Dose Selection For Phase Research Articles

Model-based meta-analysis of HbA1c reduction across SGLT2 inhibitors using dose adjusted by urinary glucose excretion

This study was aimed to evaluate whether the dose–response relationship of the sodium glucose co-transporter-2 inhibitors (SGLT2is) in patients with type 2 diabetes mellitus (T2DM)—canagliflozin, dapagliflozin, empagliflozin, ipragliflozin, luseogliflozin, and tofogliflozin—can be explained in a unified manner based on their ability to promote urinary glucose excretion (UGE). Information on HbA1c reduction at various doses of each SGLT2i was collected from literatures on randomized controlled trials and was normalized based on the daily UGE data from phase I studies. After normalizing doses, the dose–response relationship of HbA1c reduction of most of SGLT2is was represented by a unified nonlinear mixed-effect model, with the estimated maximum HbA1c (%) reduction (Emax) of 0.796 points, whereas covariate analysis showed that canagliflozin had a 1.33-fold higher Emax than those of the other drugs. Other covariates included baseline HbA1c levels, body weight, disease duration, prior treatment, and renal function. Findings from this study would influence drug selection and adjustment in clinical practice. As with SGLT2is, in cases where the efficacy cannot be easily evaluated but an appropriate pharmacodynamic marker was assessed in early clinical trials, similar approaches for other drug classes can guide strategic and evidence-based dose selection in phase III trials.

Population pharmacokinetics of eptinezumab in paediatric patients with migraine and dose selection for phase 3 paediatric migraine studies.

This population pharmacokinetics (PopPK) analysis of eptinezumab used data from a paediatric study and a prior adult PopPK model to compare eptinezumab pharmacokinetics between adult and paediatric populations to determine dose recommendations for the phase 3 paediatric studies in migraine. The data consisted of 16 adolescents and 12 children with migraine, with corresponding demographics and 278 plasma concentrations in total. PopPK analysis was performed through nonlinear mixed effect modelling and with prior knowledge taken from a previous PopPK model in adults. A two-compartment model-adjusted for body weight impact on clearances and volumes of distributions and scaled to the power of 0.75 and 1.0, respectively-was found to adequately describe the paediatric pharmacokinetic data. The simulated population showed overlap in area under the plasma concentration-time curve and maximum plasma concentration between the paediatric and adult populations, with paediatric exposures within 10%-15% above adult levels on average. To provide comparable exposure to the approved adult doses, weight-based dosing adjustments are recommended for paediatric patients weighing ≤40 kg, while no adjustments are needed for patients weighing >40 kg. These results support the dosing strategy being used in the ongoing efficacy and safety studies with eptinezumab in children and adolescents with migraine.

Dose selection in phase I trials: a review of development programs from approved drugs to investigate intrinsic and extrinsic factors on pharmacokinetics and safety.

Dose selection in phase I trials: a review of development programs from approved drugs to investigate intrinsic and extrinsic factors on pharmacokinetics and safety.

Pharmacokinetic-Pharmacometabolomic Approach in Early-Phase Clinical Trials: A Way Forward for Targeted Therapy in Type 2 Diabetes.

