Physiologically based absorption modeling to predict the bioequivalence of two apixaban formulations.

The equivalence of absorption rates and extents between generic drugs and their reference formulations is crucial for ensuring therapeutic comparability. Bioequivalence (BE) studies are widely utilized and play a pivotal role in substantiating the approval and promotional efforts for generic drugs. Virtual BE simulation is a valuable tool for mitigating risks and guiding clinical BE studies, thereby minimizing redundant in vivo BE assessments. Herein, we successfully developed a physiologically based absorption model for virtual BE simulations, which precisely predicts the BE of the apixaban test and reference formulations. The modeling results confirm that the test and reference formulations were bioequivalent under both fasted and fed conditions, consistent with clinical studies. This highlights the efficacy of physiologically based absorption modeling as a powerful tool for formulation screening and can be adopted as a methodological and risk assessment strategy to detect potential clinical BE risks.

In Vitro In Vivo Extrapolation and Bioequivalence Prediction for Immediate-Release Capsules of Cefadroxil Based on a Physiologically-Based Pharmacokinetic ACAT Model.

Physiologically based pharmacokinetic (PBPK) modeling is a mechanistic concept, which helps to judge the effects of biopharmceutical properties of drug product such as in vitro dissolution on its pharmacokinetic and in vivo performance. With the application of virtual bioequivalence (VBE) study, the drug product development using model-based approach can help in evaluating the possibility of extending BCS-based biowaiver. Therefore, the current study was intended to develop PBPK model as well as in vitro in vivo extrapolation (IVIVE) for BCS class III drug i.e. cefadroxil. A PBPK model was created in GastroPlus™ 9.8.3 utilizing clinical data of immediate-release cefadroxil formulations. By the examination of simulated and observed plasma drug concentration profiles, the predictability of the proposed model was assessed for the prediction errors. Furthermore, mechanistic deconvolution was used to create IVIVE, and the plasma drug concentration profiles and pharmacokinetic parameters were predicted for different virtual formulations with variable cefadroxil in vitro release. Virtual bioequivalence study was also executed to assess the bioequivalence of the generic verses the reference drug product (Duricef®). The developed PBPK model satisfactorily predicted Cmax and AUC0-t after cefadroxil single and multiple oral dose administrations, with all individual prediction errors within the limits except in a few cases. Second order polynomial correlation function obtained accurately predict in vivo drug release and plasma concentration profile of cefadroxil test and reference (Duricef®) formulation. The VBE study also proved test formulation bioequivalent to reference formulation and the statistical analysis on pharmacokinetic parameters reported 90% confidence interval for Cmax and AUC0-t in the FDA acceptable limits. The analysis found that a validated and verified PBPK model with a mechanistic background is as a suitable approach to accelerate generic drug development.

Bioequivalence Study of Ezetimibe Tablets After a Single Oral Dose of 10 mg in Healthy Japanese Subjects Under Fasting Conditions.

This study compared the pharmacokinetic and safety profiles between a new generic and a branded reference product of 10-mg ezetimibe (EZE) tablets in 24 healthy Japanese male volunteers under fasting conditions, obtaining sufficient evidence for the marketing approval of the new generic product. The bioequivalence study was conducted with an open-label, 2 × 2, single-dose, crossover design in which the test and reference products were administered to volunteers after fasting for ≥10 hours. Blood samples were collected 24 times before to 72 hours after the administration of the investigational drug. We evaluated the peak drug concentration and the area under the plasma concentration-time curve up to the last measured concentration of EZE, EZEG, and total EZE (EZE + ezetimibe glucuronide [EZEG]). The 90% confidence intervals of the geometric mean ratios for peak drug concentration and area under the plasma concentration-time curve up to the last measured concentration of the test and reference products fell within the bioequivalence limits of 0.80 to 1.25 for EZE, EZEG, and total EZE. The test and reference products were well tolerated, and no adverse events occurred during the study. The test product was bioequivalent to the reference product.

Flux-Based Formulation Development-A Proof of Concept Study.

