Sertindole: efficacy and safety in schizophrenia

The most commonly prescribed class of medications in the United States for chronic severe pain is opioid analgesics. Due to their low cost and widespread availability, the synthetic opioids are popular choices among clinicians and patients. However, there is an increasingly recognized risk of QT prolongation with several drugs in this class, and recently propoxyphene (Darvon) was withdrawn from the market by the Food and Drug Administration (FDA) due to, in part, the risk of QT prolongation and ventricular arrhythmias Updated Epidemiological Review of Propoxyphene Safety. [FDA Alert]. Rockville, MD: U.S. Food and Drug Administration; 2010. Available from: http://www.fda.gov/downloads/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/UCM234383.pdf on 5 May 2012.     

New era in drug interaction evaluation: US Food and Drug Administration update on CYP enzymes, transporters, and the guidance process

Predicting clinically significant drug interactions during drug development is a challenge for the pharmaceutical industry and regulatory agencies. Since the publication of the US Food and Drug Administration's (FDA's) first in vitro and in vivo drug interaction guidance documents in 1997 and 1999, researchers and clinicians have gained a better understanding of drug interactions. This knowledge has enabled the FDA and the industry to progress and begin to overcome these challenges. The FDA has continued its efforts to evaluate methodologies to study drug interactions and communicate recommendations regarding the conduct of drug interaction studies, particularly for CYP-based and transporter-based drug interactions, to the pharmaceutical industry. A drug interaction Web site was established to document the FDA's current understanding of drug interactions (http://www.fda.gov/cder/drug/drugInteractions/default.htm). This report provides an overview of the evolution of the drug interaction guidances, includes a synopsis of the steps taken by the FDA to revise the original drug interaction guidance documents, and summarizes and highlights updated sections in the current guidance document, Drug Interaction Studies-Study Design, Data Analysis, and Implications for Dosing and Labeling.     

Synthetic opioids and arrhythmia risk: a new paradigm?

The most commonly prescribed class of medications in the United States for chronic severe pain is opioid analgesics. Due to their low cost and widespread availability, the synthetic opioids are popular choices among clinicians and patients. However, there is an increasingly recognized risk of QT prolongation with several drugs in this class, and recently propoxyphene (Darvon) was withdrawn from the market by the Food and Drug Administration (FDA) due to, in part, the risk of QT prolongation and ventricular arrhythmias [1] Updated Epidemiological Review of Propoxyphene Safety. [FDA Alert]. Rockville, MD: U.S. Food and Drug Administration; 2010. Available from: http://www.fda.gov/downloads/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/UCM234383.pdf on 5 May 2012 .     

Intellectual property considerations for molecular diagnostic development with emphasis on companion diagnostics

Introduction: The development of molecular diagnostics is a complex endeavor, with multiple regulatory pathways to consider and numerous approaches to development and commercialization. Companion diagnostics, devices which are “essential for the safe and effective use of a corresponding drug or diagnostic product” (see U.S. Food & Drug Administration, In Vitro Diagnostics - Companion Diagnostics, U.S. Dept. of Health & Human Services(2016), available at https://www.fda.gov/medicaldevices/productsandmedicalprocedures/invitrodiagnostics/ucm407297.htm) and complementary diagnostics, which are more broadly associated with a class of drug, are becoming increasingly important as integral components of the implementation of precision medicine.

Areas covered: The following article will highlight the intellectual property (‘IP’) considerations pertinent to molecular diagnostics development with special emphasis on companion diagnostics.

Expert opinion/commentary Summary: For all molecular diagnostics, intellectual property (IP) concerns are of paramount concern, whether the device will be marketed only in the United States or abroad. Taking steps to protect IP at each stage of product development is critical to optimize profitability of a diagnostic product. Also the legal framework around IP protection of diagnostic technologies has been changing over the previous few years and can be expected to continue to change in the foreseeable near future, thus, a comprehensive IP strategy should take into account the fact that changes in the law can be expected.     