Pharmacometabolomics in early phase clinical trials demonstrate the metabolic profiles of a subject responding to a drug treatment in a controlled environment, whereas pharmacokinetics measure the drug plasma concentration in human circulation. Application of the personalized peak plasma concentration from pharmacokinetics in pharmacometabolomic studies provides insights into drugs’ pharmacological effects through dysregulation of metabolic pathways or pharmacodynamic biomarkers. This proof-of-concept study integrates personalized pharmacokinetic and pharmacometabolomic approaches to determine the predictive pharmacodynamic response of human metabolic pathways for type 2 diabetes. In this study, we use metformin as a model drug. Metformin is a first-line glucose-lowering agent; however, the variation of metabolites that potentially affect the efficacy and safety profile remains inconclusive. Seventeen healthy subjects were given a single dose of 1000 mg of metformin under fasting conditions. Fifteen sampling time-points were collected and analyzed using the validated bioanalytical LCMS method for metformin quantification in plasma. The individualized peak-concentration plasma samples determined from the pharmacokinetic parameters calculated using Matlab Simbiology were further analyzed with pre-dose plasma samples using an untargeted metabolomic approach. Pharmacometabolomic data processing and statistical analysis were performed using MetaboAnalyst with a functional meta-analysis peaks-to-pathway approach to identify dysregulated human metabolic pathways. The validated metformin calibration ranged from 80.4 to 2010 ng/mL for accuracy, precision, stability and others. The median and IQR for Cmax was 1248 (849–1391) ng/mL; AUC0-infinity was 9510 (7314–10,411) ng·h/mL, and Tmax was 2.5 (2.5–3.0) h. The individualized Cmax pharmacokinetics guided the untargeted pharmacometabolomics of metformin, suggesting a series of provisional predictive human metabolic pathways, which include arginine and proline metabolism, branched-chain amino acid (BCAA) metabolism, glutathione metabolism and others that are associated with metformin’s pharmacological effects of increasing insulin sensitivity and lipid metabolism. Integration of pharmacokinetic and pharmacometabolomic approaches in early-phase clinical trials may pave a pathway for developing targeted therapy. This could further reduce variability in a controlled trial environment and aid in identifying surrogates for drug response pathways, increasing the prediction of responders for dose selection in phase II clinical trials.

Abstract 10571: Phase 1 Single-Dose Study to Evaluate Apixaban in Pediatric Subjects at Risk for Venous or Arterial Thrombotic Disorder

Introduction: Standard-of-care antithrombotics in pediatric subjects (peds) include unfractionated/LMW heparin, aspirin, and vitamin K antagonists. Apixaban, a direct factor Xa (FXa) inhibitor indicated for VTE treatment (tx) and prevention in adults, may be an effective and convenient oral tx option with an acceptable safety profile in peds. Objectives: To evaluate pharmacokinetics (PK), pharmacodynamics (PD), safety, and tolerability of apixaban in peds at risk for venous or arterial thrombotic disorder; to support dose selection for apixaban pediatric program trials. Methods: This phase 1 study (NCT01707394) enrolled peds aged < 18 years (y) at risk for venous/arterial thrombotic disorder into groups by age. Peds undergoing tx/procedures or with conditions that may affect bleeding risk or apixaban exposure were excluded. A single apixaban dose (based on BSA; targeted to achieve adult exposures with apixaban 2.5 mg) was administered: 0.1 mg sprinkle capsule for age < 28 days (d); 0.4 mg/mL solution for ages 28 d to < 18 y (dose range: 1.08-2.19 mg/m 2 ). Endpoints included PK, safety, tolerability, and PD (anti-FXa activity). For PK/PD, 4-6 blood samples were collected ≤ 26 h after dosing. A population PK (PPK) model developed with data from adults and peds was used to evaluate PK. Apparent oral clearance (CL/F) included a fixed maturation function based on published data. Results: From Jan 2013 to Jun 2019, 49 peds aged 9 d to 16 y received an apixaban dose. All AEs (n = 15) resolved; most were mild/moderate; none were bleeding-related. SAEs (1 seizure; 1 limb venous thrombosis) were not tx-related. Apixaban CL/F and apparent central volume of distribution increased less than proportionally with body weight. Apixaban CL/F increased with age, reaching adult values in ages 12 to < 18 y. Maturation affected CL/F most notably in ages < 9 months. Plasma anti-FXa activity values were linearly related to apixaban concentrations with no apparent age-related differences, comparable to adults. Conclusions: Single apixaban doses were generally safe and well tolerated in peds. Study data and PPK model supported dose selection for phase 2/3 multiple-dose pediatric trials.

