Drug Administration Draft Guidance Research Articles

Role of Clinical Pharmacology in Diversity and Inclusion in Global Drug Development: Current Practices and Industry Perspectives: WhitePaper.

The 2022 United States Food and Drug Administration (US FDA) draft guidance on diversity plan (DP), which will be implemented through the Diversity Action Plans by December 2025, under the 21st Century Cures Act, marks a pivotal effort by the FDA to ensure that registrational studies adequately reflect the target patient populations based on diversity in demographics and baseline characteristics. This white paper represents the culminated efforts of the International Consortium of Quality and Innovation (IQ) Diversity and Inclusion (D&I) Working Group (WG) to assess the implementation of the draft FDA guidance by members of the IQ consortium in the discipline of clinical pharmacology (CP). This article describes current practices in the industry and emphasizes the tools and techniques of quantitative pharmacology that can be applied to support the inclusion of a diverse population during global drug development, to support diversity and inclusion of underrepresented patient populations, in multiregional clinical trials (MRCTs). It outlines strategic and technical recommendations to integrate demographics, including age, sex/gender, race/ethnicity, and comorbidities, in multiregional phase III registrational studies, through the application of quantitative pharmacology. Finally, this article discusses the challenges faced during global drug development, which may otherwise limit the enrollment of a broader, potentially diverse population in registrational trials. Based on the outcomes of the IQ survey that provided the current awareness of diversity planning, it is envisioned that in the future, industry efforts in the inclusion of previously underrepresented populations during global drug development will culminate in drug labels that apply to the intended patient populations at the time of new drug application or biologics license application rather than through post-marketing requirements.

International Society for Quality of Life Research commentary on the US Food and Drug Administration draft guidance for industry on core patient-reported outcomes in cancer clinical trials

In June 2021, the US Food and Drug Administration (FDA) released a draft guidance for industry on core patient-reported outcomes (PROs) and related considerations for instrument selection and trial design in registrational cancer clinical trials, building on prior communications about the use of PROs to assess efficacy and tolerability in oncology drug development. The International Society for Quality of Life Research (ISOQOL) Standards and Best Practices Committee led an initiative to draft a commentary about the guidance, focusing on its positive aspects and areas that would benefit from additional clarification and consideration. For comprehensiveness, the authors reviewed existing public comments on the draft guidance, and the commentary underwent a thorough review process through three ISOQOL Special Interest Groups (Psychometrics, Clinical Practice, and Regulatory and Health Technology Assessment Engagement) followed by the ISOQOL Board. The goal of this commentary is to situate this new and relevant guidance document within the context of recent regulatory efforts on PROs and highlight areas in which further work may ultimately benefit the field.

Industry Perspective on Therapeutic Peptide Drug-Drug Interaction Assessments During Drug Development: A European Federation of Pharmaceutical Industries and Associations White Paper.

Drug-drug interaction (DDI) assessments are well defined in health authority guidelines for small molecule drugs, and US Food and Drug Administration (FDA) draft guidance is now available for therapeutic proteins. However, there are currently no regulatory guidelines outlining DDI assessments for therapeutic peptides, which poses significant uncertainty and challenges during drug development for this heterogenous class of molecules. A cross-industry peptide DDI working group consisting of experts from 10 leading companies was formed under the sponsorship of the European Federation of Pharmaceutical Industries and Associations. We aimed to capture the range of DDI studies undertaken for peptide drugs by (i) anonymously surveying relevant companies involved in peptide drug development to better understand DDI study type/timing currently performed and (ii) compiling a database containing in vitro / clinical DDI data from submission packages for recently approved peptide drugs. Our analyses highlight significant gaps and uncertainty in the field. For example, the reported timing of in vitro peptide DDI studies, if performed, vary substantially across responding companies from early research to phase III. Nearly all in vitro cytochrome P450 / transporter inhibition studies reported in the survey were negative. For the few positive hits reported, no clinical follow-up studies were performed, questioning the clinical relevance of these findings. Furthermore, available submission packages reveal DDI likelihood is low for peptides >2kDa, making it reasonable to adopt a risk-based approach during drug development for larger peptides. By benchmarking the landscape of peptide DDI activities across the industry, we set the stage for future discussions with health authorities on harmonizing peptide DDI approaches.

