Thermally-Induced Supersaturation Approach for Optimizing Drug Loading and Biopharmaceutical Properties of Supersaturated Lipid-Based Formulations: Case Studies with Ibrutinib and Enzalutamide.

Lipid-based formulations (LbFs) have demonstrated success in pharmaceutical applications; however, challenges persist in dissolving entire doses of the drug into defined liquid volumes. In this study, the temperature-induced supersaturation method was employed in LbF to address drug loading and pill burden issues. Supersaturated LbFs (super-LbF) were prepared using the temperature-induced supersaturation method, where the drug load is above its equilibrium solubility. Further, the influence of the drug's physicochemical and thermal characteristics on drug loading and their relevance with an apparent degree of supersaturation (aDS) was studied using two model drugs, ibrutinib and enzalutamide. All the prepared LbFs were evaluated in terms of physical stability, dispersion, and solubilization capacity, as well as pharmacokinetic assessments. Drug re-crystallization was observed in the lipid solution on long-term storage at higher aDS values of 2-2.5. Furthermore, high-throughput lipolysis studies demonstrated a significant decrease in drug concentration across all LbFs (regardless of drug loading) due to a decline in the formulation solvation capacity and subsequent generation of in-situ supersaturation. Further, the in vivo results demonstrated comparable pharmacokinetic parameters between conventional LbF and super-LbF. The short duration of the thermodynamic metastable state limits the potential absorption benefits. However, super-LbFs of Ibr and Enz showed superior profiles, with 1.7-fold and 5.2-fold increased drug exposure compared to their respective crystalline suspensions. In summary, this study emphasizes the potential of temperature-induced supersaturation in LbF for enhancing drug loading and highlights the intricate interplay between drug properties, formulation characteristics, and in vivo performance.

Acalabrutinib in treatment-naive chronic lymphocytic leukemia.

Acalabrutinib has demonstrated significant efficacy and safety in relapsed chronic lymphocytic leukemia (CLL). Efficacy and safety of acalabrutinib monotherapy were evaluated in a treatment-naive CLL cohort of a single-arm phase 1/2 trial (ACE-CL-001). Adults were eligible for enrollment if chemotherapy was declined or deemed inappropriate due to comorbidities (N = 99). Patients had a median age of 64 years and 47% had Rai stage III/IV disease. Acalabrutinib was administered orally 200 mg once daily, or 100 mg twice daily until progression or intolerance. A total of 99 patients were treated; 57 (62%) had unmutated immunoglobulin heavy-chain variable gene, and 12 (18%) had TP53 aberrations. After median follow-up of 53 months, 85 patients remain on treatment; 14 discontinued treatment, mostly because of adverse events (AEs) (n = 6) or disease progression (n = 3). Overall response rate was 97% (90% partial response; 7% complete response), with similar outcomes among all prognostic subgroups. Because of improved trough BTK occupancy with twice-daily dosing, all patients were transitioned to 100 mg twice daily. Median duration of response (DOR) was not reached; 48-month DOR rate was 97% (95% confidence interval, 90-99). Serious AEs were reported in 38 patients (38%). AEs required discontinuation in 6 patients (6%) because of second primary cancers (n = 4) and infection (n = 2). Grade ≥3 events of special interest included infection (15%), hypertension (11%), bleeding events (3%), and atrial fibrillation (2%). Durable efficacy and long-term safety of acalabrutinib in this trial support its use in clinical management of symptomatic, untreated patients with CLL.

Combination therapy with novel androgen receptor antagonists and statin for castration-resistant prostate cancer.