SAT-094 Evaluation of IGF-1 as a Biomarker to Inform Phase 3 Clinical Trial Design and Dose Selection in Patients Born Small for Gestational Age Who Fail to Demonstrate Catch-Up Growth by Age 2–4 Years

Insulin-like growth factor-1 (IGF-1) is a key hormone in mediating the physiological response to endogenous and exogenous growth hormone (GH). Current clinical guidelines suggest use of IGF-1 for dose titration in adults with GH deficiency and for safety monitoring in adults and pediatric patients. Several GH drug development programs for pediatric indications have collected IGF-1, height standard deviation score (HSDS), and height velocity (HV), to support dose selection in Phase 3 clinical trials. In this analysis, patients born small for gestational age (SGA) who fail to demonstrate catch-up growth by age 2–4 years from different growth hormone product development programs were included. A total of 663 patients from 8 clinical trials were included in this analysis, with 7 placebo arms and 15 growth hormone treated arms. The growth hormone dosing regimen ranged from 33 ug/kg/day to 100 ug/kg/day. Both boys and girls throughout a wide range of ages (3 to 7 years old on average) were represented in this analysis. The average patient was 3 to 4 standard deviations below the age- and sex- adjusted mean height at baseline. IGF-1 was collected and standardized according to age and sex, so called the IGF-1 standard deviation score (IGF-1 SDS). At baseline, the average patient had normal IGF-1 (-1 to 0 on average). Based on preliminary findings, IGF-1 SDS change from baseline (CFB) at 6 months was correlated with HSDS CFB at 12 months. HSDS CFB at 3 months and 6 months were also correlated with HSDS CFB at 12 months, respectively. These findings were consistent across the three GH products included in the analysis, as well as age and gender. However, IGF-1 SDS CFB had much larger variability than HSDS CFB. Both HSDS CFB at 3 months and 6 months precisely and accurately predicted HSDS CFB at 12 months. IGF-1 SDS was more variable and did not add any further contribution in the prediction of HSDS at 12 months and therefore IGF-1 may not be sufficient in informing Phase 3 dose selection in such trials. Reference: 1. Shoshana Yakar, Clifford J. Rosen, Wesley G. Beamer, et al. Circulating levels of IGF-1 directly regulate bone growth and density. J Clin Invest. 2002 Sep 15; 110(6): 771–781. 2. Locatelli V, Bianchi VE. Effect of GH/IGF-1 on Bone Metabolism and Osteoporosis. Int J Endocrinol. 2014;2014:235060 Nothing to Disclose: TL, JP, BC, MZ, JV, CS

CONJUNCTIVAL PROVOCATION TESTING IN A DOSE FINDING STUDY WITH SUBCUTANEOUS IMMUNOTHERAPY WITH GRASS + MPL

Introduction The total symptom score (TSS) measured during conjunctival provocation testing (CPT) was used as primary endpoint of a Phase II study to evaluate the dose response for a subcutaneous immunotherapy (SCIT) product (1.0 ml) with modified allergen tyrosine adsorbate (MATA) and monophosphoryl lipid A (MPL) adjuvants developed for treatment of allergic rhinoconjunctivitis due to grass pollen [EudraCT 2017-000333-31]. Doses of 5100, 14400, 27600 and 35600 standardized units (SU) and placebo were evaluated. Methods CPTs were performed at screening, pre-dose and approximately 4 weeks post-treatment. TSS was calculated as the sum of 4 symptoms (eye redness, tearing, itching and irritation), each scored on a 4-point scale. Concentrations of 0.3, 1.0, 3.0, 10 and 30 Histamine Equivalent Potency units (HEP)/mL were available for testing. A TSS ≥ 6 points was required at screening and pre-dose. Results The blinded results showed a mean TSS of 7.5 (95% CI: 7.3-7.6) and 4.4 points (95% CI: 4.2-4.7) at pre-dose and post-treatment, respectively. For 251 patients of the 426 patients (58.9%) a positive post-treatment CPT was achieved at least one higher concentration of allergen compared to pre-dose. Conclusions In this Phase II study, CPT was used to establish a dose response of a grass MATA MPL SCIT product using a wide range of cumulative dose regimens. The blinded results indicate adequate CPT performance which may well support the selection of the optimal dose for Phase III, which would be an important milestone in the development of an efficacious and safe pre-seasonal state-of-the-art grass SCIT.