Proposed Best Practice Guidelines for Scientific Response Documents: A Consensus Statement from phactMI.

The Medical Information Department of a pharmaceutical manufacturer provides written scientific responses to unsolicited requests from healthcare providers for information on products that extends beyond the product labeling (off-label). These scientific response documents are non-promotional, evidence-based, and scientifically balanced, conforming with internal pharmaceutical manufacturer's procedures and the Food and Drug Administration (FDA) Draft Guidance on Responding to Unsolicited Requests for Off-Label Information. Members of phactMI™ developed this proposal to offer best practices for content generation of scientific response documents. Scientific response documents review available literature to respond to an unsolicited request; therefore, they are similar in nature to systematic reviews. The sections and elements identified in this proposed best practice guidelines for scientific response documents are based on an adaptation of the sections and elements of systematic reviews. The sections of a scientific response document should include a restatement of the unsolicited request (title); a structured summary (abstract); approved indications, black box warnings, and background information when appropriate (introduction); the literature search information and study selection (methods); summation of data from clinical trials, meta-analysis, case reports, and/or real world evidence, as appropriate (results); treatment guidelines, if applicable and available (discussion); and references. Elements for each section should be included in a scientific response document as appropriate, as some elements are not necessary in some documents, based on the question. These elements were selected for inclusion to address any potential concerns of bias and transparency and reflect the intent that scientific response documents should be non-promotional, accurate, truthful, free of commercial bias, scientifically balanced, and evidence based.

Drug-Drug Interactions of P-gp Substrates Unrelated to CYP Metabolism.

Recent US Food and Drug Administration (FDA) draft guidance on pharmacokinetic drugdrug interactions (DDIs) has highlighted the clinical importance of ABC transporters B1 or P-glycoprotein (P-gp), hepatic organic anion-transporting polypeptide transporters and breast cancer resistant protein because of their broad substrate specificity and the potential to be involved in DDIs. This guidance has indicated that digoxin, dabigatran etexilate and fexofenadine are P-gp substrate drugs and has defined P-gp inhibitors as those that increase the AUC of digoxin by ≧1.25-fold in clinical DDI studies. However, when substrate drugs of both CYPs and P-gp are involved in DDIs, it remains that the mechanisms of DDIs will be quite ambiguous in assessing how much the CYPs and/or drug transporters partially contribute to DDIs. Since there are no detailed manuscripts that summarizes P-gp interactions unrelated to CYP metabolism, this article reviews the effects of potent P-gp inhibitors and P-gp inducers on the pharmacokinetics of P-gp substrate drugs, including digoxin, talinolol, dabigatran etexilate, and fexofenadine in human studies. In addition, the present outcome were to determine the PK changes caused by DDIs among P-gp substrate drugs without CYP metabolism in human DDI studies. Our manuscript concludes that the PK changes of the DDIs among P-gp drugs unrelated to CYP metabolism are less likely to be serious, and it appears to be convincing that the absences of clinical effects caused to the PK changes by the P-gp inducers is predominant compared with the excessive effects caused to those by the P-gp inhibitors.

Four Food and Drug Administration draft guidance documents and the REGROW Act: A litmus test for future changes in human cell- and tissue-based products regulatory policy in the United States?