The work aimed to develop the Absorption Driven Drug Formulation (ADDF) concept, which is a new approach in formulation development to ensure that the drug product meets the expected absorption rate. The concept is built on the solubility-permeability interplay and the rate of supersaturation as the driving force of absorption. This paper presents the first case study using the ADDF concept where not only dissolution and solubility but also permeation of the drug is considered in every step of the formulation development. For that reason, parallel artificial membrane permeability assay (PAMPA) was used for excipient selection, small volume dissolution-permeation apparatus was used for testing amorphous solid dispersions (ASDs), and large volume dissolution-permeation tests were carried out to characterize the final dosage forms. The API-excipient interaction studies on PAMPA indicated differences when different fillers or surfactants were studied. These differences were then confirmed with small volume dissolution-permeation assays where the addition of Tween 80 to the ASDs decreased the flux dramatically. Also, the early indication of sorbitol's advantage over mannitol by PAMPA has been confirmed in the investigation of the final dosage forms by large-scale dissolution-permeation tests. This difference between the fillers was observed in vivo as well. The presented case study demonstrated that the ADDF concept opens a new perspective in generic formulation development using fast and cost-effective flux-based screening methods in order to meet the bioequivalence criteria. Graphical Abstract.

Requirements for Additional Strength Biowaivers for Modified Release Solid Oral Dosage Forms in International Pharmaceutical Regulators Programme Participating Regulators and Organisations: Differences and Commonalities.

This article describes an overview of waivers of in vivo bioequivalence studies for additional strengths in the context of the registration of modified release generic products and is a follow-up to the recent publication for the immediate release solid oral dosage forms. The current paper is based on a survey among the participating members of the Bioequivalence Working Group for Generics (BEWGG) of the International Pharmaceutical Regulators Program (IPRP) regarding this topic. Most jurisdictions consider the extrapolation of bioequivalence results obtained with one (most sensitive) strength of a product series as less straightforward for modified release products than for immediate release products. There is consensus that modified release products should demonstrate bioequivalence not only in the fasted state but also in the fed state, but differences exist regarding the necessity of additional multiple dose studies. Fundamental differences between jurisdictions are revealed regarding requirements on the quantitative composition of different strengths and the differentiation of single and multiple unit dosage forms. Differences in terms of in vitro dissolution requirements are obvious, though these are mostly related to possible additional comparative investigations rather than regarding the need for product-specific methods. As with the requirements for immediate release products, harmonization of the various regulations for modified release products is highly desirable to conduct the appropriate studies from a scientific point of view, thus ensuring therapeutic equivalence.

Anti-hypertensive medication access and affordability and their association with blood pressure control at a teaching hospital in Ghana.

INTRODUCTION: many hypertensive patients require two or more anti-hypertensive drugs, but in low- and middle-income countries there may be challenges with medication access or affordability. The objective of this study was to determine accessibility and affordability of anti-hypertensive medicines and their association with blood pressure (BP) control among hypertensive patients attending the Korle-Bu teaching hospital (KBTH) polyclinic. METHODS: a cross-sectional study was conducted among 310 systematically sampled hypertensive patients attending the KBTH Polyclinic in Ghana. A structured questionnaire was used to obtain data on patient demographics and clinical characteristics, prices, availability and mode of payment of generic anti-hypertensive medicines. RESULTS: fifty-nine patients (19.4%) made out-of-pocket payments. At the private pharmacy and hospital, 123 (40.5%) and 77 patients (25.3%) respectively could not afford four anti-hypertensive medicines. Medicines availability at KBTH was 60%. Continuous access to BP drugs at KBTH was 14.8%. Overall access was 74.9% (SD ± 41.3). Out-of-pocket affordability of the medicines was positively correlated with BP control (R=0.12, p=0.037). Obtaining medicines via health insurance only was more likely to result in BP control than making any out-of-pocket payments (OR= 2.185; 95% CI, 1.215 - 3.927). Access at KBTH was more likely to result in BP control (OR=1.642; 95% C.I, 0.843 - 3.201). CONCLUSION: there were access challenges although most patients obtained BP medication free. Out-of-pocket affordability is a challenge for some hypertensive patients. Access to affordable BP medication can improve BP control. These findings provide an impetus for urgently evaluating access to affordable anti-hypertensive medicines in other hospitals in Ghana.