A regulatory viewpoint on transporter-based drug interactions

1. Pharmacokinetic drug interactions can lead to serious adverse events and the evaluation of a new molecular entity's (NME) drug-drug interaction potential is an integral part of drug development and regulatory review before its market approval. Clinically relevant interactions mediated by transporters are of increasing interest in clinical development and research in this emerging area and it has been revealed that drug transporters can play an important role in modulating drug absorption, distribution, metabolism and elimination. 2. Acting alone or in concert with drug-metabolizing enzymes transporters can affect the pharmacokinetics and/or pharmacodynamics of a drug. The newly released drug interaction guidance by the US Food and Drug Administration (USFDA) includes new information addressing drug transporter interactions with a primary focus on P-glycoprotein (P-gp, ABCB1). 3. This paper provides a regulatory viewpoint on transporters and their potential role in drug-drug interactions. It first outlines information that might be needed during drug development and ultimately included in new drug application (NDA) submissions to address potential transporter-mediated drug interactions. Next, it explains criteria that may warrant conduct of in vivo P-gp-mediated drug interaction studies based on in vitro assessment. In addition, it includes a review case that describes the evaluation of data suggesting a P-gp-based induction interaction.     

Are literature references sufficient for dose recommendations? An FDA case study of efavirenz and rifampin

One of the numerous regulatory functions of the Food and Drug Administration (FDA) is the evaluation of drug-drug interactions and the determination of appropriate dose adjustments, if necessary, to ensure the safe and effective use of medications. The FDA considers several data sources when determining the significance of drug-drug interactions. The majority of dose adjustment recommendations are based on specific drug-drug interactions studies. The FDA reviews individual patient pharmacokinetic and safety data from drug interaction studies, determines appropriate dose adjustments, and provides recommendations to update the respective product labeling. Sometimes literature references are submitted to the FDA to support dosing recommendations. Determining an appropriate dose adjustment recommendation based on literature reports is a challenge for the FDA due to the lack of individual patient pharmacokinetic or safety data from these studies. Recently, the FDA encountered a challenging regulatory situation when evaluating literature reports to determine the appropriate dose of efavirenz and rifampin. Although numerous studies were found in the literature about this combination, a dosing recommendation cannot be concluded from the reported data. This article reviews the process the FDA used to evaluate literature to support potential dose adjustments for efavirenz when coadministered with rifampin and the challenges encountered during the process.     

Interpreting the Regulatory Perspective on Adaptive Designs

The Food and Drug Administration (FDA) Center for Drug Evaluation and Research (CDER) and Center for Biologics Evaluation and Research (CBER) released a draft guidance (DG) on adaptive clinical trials (ACT) for drugs and biologics in February, 2010. In May, 2016, FDA Center for Devices and Radiological Heath (CDRH) and CBER issued the final guidance (FG) on adaptive medical device trials. The purpose of the FG is to provide clarity on how to plan and implement adaptive designs (AD) for clinical studies used in medical device development and to further encourage companies to use AD.

While both the device FG and drug and biologics DG provided positive review of ACT, the FG position was stronger, stating that the FDA centers “further encourage companies to consider the use of AD in their clinical trials.” Both guidances emphasize the importance of preplanning to avoid Type I error inflation, strict following of the plan to minimize operational bias, and frequent and early interactions with the FDA to ensure the success of the planned ACT. Both guidances emphasize the utilities of clinical trial simulations in design of ACT and in analysis of adaptive trial data. In this article, we present our understanding the guidances.     

Assessment of the quality and quantity of drug-drug interaction studies in recent NDA submissions: study design and data analysis issues.