BACKGROUND: One of the growth mechanisms of castration-resistant prostate cancer (CRPC) is de novo androgen synthesis from intracellular cholesterol, and statins may be able to inhibit this mechanism. In addition, statins have been reported to suppress the expression of androgen receptors (ARs) in prostate cancer cell lines. In this study, we investigated a combination therapy of novel AR antagonists and statin, simvastatin, for CRPC. METHODS: LNCaP, 22Rv1, and PC-3 human prostate cancer cell lines were used. We developed androgen-independent LNCaP cells (LNCaP-LA). Microarray analysis was performed, followed by pathway analysis, and mRNA and protein expression was evaluated by quantitative real-time polymerase chain reaction and Western blot analysis, respectively. Cell viability was determined by MTS assay and cell counts. All evaluations were performed on cells treated with simvastatin and with or without AR antagonists (enzalutamide, apalutamide, and darolutamide). RESULTS: The combination of darolutamide and simvastatin most significantly suppressed proliferation in LNCaP-LA and 22Rv1 cells. In a 22Rv1-derived mouse xenograft model, the combination of darolutamide and simvastatin enhanced the inhibition of cell proliferation. In LNCaP-LA cells, the combination of darolutamide and simvastatin led to reduction in the mRNA expression of the androgen-stimulated genes, KLK2 and PSA; however, this reduction in expression did not occur in 22Rv1 cells. The microarray data and pathway analyses showed that the number of differentially expressed genes in the darolutamide and simvastatin-treated 22Rv1 cells was the highest in the pathway termed "role of cell cycle." Consequently, we focused our efforts on the cell cycle regulator polo-like kinase 1 (PLK1), cyclin-dependent kinase 2 (CDK2), and cell cycle division 25C (CDC25C). In 22Rv1 cells, the combination of darolutamide and simvastatin suppressed the mRNA and protein expression of these three genes. In addition, in PC-3 cells (which lack AR expression), the combination of simvastatin and darolutamide enhanced the suppression of cell proliferation and expression of these genes. CONCLUSIONS: Simvastatin alters the expression of many genes involved in the cell cycle in CRPC cells. Thus, the combination of novel AR antagonists (darolutamide) and simvastatin can potentially affect CRPC growth through both androgen-dependent and androgen-independent mechanisms.

Phase I clinical trial of HC-1119 soft capsule in Chinese healthy adult male subjects: Pharmacokinetics and safety of single-dose proportionality and effects of food.

BACKGROUND: Preclinical studies showed that HC-1119, a deuterated version of enzalutamide, could competitively inhibit androgen binding to androgen receptor by blocking the transmission of androgen receptor signaling pathway as enzalutamide, inducing apoptosis of prostate cancer cells and reducing the proliferation of prostate cancer cells. Animal pharmacokinetic studies also show that deuterization of enzalutamide as HC-1119 could retain the basic properties of mother drug, increases the stability of compounds to metabolic enzymes and the drug exposure in vivo, prolong the half-life and reduce the production of metabolites, which may lead to a better efficacy and safety of HC-1119 compared with enzalutamide. METHODS: To evaluate the pharmacokinetics and safety of HC-1119 and the effects of food on pharmacokinetics in healthy adult Chinese men after single-dose administration of HC-1119. A total of 47 Chinese healthy adult male subjects received HC-1119 soft capsule at a single oral dose of 40, 80, or 160 mg followed on fasting or 160 mg after high-fat meal respectively. HC-1119 prototype and its metabolites M1 and M2 in plasma were collected individually in a total 23 time points. Pharmacokinetics were determined by sensitive LC/MS/MS for dose-proportionality study. RESULTS: In subjects taking HC-1119 soft capsules on fasting, Cmax of HC-1119 prototype increased dose-dependently. Either Cmax and AUC0-∞ of M1 or Cmax of M2 showed statistically significant difference. Dose-proportionality evaluation showed linear pharmacokinetic characteristics in Cmax of HC-1119 prototype, Cmax and AUC0-∞ of M2 in dose range of 40-160 mg. Cmax of HC-1119 was significantly different between the two groups as 160 mg HC-1119 on fasting or after a high-fat diet respectively, while the other parameter were not. HC-1119 and its metabolites M1 and M2 showed a linear dynamic trend. CONCLUSIONS: HC-1119 is expected to have lower clinical dose than the similar drug enzalutamide. The absorption of HC-1119 and the main pharmacokinetic parameters of HC-1119 and its metabolites M1 and M2 were not affected by high-fat diet. The clinical application of HC-1119 soft capsule in the later stage can be recommended for both fasting and postprandial. The safety and tolerance were good in this population.