Cost-effectiveness analysis of branded and authorized generic celecoxib for patients with chronic pain in Japan.

OBJECTIVES: The aim of this study was to examine the cost-effectiveness of branded and authorized generic (AG) celecoxib for chronic pain patients with osteoarthritis (OA), rheumatoid arthritis (RA), and low back pain (LBP), using real-world cost information for loxoprofen and pharmacotherapy for gastrointestinal bleeding. METHODS: This cost-effectiveness analysis was performed as a long-term simulation using the Markov model from the Japanese public healthcare payer's perspective. The analysis was conducted using loxoprofen with real-world weighted price by branded/generic distribution (hereinafter, loxoprofen with weighted price) as a comparator. In the model, we simulated the prognosis of patients with chronic pain by OA, RA, and LBP treated with loxoprofen or celecoxib, over a lifetime period. RESULTS: A cost-increase of 129,688 JPY (1,245.00 USD) for branded celecoxib and a cost-reduction of 6,268 JPY (60.17 USD) for AG celecoxib were recognized per patient in lifetime horizon, compared to loxoprofen with weighted price. No case was recognized to reverse the results of cost-saving by AG celecoxib in one-way sensitivity analysis. The incremental cost-effectiveness ratio of branded celecoxib attained 5,403,667 JPY/QALY (51,875.20 USD/QALY), compared to loxoprofen with the weighted price. CONCLUSION: The current cost-effectiveness analysis for AG celecoxib revealed its good value for costs, considering the patients' future risk of gastrointestinal injury; also, the impact on costs due to AG celecoxib against loxoprofen will be small. It implies that the disadvantage of AG celecoxib being slightly more expensive than generic loxoprofen could be offset by the good cost-effectiveness during the prognosis.

Application of the 3Rs principles in the development of pharmaceutical generics.

Although the 3Rs are broadly applied in nonclinical testing, a better appreciation of the 3Rs is needed in the field of differentiated or value-added pharmaceutical generics because the minor changes in formulation, dosage form, indication, and application route often do not require additional safety testing. The US FDA and the EU EMA have comprehensive regulations for such drugs based on quality, therapeutic equivalence, and safety guidelines. However, no scientific publications on how the concept of replacement and reduction from 3Rs principles can be applied in the safety assessment of differentiated generics were found in the public domain. In this review, we discuss the application of 3Rs in nonclinical testing requirements for differentiated generics. Practical examples are provided in the form of case studies from regulated markets. We highlight the need for utilization of existing data to establish equivalence (differentiated generic vs innovator) in efficacy and safety. The case studies indicate that data requirements from animal experiments have been reduced to a large extent in some major markets without compromising quality and safety. In this context, we also highlight the problem that on a global scale, a true reduction of animal experiments will only be achieved when all countries adopt similar practices.

Understanding authorized generics-A review of the published clinical data.

WHAT IS KNOWN AND OBJECTIVES: Despite the large body of evidence demonstrating equivalent efficacy and safety for branded drugs and their generic counterparts, some patients and providers have the perception that generics may be less safe and effective than branded agents. Authorized generics (AGs) are a category of generic drugs defined by the United States Food and Drug Administration (FDA) as being the same as the brand-name drug without the brand's name on the label and which may have minor differences, such as tablet or capsule markings for identification. Studies in which AGs are considered along with other generics may increase our understanding of factors that may influence perceptions about generics and shed light on areas where education may be impactful. The objectives of this paper are to provide information about AGs, review studies in which they have been evaluated and explore the role that AGs may fill in the individualized treatment of patients. METHODS: A literature review was conducted on 30 September 2019 with follow-up search on 4 March 2020. The search was focussed on published papers and meeting abstracts that provided information on AGs with respect to medical and health outcomes of therapy as well as switching in individuals receiving branded, AG, or other generic agents. Information about patients' perceptions of generic medications and adherence to therapy was also included. Additional information, including relevant government sources, such as the FDA website and the Federal Trade Commission Report, was included as appropriate. RESULTS: The literature specific to AGs is limited, but available data clearly highlight the importance of patient perception of generics as well as medication appearance as factors that may affect adherence and potentially more frequent switchbacks to branded agents from generics or AGs. WHAT IS NEW AND CONCLUSION: To our knowledge, this is the first narrative review to provide a summary of the published evidence about AGs with respect to clinical and health outcomes and switching. There is a need for more research and education regarding the use of AGs in clinical practice if they are to become more recognized as a potential treatment choice for patients. Generic medications play an important role in the healthcare system, and AGs may be able to provide an option to meet the specific needs of individual patients.

