Experience Learned and Perspectives on Using Model-Integrated Evidence in the Regulatory Context for Generic Drug Products-a Meeting Report.

This report summarizes relevant insights and discussions from a 2022 FDA public workshop titled Best Practices for Utilizing Modeling Approaches to Support Generic Product Development which illustrated how model-integrated evidence has been used and can be leveraged further to inform generic drug product development and regulatory decisions during the assessment of generic drug applications submitted to the FDA. The workshop attendees discussed that model-integrated evidence (MIE) approaches for generics are being applied in the space of long-acting injectable (LAI) products to develop shorter and more cost-effective alternative study designs for LAI products. Modeling and simulation approaches are utilized to support virtual BE assessments at the site of action for locally acting drug products and to assess the impact of food on BE assessments for oral dosage forms. The factors contributing to the success of the model-informed drug development program under PDUFA VI were discussed. The generic drug industry shared that decisions on formulation candidate/formulation variant selection, on pilot in vivo bioavailability studies, and on alternative study designs for BE assessment are informed by modeling and simulation approaches. There was agreement that interactions between the regulatory agencies and the industry are desirable because they improve the industry's understanding of scientific and other regulatory considerations on implementing modeling and simulation approaches in drug development and regulatory submissions.

Commentary on the MID3 Good Practices Paper.

During the last 10 years the European Medicines Agency (EMA) organized a number of workshops on modeling and simulation, working towards greater integration of modeling and simulation (M&S) in the development and regulatory assessment of medicines. In the 2011 EMA - European Federation of Pharmaceutical Industries and Associations (EFPIA) Workshop on Modelling and Simulation, European regulators agreed to the necessity to build expertise to be able to review M&S data provided by companies in their dossier. This led to the establishment of the EMA Modelling and Simulation Working Group (MSWG). Also, there was agreement reached on the need for harmonization on good M&S practices and for continuing dialog across all parties. The MSWG acknowledges the initiative of the EFPIA Model-Informed Drug Discovery and Development (MID3) group in promoting greater consistency in practice, application, and documentation of M&S and considers the paper is an important contribution towards achieving this objective.

Pharmacokinetics of sugammadex 16 mg/kg in healthy Chinese volunteers.

OBJECTIVE: Elimination of sugammadex occurs predominantly via the kidneys, with the majority of the drug excreted unchanged in the urine. To date, most studies with sugammadex have been performed in non-Asian populations. The objectives of this open-label study were to determine the pharmacokinetics (PK) and safety of single-dose sugammadex (16 mg/kg) in healthy Chinese adult volunteers. METHODS: 12 Chinese subjects (6 male; 6 female) received intravenous sugammadex (16 mg/kg) as a 10-second bolus infusion. Blood samples were collected pre-sugammadex and at regular intervals up to 24 hours post-sugammadex for PK assessment. Safety was assessed via AEs, vital signs, electrocardiogram, and laboratory parameters. RESULTS: Following sugammadex 16 mg/kg infusion, peak sugammadex concentration was 197 µg/mL, clearance was 99.7 mL/min, and apparent volume of distribution at equilibrium was 10.5 L. Plasma sugammadex concentrations showed a polyexponential decline over time, with an overall geometric mean (CV%) terminal half-life of 145 minutes (17.9%) (139 minutes (17.7%) for males; 152 minutes (18.6%) for females). No influence of gender on the PK of sugammadex was observed. Three subjects experienced an adverse events (AE) (dysgeusia of mild intensity), which was considered possibly or probably related to sugammadex. There were no clinically significant changes in vital signs, electrocardiography or laboratory parameters. CONCLUSION: PK of sugammadex (16 mg/kg) was characterized in healthy Chinese subjects. Overall between-subject variability on clearance and apparent volume of distribution was ~ 10%. Sugammadex was generally well tolerated.

Development of in vitro-in vivo correlation for extended-release niacin after administration of hypromellose-based matrix formulations to healthy volunteers.