In vitro and clinical investigations to determine the drug-drug interaction potential of entrectinib, a small molecule inhibitor of neurotrophic tyrosine receptor kinase (NTRK).

Background Entrectinib is a CNS-active, potent inhibitor of tyrosine receptor kinases A/B/C, ROS1 and anaplastic lymphoma kinase approved for use in patients with solid tumors. We describe the in vitro and clinical studies investigating potential entrectinib drug-drug interactions. Methods In vitro studies with human biomaterials assessed the enzymes involved in entrectinib metabolism, and whether entrectinib modulates the activity of the major cytochrome P450 (CYP) enzymes or drug transporter P-glycoprotein. Clinical studies investigated the effect of a strong CYP3A4 inhibitor (itraconazole) and inducer (rifampin) on single-dose entrectinib pharmacokinetics. The effect of entrectinib on sensitive probe substrates for CYP3A4 (midazolam) and P-glycoprotein (digoxin) were also investigated. Results Entrectinib is primarily metabolized by CYP3A4. In vitro, entrectinib is a CYP3A4/5 inhibitor (IC50 2 µM) and a weak CYP3A4 inducer. Entrectinib inhibited P-glycoprotein (IC50 1.33 µM) but is a poor substrate. In healthy subjects, itraconazole increased entrectinib Cmax and AUC by 73% and 504%, respectively, and rifampin decreased entrectinib Cmax and AUC by 56% and 77%, respectively. Single dose entrectinib did not affect midazolam AUC, although Cmax decreased by 34%. Multiple dose entrectinib increased midazolam AUC by 50% and decreased Cmax by 21%. Single dose entrectinib increased digoxin AUC and Cmax by 18% and 28%, respectively, but did not affect digoxin renal clearance. Conclusions Entrectinib is a CYP3A4 substrate and is sensitive to the effects of coadministered moderate/strong CYP3A4 inhibitors and strong inducers, and requires dose adjustment. Entrectinib is a weak inhibitor of CYP3A4 and P-glycoprotein and no dose adjustments are required with CYP3A4/P- glycoprotein substrates.Registration Number (Study 2) NCT03330990 (first posted online November 6, 2017) As studies 1 and 3 are phase 1 trials in healthy subjects, they are not required to be registered.

Improved characterization of the pharmacokinetics of acalabrutinib and its pharmacologically active metabolite, ACP-5862, in patients with B-cell malignancies and in healthy subjects using a population pharmacokinetic approach.

This analysis aimed to describe the pharmacokinetics (PK) of acalabrutinib and its active metabolite, ACP-5862. A total of 8935 acalabrutinib samples from 712 subjects and 2394 ACP-5862 samples from 304 subjects from 12 clinical studies in patients with B-cell malignancies and healthy subjects were analysed by nonlinear mixed-effects modelling. Acalabrutinib PK was characterized by a 2-compartment model with first-order elimination. The large variability in absorption was adequately described by transit compartment chain and first-order absorption, with between-occasion variability on the mean transit time and relative bioavailability. The PK of ACP-5862 was characterized by a 2-compartment model with first-order elimination, and the formation rate was defined as the acalabrutinib clearance multiplied by the fraction metabolized. Health status, Eastern Cooperative Oncology Group performance status, and coadministration of proton-pump inhibitors were significant covariates. However, none of the investigated covariates led to clinically meaningful changes in exposure, supporting a flat dosing of acalabrutinib.

Exposure-response analysis of acalabrutinib and its active metabolite, ACP-5862, in patients with B-cell malignancies.