Development of a Pediatric Relative Bioavailability/Bioequivalence Database and Identification of Putative Risk Factors Associated With Evaluation of Pediatric Oral Products.

Generally, bioequivalence (BE) studies of drug products for pediatric patients are conducted in adults due to ethical reasons. Given the lack of direct BE assessment in pediatric populations, the aim of this work is to develop a database of BE and relative bioavailability (relative BA) studies conducted in pediatric populations and to enable the identification of risk factors associated with certain drug substances or products that may lead to failed BE or different pharmacokinetic (PK) parameters in relative BA studies in pediatrics. A literature search from 1965 to 2020 was conducted in PubMed, Cochrane Library, and Google Scholar to identify BE studies conducted in pediatric populations and relative BA studies conducted in pediatric populations. Overall, 79 studies covering 37 active pharmaceutical ingredients (APIs) were included in the database: 4 bioequivalence studies with data that passed BE evaluations; 2 studies showed bioinequivalence results; 34 relative BA studies showing comparable PK parameters, and 39 relative BA studies showing differences in PK parameters between test and reference products. Based on the above studies, common putative risk factors associated with differences in relative bioavailability (DRBA) in pediatric populations include age-related absorption effects, high inter-individual variability, and poor study design. A database containing 79 clinical studies on BE or relative BA in pediatrics has been developed. Putative risk factors associated with DRBA in pediatric populations are summarized.

Bioequivalence of a Generic Nateglinide Formulation in Healthy Chinese Volunteers under Fasting and Fed Conditions: A Randomized, Open-Label, Double-Cycle, Double-Crossover Study.

INTRODUCTION: Nateglinide or N-(trans-4-isopropylcyclohexyl-1-carbonyl)-D-phenylalanine is a drug with a rapid hypoglycemic effect that is mainly used in the treatment of type 2 diabetes. Very few studies have assessed bioequivalence based on feeding status. This study aimed to assess the pharmacokinetic bioequivalence and safety of nateglinide-containing tablets (0.12 g) in healthy Chinese volunteers under fasting and fed conditions. METHODS: The studies were performed in 2017-2018 in the Phase I Clinical Trial Ward of the Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, China. Eligible Chinese volunteers received a single 0.12-g dose of the test or reference formulation, followed by a 7-day washout period and administration of the alternate formulation. Blood samples were collected at various time intervals, and plasma nateglinide concentrations were analyzed by liquid chromatography-tandem mass spectrometry. Then, the adverse events, laboratory test results, vital signs, and physical exam findings were compared between the 2 groups. RESULTS: The ratios of the geometric means of Cmax, AUC0-t, and AUC0-inf of the tested to reference preparations under fasting conditions were 105.03% (90% confidence interval [CI]: 99.53-110.83%), 104.02% (90% CI: 101.37-106.74%), and 104.04% (90% CI: 101.38-106.77%), respectively. The same ratios under fed conditions were 96.55% (90% CI: 85.80-108.65%), 103.08% (90% CI: 100.07-106.18%), and 103.07% (90% CI: 100.21-106.01%), respectively. The 90% CI values for Cmax, AUC0-t, and AUC0-inf fell within the accepted range of bioequivalence (80.00-125.0%). Common adverse events included hypoglycemia, heart rate increase, palpitation, sweating, dizziness, and diarrhea. CONCLUSIONS: The test formulation (0.12 g) met the CFDA's regulatory definition for bioequivalence to the reference formulation. Both formulations were well tolerated by healthy Chinese subjects. TRIAL REGISTRATION: This trial has been registered in the Chinese Clinical trial registry (ChiCTR2000030694), March 10, 2020.

Can Pharmacokinetic Studies Assess the Pulmonary Fate of Dry Powder Inhaler Formulations of Fluticasone Propionate?

