The Global Bioequivalence Harmonization Initiative: Summary report for EUFEPS international conference

Open forum conference on the ICH M13A bioequivalence guideline

The Network on Bioavailability and Biopharmaceutics of EUFEPS (European Federation for Pharmaceutical Sciences) had organised an Open Discussion Forum on the ICH M13A draft "Guideline on bioequivalence for immediate-release solid oral dosage forms". This conference was cosponsored by the Arbeitsgemeinschaft Pharmazeutische Verfahrenstechnik (APV) and the Frankfurt Foundation Quality of Medicines. Scientists from academia and industry attended this workshop on May 15, 2023, in Frankfurt/Germany, to discuss the suggested regulations with the European members of the ICH drafting group. The aim of this report is to summarise and highlight the main discussion points such as choice of study population (females and/or males), request for fasted and/or fed studies, consequences of differences in drug product content, handling of aberrant plasma profiles and additional requirements in case of pH-dependant solubility. During the discussion important arguments were presented for a revision of certain requirements suggested in the draft guideline.

Global harmonization of immediate-release solid oral drug product bioequivalence recommendations and the impact on generic drug development

Immediate-release (IR) solid oral drug products constitute a significant portion of approved drug products and products under development. Bioequivalence (BE) assessment for these oral products is important for establishing therapeutic equivalence for generic products to their respective comparator products. In December 2022, the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) published the first new draft guideline on BE for IR solid oral dosage forms (M13A). To support the development of ICH M13A, we comprehensively reviewed the landscape of oral IR products approved by the U.S. Food and Drug Administration (FDA) and compared BE recommendations for these products in the current U.S. FDA and European Medicines Agency (EMA) BE guidances. We utilized databases including Drugs@FDA, Orange Book, and product-specific guidances (PSGs) published on the U.S. FDA and EMA websites to collect information. Oral IR products account for 46% of all FDA-approved new drug applications currently listed in Orange Book with 82.5% solids, 0.9% semi-solids, and 16.6% liquids. For all published U.S. FDA PSGs for solid oral IR products, in vivo BE studies with pharmacokinetic (PK) endpoints account for 88% of BE approaches recommended. Of these PK BE studies, 86.5% recommended fasting and fed BE studies, while only 15.9% EMA PSGs recommended both fasting and fed BE studies. This review helps clarify the scope of U.S. solid oral IR products impacted by the new ICH M13A draft guideline and demonstrates how recommendations in draft ICH M13A could significantly harmonize BE recommendations for IR oral products to facilitate global drug development.

The Global Bioequivalence Harmonisation Initiative (GBHI): Report of the fifth international EUFEPS/AAPS conference

The series of conferences of the Global Bioequivalence Harmonisation Initiative (GBHI) was started in 2015 by the European Federation for Pharmaceutical Sciences (EUFEPS). All GBHI meetings so far were co-organised together with the American Association of Pharmaceutical Scientists (AAPS). Beginning with the 3rd workshop US-FDA joined as co-sponsor - to support global harmonisation of regulatory recommendations for bioequivalence (BE) assessment. At the 5th GBHI conference, the following BE topics were intensively discussed, and the following main conclusions were drawn: (1) Statistical considerations for BE assessment in specific situations covering scaling approaches for highly variable drug (HVD) products, two-stage adaptive design and opportunities of modelling and simulation to support BE: even though special BE study concepts like adaptive designs are not often used in practise so far, a majority of the workshop participants were in favour of a more frequent application of such approaches. The regulatory conditions relevant in this context need further concretisation and harmonisation between the regions. Moreover, modelling and simulation were considered as a promising and evolving approach, also for BE development programmes. (2) Fed versus fasting conditions in BE trials: Findings that BE between generic products could be confirmed only after fasted administration but failed under fed conditions seem more an exception than the rule. Obviously, BCS class IV compounds are most problematic in this context. Differences in critical excipients such as surfactants or pH-modifiers may be relevant reasons for different sensitivity for interactions in fasted versus fed conditions. Consequently, such deviations in composition of generic preparations should be avoided. Moreover, confirmation of BE may be generally difficult comparing different dosage forms, such like capsules versus tablets, especially in fed state. (3) BE assessment of locally acting drug products applied topically to the skin: Appropriateness and potential benefit of in-vitro tests as alternatives to clinical efficacy studies have been comprehensively discussed. In addition to the already well-established in-vitro release and permeation tests, other techniques were suggested, e.g., Raman spectroscopy or dermal open flow microperfusion. Validation of those methods is challenging and, despite significant progress already achieved during previous years, more research is needed before they may be fully accepted for regulatory purposes. (4) BE evaluation of narrow therapeutic index (NTI) drugs: The discrepancies amongst regulatory agencies in necessity of tighter BE acceptance ranges, the recommendations for inclusion of peak and total drug exposure into BE assessment with more restrictive criteria and the importance of comparison of the product-related within-subject variability for NTI drugs were debated. Arguments in favour and against the different approaches were presented and discussed but need further consideration before harmonisation can be achieved. The highly interactive meeting and extensive exchange between regulators and scientists from industry and academia resulted in useful progress in open BE issues and supported the goal of science-driven harmonisation.