Development of in vitro-in vivo correlations (IVIVCs) for extended-release (ER) products is commonly pursued during pharmaceutical development to increase product understanding, set release specifications, and support biowaivers. This manuscript details the development of Level C and Level A IVIVCs for ER formulations of niacin, a highly variable and extensively metabolized compound. Three ER formulations were screened in a cross-over study against immediate-release niacin. A Multiple Level C IVIVC was established for both niacin and its primary metabolite nicotinuric acid (NUA) as well as total niacin metabolites urinary excretion. For NUA, but not for niacin, Level A IVIVC models with acceptable prediction errors were achievable via a modified IVIVC rather than a traditional deconvolution/convolution approach. Hence, this is in contradiction with current regulatory guidelines that suggest that when a Multiple Level C IVIVC is established, Level A models should also be readily achievable. We demonstrate that for a highly variable, highly metabolized compound such as niacin, development of a Level A IVIVC model fully validated according to agency guidelines may be challenging. However, Multiple Level C models are achievable and could be used to guide release specifications and formulation/manufacturing changes.

Effect of sugammadex on QT/QTc interval prolongation when combined with QTc-prolonging sevoflurane or propofol anaesthesia.

BACKGROUND: We evaluated the potential for QT/corrected QT (QTc) interval prolongation after sugammadex given with propofol or sevoflurane anaesthesia. METHODS: This was a two-factorial, randomized, parallel-group study in 132 healthy subjects. Anaesthesia was maintained with sevoflurane or propofol. At ~20 min following sevoflurane/propofol initiation, sugammadex 4 mg/kg or placebo was administered. Neuromuscular blocking agents were not administered. Electrocardiograms were recorded regularly. The primary variable was the time-matched mean difference in the Fridericia-corrected QT interval (QTcF) change from baseline for sugammadex versus placebo when combined with propofol or sevoflurane. No relevant QTcF prolongation was concluded if the upper one-sided 95 % confidence interval (CI) was below the 10 ms margin of regulatory non-inferiority, up to 30 min post-study drug. Blood samples were taken for pharmacokinetic analysis. An exploratory analysis evaluated potential QT/QTc effects of neostigmine 50 µg/kg/glycopyrrolate 10 µg/kg in combination with propofol. RESULTS: The estimated mean QTcF differences between sugammadex and placebo ranged from -2.4 to 0.6 ms when combined with either anaesthetic. The largest upper one-sided 95 % CI for the mean QTcF difference between sugammadex and placebo was 2 ms, occurring 2 min post-dosing. Propofol and sevoflurane resulted in mean QTcF increases exceeding 10 and 30 ms, respectively. On top of these prolongations, the effect of sugammadex was negligible at all timepoints. The mean peak sugammadex concentration was 66.5 µg/mL, with exposure similar in the sevoflurane/propofol groups. The mean QTcF changes from baseline following neostigmine/glycopyrrolate in 10 healthy subjects ranged between -1.4 and 3.6 ms. CONCLUSION: Sugammadex 4 mg/kg does not cause clinically relevant QTc interval prolongation versus placebo when combined with propofol or sevoflurane.

Bioequivalence and x-ray visibility of a radiopaque etonogestrel implant versus a non-radiopaque implant: a 3-year, randomized, double-blind study.