In the context of streamlining generic approval, this study assessed whether pharmacokinetics (PK) could elucidate the pulmonary fate of orally inhaled drug products (OIDPs). Three fluticasone propionate (FP) dry powder inhaler (DPI) formulations (A-4.5, B-3.8, and C-3.7), differing only in type and composition of lactose fines, exhibited median mass aerodynamic diameter (MMAD) of 4.5 µm (A-4.5), 3.8 µm (B-3.8), and 3.7 µm (C-3.7) and varied in dissolution rates (A-4.5 slower than B-3.8 and C-3.7). In vitro total lung dose (TLDin vitro) was determined as the average dose passing through three anatomical mouth-throat (MT) models and yielded dose normalization factors (DNF) for each DPI formulation X (DNFx = TLDin vitro,x/TLDin vitro,A-4.5). The DNF was 1.00 for A-4.5, 1.32 for B-3.8, and 1.21 for C-3.7. Systemic PK after inhalation of 500 µg FP was assessed in a randomized, double-blind, four-way crossover study in 24 healthy volunteers. Peak concentrations (Cmax) of A-4.5 relative to those of B-3.8 or C-3.7 lacked bioequivalence without or with dose normalization. The area under the curve (AUC0-Inf) was bio-IN-equivalent before dose normalization and bioequivalent after dose normalization. Thus, PK could detect differences in pulmonary available dose (AUC0-Inf) and residence time (dose-normalized Cmax). The differences in dose-normalized Cmax could not be explained by differences in in vitro dissolution. This might suggest that Cmax differences may indicate differences in regional lung deposition. Overall this study supports the use of PK studies to provide relevant information on the pulmonary performance characteristics (i.e., available dose, residence time, and regional lung deposition).

A Survey of the Regulatory Requirements for the Waiver of In Vivo Bioequivalence Studies of Generic Products in Certain Dosage Forms by Participating Regulators and Organisations of the International Pharmaceutical Regulators Programme.

The requirements to waive in vivo bioequivalence studies for immediate release solid oral dosage forms based on the Biopharmaceutics Classifications System (BCS) are well known, and biowaivers[1] for other types of oral dosage forms based on pre-defined criteria may also be acceptable. Similarly, biowaivers for dosage forms such as injectable products may also be allowed if certain criteria are met. The current paper summarises the biowaiver requirements for oral solutions and suspensions, soft gelatin capsules and injectable products (intravenous injections, subcutaneous and intramuscular injections, emulsions for injection and micellar solutions for injection) among the participants of the Bioequivalence Working Group for Generics (BEWGG) of the International Pharmaceutical Regulators Programme (IPRP). A review of the requirements indicated that there was a trend towards convergence when the dosage form became less complex; however, the most common approach used by each of the jurisdictions was a case-by-case approach given that most jurisdictions do not have well defined guidelines to support all possible scenarios. Even in the simplest case of intravenous solutions, the acceptability of qualitative changes in excipients differ between the IPRP members.  Notwithstanding the differences, the dissemination of the information is a first step towards regulatory convergence regarding biowaivers for certain dosage forms and should be useful for pharmaceutical companies currently developing generic medicinal products for IPRP jurisdictions.

Evaluation of the Physicochemical Properties of the Iron Nanoparticle Drug Products: Brand and Generic Sodium Ferric Gluconate.

Complex iron nanoparticle-based drugs are one of the oldest and most frequently administered classes of nanomedicines. In the US, there are seven FDA-approved iron nanoparticle reference drug products, of which one also has an approved generic drug product (i.e., sodium ferric gluconate (SFG)). These products are indicated for the treatment of iron deficiency anemia and are administered intravenously. On the molecular level, iron nanomedicines are colloids composed of an iron oxide core with a carbohydrate coating. This formulation makes nanomedicines more complex than conventional small molecule drugs. As such, these products are often referred to as nonbiological complex drugs (e.g., by the nonbiological complex drugs (NBCD) working group) or complex drug products (e.g., by the FDA). Herein, we report a comprehensive study of the physiochemical properties of the iron nanoparticle product SFG. SFG is the single drug for which both an innovator (Ferrlecit) and generic product are available in the US, allowing for comparative studies to be performed. Measurements focused on the iron core of SFG included optical spectroscopy, inductively coupled plasma mass spectrometry (ICP-MS), X-ray powder diffraction (XRPD), 57Fe Mössbauer spectroscopy, and X-ray absorbance spectroscopy (XAS). The analysis revealed similar ferric-iron-oxide structures. Measurements focused on the carbohydrate shell comprised of the gluconate ligands included forced acid degradation, dynamic light scattering (DLS), analytical ultracentrifugation (AUC), and gel permeation chromatography (GPC). Such analysis revealed differences in composition for the innovator versus the generic SFG. These studies have the potential to contribute to future quality assessment of iron complex products and will inform on a pharmacokinetic study of two therapeutically equivalent iron gluconate products.

