Post-marketing studies of drug efficacy: why?

Off-Label Use of COVID-19 Vaccines from Ethical Issues to Medico-Legal Aspects: An Italian Perspective

During the COVID-19 outbreak, the lack of official recommendations on the treatment has led healthcare workers to use multiple drugs not specifically tested and approved for the new insidious disease. After the availability of the first COVID-19 vaccines (Comirnaty Pfizer-BioNTech and Moderna COVID19 vaccine), an authorization was issued by national and international Drug Regulatory Agencies in order to speed up their introduction on the market and their administration on a large scale. Despite the authorization, the off-label use of these vaccines may still be possible especially to answer specific concerns as the lack of vaccine doses, the delay in the delivery of planned doses or the pressure from public opinion and political influence also in relation to the evolution of the pandemic. This paper aims to assess the possible off-label use of COVID-19 vaccines and the ethical and medico-legal implications of this eventuality. The scope of this paper is to point out the possible consequences of off-label use of COVID-19 vaccines and possible mitigation and preventive measures to be taken by healthcare workers involved in vaccination procedures.

When and How Can Real World Data Analyses Substitute for Randomized Controlled Trials?

Regulators consider randomized controlled trials (RCTs) as the gold standard for evaluating the safety and effectiveness of medications, but their costs, duration, and limited generalizability have caused some to look for alternatives. Real world evidence based on data collected outside of RCTs, such as registries and longitudinal healthcare databases, can sometimes substitute for RCTs, but concerns about validity have limited their impact. Greater reliance on such real world data (RWD) in regulatory decision making requires understanding why some studies fail while others succeed in producing results similar to RCTs. Key questions when considering whether RWD analyses can substitute for RCTs for regulatory decision making are WHEN one can study drug effects without randomization and HOW to implement a valid RWD analysis if one has decided to pursue that option. The WHEN is primarily driven by externalities not controlled by investigators, whereas the HOW is focused on avoiding known mistakes in RWD analyses.

Postmarketing Surveillance of Drugs: An Overview

The complete safety profile of a drug cannot be made before marketing because of the limited scope of the controlled clinical trials. Postmarketing surveillance (PMS) is the collection and analysis of information about a drug after it has been marketed. A PMS system ideally must be able to detect a rare event, determine its incidence, and validate the causality. Because an ideal system has not been devised, a combination of methods is used. The advantages and limitations of various methods of adverse drug reaction (ADE) reporting are described, and problems and concerns associated with ADE reporting are discussed. Postmarketing surveillance will continue to benefit from spontaneous reporting of ADEs by clinicians (ie, literature reports, reports to manufacturers and national regulatory agencies) to detect rare events and will be complemented by the selective use of formal PMS methods in appropriate circumstances. Increased clinician awareness of serious, potentially drug-related events together with comprehensive and complete reporting of these events will begin to address the problems of underreporting, assessment of causality, and misclassification of events.

A secure distributed logistic regression protocol for the detection of rare adverse drug events

Background

There is limited capacity to assess the comparative risks of medications after they enter the market. For rare adverse events, the pooling of data from multiple sources is necessary to have the power and sufficient population heterogeneity to detect differences in safety and effectiveness in genetic, ethnic and clinically defined subpopulations. However, combining datasets from different data custodians or jurisdictions to perform an analysis on the pooled data creates significant privacy concerns that would need to be addressed. Existing protocols for addressing these concerns can result in reduced analysis accuracy and can allow sensitive information to leak.

Objective

To develop a secure distributed multi-party computation protocol for logistic regression that provides strong privacy guarantees.

Methods

We developed a secure distributed logistic regression protocol using a single analysis center with multiple sites providing data. A theoretical security analysis demonstrates that the protocol is robust to plausible collusion attacks and does not allow the parties to gain new information from the data that are exchanged among them. The computational performance and accuracy of the protocol were evaluated on simulated datasets.

