 3-weekly and pharmacokinetic (PK) profiles of TP300, TP3076 and TP3011 were analysed. Polymorphisms in CYP2D6, AOX1 and UGT1A1 were studied and DNA strand-breaks measured in peripheral blood mononuclear cells (PBMCs). RESULTS: 32 patients received TP300 at 1, 2, 4, 6, 8, 10, 12 mg/m(2). MTD was 10 mg/m(2); DLTs at 12 (2/4 patients) and 10 mg/m(2) (3/12) included thrombocytopenia and febrile neutropenia; diarrhoea was uncommon. Six patients (five had received irinotecan), had stable disease for 1.5-5 months. TP3076 showed dose proportionality in AUC and Cmax from 1-10 mg/m(2). Genetic polymorphisms had no apparent influence on exposure. DNA strand-breaks were detected after TP300 infusion. CONCLUSIONS: TP300 had predictable hematologic toxicity, and diarrhoea was uncommon. AUC at MTD is substantially greater than for SN38. TP3076 and TP3011 are equi-potent with SN38, suggesting a PK advantage. TRIAL REGISTRATION: EU-CTR2006-001345-33.

Absence of adverse effects of oseltamivir on sleep: a double-blind, randomized study in healthy volunteers in Japan.

Influenza-associated neuropsychiatric symptoms include parasomnias such as sleepwalking which is a common sleep disturbance in childhood. Oseltamivir is a widely used antiviral drug for influenza. Recently, sleepwalking-like events have been reported in patients with influenza receiving oseltamivir. We investigated whether oseltamivir itself has effects on sleep. In this crossover study, healthy Japanese male volunteers were randomized into two treatment groups, each of which comprised two double-blind 4-day treatment periods. In the first period, group A received 75 mg oseltamivir (evening dose) on day 3, followed by 75 mg b.i.d. on day 4, and placebo in the second period. Group B received the same treatments, but in reverse order. Polysomnographic assessments were performed on all four nights of each treatment period. Pharmacokinetics were assessed during a 2-day open-label phase beginning on day 12. Thirty-one volunteers aged 20-24 years were enrolled. No volunteer had electroencephalographic abnormalities, and no abnormal behaviour was observed. Sleep parameters measured over the whole night and during early- and late sleep periods (first and last thirds of the night) were very similar for oseltamivir and placebo, although the amount of stage 2 sleep in the middle sleep period was slightly greater with oseltamivir. Pharmacokinetics for oseltamivir phosphate in groups A and B were very similar, but for oseltamivir carboxylate, AUC and C(max) values were higher in group B, probably because this group received oseltamivir on the evening of day 11. Oseltamivir was well tolerated. Oseltamivir did not produce clinically relevant changes on nocturnal polysomnographic variables in young Japanese men.

Pharmacokinetics of oseltamivir in young and very elderly subjects.

BACKGROUND: Pharmacokinetic studies of oseltamivir in very elderly patients (> or = 80 y) have not previously been performed. OBJECTIVE: To compare the pharmacokinetics of oseltamivir and the active carboxylate metabolite in healthy young and very elderly Japanese subjects. METHODS: Young (20-35 y, fasting, n = 7) and very elderly subjects (> or = 80 y, fed, n = 5) were enrolled in single-center studies and received a single oral dose of oseltamivir 75 mg. Plasma and urine samples were collected (24 h) for pharmacokinetic analysis, and safety was assessed. RESULTS: The time to maximum plasma concentration (tmax) for oseltamivir was delayed in the very elderly compared with the young subjects (2.30 vs 0.71 h, respectively). Furthermore, oseltamivir maximum plasma concentration (Cmax) and AUC(inf) were 52% and 80% higher, respectively, in the very elderly compared with the young subjects. Oral clearance was 45% lower in elderly patients, possibly due to the effects of administration of oseltamivir with a meal. For the active metabolite, oseltamivir carboxylate, Cmax and AUC(inf) values were, respectively, 22% and 91% higher in the very elderly subjects than in the young subjects, while oral clearance was 50% lower in the elderly population. The increased exposure of the active metabolite is likely to correlate with an age-related decline in renal function. For both oseltamivir and the active metabolite, there was large interpatient variability in the Cmax values. The data reported here indicate that oseltamivir would be effective in both of these populations, as trough concentrations for the active metabolite at 12 and 24 hours exceeded the 50% inhibitory concentration against the neuraminidase of influenza A and B isolates by more than 50-fold. Oseltamivir was well tolerated in both groups. CONCLUSIONS: Exposures (AUC(inf)) to both the parent drug and active metabolite were increased by more than 80% in the small number of very elderly subjects presented here. However, oseltamivir was well tolerated by these subjects.