Modern regenerative medicine research has expanded well past the development of traditional drugs and medical devices with many promising new therapies encompassing an increasingly diverse range of substances, notably cell‐based therapies. These substantial recent developments and the progress in the health care and therapeutics fields necessitate a new regulatory framework agile enough to accommodate these unique therapies and acknowledge their differences with traditional pharmaceuticals. In the United States, recent proposed changes in the regulatory framework for autologous human cells, tissues, and cellular and tissue‐based products (HCT/Ps) and their perceived risk–benefit analysis for patients remain controversial in the scientific field. To provide perspective on of the current status of the most recent attempts to redefine and conceptualize these changes in the United States, we will examine 4 draft guidance documents implemented by the Food and Drug Administration in interpreting relevant concepts and terminology pertaining to HCT/Ps: the Bipartisan Policy Center think tank report, “Advancing Regenerative Cellular Therapy: Medical Innovation for Healthier Americans,” the proposed REGROW Act for HCT/Ps, and the current 24 Food and Drug Administration‐approved HCT/Ps and related products in the United States.

Bacterial screening of apheresis platelets with a rapid test: a 113-month single center experience.

The 2016 Food and Drug Administration draft guidance describes the use of a rapid test (RT) to enhance platelet transfusion safety and availability. This study reports a 113-month experience of screening of apheresis platelets (APs) by RT. From July 2008 to October 2015, all APs underwent an RT on Day 4. Day 6 and 7 units were transfused with transfusion medicine physician approval. Any units remaining on Day 8 had a second RT performed. From November 2015 to November 2017, APs underwent an RT on Day 5 with a repeat RT on Days 6 and 7. During both periods, positive RTs underwent confirmatory testing with culture when repeat testing was positive. A total of 9009 APs underwent an RT on Day 4 or 5. Of these, 45 (0.5%) were RT positive, with no true positives. A total of 754 underwent a second RT on Day 8, with no positives. Since November 2015, 1152 platelets have undergone a second RT on Day 6; 391 have undergone a third RT on Day 7. Of these, five (0.4%) were RT positive on Day 6, with no true positives. There were no septic transfusion reactions identified by passive surveillance at our institution during either study period. To date, we have not detected any true positives after performing 11,306 tests on 9009 APs. A total of 1906 underwent testing twice, and 391 underwent testing three times. We did not identify any conversions from negative to positive on repeat testing.

A phase-3, double-blind, placebo-controlled study of the effectiveness and safety of single oral doses of secnidazole 2 g for the treatment of women with bacterial vaginosis

A novel single oral dose granule formulation of secnidazole 2 g, a 5-nitroimidazole with a longer half-life (∼17 hours) than metronidazole (∼8 hours), is being developed to treat bacterial vaginosis. We sought to evaluate the effectiveness and safety of single-dose secnidazole 2 g compared to placebo for the treatment of women with bacterial vaginosis. In all, 189 women with bacterial vaginosis were randomized 2:1 to receive a single oral dose of secnidazole 2 g (N= 125) or matched placebo (N= 64) at 21 centers in the United States. The primary endpoint was the proportion of clinical outcome responders, defined as those with: (1) normal vaginal discharge; (2) negative 10% potassium hydroxide whiff test; and (3) <20% clue cells of total epithelial cell count on microscopic examination of the vaginal wet mount, using saline at the test of cure/end of study visit (study days 21-30). Secondary efficacy analyses included clinical cure rates, defined as: (1) responders with normal vaginal discharge; (2) negative potassium hydroxide whiff tests; and (3) clue cells <20% assessed at the interim visit (study days 7-14), and test of cure/end of study (study days 21-30). In addition, based on the 2016 US Food and Drug Administration draft guidance, patients with baseline Nugent scores 7-10 were evaluated for clinical cure using the following clinical assessments on study days 7-14: (1) resolution of the abnormal vaginal discharge; (2) a negative potassium hydroxide whiff test; and (3) clue cells <20%. The study was designed and powered todemonstrate the efficacy of single-dose secnidazole 2 g compared toplacebo; safety and tolerability were also assessed. Due to a prespecified institutional review board-approved protocol calling for withdrawal of randomized, treated patients with a Nugent score <4 or with a separate sexually transmitted infection, this modified intent-to-treat population was the primary analysis population. Statistical comparisons used a stratified Cochran-Mantel-Haenszel test with a .05 level of significance (2-sided). Single-dose secnidazole 2 g was superior to placebo for the primary and all secondary efficacy measures in the modified intent-to-treat population, with clinical outcome responder rates of 53.3% (57/107) vs 19.3% (11/57; P < .001). Clinical cure rates, based on an alternate definition of responder, which accounted for resolution of abnormal discharge consistent with bacterial vaginosis, were consistent with the clinical outcome responder rate analysis (58.9% vs 24.6%; P < .001) for single-dose secnidazole 2 g vs placebo. Clinical cure rates based on the 2016 US Food and Drug Administration guidance were 64.0% vs 26.4% for single-dose secnidazole 2 g vs placebo. Based on the investigator's clinical assessment at the test of cure/end of study visit, significantly more patients receiving single-dose secnidazole 2 g vs placebo required noadditional bacterial vaginosis treatment (68.0% [68/100] vs 29.6% [16/54]; P < .001). Adverse events considered by the investigator to be related to study drug occurred in only 20.0% of single-dose secnidazole 2 g-treated patients vs 10.9% of placebo patients, and they included diarrhea (4.0% vs 1.6%), headache (4.0% vs 3.1%), nausea (4.8% vs 1.6%), and vulvovaginal candidiasis (4.0% vs 3.1%). Single-dose secnidazole 2 g was superior to placebo on all primary and secondary outcomes and was well tolerated; these results support its role for the treatment of women with bacterial vaginosis.