Strategies for clinical development of monoclonal antibodies beyond first-in-human trials: tested doses and rationale for dose selection

Background:Our previous survey on first-in-human trials (FIHT) of monoclonal antibodies (mAbs) showed that, due to their limited toxicity, the recommended phase II dose (RP2D) was only tentatively defined.Methods:We identified, by MEDLINE search, articles on single-agent trials of mAbs with an FIHT included in our previous survey. For each mAb, we examined tested dose(s) and dose selection rationale in non-FIHTs (NFIHTs). We also assessed the correlation between doses tested in the registration trials (RTs) of all FDA-approved mAbs and the corresponding FIHT results.Results:In the 37 dose-escalation NFIHTs, the RP2D indication was still poorly defined. In phase II–III NFIHTs (n=103 on 37 mAbs), the FIHT RP2D was the only dose tested for five mAbs. For 16 mAbs, only doses different from the FIHT RP2D or the maximum administered dose (MAD) were tested and the dose selection rationale infrequently indicated. In the 60 RTs on 27 FDA-approved mAbs with available FIHT, the FIHT RP2D was tested only for two mAbs, and RT doses were much lower than the FIHT MAD.Conclusions:The rationale beyond dose selection in phase II and III trials of mAbs is often unclear in published articles and not based on FIHT data.

Advanced Methods for Dose and Regimen Finding During Drug Development: Summary of the EMA/EFPIA Workshop on Dose Finding (London 4-5 December 2014).

Inadequate dose selection for confirmatory trials is currently still one of the most challenging issues in drug development, as illustrated by high rates of late‐stage attritions in clinical development and postmarketing commitments required by regulatory institutions. In an effort to shift the current paradigm in dose and regimen selection and highlight the availability and usefulness of well‐established and regulatory‐acceptable methods, the European Medicines Agency (EMA) in collaboration with the European Federation of Pharmaceutical Industries Association (EFPIA) hosted a multistakeholder workshop on dose finding (London 4–5 December 2014). Some methodologies that could constitute a toolkit for drug developers and regulators were presented. These methods are described in the present report: they include five advanced methods for data analysis (empirical regression models, pharmacometrics models, quantitative systems pharmacology models, MCP‐Mod, and model averaging) and three methods for study design optimization (Fisher information matrix (FIM)‐based methods, clinical trial simulations, and adaptive studies). Pairwise comparisons were also discussed during the workshop; however, mostly for historical reasons. This paper discusses the added value and limitations of these methods as well as challenges for their implementation. Some applications in different therapeutic areas are also summarized, in line with the discussions at the workshop. There was agreement at the workshop on the fact that selection of dose for phase III is an estimation problem and should not be addressed via hypothesis testing. Dose selection for phase III trials should be informed by well‐designed dose‐finding studies; however, the specific choice of method(s) will depend on several aspects and it is not possible to recommend a generalized decision tree. There are many valuable methods available, the methods are not mutually exclusive, and they should be used in conjunction to ensure a scientifically rigorous understanding of the dosing rationale.

Pharmacometric Modeling of Naloxegol Efficacy and Safety: Impact on Dose and Label.

Naloxegol is a peripherally acting μ-opioid receptor antagonist that was developed for the treatment of opioid-induced constipation. Modeling and simulation of naloxegol efficacy and tolerability informed selection of doses for phase III studies and provided comprehensive dosage recommendations for the naloxegol US package insert.