BACKGROUND: The etonogestrel (ENG)-releasing implant is a subdermal progestogen-only contraceptive that provides coverage for up to 3 years. This long-acting hormonal contraceptive has been available in Europe since 1998 and in the US since 2006. To date, localization of non-palpable implants at insertion and before removal has been dependent on ultrasound or magnetic resonance imaging by an experienced clinician. To facilitate localization in rare cases of non-palpable implants using widely available equipment without the need for a specialist, a radiopaque ENG implant has been developed that is detectable by two-dimensional x-ray imaging. OBJECTIVE: This study aimed to establish whether the radiopaque ENG implant is bioequivalent in situ compared with the original non-radiopaque ENG implant, and to assess x-ray visibility of the radiopaque ENG implant. METHODS: This was a 3-year, randomized, double-blind, parallel-group study carried out in nine international clinical trial centres. Women aged 18-40 years at the time of screening, with menstrual cycles of a usual length of 24-35 days and a body mass index of between ≥18 and ≤29 kg/m(2) were included. Women were assigned to either the radiopaque or non-radiopaque ENG implant in a 1 : 1 ratio via a block randomization by centre. Bioequivalence testing was performed based on the peak ENG concentration (C(max)), and the area under the curve (AUC) for ENG at 6, 24 and 36 months (AUC(6 mo), AUC(24 mo) and AUC(36 mo)) after insertion. For this purpose, blood sampling for pharmacokinetic determination was performed prior to insertion and for up to 3 years afterwards. Bioequivalence was defined as the 90% confidence interval (CI) of the ratio radiopaque implant/non-radiopaque implant of the geometric means (GMR) within the acceptance range of 0.80-1.25. x-Ray visibility was assessed by two-dimensional x-ray imaging after insertion and before removal of the implant. RESULTS: The pharmacokinetic profiles of ENG indicated that the radiopaque and non-radiopaque implants were bioequivalent with respect to the geometric mean of C(max) (GMR 1.06; 90% CI 0.91, 1.23), AUC(6 mo) (GMR 1.00; 90% CI 0.91, 1.10), AUC(24 mo) (GMR 0.98; 90% CI 0.88, 1.10) and AUC(36 mo) (GMR 1.00; 90% CI 0.89, 1.11). The radiopaque ENG implant was clearly visible in 50 out of 52 women after insertion and in all 52 women before removal, whereas none of the non-radiopaque implants were visible. CONCLUSION: The radiopaque ENG implant is bioequivalent in situ compared with the original non-radiopaque ENG implant and is clearly visible using x-ray imaging. CLINICAL TRIALS REGISTRATION: Registered as ClinicalTrials.gov identifier NCT00620464.

Population pharmacokinetic-pharmacodynamic analysis for sugammadex-mediated reversal of rocuronium-induced neuromuscular blockade.

AIMS: An integrated population pharmacokinetic-pharmacodynamic model was developed with the following aims: to simultaneously describe pharmacokinetic behaviour of sugammadex and rocuronium; to establish the pharmacokinetic-pharmacodynamic model for rocuronium-induced neuromuscular blockade and reversal by sugammadex; to evaluate covariate effects; and to explore, by simulation, typical covariate effects on reversal time. METHODS: Data (n= 446) from eight sugammadex clinical studies covering men, women, non-Asians, Asians, paediatrics, adults and the elderly, with various degrees of renal impairment, were used. Modelling and simulation techniques based on physiological principles were applied to capture rocuronium and sugammadex pharmacokinetics and pharmacodynamics and to identify and quantify covariate effects. RESULTS: Sugammadex pharmacokinetics were affected by renal function, bodyweight and race, and rocuronium pharmacokinetics were affected by age, renal function and race. Sevoflurane potentiated rocuronium-induced neuromuscular blockade. Posterior predictive checks and bootstrapping illustrated the accuracy and robustness of the model. External validation showed concordance between observed and predicted reversal times, but interindividual variability in reversal time was pronounced. Simulated reversal times in typical adults were 0.8, 1.5 and 1.4 min upon reversal with sugammadex 16 mg kg(-1) 3 min after rocuronium, sugammadex 4 mg kg(-1) during deep neuromuscular blockade and sugammadex 2 mg kg(-1) during moderate blockade, respectively. Simulations indicated that reversal times were faster in paediatric patients and slightly slower in elderly patients compared with adults. Renal function did not affect reversal time. CONCLUSIONS: Simulations of the therapeutic dosing regimens demonstrated limited impact of age, renal function and sevoflurane use, as predicted reversal time in typical subjects was always <2 min.

Assessment of the potential for displacement interactions with sugammadex: a pharmacokinetic-pharmacodynamic modelling approach.