Results

The computational performance scales linearly as the dataset sizes increase. The addition of sites results in an exponential growth in computation time. However, for up to five sites, the time is still short and would not affect practical applications. The model parameters are the same as the results on pooled raw data analyzed in SAS, demonstrating high model accuracy.

Conclusion

The proposed protocol and prototype system would allow the development of logistic regression models in a secure manner without requiring the sharing of personal health information. This can alleviate one of the key barriers to the establishment of large-scale post-marketing surveillance programs. We extended the secure protocol to account for correlations among patients within sites through generalized estimating equations, and to accommodate other link functions by extending it to generalized linear models.

Enhancing pharmacosurveillance with systematic collection of treatment indication in electronic prescribing: a validation study in Canada

BACKGROUND

Adverse drug reaction reports used in pharmacosurveillance often lack complete information on treatment indication that is important for benefit-risk analyses and clinical and regulatory decision making. A systematic documentation of treatment indication using electronic prescribing applications provides an opportunity to develop new pharmacosurveillance tools that will allow evaluation of drugs by weighing benefits and risks for specific indications, and evaluate off-label prescribing. In addition, interfacing indications with reminders and clinical guidelines can enhance clinical decision making. We investigated the validity of treatment indications documented using an electronic prescribing system at the time of prescribing.

OBJECTIVES

To determine the sensitivity and positive predictive value (PPV) of an electronic prescribing system in documenting treatment indications at the time of drug prescribing, and to investigate the use of treatment indication data to evaluate off-label prescribing in primary-care practice.

STUDY DESIGN AND SETTING

We prospectively assessed the validity of documenting treatment indication using an electronic prescribing system by comparing it with treatment indications documented by physician-facilitated medical chart review ('gold standard'). Sensitivity and PPV were evaluated in 338 patients of 22 community-based primary-care physicians in Quebec, Canada, in 2006.

RESULTS

The sensitivity of the electronic prescribing system in documenting treatment indication was 98.5% (95% CI 96.5, 99.5) and the PPV of the system in accurately identifying the treatment indication was 97.0% (95% CI 94.2, 98.6). The treatment indication data collected using this system allowed assessment of off-label prescribing.

CONCLUSIONS

The electronic prescribing system offers a valid method for documenting treatment indication at the time of prescribing. Our results provide strong evidence to support incorporating mandatory recording of treatment indication in integrated electronic prescribing systems to provide a critical piece of information for the evaluation of safety and effectiveness of drugs.

Use of computerized databases to survey drug utilization in relation to diagnoses

Many studies of drug utilization have suffered from the absence of information on the indications for therapy. A few data sets on drug utilization are available which include indication information. In addition, a number of computerized collections of medical billing data now exist in North America which can be used for such studies. These include data from the Kaiser Permanente Medical Plan; the Group Health Cooperative of Puget Sound; the Commission on Professional and Hospital Activities' Professional Activity Study; the U.S. state of Rhode Island; the Saskatchewan Health Plan in Canada; and Medicaid, the state run but federally financed health insurance plan for economically or medically needy individuals in the United States. These databases have a number of general advantages and disadvantages, which are reviewed. In addition, the differences among these databases are also explored. Finally, examples are presented demonstrating how these databases can be used for: 1) descriptive research on drug utilization, 2) evaluating the appropriateness of drug utilization, and 3) interventions designed to improve the appropriateness of prescribing.

Prioritizing future research on off-label prescribing: results of a quantitative evaluation

STUDY OBJECTIVE

To develop a prioritized list of individual drugs for which future research regarding off-label uses is warranted.

DESIGN

Retrospective, cross-sectional study.

DATA SOURCES

Commercial database that provides ongoing estimates of drug prescribing practices of office-based physicians in the United States and an Internet database of comprehensive evidence-based drug information.