AIMS: Examine relationships between the systemic exposure of acalabrutinib, a highly selective, next-generation Bruton tyrosine kinase inhibitor, and its active metabolite (ACP-5862) vs. efficacy and safety responses in patients with B-cell malignancies who received acalabrutinib as monotherapy or in combination with obinutuzumab. METHODS: For exposure-efficacy analyses, patients with untreated chronic lymphocytic leukaemia were assessed for best overall response, progression-free survival and tumour regression. For exposure-safety analyses, incidences of grade ≥2 adverse events (AEs), grade ≥3 AEs and grade ≥2 events of clinical interest were assessed in patients with B-cell malignancies. Acalabrutinib and ACP-5862 pharmacokinetic (PK) parameter estimates were obtained from population PK modelling. Exposure calculations were based on study dosing regimens. Total active moieties were calculated to account for contributions of ACP-5862 to overall efficacy/safety. RESULTS: A total of 573 patients were included (exposure-efficacy analyses, n = 274; exposure-safety analyses, n = 573). Most patients (93%) received acalabrutinib 100 mg twice daily. Median total active area under the concentration-time curve (AUC24h,ss ) and total active maximal concentration at steady-state (Cmax,ss ) were similar for patients who received acalabrutinib as monotherapy or in combination with obinutuzumab, and for responders and nonresponders. No relationship was observed between AUC24h,ss /Cmax,ss and progression-free survival or tumour regression. Acalabrutinib AUC24h,ss and Cmax,ss were generally comparable across groups regardless of AE incidence. CONCLUSION: No clinically meaningful correlations between acalabrutinib PK exposure and efficacy and safety outcomes were observed. These data support the fixed acalabrutinib dose of 100 mg twice daily in the treatment of patients with B-cell malignancies.

Phase I clinical trial of HC-1119: A deuterated form of enzalutamide.

The purpose of our study was to investigate the safety, pharmacokinetics (PK), and initial antitumor efficacy of HC-1119 in patients with metastatic castration-resistant prostate cancer (mCRPC). Eligible mCRPC patients were included in our study (NCT03774056) with two parts. Part A was a dose escalation study in which patients received a dose escalation of HC-1119 (40, 80, 160 and 200 mg/day). Part B was a dose expansion study in which patients received HC-1119 at the dose of 80 and 160 mg. Safety assessment and pharmacokinetic samplings were performed for all patients at the given time points; preliminary tumor response was also assessed. Twenty-four patients were enrolled in part A and 19 patients in part B, respectively. HC-1119 was safe, well tolerated and no dose-limiting toxicity was observed. Fatigue was the most common treatment-related adverse event and no seizures were observed. At the dose levels of 40, 80 and 160 mg, the AUC and Cmax of HC-1119 in plasma increased almost dose-proportionally at the steady state in mCRPC patients. Maximum prostate-specific antigen (PSA) response rates (≥50% reduction from the baseline) in dose escalation and dose expansion cohorts were 77% and 75%, respectively; the overall disease control rate (22 patients available for imaging analysis) was 72.7%, with PR in 4 patients, SD in 12 patients and PD in 6 patients; the 2-year overall survival rate in patients from Part B was 56.8%. HC-1119 was safe, well tolerated and efficacious and HC-1119 at 80 mg/day is recommended for further studies.

Phase 1 study of tazemetostat in Japanese patients with relapsed or refractory B-cell lymphoma.

BACKGROUND: Tazemetostat is a selective and orally available inhibitor of enhancer of zeste homolog 2 (EZH2), a histone methyltransferase and epigenetic regulator of cellular differentiation programs. We carried out a phase I study of tazemetostat in Japanese patients with relapsed or refractory B-cell non-Hodgkin-type lymphoma (B-NHL) to evaluate its tolerability, safety, pharmacokinetics, and preliminary antitumor activity. METHODS: Tazemetostat was given orally at a single dose of 800 mg on the first day and 800 mg twice daily (BID: total 1600 mg/d) on following days in a 28-day/cycle manner. Tazemetostat dose-limiting toxicity (DLT) was evaluated up to the end of the first treatment cycle. Archival tumor tissues were analyzed for hotspot EZH2 mutations. RESULTS: As of 15 January 2018, seven patients (four follicular lymphoma [FL] and three diffuse large B-cell lymphoma [DLBCL]) were enrolled. The median age was 73 (range, 59-85) years, and the median number of prior chemotherapy regimens was three (range, one to five). No DLT was observed (one patient was not evaluable due to early disease progression). The common treatment-related adverse events (AEs) were thrombocytopenia and dysgeusia (three patients each; 42.9%). No treatment-related serious AEs were observed. The objective response rate was 57% (4/7 patients), including responses in three of four patients with FL and one of three patients with DLBCL. An EZH2 mutation was detected in one patient with FL responding to treatment. CONCLUSIONS: Tazemetostat at 800 mg BID showed an acceptable safety profile and promising antitumor activity in Japanese patients with relapsed or refractory B-NHL.