Exploring the Potential Challenges for Developing Generic Orphan Drugs for Rare Diseases: A Survey of US and European Markets

OBJECTIVES

The US Food and Drug Administration in 1983 and the European Union's European Medicines Agency in 2000 implemented the orphan drug development program for rare diseases. The study aimed to find the potential challenges encountered by generic companies in developing generics for rare diseases.

METHODS

We performed a thematic analysis, which consists of qualitative and quantitative research. For data analysis of approved orphan drugs, we used statistical methods, and for the industrial case study, we selected 14 generic companies and conducted semistructured interviews related to 10 critical areas of drug development.

RESULTS

The orphan drug approvals were classified into 4 categories: the number of orphan approvals, pediatric claims, formulation, and therapeutic areas. We analyzed the approvals from 2001 to 2021; the Food and Drug Administration approved 815 drugs and European Medicines Agency approved 258 drugs. The pediatric orphan approvals were analyzed from 2010 to 2021; the average percentage of orphan drugs claim pediatric exclusivity during this period was found to be 31.8%. In formulation, we found the highest percentage of drugs belong to small molecules at 71%. In the therapeutic class, oncology drugs have a majority of approvals at 25%. The industrial case study responses revealed that the major challenge for drug development is the complexity of the disease at 21%, followed by the limited market at 17%.

CONCLUSIONS

There is a high need for generic orphan drugs in the developing countries. The generic companies can use the opportunities provided by health authorities for the benefit of both the company and the patient perspective.

Development of In Vitro Dissolution Testing Methods to Simulate Fed Conditions for Immediate Release Solid Oral Dosage Forms

In vitro dissolution testing is widely used to mimic and predict in vivo performance of oral drug products in the gastrointestinal (GI) tract. This literature review assesses the current in vitro dissolution methodologies being employed to simulate and predict in vivo drug dissolution under fasted and fed conditions, with emphasis on immediate release (IR) solid oral dosage forms. Notable human GI physiological conditions under fasted and fed states have been reviewed and summarized. Literature results showed that dissolution media, mechanical forces, and transit times are key dissolution test parameters for simulating specific postprandial conditions. A number of biorelevant systems, including the fed stomach model (FSM), GastroDuo device, dynamic gastric model (DGM), simulated gastrointestinal tract models (TIM), and the human gastric simulator (HGS), have been developed to mimic the postprandial state of the stomach. While these models have assisted in expanding physiological relevance of in vitro dissolution tests, in general, these models lack the ability to fully replicate physiological conditions/processes. Furthermore, the translatability of in vitro data to an in vivo system remains challenging. Additionally, physiologically based pharmacokinetic (PBPK) modeling has been employed to evaluate the effect of food on drug bioavailability and bioequivalence. Here, we assess the current status of in vitro dissolution methodologies and absorption PBPK modeling approaches to identify knowledge gaps and facilitate further development of in vitro dissolution methods that factor in fasted and fed states. Prediction of in vivo drug performance under fasted and fed conditions via in vitro dissolution testing and modeling may potentially help efforts in harmonizing global regulatory recommendations regarding in vivo fasted and fed bioequivalence studies for solid oral IR products.