MEASUREMENTS AND MAIN RESULTS

The base analyses incorporated three key factors based on the theory of value of information: volume of off-label use with inadequate evidence, drug safety, and cost and market considerations. Nationally representative prescribing data were used to estimate the number of off-label drug uses by indication from January 1, 2005-June 30, 2007, in the United States, and these indications were then categorized according to the adequacy of scientific support. Black-box warnings and safety alerts, drug cost, date of market entry, and marketing expenditures were also incorporated into the final model to produce a priority score. Sensitivity analyses were conducted by varying key model parameters. Our findings identified a high volume of off-label prescribing in the absence of good evidence for a substantial number of drugs, particularly antidepressants, antipsychotics, and anxiolytic-sedatives. Drugs that consistently ranked high in both our base model and sensitivity analyses were quetiapine, warfarin, escitalopram, risperidone, montelukast, bupropion, sertraline, venlafaxine, celecoxib, lisinopril, duloxetine, trazodone, olanzapine, and epoetin alfa.

CONCLUSION

Future research into off-label drug use should focus on drugs used frequently with inadequate supporting evidence, particularly if further concerns are raised by known safety issues, high drug cost, recent market entry, and extensive marketing. Our quantitative analysis identified particular concerns with the off-label use of antipsychotic and antidepressant drugs. Targeted research and policy activities on our list of prioritized drugs have high potential value.

Off-label therapies in oncology

Az indikáción kívüli (off-label) kezelések speciális problémát jelentenek az onkológiában, mivel a jogi szabályozás és a szabad orvosi gyakorlat határterületén állnak. Bár Magyarországon az off-label kezelés a 2008. október végén életbe léptetett rendelet megjelenéséig engedély nélküli klinikai vizsgálatnak minősült, egyes szakemberek mégis azzal érveltek alkalmazása mellett, hogy a klinikai gyakorlat gyorsabban változik, mint az alkalmazási előirat. Mi több, a gyártók még megfelelő evidencia esetén sem kötelesek az indikáció bővítésére. Az off-label kezelések szabályozása egyaránt meg kell hogy feleljen a szabad orvosi gyakorlatnak, az evidencián alapuló medicinának, a betegek új esélyekhez való igényének és a hatóságok elvárásainak. A közleményben a hazai helyzet és a törvény bírálata, illetve a nemzetközi gyakorlat áttekintése után egy, a fenti szempontoknak megfelelő lehetséges szabályozás kereteit vázolja a szerző, külön-külön kifejtve a kezelőorvos és a hatóságok szerepét.

Methodologic challenges to studying patient safety and comparative effectiveness

Studies of patient safety and comparative effectiveness entail unique methodologic challenges. These studies may be susceptible to systematic error, including selection bias, exposure misclassification, and outcome misclassification. They may also be vulnerable to random error, or confounding by a variable such as another drug, a disease, or the drug indication itself. Finally, special logistical issues can arise, including data access problems, difficulties in conveying the need for studies of certain interventions, and obstacles to gaining institutional review board approval. This article provides a conceptual overview of these methodologic issues.

Antidiabetic drugs and heart failure risk in patients with type 2 diabetes in the U.K. primary care setting

OBJECTIVE

To assess the effects of antidiabetic drugs on the risk of heart failure in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted a retrospective cohort study with a newly diagnosed diabetes cohort of 25,690 patients registered in the U.K. General Practice Research Database, 1988-1999. We categorized person-time drug exposures to monotherapies in insulin, sulfonylureas (SUs), metformins, and other oral hypoglycemic agents (i.e., acarbose, guar gum) and combination therapy including insulin, combination therapy without insulin, and triple combination therapy with or without insulin. A drug-free time interval served as a reference category. Cox interval-wise (piece-wise) regression analyses were used. The main outcome was incident heart failure.

RESULTS

Among 43,390 drug exposure intervals for 25,690 patients who had a mean follow-up period of 2.5 years, 1,409 patients developed heart failure. Heart failure occurred most frequently in SU monotherapy exposure. After adjusting for duration of diabetes, the timing and order of treatments received, and known risk factors for heart failure, we found no differential effects among type-specific therapies. Patients with any drug use within the first year after diabetes diagnosis had a 4.75-fold higher risk (hazard ratio) for heart failure than those with drug-free status but had no increased risk during subsequent years.