Performance of toxicity probability interval based designs in contrast to the continual reassessment method

Toxicity probability interval designs have received increasing attention as a dose-finding method in recent years. In this study, we compared the two-stage, likelihood-based continual reassessment method (CRM), modified toxicity probability interval (mTPI), and the Bayesian optimal interval design (BOIN) in order to evaluate each method's performance in dose selection for phase I trials. We use several summary measures to compare the performance of these methods, including percentage of correct selection (PCS) of the true maximum tolerable dose (MTD), allocation of patients to doses at and around the true MTD, and an accuracy index. This index is an efficiency measure that describes the entire distribution of MTD selection and patient allocation by taking into account the distance between the true probability of toxicity at each dose level and the target toxicity rate. The simulation study considered a broad range of toxicity curves and various sample sizes. When considering PCS, we found that CRM outperformed the two competing methods in most scenarios, followed by BOIN, then mTPI. We observed a similar trend when considering the accuracy index for dose allocation, where CRM most often outperformed both mTPI and BOIN. These trends were more pronounced with increasing number of dose levels. Copyright © 2016 John Wiley & Sons, Ltd.

Cabotegravir long-acting for HIV-1 prevention

Preexposure prophylaxis (PrEP) with daily Truvada has demonstrated clinical efficacy against HIV-1 acquisition that correlates with high adherence. Long-acting antiretroviral drugs offer an alternative to daily regimens and may improve PrEP adherence. This review summarizes the preclinical nonhuman primate studies for evaluating the efficacy of cabotegravir long-acting as PrEP and the ongoing phase 2a studies assessing safety, tolerability, and acceptability of cabotegravir long-acting. Cabotegravir is an HIV-1 integrase strand transfer inhibitor with intrinsic properties that permit its formulation as a long-acting injectable suspension. In clinical evaluation, cabotegravir long-acting has a half-life that permits infrequent dosing, possibly once every 3 months. In validated macaque models, cabotegravir long-acting demonstrated high protection against both rectal and vaginal transmission at clinically achievable drug concentrations. PrEP, after approval of Truvada, continues to evolve to address adherence limitations of daily dosing. As a long-acting injectable antiretroviral drug, cabotegravir long-acting permits quarterly dosing and demonstrated high efficacy in macaque models supporting dose selection and clinical development. Clinical studies have confirmed dose selection in phase 2a trials with cabotegravir long-acting to ultimately lead to phase 2b/3 PrEP efficacy trials.

Safety, tolerability, and pharmacokinetics of pregabalin in children with refractory partial seizures: A phase 1, randomized controlled study

To evaluate the safety, tolerability, and pharmacokinetics (PK) of pregabalin as adjunctive therapy in children with refractory partial seizures. This was a phase 1, randomized, placebo-controlled, parallel-group, escalating-dose, multiple-dose study comprising a 7-day, double-blind treatment period and a single-blind, single dose of pregabalin administered to all children on day 8. Children in four age cohorts (1-23 months, 2-6, 7-11, and 12-16 years) received one of four doses of pregabalin (2.5, 5, 10, or 15 mg/kg/day) or placebo. Safety and tolerability were assessed throughout the study. Steady-state and single-dose PK parameters on day 8 were analyzed using standard noncompartmental procedures. Sixty-five children received at least one dose of treatment. Four pregabalin-treated children discontinued treatment, three of whom received 15 mg/kg/day. Two children experienced serious adverse events, one of whom received pregabalin 15 mg/kg/day. During double-blind treatment, the most common adverse events reported in the pregabalin-treated population were somnolence (27.1%) and dizziness (12.5%). Steady-state pregabalin peak and total exposure in each age cohort appeared to increase linearly with dose. Apparent oral clearance (CL/F) was directly related to creatinine clearance, consistent with adults. CL/F normalized for body weight was 43% higher in patients weighing <30 kg. Steady-state and single-dose PK were consistent. Pregabalin at doses up to 10 mg/kg/day in children aged 1 month to 16 years, and at doses up to 15 mg/kg/day in those aged <6 years, demonstrated acceptable safety and tolerability. For children weighing <30 kg, a dose increase of 40% (mg/kg dosing) is required to achieve comparable exposure with adults or children weighing ≥30 kg. These data will inform dose selection in phase 3 trials of the efficacy and safety of adjunctive pregabalin in children with refractory partial seizures.