This report investigates the quality and quantity of drug-drug interaction studies in recent new drug applications (NDAs). Eighty-nine studies contained in 14 NDAs submitted between December 1995 and November 1996 to the U.S. Food and Drug Administration (FDA) were reviewed. The results indicated that the median number of clinical drug-drug interaction studies per NDA was 6, almost double that of a 1994-1995 survey. In vitro metabolism data were present in 70% of the submissions. More than 50% of the submissions contained interaction studies using a battery of drugs (cimetidine, digoxin, or warfarin) without optimal use of the in vitro metabolism or in vivo mass balance data. Various study designs using a median number of 12 subjects were employed in the evaluation of drug-drug interactions. Some of the important study design factors such as dose size, dosing regimen, dosing duration, and timing of coadministration were considered, although not consistently, by the sponsors in their study design. Seventy-five percent of the studies used normal, healthy male subjects, and 25% used patients for whom the new molecular entities were intended. In 33% of the studies, female subjects were also recruited. Although the majority (80%) of the submissions still used p-values to determine the significance of drug interactions, 30% used a more relevant equivalence approach with 90% confidence intervals for key pharmacokinetic and/or pharmacodynamic parameter ratios to assess the extent of drug interactions. Overall, 82% of the studies concluded no interaction. Although population pharmacokinetic analysis can be a useful tool in studying drug-drug interactions, only 21% of the submissions used this approach. In summary, this assessment reveals that the quantity and quality of drug-drug interaction studies in NDAs have improved over the years. These improvements, as well as others that can be implemented, should result in more informative labeling and better patient care. FDA guidance for industry dealing with the design, analysis, and labeling language of in vivo metabolic drug-drug interactions has been developed to assist sponsors and FDA reviewers with these issues.     

FDA“间质性膀胱炎/膀胱疼痛综合征：制定治疗药物开发方案的供企业用的指导原则草案”介绍

美国食品药品管理局（FDA）2023年6月宣布了“间质性膀胱炎/膀胱疼痛综合征：制定治疗药物开发方案的供企业用的指导原则草案”（修订版1）。该修订版取代了FDA于2019年12月发布的“间质性膀胱炎/膀胱疼痛综合征（IC/BPS）：确定治疗药物的有效性的供企业用的指导原则草案”。该指导原则修订版，针对治疗间质性膀胱炎/膀胱疼痛综合征（IC/BPS）的药物临床开发的难点，为其临床研究方案提出了许多详细而具体的建议，这些建议有重要的指导意义和参考价值。而我国目前还没有类似的指导原则。详细介绍FDA该指导原则修订版，期望对我国这类药物开发的临床研究和审评有所裨益。     

Topical treatment of glaucoma: established and emerging pharmacology

Introduction: Glaucoma is a collection of optic neuropathies consisting of retinal ganglion cell death and corresponding visual field loss. Glaucoma is the leading cause of irreversible vision loss worldwide and is forecasted to precipitously increase in prevalence in the coming decades. Current treatment options aim to lower intraocular pressure (IOP) via topical or oral therapy, laser treatment to the trabecular meshwork or ciliary body, and incisional surgery. Despite increasing use of trabecular laser therapy, topical therapy remains first-line in the treatment of most forms of glaucoma.

Areas covered: Novel glaucoma therapies are a long-standing focus of investigational study. More than two decades have passed since the last United States Food and Drug Administration (FDA) approval of a topical glaucoma drug. Here, the authors review established topical glaucoma drops as well as those currently in FDA phase 2 and 3 clinical trial, nearing clinical use.

Expert opinion: Current investigational glaucoma drugs lower IOP, mainly through enhanced trabecular meshwork outflow. Although few emerging therapies show evidence of retinal ganglion cell and optic nerve neuroprotection in animal models, emerging drugs are focused on lowering IOP, similar to established medicines.     

FDA “肽类药物产品临床药理学的考虑的供企业用的指导原则草案” 及其启示

美国食品药品管理局（FDA）于2023年9月发布了“肽类药物产品临床药理学的考虑的供企业用的指导原则草案”。该指导原则描述了FDA对肽类药物产品开发方案的临床药理学的建议,包括肝损害、药物-药物相互作用评估、心电图按心率校正的QT间期（QTc）延长风险评估以及免疫原性风险及其对药动学、安全性和有效性评估的影响。详细介绍FDA该指导原则的主要内容,期望对我国肽类药物产品临床药理学研究和监管有所启示。     

Design and implementation of mobile APP for medication guidance related to pharmacogenomic based on APICloud platform