Bioequivalence study of two perindopril tert-butylamine tablet formulations in healthy Chinese subjects under fasting and fed conditions: A randomized, open-label, single-dose, crossover trial.

BACKGROUND: To evaluate the bioequivalence between test and reference formulations of perindopril tert-butylamine under fasting and fed conditions and to assess their pharmacokinetic (PK) and safety profiles. METHOD: A randomized, open-label, single-dose, crossover trial was conducted in healthy Chinese subjects. Test or reference perindopril tert-butylamine tablets (4 mg) were randomly given to subjects under fasting (2-period crossover, with an administration sequence of test tablet (T), reference tablet (R) or RT) and fed (4-period crossover, with an administration sequence of TRTR or RTRT) conditions, while each single administration was followed by a 14-day washout period. The plasma concentrations and corresponding non-compartmental PK parameters of perindopril and perindoprilat were determined. The two formulations were considered to be bioequivalent if the 90 % confidence intervals (CIs) of the geometric mean (GM) ratio (test/reference) for Cmax, AUC0-t, and AUC0-∞ (perindopril) was both within the range of 80-125 %. Safety assessments including vital signs, physical examination, laboratory examination, 12-lead ECG and reports of treatment emergent adverse events (TEAEs) were carefully documented. RESULTS: A total of 64 subjects (32 in each trial) were randomized and all completed the trials. Regardless of fasting or fed trials, the PK characteristics of perindopril and perindoprilat for the test formulation were similar to those of the reference formulation (all P > 0.05). The 90 % CIs of the geometric mean (GM) ratio for Cmax, AUC0-t, and AUC0-∞, respectively, were 92.86-106.81 %, 98.44-102.88 % and 98.48-103.02 % under the fasting condition and 90.64-110.04 %, 96.95-101.90 % and 96.83-101.78 % under the fed condition, which were both within the pre-specified range of 80-125 %. A total of 10 (31.3 %) fasted subjects and 11 (34.4 %) fed subjects experienced 11 and 24 TEAEs, respectively, all of which were within the severity of grade 1. The incidence of TEAEs and drug-related TEAEs were similar between test and reference formulations (all P > 0.05) and no serious TEAEs or deaths occurred during the trials. CONCLUSIONS: The test and reference formulations of perindopril tert-butylamine tablets (4 mg) were bioequivalent and well tolerated in healthy Chinese subjects under fasting and fed conditions.

Comparison of the Pharmacokinetics of Generic Versus Branded Obeticholic Acid in a Chinese Population: Effects of Food and Sex.

The present study assessed the pharmacokinetics and bioequivalence of a single 10-mg dose of a generic and the branded formulation (Ocaliva) of obeticholic acid (OCA) in healthy Chinese subjects under fasting and fed conditions. The possible effects of food and sex on the pharmacokinetics of OCA and its 2 active metabolites (glyco-OCA and tauro-OCA) were evaluated. Plasma concentrations of OCA and its 2 active metabolites were measured by liquid chromatography-tandem mass spectrometry. The 90%CIs of the ratios of the test and reference formulations for Cmax , AUC0-t , and AUC0-∞ of OCA, glyco-OCA, and tauro-OCA were contained entirely within the 80% to 125% range required for bioequivalence under fasting and fed conditions. Plasma exposure of OCA was 30% to 36% higher under fed compared with fasting conditions. Plasma exposure of OCA, glyco-OCA, and tauro-OCA was 39% to 66%, 22% to 58%, and 37% to 84% higher, respectively, in women compared with men under fasting and fed conditions. In conclusion, OCA was well tolerated in healthy Chinese subjects under fasting and fed conditions. The single 10-mg dose of a generic OCA formulation was bioequivalent to Ocaliva. Food and sex impacted the pharmacokinetics of OCA and/or its 2 active metabolites. Further studies are required to determine if these effects are clinically relevant.