Pharmacometric Approaches to Guide Dose Selection of the Novel GPR40 Agonist TAK‐875 in Subjects With Type 2 Diabetes Mellitus

The G-protein-coupled receptor 40 agonist (GPR40) TAK-875 is being developed as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus. Pharmacometric approaches such as model-based exposure-response and meta-analyses were applied to (i) characterize exposure/dose–efficacy responses of TAK-875, (ii) characterize the time course of glycosylated hemoglobin A1c (HbA1c) response with TAK-875 6.25 to 200 mg q.d. doses for 12 weeks, (iii) project and compare HbA1c response with dipeptidyl peptidase 4 (DPP-4) inhibitors and TAK-875 up to 24 weeks, and (iv) provide a quantitative rationale for dose selection in phase 3. On the basis of phase 2 data, relationships between TAK-875 concentrations and HbA1c were well characterized by exposure–response models. EC50 and Emax of TAK-875 were estimated to be 3.16 µg/ml and 0.366, respectively. Model-based simulations over 24 weeks indicated that the 25- and 50-mg q.d. doses of TAK-875 achieve efficacy as comparable with or better than that of commonly used antidiabetic agents.

Sequential research-related biopsies in phase I trials: acceptance, feasibility and safety

Sequential tumour biopsies are of potential interest for the rational development of molecular targeted therapies. From June 2004 to July 2009, 186 patients participated in 14 phase I clinical trials in which sequential tumour biopsies (13 trials) and/or sequential normal skin biopsies (6 trials) were optional. All patients had to sign an independent informed consent for the biopsies. Tumour biopsies were proposed to 155 patients and 130 (84%) signed the consent while normal skin biopsies were proposed to 70 patients and 57 (81%) signed the consent. Tumour biopsies could not be carried out in 41 (31%) of the 130 consenting patients. Tumour biopsies were collected at baseline in 33 patients, at baseline and under treatment in 56 patients. Tumour biopsies were obtained using an 18-gauge needle, under ultrasound or computed tomography guidance. Only nine minor complications were recorded. Most tumour biopsy samples collected were intended for ancillary molecular studies including protein or gene expression analysis, comparative genomic hybridization array or DNA sequencing. According to the results available, 70% of the biopsy samples met the quality criteria of each study and were suitable for ancillary studies. In our experience, the majority of the patients accepted skin biopsies as well as tumour biopsies. Sequential tumour and skin biopsies are feasible and safe during early-phase clinical trials, even when patients are exposed to anti-angiogenic agents. The real scientific value of such biopsies for dose selection in phase I trials has yet to be established.

Bayesian Optimal Adaptive Designs for Delayed-Response Dose-Finding Studies

Bayesian adaptive design has been broadly recognized as a method of improving the efficiency of determining dose-response relationships in clinical trials, thus leading to reliable dose selection for phase III clinical trials. However, in some disease areas such as diabetes and obesity, patients may need to be studied for several weeks or months for a drug effect to emerge. These delayed-response studies provide challenges for using traditional adaptive design methods. Many current methods for analyzing the data at the time of the interim analysis only use the last observation from patients who have completed the study. Data for those patients who have not completed the study are often ignored or imputed via last observation carried forward (LOCF) or other imputation method. Therefore, data collected at intermediate timepoints are not fully used for decision making. These approaches are useful for studies where the final responses can be quickly observed. However, in delayed-response studies, where longitudinal data are normally collected for each patient, using all available information instead of just endpoint values is critical to improving efficiency. Fu and Manner (2010) proposed an integrated two-component prediction (ITP) model for delayed-response adaptive design. In this paper, we extend their ITP model to incorporate a dose-response model in it and propose an ITP Emax model. Furthermore, we derive a method to find the minimum effective dose (MED) for our newly proposed model by using an optimal design theorem. By using the proposed method, a better understanding of the dose-response relationship and the MED was achieved more efficiently. Potential sample size reduction is also discussed in this paper.