Implications of the US Food and Drug Administration draft guidance for mitigating septic reactions from platelet transfusions.

In March 2016, the US Food and Drug Administration (FDA) issued the second draft guidance entitled “Bacterial Risk Control Strategies for Blood Collection Establishments and Transfusion Services to Enhance the Safety and Availability of Platelets for Transfusion.”1 This draft guideline addresses the residual risk of bacterial contamination of platelet products, which may result in septic transfusion reactions. Among blood products, platelet products are most frequently associated with septic transfusion reactions, as they are stored at room temperature. Since 2004, multiple steps have been implemented to decrease the risk of contamination. These include skin cleansing, diversion pouch, and bacterial screening. These steps have decreased the rate of septic reactions from a reported range of 10 to 400 to 7 to 25 per 1 000 000, and the rate of fatal septic reactions from a reported range of 2 to 63 to 2 to12 per 1 000 000 apheresis platelet products transfused.2 Thus, the overall risk has decreased by approximately two thirds. In the last couple of years, additional steps to decrease risk of septic reactions have been FDA approved, including pathogen-reduction technologies (PRT) and point-of-issue (POI) (also known as point-of-release) testing capabilities. At the New York Blood Center (NYBC), the residual risk as reported from hospitals is septic reaction rate of 1 per 250 065.3 Recent data using prospective testing report 20 per 51 400 (1/2570) platelet products contaminated resulting in 4 per 51 400 (1/12 800) reactions (1 being fatal [1/51 400]).4 PRT decreases most bacteria load by >4 logs. Hemovigilance data have not reported septic transfusion cases with pathogen-reduced (PR) platelets.5 Prospective screening of apheresis platelets using the Pan Genera Detection (PGD) test (Verax Biomedical, Marlborough, MA), a POI test, demonstrated a residual bacterial contamination risk of 1 per 2302 (75% detected with PGD) apheresis platelets. The PGD has a false positive rate of 0.51% and a false negative rate of 1 in 9206.6 The FDA-reported fatality rates due to bacteria contamination of platelets (both pooled and apheresis) range from 1 to 4 per year from 2011 to 2015 in ∼2.1 million annual platelets transfused.7,8 Staphylococcus aureus was the contaminant in the majority of contaminated apheresis platelets. The FDA draft guidance asks for implementation of PRT, POI testing, or a second bacterial culture, or to shorten the shelf life of the platelet product from 5 to 3 days. Each of these methods has considerable logistical and clinical issues. In June 2016, during the open comment period, the NYBC, as well as other blood centers, including AABB (formerly known as the American Association of Blood Banks) and ABC (America’s Blood Centers), expressed their opinions regarding the impact of implementing the draft guidance as written (https://www.regulations.gov/docket?D=FDA-2014-D-1814). We have recently submitted additional comments and have urged the FDA to reopen the comment period to encourage a broader community to remark. Options for meeting these new guidelines based upon days from collection are shown in Table 1. Once the guidance is finalized, there is a proposed 1-year implementation date. Table 1. Platelet product shelf-life and draft guidance options