BACKGROUND: Sugammadex is a γ-cyclodextrin that binds with high affinity to the neuromuscular blocking agents (NMBAs) rocuronium (bromide) and vecuronium (bromide) by encapsulation. Cyclodextrins are known to form inclusion complexes with other compounds. OBJECTIVES: We utilized a previously developed pharmacokinetic-pharmacodynamic model to identify potential clinically relevant displacement interactions with sugammadex. The potential for sugammadex to capture other drug molecules, thereby reducing their efficacy, is not discussed here. METHODS: Isothermal titration calorimetry (ITC) was used to determine the binding affinity (estimated by association rate constant [k(ass)]) between sugammadex and 300 commonly prescribed drugs. The screening included drugs commonly used in or shortly after anaesthesia, commonly prescribed drugs such as antidepressants and cardiovascular drugs, drugs (both steroidal and nonsteroidal) acting on steroidal receptors (such as the corticosteroids hydrocortisone, prednisolone and dexamethasone), and the selective estrogen receptor modulator toremifene. The model took into account the population pharmacokinetic-pharmacodynamic relationships of sugammadex, rocuronium and vecuronium, the binding affinities of the NMBAs and other compounds as determined by ITC, and the relationship between the free concentration of NMBA with sugammadex in the presence of a third complexed compound. Using the model, the critical concentrations of a concomitantly administered compound required to result in a train-of-four (TOF) ratio of <0.9, indicating reoccurrence of neuromuscular blockade, for each plasma concentration of sugammadex and NMBA were calculated. For compounds with a k(ass) value of ≥ 2.5 × 104 mol/L likely to be administered during sugammadex reversal, the combinations of k(ass) and maximum plasma drug concentration (C(max)) were entered into a graph, consisting of a critical line established using a conservative approach, and those compounds above this critical line potentially resulting in a TOF ratio <0.9 were subsequently identified. Clinical validation was performed in a post hoc analysis of data from ten sugammadex studies, in which the impact of various drugs administered perioperatively on neuromuscular recovery was assessed for up to 1 hour after sugammadex administration. RESULTS: ITC analysis demonstrated that the binding affinity of rocuronium and vecuronium for sugammadex was very high, with k(ass) values of 1.79 × 107 mol/L and 5.72 × 106 mol/L, respectively. Only three compounds (flucloxacillin, fusidic acid and toremifene) were found to have critical combinations of k(ass) and C(max), and thus the potential for displacement. Sugammadex was administered to 600 patients for reversal of rocuronium- or vecuronium-induced blockade in the ten analysed studies, in which 21 co-administered drugs were selected for analysis. No reoccurrence of blockade occurred in any patient. CONCLUSION: Of 300 drugs screened, only three (flucloxacillin, fusidic acid and toremifene) were found to have potential for a displacement interaction with sugammadex, which might potentially be noticed as a delay in recovery of the TOF ratio to 0.9. A clinical study found no evidence of a clinically relevant displacement interaction of flucloxacillin with sugammadex; these findings confirm the highly conservative nature of the modelling and simulation assumptions in the present study.

Safety, tolerability and pharmacokinetics of sugammadex using single high doses (up to 96 mg/kg) in healthy adult subjects: a randomized, double-blind, crossover, placebo-controlled, single-centre study.

BACKGROUND AND OBJECTIVE: Sugammadex facilitates rapid reversal of rocuronium- and vecuronium-induced neuromuscular blockade. This study aimed to evaluate the safety, tolerability and pharmacokinetics of high doses of sugammadex (up to 96 mg/kg) in healthy subjects. METHODS: In this randomized, double-blind, crossover, placebo-controlled, single-centre study, 13 healthy adults were scheduled to receive three single intravenous doses of sugammadex in ascending order (32, 64 and 96 mg/kg) and placebo (interspersed between sugammadex doses), each separated by a 1-week washout period. Subjects were randomized to one of four treatment sequences, receiving doses as constant rate infusions over 5 minutes. Safety was assessed by adverse events, 12-lead ECGs, vital signs, and blood and urine laboratory parameters; pharmacokinetics were evaluated from blood and urine sugammadex concentrations. RESULTS: Sugammadex was well tolerated in 12 of the 13 subjects, with adverse events being generally mild, of limited duration and more frequent at higher doses. The most common adverse event was dysgeusia; there were no serious adverse events. One subject was withdrawn from the study after experiencing several adverse events following first exposure to sugammadex, related to a probable hypersensitivity reaction to sugammadex. Pharmacokinetics were dose linear over the dose range studied (32-96 mg/kg), and 90-93% of the sugammadex dose was excreted unchanged in urine within 48 hours. CONCLUSION: High doses of sugammadex (up to 96 mg/kg) were well tolerated in 12 of the 13 subjects. One male subject experienced several adverse events associated with a probable hypersensitivity reaction to sugammadex. Pharmacokinetics were dose linear over the range 32-96 mg/kg, with elimination predominantly via the renal route.