The mobile APP for medication guidance related to pharmacogenomic is developed to solve various practical problems, such as inconvenient reading of English database, slow updating of paper reference books and lack of shortcut for access. We extracted the medication guidance information related to the pharmacogenomic from ‘Dosing Guidelines’ (http://www.pharmgkb.com), ´Table of Pharmacogenomic Biomarkers in Drug Labeling´ (http://www.fda.gov/drugs/scienceresearch) and relevant authoritative books. SQLite was used to build the medication guidance information database. We designed and implemented a mobile APP for medication guidance by JavaScript programming language. The APP contained 197 drugs that have been extensively studied and have high levels of evidence. It covered 25 categories, such as anticoagulant and antiplatelet drugs, general antitumor, immunosuppressant drugs, targeted antitumor drugs, antipsychotic drugs, antiepileptic drugs, and proton pump inhibitors and so on. Users can obtain clinical significance and guidance information related to the genotype of the drug by entering the pinyin initials of the generic name of the drug. The mobile APP for medication guidance related to pharmacogenomic based on APICloud could provide practical and convenient pharmaceutical information service for clinical use.     

Population pharmacokinetics. A regulatory perspective.

The application of population approaches to drug development is recommended in several US Food and Drug Administration (FDA) guidance documents. Population pharmacokinetic (and pharmacodynamic) techniques enable identification of the sources of inter- and intra-individual variability that impinge upon drug safety and efficacy. This article briefly discusses the 2-stage approach to the estimation of population pharmacokinetic parameters, which requires serial multiple measurements on each participant, and comprehensively reviews the nonlinear mixed-effects modelling approach, which can be applied in situations where extensive sampling is not done on all or any of the participants. Certain preliminary information, such as the compartment model used in describing the pharmacokinetics of the drug, is required for a population pharmacokinetic study. The practical design considerations of the location of sampling times, number of samples/participants and the need to sample an individual more than once should be borne in mind. Simulation may be useful for choosing the study design that will best meet study objectives. The objectives of the population pharmacokinetic study can be secondary to the objectives of the primary clinical study (in which case an add-on population pharmacokinetic protocol may be needed) or primary (when a stand-alone protocol is required). Having protocols for population pharmacokinetic studies is an integral part of 'good pharmacometric practice'. Real-time data assembly and analysis permit an ongoing evaluation of site compliance with the study protocol and provide the opportunity to correct violations of study procedures. Adequate policies and procedures should be in place for study blind maintenance. Real-time data assembly creates the opportunity for detecting and correcting errors in concentration-time data, drug administration history and covariate data. Population pharmacokinetic analyses may be undertaken in 3 interwoven steps: exploratory data analysis, model development and model validation (i.e. predictive performance). Documentation for regulatory purposes should include a complete inventory of key runs in the analyses undertaken (with flow diagrams if possible), accompanied by articulation of objectives, assumptions and hypotheses. Use of diagnostic analyses of goodness of fit as evidence of reliability of results is advised. Finally, the use of stability testing or model validation may be warranted to support label claims. The opinions expressed in this article were revised by incorporating comments from various sources and published by the FDA as 'Guidance for Industry: Population Pharmacokinetics' (see the FDA home page http:/(/)www.fda.gov for further information).     

New and incremental FDA black box warnings from 2008 to 2015

Background: The boxed warning (also known as ‘black box warning [BBW]’) is one of the strongest drug safety actions that the U.S. Food & Drug Administration (FDA) can implement, and often warns of serious risks. The objective of this study was to comprehensively characterize BBWs issued for drugs after FDA approval.

Methods: We identified all post-marketing BBWs from January 2008 through June 2015 listed on FDA’s MedWatch and Drug Safety Communications websites. We used each drug’s prescribing information to classify its BBW as new, major update to a preexisting BBW, or minor update. We then characterized these BBWs with respect to pre-specified BBW-specific and drug-specific features.

Results: There were 111 BBWs issued to drugs on the US market, of which 29% (n = 32) were new BBWs, 32% (n = 35) were major updates, and 40% (n = 44) were minor updates. New BBWs and major updates were most commonly issued for death (51%) and cardiovascular risk (27%). The new BBWs and major updates impacted 200 drug formulations over the study period, of which 64% were expected to be used chronically and 58% had available alternatives without a BBW.