“The safety of sodium reduction in the food supply: A cross-discipline balancing act”—Workshop proceedings

ABSTRACTThis workshop, jointly presented by the ILSI North America Technical Committees on Food Microbiology and Sodium, aimed to provide greater knowledge and appreciation of the opportunities and challenges facing the food industry in answering the public health community's call to reduce sodium levels in the food supply. One major challenge is finding effective substitutes for the various antimicrobial and functional roles that sodium plays across different food categories. Sodium plays a critical role in retarding the growth of pathogens and food spoilage bacteria. Moreover, taste is an important factor for consumers when they choose food products, and the flavor changes that occur when salt is reduced or replaced must be considered and ingredients and processes adjusted accordingly. The workshop provided a platform for a multidisciplinary discussion among the microbiology, food science, nutrition, and public health communities to share progress and propose solutions, including the formation of public-private partnerships, to develop coordinated and comprehensive strategies. This paper provides an overview of the issues raised, rather than a specific summary of workshop discussions. The Food and Drug Administration's Draft Guidance for Industry on voluntary sodium reduction and the 2015 US Dietary Guidelines for Americans were released subsequent to the workshop and are also discussed.

Bioequivalence Demonstration for Ω-3 Acid Ethyl Ester Formulations: Rationale for Modification of Current Guidance

The US Food and Drug Administration (FDA) draft guidance for establishing bioequivalence (BE) of ω-3 acid ethyl esters (containing both eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA] as ethyl esters), used to treat severe hypertriglyceridemia, recommends the conduct of 2 studies: one with participants in the fasting state and one with participants in the fed state. For the fasting study, the primary measures of BE are baseline-adjusted EPA and DHA levels in total plasma lipids. For the fed study, the primary measures of BE are EPA and DHA ethyl esters in plasma. This guidance differs from that established for icosapent ethyl (EPA ethyl esters) in which the primary measure of BE is baseline-adjusted total EPA in plasma lipids for both the fasting and fed states. The FDA guidance for ω-3 acid ethyl esters is not supported by their physiologic characteristics and triglyceride-lowering mechanisms because EPA and DHA ethyl esters are best characterized as pro-drugs. This article presents an argument for amending the FDA draft guidance for ω-3 acid ethyl esters to use baseline-adjusted EPA and DHA in total plasma lipids as the primary measures of BE for both fasting and fed conditions. This change would harmonize the approaches for demonstration of BE for ω-3 acid ethyl esters and icosapent ethyl (EPA ethyl esters) products for future development programs and is the most physiologically rational approach to BE testing.

DIA's Adaptive Design Scientific Working Group (ADSWG): Best Practices Case Studies for "Less Well-understood" Adaptive Designs.