The Global Bioequivalence Harmonisation Initiative (GBHI): Report of EUFEPS/AAPS fourth conference

This report provides a summary of the 4^th International Conference on Global Bioequivalence Harmonisation Initiative (GBHI) that was co-organised by the European Federation of Pharmaceutical Sciences (EUFEPS) and the American Association of Pharmaceutical Scientists (AAPS). The goal of the GBHI conference is to offer the most informative and up to date science and regulatory thinking of bioequivalence (BE) in global drug development to support the intended process of a scientific global harmonisation. The workshop provided an open forum for pharmaceutical scientists from academia, industry and regulatory agencies to discuss three BE topics of interest, (a) BE assessment for long-acting injectables and implants, (b) necessity of fed BE studies for immediate-release products and (c) procedures to demonstrate equivalence of orally inhaled products. Moreover, in keynote lectures, a potential road map to an international BE reference product was discussed, and visions and perspectives for future global BE harmonisation activities have been presented. The meeting delivered a cutting-edge insight into the topics in an interactive and at the same time focused way.

Innovating on Inhaled Bioequivalence: A Critical Analysis of the Current Limitations, Potential Solutions and Stakeholders of the Process

Orally inhaled drug products (OIDPs) are an important group of medicines traditionally used to treat pulmonary diseases. Over the past decade, this trend has broadened, increasing their use in other conditions such as diabetes, expanding the interest in this administration route. Thus, the bioequivalence of OIDPs is more important than ever, aiming to increase access to affordable, safe and effective medicines, which translates into better public health policies. However, regulatory agencies leading the bioequivalence process are still deciding the best approach for ensuring a proposed inhalable product is bioequivalent. This lack of agreement translates into less cost-effective strategies to determine bioequivalence, discouraging innovation in this field. The Next-Generation Impactor (NGI) is an example of the slow pace at which the inhalation field evolves. The NGI was officially implemented in 2003, being the last equipment innovation for OIDP characterization. Even though it was a breakthrough in the field, it did not solve other deficiencies of the BE process such as dissolution rate analysis on physiologically relevant conditions, being the last attempt of transferring technology into the field. This review aims to reveal the steps required for innovation in the regulations defining the bioequivalence of OIDPs, elucidating the pitfalls of implementing new technologies in the current standards. To do so, we collected the opinion of experts from the literature to explain these trends, showing, for the first time, the stakeholders of the OIDP market. This review analyzes the stakeholders involved in the development, improvement and implementation of methodologies that can help assess bioequivalence between OIDPs. Additionally, it presents a list of methods potentially useful to overcome some of the current limitations of the bioequivalence standard methodologies. Finally, we review one of the most revolutionary approaches, the inhaled Biopharmaceutical Classification System (IBCs), which can help establish priorities and order in both the innovation process and in regulations for OIDPs.

Current Bioequivalence Study Designs in South Korea: A Comprehensive Analysis of Bioequivalence Study Reports Between 2013 and 2019

Demonstration of bioequivalence (BE) is mandatory while developing generic drugs. The scientific concept of BE applies equally to different regulatory agencies. However, the application of the concept may differ for each agency, which can affect the design of BE studies. To evaluate the study practices in terms of the BE concept in South Korea, we retrospectively analyzed BE study reports available from Ministry of Food and Drug Safety between 2013 and 2019. Statistical estimation of the pharmacokinetic parameters, including peak concentration and area under the concentration-time curve to the last measurable concentration, as well as study design, number of subjects in a study, study duration, fasting status, and formulation of specific drugs were obtained. The drugs were classified per World Health Organization Anatomical Therapeutic Chemical Classification and Biopharmaceutics Classification System. Post-hoc intrasubject coefficient of variation and corresponding sample sizes were calculated from the 90% confidence intervals of pharmacokinetic parameters. A total of 143 generic drugs in 588 BE studies were analyzed. The largest number of studies were performed in the area of Cardiovascular system (172 studies), followed by Nervous system (143 studies) and Alimentary tract and metabolism (92 studies). Overall, BE studies in South Korea were conducted in accordance with the global guideline despite the differences in details. BE studies were focused on the several therapeutic areas and conducted in a similar manner. The number of subjects was generally larger than that estimated with 90% power.