CONCLUSIONS

In conclusion, the use of any pharmacological therapy for type 2 diabetes appears to be associated with an increased risk of heart failure. This risk does not persist beyond the first year after diagnosis of diabetes and does not appear to differ among the types of drug therapy examined. This observation suggests that the severity of diabetes or the preclinical duration of diabetes and the need for drug therapy, and not the therapy itself, is an explanation for heart failure in patients with type 2 diabetes.

Approaches to combat with confounding by indication in observational studies of intended drug effects

There has been a resurgence of controversy about the usefulness of observational data to study the efficacy of drugs. Nearly every week a researcher makes some criticism of clinical trials or justifies observational research into intended effects, with other researchers offering a contradictory viewpoint. Literature reviews are not useful in this regard because the contradictory studies will not usually be carried out. Some methods are discussed which may have potential utility in the study of intended effects. There may be a marginal role for statistical techniques such as propensity scores and confounder scores. More promising techniques may include ecological analyses, restriction of subjects and blinded prospective review. Because it is currently unknown when the observational study of drug efficacy is possible, we should arguably always carry out a study of the determinants of prescribing first, and possibly consider using the various techniques that are outlined in this article.

Intranasal steroids and the risk of emergency department visits for asthma

BACKGROUND

In patients with asthma, treatment for associated conditions, such as rhinitis, is recommended. It is unknown whether this treatment can reduce the risk for emergency department (ED) visits for asthma.

OBJECTIVES

We sought to determine whether treatment with intranasal steroids or prescription antihistamines in persons with asthma is associated with a reduced risk for ED visits caused by asthma.

METHODS

We performed a retrospective cohort study of members of a managed care organization aged greater than 5 years who were identified during the period of October 1991 to September 1994 as having a diagnosis of asthma by using a computerized medical record system. The main outcome measure was an ED visit for asthma.

RESULTS

Of the 13,844 eligible persons, 1031 (7.4%) had an ED visit for asthma. The overall relative risk (RR) for an ED visit among those who received intranasal corticosteroids, adjusted for age, sex, frequency of orally inhaled corticosteroid and beta-agonist dispensing, amount and type of ambulatory care for asthma, and diagnosis of an upper airways condition (rhinitis, sinusitis, or otitis media), was 0.7 (95% confidence interval [CI], 0.59-0.94). For those receiving prescription antihistamines, the risk was indeterminate (RR, 0.9; 95% CI, 0.78-1.11). When different rates of dispensing for intranasal steroids were examined, a reduced risk was seen in ED visits in those with greater than 0 to 1 (RR, 0.7; 95% CI, 0.57-0.99) and greater than 3 (RR, 0.5; 95% CI, 0.23-1.05) dispensed prescriptions per year.

CONCLUSIONS

Treatment of nasal conditions, particularly with intranasal steroids, confers significant protection against exacerbations of asthma leading to ED visits for asthma. These results support the use of intranasal steroids by individuals with asthma and upper airways conditions.

Impact of inhaled antiinflammatory therapy on hospitalization and emergency department visits for children with asthma

OBJECTIVE

Although the efficacy of inhaled antiinflammatory therapy in improving symptoms and lung function in childhood asthma has been shown in clinical trials, the effectiveness of these medications in real-world practice settings in reducing acute health care use has not been well-evaluated. This study examined the effect of inhaled antiinflammatory therapy on hospitalizations and emergency department (ED) visits by children for asthma.

DESIGN

Defined population cohort study over 1 year. Setting. Three managed care organizations (MCOs) in Seattle, Boston, and Chicago participating in the Pediatric Asthma Care-Patient Outcome Research and Treatment II trial. Participants. All 11 195 children, between 3 to 15 years old, with a diagnosis of asthma who were enrolled in the 3 MCOs between July 1996 and June 1997.