Adaptive design (AD) clinical trials use accumulating subject data to modify the parameters of the design of an ongoing study, without compromising the validity and integrity of the study. The 2010 US Food and Drug Administration (FDA) Draft Guidance on Adaptive Design Clinical Trials described a subset of 7 primary design types as "less well-understood." FDA defined these designs as those with limited regulatory experience. To better understand the properties of these less well-understood ADs and to promote their use when applicable, the Best Practices Subteam for DIA's Adaptive Design Scientific Working Group conducted an extensive nonsystematic search and reviewed trials from multiple sponsors who had employed these designs. Here, we review 10 specific case studies for which less well-understood ADs were employed and share feedback about their challenges and successes, as well as details about the regulatory interactions from these trials. We learned that these designs and associated statistical methodologies can make difficult research situations more amenable for study and, therefore, are needed in our toolbox. While they can be used to study many diseases, they are particularly valuable for rare diseases, small populations, studies involving terminal illnesses, and vaccine trials, in which it is important to find efficient ways to bring effective treatments to market more rapidly. It is imperative, however, that these methodologies be utilized appropriately, which requires careful planning and precise operational execution.

Drugs and Diseases Interacting with Cigarette Smoking in US Prescription Drug Labelling.

The US Food and Drug Administration (FDA) draft guidance for industry on drug interaction studies recommends, but does not mandate, that both cigarette smokers and non-smokers can be used to study drug metabolism in clinical trials, and that important results related to smoking should be included in drug labelling to guide medication usage. This study aimed to provide a comprehensive review of drugs or diseases interacting with smoking, as presented in all US drug labelling. The 62,857 drug labels deposited in the FDA Online Label Repository were searched using the keywords 'smoke', 'smoker(s)', 'smoking', 'tobacco' and 'cigarette(s)' on 19 June 2014. The resultant records were refined to include only human prescription drug labelling, for manual examination. For 188 single-active-ingredient drugs and 36 multiple-active-ingredient drugs, the labelling was found to contain smoking-related information. The pharmacokinetics of 29 and 21 single-active-ingredient drugs were affected and unaffected, respectively, by smoking. For the remaining drugs, the provided information related to smoking affecting efficacy, safety or diseases but not pharmacokinetics. Depending on the nature of specific drugs, the perturbation in pharmacokinetic parameters in smokers ranged from 13 to 500%, in comparison with non-smokers. Dosage modifications in smokers are necessary for four drugs and may be necessary for six drugs, but are unnecessary for seven drugs although the pharmacokinetic parameters of four of them are affected by smoking. Cigarette smoking is a risk factor for 16 types of diseases or adverse drug reactions. For one single-active-ingredient contraceptive drug and 10 multiple-active-ingredient contraceptive drugs, a black box warning (the FDA's strongest safety warning) is included in the labelling for increased risks of heart attacks and strokes in female smokers, and "women are strongly advised not to smoke" when using these drugs. This study presents the first comprehensive overview of cigarette smoking interacting with drugs and/or diseases, as presented in US drug labelling.

Compliance Within Medical Information and the Emergence of a Medical Information-Dedicated Compliance Person: A Benchmarking Survey.

In light of the increasing scrutiny by governing authorities, compliance requirements for medical information (MI) departments have increased over the past few years. In response to the Food and Drug Administration (FDA) draft guidance for industry, entitled Responding to Unsolicited Requests for Off-label Information About Prescription Drugs and Medical Devices, MI groups may be changing their policies and procedures to further ensure compliance. The primary objective of this study was to benchmark industry-specific practices related to maintaining compliance in MI, particularly whether there is an emergence of a dedicated compliance person working within the MI department, whom we refer to as the MI-dedicated compliance person hereafter. A secondary objective was to identify changes to MI interactions with internal and external stakeholders that occurred in the last 2 years in response to an evolving regulatory climate. A web-based survey was disseminated to MI professionals from 49 companies between December 2012 and February 2013. Practices that were assessed include MI team training, monitoring, audits, and creation of letter responses. The results may be useful for MI groups interested in changing or comparing their compliance practices to those currently utilized by their peers.