Conclusions: New BBWs and incremental updates to existing BBWs are frequently added to drug labels after regulatory approval.     

Modeling and simulation for medical product development and evaluation: highlights from the FDA-C-Path-ISOP 2013 workshop

Medical-product development has become increasingly challenging and resource-intensive. In 2004, the Food and Drug Administration (FDA) described critical challenges facing medical-product development by establishing the critical path initiative [1]. Priorities identified included the need for improved modeling and simulation tools, further emphasized in FDA’s 2011 Strategic Plan for Regulatory Science [Appendix]. In an effort to support and advance model-informed medical-product development (MIMPD), the Critical Path Institute (C-Path) [www.c-path.org], FDA, and International Society of Pharmacometrics [www.go-isop.org] co-sponsored a workshop in Washington, D.C. on September 26, 2013, to examine integrated approaches to developing and applying model- MIMPD. The workshop brought together an international group of scientists from industry, academia, FDA, and the European Medicines Agency to discuss MIMPD strategies and their applications. A commentary on the proceedings of that workshop is presented here.     

Assuring Safety of Inherently Unsafe Medications: the FDA Risk Evaluation and Mitigation Strategies

The decision to approve a drug for clinical use is based on an understanding of its benefits versus the risks. Although efficacy is generally understood at the time of submission to the FDA for approval, the risks are more difficult to assess. Both PubMed (from 2000 to 2012) and the FDA website (www.fda.gov) were searched using the search terms “risk evaluation and mitigation strategy” (REMS). Articles for review were selected by relevance to topic, and their references were searched as well for additional relevant resources. Since the search results were not expected to contain research studies, formal quality assessment and inclusion and exclusion criteria were not utilized resulting in a narrative review. Few directly relevant research studies exist, although supporting documents such as government reports were available. For effective drugs with unclear or concerning safety records, the FDA has the option of requiring a risk evaluation and mitigation strategy, which allows a systematic approach to track and assure safe medication use. Over 100 different medications are currently covered by REMS, and each REMS is developed individually based on the needs of the specific drug or class. Although likely associated with improvements in medication safety, the potential benefit, limitations, and consequences of REMS are not yet fully understood.     

A regulatory viewpoint on transporter-based drug interactions

1.?Pharmacokinetic drug interactions can lead to serious adverse events and the evaluation of a new molecular entity's (NME) drug–drug interaction potential is an integral part of drug development and regulatory review before its market approval. Clinically relevant interactions mediated by transporters are of increasing interest in clinical development and research in this emerging area and it has been revealed that drug transporters can play an important role in modulating drug absorption, distribution, metabolism and elimination.

2.?Acting alone or in concert with drug-metabolizing enzymes transporters can affect the pharmacokinetics and/or pharmacodynamics of a drug. The newly released drug interaction guidance by the US Food and Drug Administration (USFDA) includes new information addressing drug transporter interactions with a primary focus on P-glycoprotein (P-gp, ABCB1).

3.?This paper provides a regulatory viewpoint on transporters and their potential role in drug–drug interactions. It first outlines information that might be needed during drug development and ultimately included in new drug application (NDA) submissions to address potential transporter-mediated drug interactions. Next, it explains criteria that may warrant conduct of in vivo P-gp-mediated drug interaction studies based on in vitro assessment. In addition, it includes a review case that describes the evaluation of data suggesting a P-gp-based induction interaction.     

Experience with Reviewing Bayesian Medical Device Trials

The purpose of this paper is to present a statistical reviewer's perspective on some technical aspects of reviewing Bayesian medical device trials submitted to the Food and Drug Administration. The discussion reflects the experiences of the authors and should not be misconstrued as official guidance by the FDA. A variety of applications are described, reflecting our experience with therapeutic and diagnostic devices. In addition to Bayesian analysis of trials, Bayesian trial design and Bayesian monitoring are discussed. Analyses were implemented in WinBUGS (http://www.mrc-bsu.cam.ac.uk/bugs/winbugs/contents.shtml), with the code provided.