Modernization and Strengthening of Bioequivalence Guidelines in Japan

Until now, human bioequivalence (BE) studies were conducted based on the revised 'Guideline for Bioequivalence Studies of Generic Products' issued in 2012 by the Ministry of Health, Labour and Welfare (MHLW) in Japan. However, revisions of BE guidelines were required to account for the globalization of pharmaceutical development, new technology, and scientific rationales over the last 8 years. Therefore, the MHLW published the revised 'Guideline for Bioequivalence Studies of Generic Products' in 2020. In this article, we introduce the main revised contents, such as the addition of a fed-state BE study, reconsideration of the pilot study and add-on study, acceptance of foreign subjects in a BE study, and clarification of the requirement of a reference product. Furthermore, we compare the BE evaluations of generic oral solid dosage forms with those of the Pharmaceuticals and Medical Devices Agency (PMDA), the US Food and Drug Administration (FDA), and the European Medicines Agency (EMA).

Method for evaluating the human bioequivalence of acarbose based on pharmacodynamic parameters

Objective

To explore a method for evaluating the bioequivalence of acarbose based on pharmacodynamic parameters using a single-dose, randomized-sequence, three-way crossover study of acarbose test (T) and reference (R) formulations.

Methods

Baseline-adjusted, pre-dose value deduction, and direct comparison methods were used to evaluate the geometric T/R ratios and 90% confidence intervals (CIs) of the ln-transformed pharmacodynamic parameters to identify the most suitable evaluation system. Twelve participants were randomly divided into three groups to receive treatment in the following sequences: TRR, RTR, and RRT, each including a 7-day washout period between treatment periods. The serum glucose concentration (baseline) was determined. Pharmacodynamic parameters, including the maximum reduction in serum glucose concentrations (ΔC_SG,max) and difference of the AUC of glucose between before and after acarbose exposure (ΔAUEC), were tested.

Results

Using the direct comparison method, the geometric mean ratios of C_SG,max, AUEC_(0-2h), and AUEC_(0-4h) were 94.13%, 97.82% and 99.76%, respectively. The 90% CIs of the geometric T/R ratios for C_SG,max, AUEC_(0-2h), and AUEC_(0-4h) all fell between 80% and 125%. Conversely, ΔC_SG,max and ΔAUEC_(0-4h) were less reliable measures of acarbose bioequivalence.

Conclusions

Pre-dose value deduction and direct comparison methods can be initially considered suitable for assessing acarbose bioequivalence.

Between-Batch Bioequivalence (BBE): a Statistical Test to Evaluate In Vitro Bioequivalence Considering the Between-Batch Variability

Bioequivalence testing is an essential step during the development of generic drugs. Regulatory agencies have drafted recommendations and guidelines to frame this step but without finding any consensus. Different methodologies are applied depending on the geographical region. For instance, in the EU, EMA recommends using average bioequivalence test (ABE), while in the USA, FDA recommends using population bioequivalence (PBE) test. Both methods present some limitations (e.g., when batch variability is non-negligible) making it difficult to conclude to equivalence without subsequently increasing the sample size. This article proposes an alternative method to evaluate bioequivalence: between-batch bioequivalence (BBE). It is based on the comparison between the mean difference (Reference - Test) and the Reference between-batch variability. After presenting the theoretical concepts, BBE relevance is evaluated through simulation and real case (nasal spray) studies. Simulation results showed high performance of the method based on false positive and false negative rate estimations (type I and type II errors respectively). Especially, BBE has shown significantly greater true positive rates than ABE and PBE when the Reference residual standard deviation is higher than 15%, depending on the between-batch variability and the number of batches. Finally, real case applications revealed that BBE is more efficient than ABE and PBE to demonstrate equivalence, in some well-known situations where the between-batch variability is not negligible. These results suggest that BBE could be considered as an alternative to the state-of-the-art methods allowing costless development. Graphical abstract.