Latrepirdine increases cerebral glucose utilization in aged mice as measured by [18F]-fluorodeoxyglucose positron emission tomography

Latrepirdine is hypothesized to exert a unique mechanism of action involving stabilization of mitochondria that may have utility in treating Alzheimer's disease. However, the ability of latrepirdine to improve cognition in Alzheimer's disease (AD) is controversial due to a discrepancy between the positive signal reported in the multi-site phase II clinical trial where latrepirdine met all primary and secondary endpoints [Doody et al. (2008) Lancet 372:207-215], and the subsequent null effect observed in a multicenter, phase III trial. While dysfunction of mitochondria and abnormal energy metabolism has been linked to AD pathology, no studies have been reported that investigate latrepirdine's effect on cerebral glucose utilization (CGU). Glucose metabolism, following acute latrepirdine administration, can be used to help dose selection in Phase I dose-ranging studies. The aim of the current study was to assess changes in CGU in young and aged mice in vivo using [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) after acute treatment with latrepirdine. Two ages of B6SJLF2 mice (5 and 20 months old) were tested. Three test-retest FDG-PET baseline scans were assessed across all subjects. As CGU was heterogeneous in aged mice, compared to young mice, aged subjects were rank ordered and then counterbalanced into two CGU homogenous groups. In Studies 1 and 2, latrepirdine (1.0 mg/kg) significantly enhanced CGU in aged mice. In contrast, Study 3 revealed that latrepirdine did not modulate CGU in young mice. Monitoring changes in CGU in response to acute drug administration may represent an imaging biomarker for dose selection in AD. Further studies that would establish the translation from mice to non-human primates to humans need to be investigated to confirm the utility of FDG-PET in dose-selection for mitochondrial modulators.

Effect of apixaban, an oral and direct factor Xa inhibitor, on coagulation activity biomarkers following acute coronary syndrome

Apixaban is an oral, direct factor Xa inhibitor under development for secondary prevention in acute coronary syndrome (ACS). Apixaban's effect on D-dimer and prothrombin fragment 1.2 (F1.2) (coagulation activity biomarkers ) was determined in a randomised, double-blinded, placebo-controlled, phase 2 study. Patients (n=1,715) with either ST- segment elevation or non-ST-segment elevation ACS received either placebo or apixaban 2.5 mg twice daily, 10 mg once daily, 10 mg twice daily or 20 mg once daily for six months. Samples were obtained at baseline (before study drug administration), week 3 and week 26. Apixaban plasma concentrations were measured directly by liquid chromatography/mass spectometry, and anti-Xa activity was determined using apixaban as a reference standard. D-dimer and F 1.2 were measured using ELISA-based methods. Most patients had elevated D-dimer and F1.2 levels at baseline. Both coagulation activity biomarkers decreased by week 3 in all treatment groups, but to a greater degree with apixaban than placebo (p<0.001). In a multivariable analysis, apixaban was independently associated with a change in biomarkers over time (p<0.0001). While the overall decrease did not differ significantly among the three highest apixaban doses, F1.2 was suppressed more rapidly by the 10 mg once daily than the 2.5 mg twice daily dose (p<0.05). There was a strong and direct relationship between apixaban plasma concentrations and anti-Xa-apixaban levels, and an inverse relationship for both measures with coagulation activity biomarkers. In conclusion, the oral direct factor Xa inhibitor apixaban significantly reduced coagulation activity biomarkers among patients with ACS. The 10 mg once daily dose reduced thrombin generation (F 1.2) and fibrin formation (D-dimer) more rapidly and robustly than the 2.5 mg twice daily dose. The effect on both D-dimer and F 1.2 was apixaban concentration-and factor Xa inhibition dependent, durable and provided general guidance for dose selection in phase 3 investigation.

Dose Selection in Phase I Studies: Why We Should Always Go for the Most Effective

Dose Selection in Phase I Studies: Why We Should Always Go for the Most Effective

Dose Selection in Phase I Studies: Why We Should Always Go for the Top

Dose Selection in Phase I Studies: Why We Should Always Go for the Top