OUTCOME MEASURES

We identified children with 1 or more asthma diagnoses using automated encounter data. Medication dispensings were identified from automated pharmacy data. Multivariate logistic regression analysis was used to calculate effects of inhaled antiinflammatory therapy on the adjusted relative risk (RR) for hospitalization and ED visits for asthma.

RESULTS

Over 12 months, 217 (1.9%) of children had an asthma hospitalization, and 757 (6.8%) had an ED visit. After adjustment for age, gender, MCO, and reliever dispensing, compared with children who did not receive controllers, the adjusted RRs for an ED visit were: children with any (>/=1) dispensing of cromolyn, 0.4 (95% confidence interval [CI]: 0.3, 0.5); any inhaled corticosteroid (ICS), 0.5 (95% CI: 0.4, 0.6); any cromolyn or ICS combined (any controller), 0.4 (95% CI: 0.3, 0.5). For hospitalization, the adjusted RR for cromolyn was 0.6 (95% CI: 0.4, 0.9), for ICS 0.4 (95% CI: 0.3, 0.7), and for any controller 0.4 (95% CI: 0.3, 0.6). A significant protective effect for both events was seen among children with 1 to 5 and with >5 antiinflammatory dispensings. When the analysis was stratified by frequency of reliever dispensing, there was a significant protective effect for controllers on ED visits for children with 1 to 5 and with >5 reliever dispensings and on the risk of hospitalization for children with >5 reliever dispensings.

CONCLUSIONS

Inhaled antiinflammatory therapy is associated with a significant protective effect on the risk for hospitalization and ED visits in children with asthma. Cromolyn and ICSs were associated with similar effects on risks.asthma drug therapy, inhaled antiinflammatory agents, health maintenance organizations, hospitalization, emergency department.

Design issues for drug epidemiology

Despite the difficulties involved in designing drug epidemiology studies, these studies are invaluable for investigating the unexpected adverse effects of drugs. The aim of this paper is to discuss various aspects of study design, particularly those issues that are not easily found in either textbooks or review papers. We have also compared and contrasted drug epidemiology with the randomized controlled trial (RCT) wherever possible. Drug epidemiology is especially useful in the many situations where the RCT is not suitable, or even possible. The study base has to be defined before the appropriate cohort of subjects is assembled. If all of the cases are identified, then a referent sample of controls may be assembled by random sampling of the study base. If all of the cases cannot be assembled, a hypothetical secondary base may need to be created. Preferably, only new-users of the drug should be included, and the risk-ratio will be different for acute users and chronic users. Studies will usually only be possible when researching the unintended effects of drugs. It is difficult to study efficacy because of confounding by indication. In occasional circumstances it may be possible to study efficacy (examples are given). Discussion of the dangers of designing with generalisability in mind is provided. Additionally, the similarities in study design between drug epidemiology and the RCT are discussed in detail, as well as the design-characteristics that cannot be shared between the two methods.

First treatment with inhaled corticosteroids and the prevention of admissions to hospital for asthma

BACKGROUND

Early treatment with inhaled corticosteroids appears to improve clinical symptoms in asthma. Whether a first treatment initiated in the year following the recognition of asthma can prevent major outcomes such as admission to hospital has yet to be studied.

METHODS

A case-control study nested within a cohort of 13,563 newly treated asthmatic subjects selected from the databases of Saskatchewan Health (1977-1993) was undertaken to investigate the effectiveness of a first treatment with inhaled corticosteroids in preventing admissions to hospital for asthma. Study subjects were aged between five and 44 years at cohort entry. First time users of inhaled corticosteroids were compared with first time users of theophylline for a maximum of 12 months of treatment. The two treatments under study were further classified into initial and subsequent therapy to minimize selection bias and confounding by indication. Odds ratios associated with hospital admissions for asthma were estimated using conditional logistic regression. Markers of asthma severity, as well as age and sex, were considered as potential confounders.