Safety and antitumor activity of acalabrutinib for relapsed/refractory B-cell malignancies: A Japanese phase I study.

This multicenter, open-label, phase I study assessed the safety and antitumor activity of acalabrutinib in Japanese patients with relapsed/refractory (r/r) B-cell malignancies. Parts 1 (dose confirmation) and 2 (dose expansion) of this three-part study are reported. Treatment was a single dose of 100 mg acalabrutinib (day 1), followed by a washout period and then twice daily 100 mg acalabrutinib in part 1, or twice daily 100 mg acalabrutinib in part 2. Patients from parts 1 and 2 with r/r chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), and r/r mantle cell lymphoma (MCL) were assessed as r/r CLL/SLL and r/r MCL cohorts, respectively. Twenty-five patients received treatment (part 1, n = 6). Median age was 71.0 years. Nine (one patient from part 1) and 13 (two patients from part 1) patients were included in the r/r CLL/SLL and r/r MCL cohorts, respectively. Treatment-related adverse events (AEs) occurred in 88% of patients (grade ≥3, 36%); the most common were headache (28%) and purpura (24%), both grade 1/2. No AEs resulted in treatment discontinuation or death. Median duration of treatment was 31, 20, and 7 months for part 1, r/r CLL/SLL cohort, and r/r MCL cohort, respectively. Overall response rate (ORR) was 89% and 62% for the r/r CLL/SLL and r/r MCL cohorts, respectively. The median progression-free survival (PFS) was not reached for the r/r CLL/SLL cohort and was 7 months for the r/r MCL cohort. Acalabrutinib (100 mg twice daily) was generally safe and well-tolerated in adult Japanese patients with B-cell malignancies.

Oral Tecovirimat for the Treatment of Smallpox.

BACKGROUND: Smallpox was declared eradicated in 1980, but variola virus (VARV), which causes smallpox, still exists. There is no known effective treatment for smallpox; therefore, tecovirimat is being developed as an oral smallpox therapy. Because clinical trials in a context of natural disease are not possible, an alternative developmental path to evaluate efficacy and safety was needed. METHODS: We investigated the efficacy of tecovirimat in nonhuman primate (monkeypox) and rabbit (rabbitpox) models in accordance with the Food and Drug Administration (FDA) Animal Efficacy Rule, which was interpreted for smallpox therapeutics by an expert advisory committee. We also conducted a placebo-controlled pharmacokinetic and safety trial involving 449 adult volunteers. RESULTS: The minimum dose of tecovirimat required in order to achieve more than 90% survival in the monkeypox model was 10 mg per kilogram of body weight for 14 days, and a dose of 40 mg per kilogram for 14 days was similarly efficacious in the rabbitpox model. Although the effective dose per kilogram was higher in rabbits, exposure was lower, with a mean steady-state maximum, minimum, and average (mean) concentration (Cmax, Cmin, and Cavg, respectively) of 374, 25, and 138 ng per milliliter, respectively, in rabbits and 1444, 169, and 598 ng per milliliter in nonhuman primates, as well as an area under the concentration-time curve over 24 hours (AUC0-24hr) of 3318 ng×hours per milliliter in rabbits and 14,352 ng×hours per milliliter in nonhuman primates. These findings suggested that the nonhuman primate was the more conservative model for the estimation of the required drug exposure in humans. A dose of 600 mg twice daily for 14 days was selected for testing in humans and provided exposures in excess of those in nonhuman primates (mean steady-state Cmax, Cmin, and Cavg of 2209, 690, and 1270 ng per milliliter and AUC0-24hr of 30,632 ng×hours per milliliter). No pattern of troubling adverse events was observed. CONCLUSIONS: On the basis of its efficacy in two animal models and pharmacokinetic and safety data in humans, tecovirimat is being advanced as a therapy for smallpox in accordance with the FDA Animal Rule. (Funded by the National Institutes of Health and the Biomedical Advanced Research and Development Authority; ClinicalTrials.gov number, NCT02474589 .).