Exploring Medication Adherence with P2Y12 Inhibitors Using Conditional and Unconditional Quantile Regression Approaches.

BACKGROUND: Previous research assessing medication adherence with P2Y12 inhibitors has shown good adherence rates, ranging from 78% to 92%. Studies that used administrative claims data defined adherence using an arbitrary cut point of ≥ 80% medication possession ratio (MPR) or proportion of days covered (PDC). While this method is used frequently, it does not allow the researcher to observe how each factor impacts adherence along the entire distribution. The objective of the study was to use conditional quantile regression (CQR) and unconditional quantile regression (UQR) to assess heterogenous effects of adherence to P2Y12 inhibitors and covariates of interest and compare these results to those from a traditional logistic regression framework. METHODS AND RESULTS: This study used the commercial claims and encounters databases from IBM® MarketScan® from 2010 to 2017. We included patients who had an incident percutaneous coronary intervention, used a drug-eluting stent, and filled an incident prescription for a P2Y12 inhibitor. Adherence was measured for 185 days using PDC. Adherence to branded clopidogrel, generic clopidogrel, branded prasugrel, and branded ticagrelor was assessed, along with factors that could impact adherence, using logistic regression, CQR, and UQR. We found that while adherence to the antiplatelets was generally high, prasugrel and ticagrelor had significantly lower PDC compared to branded clopidogrel, especially around the 30th percentile. Across all quantiles in both the CRQ and UQR frameworks, comorbidities such as diabetes and depression and living in the southern region had significant negative effects on adherence, although the relative impact differed across quantiles. CONCLUSIONS: Using CQR and UQR allowed for heterogenous assessment of covariates along the adherence distribution, which is not possible with the traditional logistic regression method. The UQR framework revealed patients who initiate prasugrel or ticagrelor generally have lower adherence compared to those treated with branded clopidogrel, especially around the 30th quantile. Using these methods in other types of data sets, such as electronic health records, could help strengthen our results to develop policies to improve antiplatelet adherence in a targeted population.

Pharmacokinetics and Bioequivalence of 2 Immediate-Release Tofacitinib Tablet Formulations in Chinese Healthy Volunteers Under Fasting and Fed Conditions.

The purpose of this study was to evaluate the bioequivalence of a generic immediate-release tofacitinib tablet versus a brand-named immediate-release tofacitinib tablet under fasting and fed conditions, and the food effect on pharmacokinetic profiles of the both formulations. This randomized, open-label, 2-period, crossover, bioequivalence study included 52 healthy Chinese subjects (fasting cohort: n = 26; fed cohort: n = 26). The subjects were assigned to receive a single 5-mg dose of generic or brand-named tofacitinib. Blood samples were collected at predosing and up to 14 hours after dosing. Tofacitinib concentrations in plasma were analyzed by high-performance liquid chromatography-tandem mass spectrometry. Safety was monitored. There were no significant differences in maximum plasma concentration, area under the plasma concentration-time curve from time zero to time t (AUC0-t ), AUC from time zero to infinity (AUC0-∞ ), and terminal elimination half-life between the test and reference formulations (all P > .05); high-fat food had no significant effect on AUC0-t , AUC0-∞, or terminal elimination half-life of immediate-release tofacitinib tablets (all P > .05). The 90% confidence intervals of the test/reference ratios of log-transformed maximum plasma concentration, AUC0-t , and AUC0-∞ were within the range of 80% to 125% under both fasting and fed conditions. No serious adverse events were reported. The 2 formulations of immediate-release tofacitinib tablets are bioequivalent and well tolerated under both fasting and fed conditions in healthy Chinese volunteers. Food had no clinically relevant effects on drug exposure of tofacitinib.