A Review of FDA Warning Letters and Notices of Violation Issued for Patient-Reported Outcomes Promotional Claims between 2006 and 2012

ObjectiveTo ascertain the frequency and types of patient-reported outcome (PRO) violations made in US pharmaceutical promotional materials between 2006 and 2012 and determine whether there were increases in violation warnings after issuance of the Food and Drug Administration (FDA) draft and final PRO Guidance. MethodsAll warning letters (WLs) or notices of violation (NOVs) issued by the FDA’s Office of Prescription Drug Promotion were reviewed for PRO violations (n = 213). Each letter containing a PRO violation was reviewed to determine the type of violation: 1) PRO measure not fit for purpose, 2) study design/interpretation of results, 3) statistical analysis, and 4) no treatment benefit. ResultsForty-one (19%) letters contained information about PRO infringements. Noticeable spikes in letters were shown in 2007 (37%) and 2010 (31%) after the issuance of the draft and final PRO Guidance, respectively. The most common violation was PRO measure not fit for purpose (54%), specifically: use of individual items (45%), insufficient evidence of content validity (36%), and broadening of the claim beyond what the PRO measures (27%). Issues with study design/interpretation of results were also high (49%), particularly broadening of claim beyond what was measured in the trial (55%) and no PRO measure used (50%). ConclusionsA fifth of the letters issued to companies contained PRO violations, with most related to poor selection of the PRO measure used or trying to broaden the claim. More guidance from the Office of Prescription Drug Promotion about what is considered “substantial evidence” in this area could help reduce the number of letters issued.

Comparison of in vitro release rates of acyclovir from cream formulations using vertical diffusion cells.

Acyclovir, indicated in the treatment of herpes labialis ("cold sores"), is formulated as semisolid topical dosage forms and marketed in numerous countries. Since the formulations of the various acyclovir products may differ from country to country, this study was undertaken to compare the in vitro release of acyclovir from various generic cream products available on the South African and Indian markets using the respective brand/innovator product as the reference product. The in vitro studies were carried out using vertical diffusion cells with a diffusional surface area of 1.767cm(2) and various commercially available membranes. Normal saline was used as receptor fluid and the temperature maintained at 32 ± 0.5°C. The in vitro release comparisons were based on the recommendations described in the US Food and Drug Administration Draft Guidance for acyclovir ointment and the SUPAC-SS Guidance for non-sterile semisolid dosage forms. The release rates (slope) of the test (T) and the relevant reference product (R) were monitored and compared. The comparative release of acyclovir from the various generic formulations compared with the reference product was found to be within the limits of 75-133.33% with a 90% confidence interval. These experiments indicate that the generic acyclovir cream formulations exhibited release rates that were comparable to the innovator product and could be considered to be bioequivalent.

Rethinking the Food and Drug Administration's 2013 guidance on developing drugs for early-stage Alzheimer's disease

The February 2013 Food and Drug Administration (FDA) draft guidance for developing drugs for early-stage Alzheimer's disease (AD) creates certain challenges as they guide toward the use of one cognitive outcome to gain accelerated marketing approval for preclinical AD drugs, and a composite clinical scale – the Clinical Dementia Rating Scale in particular – for the primary outcome for prodromal AD clinical trials.In light of the developing knowledge regarding early stage diagnoses and clinical trials outcomes, we recommend that FDA describe its requirements for validating preclinical AD diagnoses for drug development purposes, maintain the principle for requiring coprimary outcomes, and encourage the advancement of outcomes for early stage AD trials. The principles for drug development for early stage AD should not differ from those for clinical AD, especially as the diagnoses of prodromal and early AD impinge on each other. The FDA should not recommend that a composite scale be used as a sole primary efficacy outcome to support a marketing claim unless it requires that the cognitive and functional components of such a scale are demonstrated to be individually meaningful. The current draft guidelines may inadvertently constrain efforts to better assess the clinical effects of new drugs and inhibit innovation in an area where evidence-based clinical research practices are still evolving.