Characterization of the pharmacokinetics of entrectinib and its active M5 metabolite in healthy volunteers and patients with solid tumors.

BACKGROUND: Entrectinib is an oral, CNS-active, potent inhibitor of tyrosine receptor kinases A/B/C, tyrosine kinase ROS proto-oncogene 1, and anaplastic lymphoma kinase approved for use in patients with solid tumors. We describe 3 clinical studies, including one investigating the single/multiple dose pharmacokinetics of entrectinib in patients and two studies in healthy volunteers investigating the absorption/distribution/metabolism/excretion (ADME) of entrectinib, its relative bioavailability, and effect of food on pharmacokinetics. METHODS: The patient study is open-label with dose-escalation and expansion phases. Volunteers received entrectinib (100-400 mg/m2, and 600-800 mg) once daily with food in continuous 28-day cycles. In the ADME study, volunteers received a single oral dose of [14C]entrectinib 600 mg. In the third study, volunteers received single doses of entrectinib 600 mg as the research and marketed formulations in the fasted state (Part 1), and the marketed formulation in the fed and fasted states (Part 2). Entrectinib and its major active metabolite M5 were assessed in all studies. RESULTS: Entrectinib was absorbed in a dose-dependent manner with maximum concentrations at ~4 h postdose and an elimination half-life of ~20 h. Entrectinib was cleared mainly through metabolism and both entrectinib and metabolites were eliminated mainly in feces (minimal renal excretion). At steady-state, the M5-to-entrectinib AUC ratio was 0.5 (with 600 mg entrectinib research formulation in patients). The research and marketed formulations were bioequivalent and food had no relevant effect on pharmacokinetics. CONCLUSIONS: Entrectinib is well absorbed, with linear PK that is suitable for once-daily dosing, and can be taken with or without food.

Comparison of the drug-drug interactions potential of ibrutinib and acalabrutinib via inhibition of UDP-glucuronosyltransferase.

Ibrutinib and acalabrutinib are two Bruton's tyrosine kinase (BTK) inhibitors which have gained Food and Drug Administration (FDA) approval for the treatment of various B cell malignancies. Herein, we investigated the effects of the two drugs on UDP-glucuronosyltransferase (UGT) activities to evaluate their potential risk for drug-drug interactions (DDIs) via UGT inhibition. Our data indicated that ibrutinib exerted broad inhibition on most of UGTs, including a potent competitive inhibition against UGT1A1 with a Ki value of 0.90 ± 0.03 µM, a noncompetitive inhibition against UGT1A3 and UGT1A7 with Ki values of 0.88 ± 0.03 µM and 2.52 ± 0.23 µM, respectively, while acalabrutinib only exhibited weak UGT inhibition towards all tested UGT isoforms. DDI risk prediction suggested that the inhibition against UGT1A1 and UGT1A3 by ibrutinib might bring a potential DDIs risk, while acalabrutinib was unlikely to trigger clinically significant UGT-mediated DDIs due to its weak effects. Our study raises an alarm bell about potential DDI risk associated with ibrutinib, however, the extrapolation from in vitro data to in vivo drug interactions should be taken with caution, and additional systemic study is needed.

Phase 1 trial of entinostat as monotherapy and combined with exemestane in Japanese patients with hormone receptor-positive advanced breast cancer.