Converging Generic Drug Product Development: Bioequivalence Design and Reference Product Selection

Different regulatory agencies provide criteria for selecting a reference product for bioequivalence (BE) studies. In most cases, the criteria vary from one regulatory agency to another, and, consequently, the generic companies often have to repeat the BE studies comparing the same test product with the reference product purchased from a particular country. In addition to being a cost-intensive exercise, this practice is also unethical. The purpose of this article is to discuss the current policy of major regulatory authorities on the selection of the reference product for pharmaceutical equivalence (PE) and BE studies, the cost implications of such regulatory practices, and to also explore the opportunity to harmonize the reference product selection criteria for reducing repetitive BE studies. The regulatory guidance documents of major jurisdictions are reviewed for similarities and differences in generic product definition, BE study design and conduct, and reference product selection criteria for PE and BE studies. A case study is presented to understand how harmonisation can be achieved and how the economic benefits of this harmonisation cannot be underestimated. Harmonisation in reference product selection criteria can pave the way for a common BE study(s) that would be acceptable to the majority of regulatory agencies, and would not only significantly reduce operating costs but would also minimize the exposure of healthy human beings to drugs.

Access to unauthorized hepatitis C generics: Perception and knowledge of physicians, pharmacists, patients and non-healthcare professionals

OBJECTIVES

Hepatitis C virus (HCV) causes both acute and chronic infection, which can potentially develop into cirrhosis and liver cancer. Healthcare systems are struggling to finance costly direct-acting antiviral agents through public funding for uninsured patients, despite the unprecedented high cure rates of these agents. Vulnerable populations are at higher risk of HCV infection. The personal importation scheme is based on the legal right to import any unauthorized generics for personal use. This study was designed to assess the knowledge and perceptions of stakeholders on unauthorized generics.

METHODS

We conducted an anonymous online survey based on the fictitious situation of a patient diagnosed with HCV who lacked mandatory health insurance and personal financial resources.

RESULTS

We obtained a sample of 781 respondents: 445 physicians, 77 pharmacists, 51 patients and 207 non-healthcare professionals. We found that only 36% and 58% of respondents believe that the quality and efficacy, respectively, of unauthorized generics are equivalent to their corresponding brand. An overwhelming majority (98%) favoured quality control upon arrival, and 31% felt they could recognize fraudulent websites. A total of 79% expressed support for financial assistance for vulnerable patients, and support among physicians was 83%.

CONCLUSIONS

Overall, the limited knowledge of the efficacy and quality of unauthorized generics, despite evidence in peer-reviewed literature, contrasts with the overwhelmingly positive attitudes toward financial assistance for personal import. This finding emphasizes the need for clearer information on imported generics and the potential safety provided by buyers' club schemes to complete the WHO agenda of eradicating viral hepatitis by 2030 within otherwise excluded vulnerable populations.

Summary report of second EUFEPS/AAPS conference on global harmonization in bioequivalence

The Global Bioequivalence Harmonization Initiative (GBHI) was launched by the Network on Bioavailability and Biopharmaceutics (BABP) under the auspices of European Federation for Pharmaceutical Sciences (EUFEPS) several years ago. Since 2015, EUFEPS in collaboration with the American Association of Pharmaceutical Scientists (AAPS) has organized three international conferences to support global harmonization of regulatory requirements for bioequivalence (BE) assessment. These conferences provided an open forum for pharmaceutical scientists from academia, industry and regulatory agencies to discuss various BE topics at issue. The current report summarizes the discussion of BE issues at the 2nd GBHI conference held in 2016, Rockville, USA. Three important BE topics were discussed at the meeting: (a) prodrugs and compounds with pre-systemic extraction, (b) scaling procedures and two-stage designs, and (c) exclusion of pharmacokinetic data in BE assessment. The presentations and discussions of these issues have enhanced the mutual understanding of scientific background for BE evaluation and further facilitated harmonization of regulatory approaches for establishing BE of multisource drug products.