Evaluation of 23 Lots of Commercially Available Cryopreserved Hepatocytes for Induction Assays of Human Cytochromes P450

Due to the importance of in vitro cytochrome P450 (P450) induction assay to assess the possible drug-drug interaction events, the recent US Food and Drug Administration draft guidance and European Medicines Agency guideline recommend to assess P450 induction using fresh or cryopreserved hepatocytes at mRNA level and/or enzyme activity level. Although cryopreserved hepatocytes are commercially available for P450 induction assays, feasibility and practicability of these hepatocytes have not been fully investigated. In this study, a total of 23 lots of human cryopreserved hepatocytes were treated with three typical inducers (omeprazole, phenobarbital, and rifampicin), and induction of CYP1A2, CYP2B6, and CYP3A4 enzyme activity was measured. In 8 of these 23 hepatocyte lots, induction of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, and CYP3A4 mRNA was also analyzed. The results revealed that CYP1A2, CYP2B6, and CYP3A4 were induced (>2.0-fold) by omeprazole, phenobarbital, and rifampicin, respectively, in all the hepatocyte lots tested at enzyme activity level (23 lots) and mRNA level (8 lots). In contrast, of the 8 hepatocyte lots treated with rifampicin, CYP2C8 and CYP2C9 mRNA were not induced in 5 and 2 hepatocyte lots, respectively, and CYP2C19 mRNA was not induced in any of the 8 hepatocyte lots tested. These results suggest that induction of CYP1A2, CYP2B6, and CYP3A4 can be readily assessed, but evaluation for CYP2C mRNA induction might not be feasible, using commercially available human cryopreserved hepatocytes.

Adaptive Clinical Trial Design

In recent years, the use of adaptive design methods in clinical trials based on accumulated data at interim has received much attention because of its flexibility and efficiency in pharmaceutical/clinical development. In practice, adaptive design may provide the investigators a second chance to modify or redesign the trial while the study is still ongoing. However, it is a concern that a shift in target patient population may occur after significant adaptations are made. In addition, the overall type I error rate may not be preserved. Moreover, the results may not be reliable and hence are difficult to interpret. As indicated by the US Food and Drug Administration draft guidance on adaptive design clinical trials, the adaptive design has to be a prospectively planned opportunity and should be based on information collected within the study, with or without formal statistical hypothesis testing. This article reviews the relative advantages, limitations, and feasibility of commonly considered adaptive designs in clinical trials. Statistical concerns when implementing adaptive designs are also discussed.

Telavancin for Hospital-Acquired Pneumonia: Clinical Response and 28-Day Survival

U.S. Food and Drug Administration draft guidance for future antibiotic clinical trials of bacterial nosocomial pneumonia recommends the use of diagnostic criteria according to American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines and the use of a primary endpoint of 28-day all-cause mortality. The effect of applying these guidelines on outcomes of phase III nosocomial pneumonia studies of telavancin was evaluated in a post hoc analysis. ATS/IDSA criteria were applied in a blind fashion to the original all-treated (AT) group. Clinical cure rates at final follow-up were determined in the refined AT and clinically evaluable (CE) groups (ATS/IDSA-AT and ATS/IDSA-CE, respectively). The exploratory endpoint of 28-day survival was evaluated for the ATS/IDSA-AT group. Noninferiority of telavancin versus vancomycin was demonstrated, with similar cure rates in the ATS/IDSA-AT (59% versus 59%) and ATS/IDSA-CE (83% versus 80%) groups. Cure rates favored telavancin in ATS/IDSA-CE patients where Staphylococcus aureus was the sole pathogen (86% versus 75%). Overall, 28-day survival rates were similar in the telavancin (76%) and vancomycin (77%) groups but lower in telavancin-treated patients with preexisting moderate-to-severe renal impairment (creatinine clearance [CLCR] of <50 ml/min). Telavancin should be administered to patients with moderate-to-severe renal impairment only if treatment benefit outweighs the risk or if no suitable alternatives are available.