BACKGROUND: Entinostat is an oral inhibitor of class I histone deacetylases intended for endocrine therapy-resistant patients with hormone receptor-positive (HR+) advanced or metastatic breast cancer (BC). We examined the safety, efficacy, and pharmacokinetics of entinostat monotherapy and combined entinostat/exemestane in Japanese patients. METHODS: This phase 1 study (3 + 3 dose-escalation design) enrolled postmenopausal women with advanced/metastatic HR+ BC previously treated with nonsteroidal aromatase inhibitors. Dose-limiting toxicities (DLTs) of entinostat monotherapy (3 mg/qw, 5 mg/qw, or 10 mg/q2w) and entinostat+exemestane (5 mg/qw + 25 mg/qd) were assessed. Pharmacokinetics, lysine acetylation (Ac-K), and T-cell activation markers were measured at multiple time points. RESULTS: Twelve patients were enrolled. No DLTs or grade 3-5 adverse events (AEs) occurred. Drug-related AEs (≥ 2 patients) during DLT observation were hypophosphatemia, nausea, and platelet count decreased. Six patients (50%) achieved stable disease (SD) for ≥ 6 months, including one treated for > 19 months. Median progression-free survival was 13.9 months (95% CI 1.9-not calculable); median overall survival was not reached. Area under the plasma concentration-time curve and Ac-K in peripheral blood CD19+ B cells increased dose-proportionally. The changing patterns of entinostat concentrations and Ac-K levels were well correlated. T-cell activation markers increased over time; CD69 increased more in patients with SD ≥ 6 months vs. SD < 6 months. CONCLUSIONS: Entinostat monotherapy and combined entinostat/exemestane were well tolerated in Japanese patients, with no additional safety concerns compared with previous reports. The correlation between pharmacokinetics and Ac-K in peripheral blood CD19+ B cells, and also T-cell activation markers, merits further investigation. TRIAL REGISTRATION: JAPIC Clinical Trial Information, JapicCTI-153066 . Registered 12 November 2015. ClinicalTrials.gov, NCT02623751 . Registered 8 December 2015.

A Signal Processing Approach to Pharmacokinetic Data Analysis.

The connection between pharmacokinetic models and system theory has been established for a long time. In this approach, the drug concentration is seen as the output of a system whose input is the drug administered at different times. In this article we further explore this connection. We show that system theory can be used to easily accommodate any therapeutic regime, no matter its complexity, allowing the identification of the pharmacokinetic parameters by means of a non-linear regression analysis. We illustrate how to exploit the properties of linear systems to identify non-linearities in the pharmacokinetic data. We also explore the use of bootstrapping as a way to compare populations of pharmacokinetic parameters and how to handle the common situation of using multiple hypothesis tests as a way to distinguish two different populations. Finally, we demonstrate how the bootstrap values can be used to estimate the distribution of derived parameters, as can be the allometric scale factors.

Apalutamide, darolutamide and enzalutamide in nonmetastatic castration-resistant prostate cancer: a meta-analysis.

Aim: Comparison of the efficacy/safety/health-related quality of life of apalutamide, enzalutamide and darolutamide in Phase III clinical trials involving patients with nonmetastatic castration-resistant prostate cancer was performed. Materials & methods: Relevant studies were identified by searching PubMed as well as conference abstracts reporting updated overall survival. Three pivotal trials were identified, SPARTAN (apalutamide), PROSPER (enzalutamide) and ARAMIS (darolutamide), and form the basis of this analysis. Results: All three drugs significantly prolonged metastasis-free survival, prostate-specific antigen response and overall survival versus placebo, and were generally well tolerated. Conclusion: Drug selection will likely be influenced by tolerability/safety and other factors, such as the propensity for drug-drug interactions and the presence of comorbidities, that affect the risk-benefit balance in individual patients.

Toxicokinetics of U-47700, tramadol, and their main metabolites in pigs following intravenous administration: is a multiple species allometric scaling approach useful for the extrapolation of toxicokinetic parameters to humans?

New synthetic opioids (NSOs) pose a public health concern since their emergence on the illicit drug market and are gaining increasing importance in forensic toxicology. Like many other new psychoactive substances, NSOs are consumed without any preclinical safety data or any knowledge on toxicokinetic (TK) data. Due to ethical reasons, controlled human TK studies cannot be performed for the assessment of these relevant data. As an alternative animal experimental approach, six pigs per drug received a single intravenous dose of 100 µg/kg body weight (BW) of U-47700 or 1000 µg/kg BW of tramadol to evaluate whether this species is suitable to assess the TK of NSOs. The drugs were determined in serum and whole blood using a fully validated method based on solid-phase extraction and LC-MS/MS. The concentration-time profiles and a population (pop) TK analysis revealed that a three-compartment model best described the TK data of both opioids. Central volumes of distribution were 0.94 L/kg for U-47700 and 1.25 L/kg for tramadol and central (metabolic) clearances were estimated at 1.57 L/h/kg and 1.85 L/h/kg for U-47700 and tramadol, respectively. The final popTK model parameters for pigs were upscaled via allometric scaling techniques. In comparison to published human data, concentration-time profiles for tramadol could successfully be predicted with single species allometric scaling. Furthermore, possible profiles for U-47700 in humans were simulated. The findings of this study indicate that unlike a multiple species scaling approach, pigs in conjunction with TK modeling are a suitable tool for the assessment of TK data of NSOs and the prediction of human TK data.