Comparison of ethinylestradiol pharmacokinetics in three hormonal contraceptive formulations: the vaginal ring, the transdermal patch and an oral contraceptive.

This open-label, randomized study compared the pharmacokinetics of ethinylestradiol (EE) from the contraceptive vaginal ring NuvaRing (15 microg EE/day), the transdermal patch (20 microg EE/day) and a combined oral contraceptive (COC) containing 30 microg EE. After 2-8 weeks of synchronization by COC treatment, subjects were randomized to 21 days of treatment with NuvaRing, patch or COC. Analysis of area under the EE concentration-versus-time curve (AUC) during 21 days of treatment showed that exposure to EE in the NuvaRing group was 3.4 times lower than in the patch group (p < .05) and 2.1 times lower than in the pill group (p < .05). Serum EE levels of subjects showed much lower variation with NuvaRing than with the patch or the COC. Thus, exposure to EE was significantly lower with NuvaRing than with the patch and pill methods, demonstrating that NuvaRing is a low-estrogen-dose contraceptive method that also results in low estrogen exposure.

Absence of pharmacokinetic interactions of the combined contraceptive vaginal ring NuvaRing with oral amoxicillin or doxycycline in two randomised trials.

BACKGROUND: Two pharmacokinetic studies were performed to investigate whether there is any interaction between etonogestrel or ethinylestradiol released from the combined contraceptive vaginal ring NuvaRing and concomitant treatment with orally administered amoxicillin or doxycycline. METHODS: In one study, healthy women were randomised to receive either NuvaRing alone for 21 days or NuvaRing for 21 days plus amoxicillin on days 1-10. After a 7-day ring-free washout period, women were crossed over to the alternate regimen for a further 21-day treatment period. The other study used an identical design except that women received doxycycline instead of amoxicillin. The amoxicillin study measured serum etonogestrel and ethinylestradiol levels and area under the serum concentration-time curve (AUC) values over the initial 12 hours on days 1 (AUC(12)) and 10 (AUC(216-228)) and the whole of days 1-11 (AUC(240)) and 1-22 (AUC(504)). The doxycycline study measured AUC values over the initial 24 hours on days 1 (AUC(24)) and 10 (AUC(216-240)) and the whole of days 1-11 (AUC(240)) and 1-22 (AUC(504)). RESULTS: No differences in etonogestrel or ethinylestradiol serum concentrations were observed between subjects using NuvaRing alone versus those receiving the ring plus either of the antibiotics. Calculation of etonogestrel and ethinylestradiol interaction/control ratios confirmed the absence of pharmacokinetic interactions. CONCLUSION: The results from these studies demonstrate the absence of pharmacokinetic interactions between etonogestrel and ethinylestradiol released from NuvaRing and the oral antibiotics amoxicillin and doxycycline, suggesting that contraceptive efficacy would also be unaffected.

Two sensitive and rapid chromogenic assays of fondaparinux sodium (Arixtra) in human plasma and other biological matrices.

Fondaparinux is a synthetic selective inhibitor of factor Xa recently approved for thromboprophylaxis after major orthopedic surgery. Determination of its concentration gives valuable insight into specific pharmacokinetics or safety studies. The aim of the study was to develop direct, sensitive, precise and accurate assays of fondaparinux sodium in different biological matrices. Consistency with the recommended chromogenic assay for low molecular weight heparin required a similar method. However, recent data indicated some variability in the determination of anti-Xa level between commercial chromogenic assays. Consequently, we developed and validated two chromogenic methods (A and B) for assaying fondaparinux in plasma and other biological matrices. The assays are calibrated with fondaparinux, a pure chemical entity, and the result is expressed as amount (microg) of the fondaparinux calibrator. Results showed that precision was lower than 5.2% in plasma or plasma water and 13% in placental medium. The accuracy was lower than 7.6% in plasma or plasma water and 10.2% in placental medium. The lower limit of quantification in plasma was 0.042 microg/mL with automated Method A and 0.019 microg/mL with Method B. The assay was not affected by the source of the samples, the presence of blood cells, EDTA, citrate or repeated cycles of freezing and thawing. The two chromogenic assays calibrated with fondaparinux sodium reach the equivalence criteria for plasma samples and provide reliable and reproducible results.