Simultaneous quantification and pharmacokinetic evaluation of roflumilast and its N-oxide in cynomolgus monkey plasma by LC-MS/MS method.

Roflumilast (ROF), a nonsteroidal anti-inflammatory drug, has successfully been used to treat systemic and pulmonary inflammation associated with chronic obstructive pulmonary disease. To evaluate its pharmacokinetics in monkeys, a sensitive, rapid and reliable liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of ROF and its N-oxide metabolite (RNO). The mobile phase contained 0.1% formic acid aqueous solution (A) and 0.1% formic acid acetonitrile solution (B). All monkey plasma samples were pretreated using protein precipitation with methanol-acetonitrile (50:50, v/v) in 50 µl plasma samples. Chromatographic separation was performed with mass spectral acquisition performed in positive electrospray ionization, utilizing multiple reaction monitoring. This method was successfully applied to a pharmacokinetic study in cynomolgus monkeys. Following administration of a single oral dose of 1 mg/kg ROF in monkeys, pharmacokinetic data for ROF and RNO was reported for the first time. After oral administration, ROF was rapidly absorbed and metabolized to its metabolite RNO. The mean area under the curve value of RNO was ~13 times larger than that of ROF, suggesting that most ROF was metabolized to RNO in cynomolgus monkeys.

The magic of small structure differences in a sodium-glucose cotransporter drug discovery project-14 C-labelled drug candidates in a key-differentiating study.

We describe the dramatic differences in the synthesis and physiological and pharmacokinetical profiling of two sodium-glucose cotransporter (SGLT) drug candidates AVE2268 and AVE8887 with very similar chemical structures. It is a classic example of how a radioactive study was able to spare resources in preclinical development prior to entering a costly clinical program. It also demonstrated that radioactive compounds can be used to study differences between two very similar compounds in vivo.

Serotonergic-Muscarinic Interaction within the Prefrontal Cortex as a Novel Target to Reverse Schizophrenia-Related Cognitive Symptoms.

Recent studies revealed that the activation of serotonergic 5-HT1A and muscarinic M1, M4, or M5 receptors prevent MK-801-induced cognitive impairments in animal models. In the present study, the effectiveness of the simultaneous activation of 5-HT1A and muscarinic receptors at preventing MK-801-induced cognitive deficits in novel object recognition (NOR) or Y-maze tests was investigated. Activators of 5-HT1A (F15599), M1 (VU0357017), M4 (VU0152100), or M5 (VU0238429) receptors administered at top doses for seven days reversed MK-801-induced deficits in the NOR test, similar to the simultaneous administration of subeffective doses of F15599 (0.05 mg/kg) with VU0357017 (0.15 mg/kg), VU0152100 (0.05 mg/kg), or VU0238429 (1 mg/kg). The compounds did not prevent the MK-801-induced impairment when administered acutely. Their activity was less evident in the Y-maze. Pharmacokinetic studies revealed high brain penetration of F15599 (brain/plasma ratio 620%), which was detected in the frontal cortex (FC) up to 2 h after administration. Decreases in the brain penetration properties of the compounds were observed after acute administration of the combinations, which might have influenced behavioral responses. This negative effect on brain penetration was not observed when the compounds were administered repeatedly. Based on our results, prolonged administration of a 5-HT1A activator with muscarinic receptor ligands may be effective at reversing cognitive decline related to schizophrenia, and the FC may play a critical role in this interaction.