RESULTS

Three hundred and three patients admitted to hospital with asthma were identified and 2636 matched controls were selected. subjects initially treated with regular inhaled corticosteroids were 40% less likely to be admitted to hospital for asthma than regular users of theophylline (odds ratio 0.6; 95% CI 0.4 to 1.0). The odds ratio decreased to 0.2 (95% CI 0.1 to 0.5) when inhaled corticosteroids and theophylline were given subsequently.

CONCLUSION

The first regular treatment with inhaled corticosteroids initiated in the year following the recognition of asthma can reduce the risk of admission to hospital for asthma by up to 80% compared with regular treatment with theophylline. This is probably due, at least in part, to reducing the likelihood of a worsening in the severity of asthma.

Pharmacoepidemiology in practice. Current status and future trends

Pharmacoepidemiology is the application of epidemiological reasoning, methods and knowledge to the study of the uses and effects (beneficial and adverse) of drugs in human populations. As referred to by the term 'pharmacoepidemiology', the discipline now enters into its second decade, although its origins go back to the beginnings of this century. This article reviews the opinions of leading pharmacoepidemiologists on the scope and prospects for pharmacoepidemiology, and summarises the most important challenges that the discipline faces on its way towards the next century. The future of pharmacoepidemiology requires the development of research methods more able to cope with the specific problems posed by the study of drugs, notably the issue of confounding by indication and the ability to adjust accurately for severity of disease. Capacity building should also continue during the next years; training of professionals, the optimisation of computerised databases for research purposes and their joint use with more traditional epidemiological methods are major challenges. From a public health perspective, a critical task is to assess the impact that vaccines and drugs have on the overall patterns of disease in well defined populations.

Sick population--treated population: the need for a better definition. The VALIDATA Group

There are many questions concerned with therapy and its application. Depending on the perspective of the study there can be several "populations" which, when considered individually, may give different, or even inconsistent conclusions. These populations are: the sick population, the therapist's target population, the eligible population for a study, the study population, the treatment target population, and the treatment distribution population. Semantic precision, giving a better definition of the populations, is an essential prerequirement in order to tackle scientifically all the facets of assessment of therapy. Accurate definition will help in the study of areas as varied as the methodology, the therapeutic studies, the validity of the recommendations made, the impact of these recommendations on prescription, and finally, the consequences of the prescription in terms of public health (clinical and economical). Several examples are given to show the relationship between these populations and the importance of an accurate definition for each. Guidelines for the identification of these populations are provided. In this overall approach to therapy, epidemiology is an essential, complementary tool to clinical trials.

Early treatment with intravenous metoprolol for suspected acute myocardial infarction: a phase IV United States trial. Phase IV Metoprolol in Myocardial Infarction Study Group

Recent randomized clinical trials have shown that total mortality and cardiovascular mortality are reduced by the early intravenous administration of beta-blockers to patients suspected of suffering from acute myocardial infarction. These trials were conducted on patients meeting strict entry criteria. In order to assess this therapy when applied to a broader range of myocardial infarction patients, we performed a Phase IV study of metoprolol in acute myocardial infarction. The study was designed to test whether early (less than 8 hours from onset of chest pain) intervention by practicing physicians with open label intravenous metoprolol for cases of suspected acute myocardial infarction achieved mortality results similar to those obtained in large randomized clinical trials. We studied 3824 patients treated by 741 physicians representing a broad spectrum of clinical practice in the United States. Seventy-two percent of the patients entered into the study had confirmed myocardial infarction (39% anterior, 39% inferior, 22% other locations) and 85% of all individuals treated tolerated the full intravenous dose of 15 mg of metoprolol. The 15 day total mortality and cardiovascular mortality rates were 4.9% and 4.5%; 90 day mortality rates were 6.9 and 5.9%. Patients with anterior infarctions had a significantly greater cumulative mortality rate than patients with other types of infarctions. Marked bradycardia (heart rate less than 45 beats per minute) in the first 8 hours post treatment occurred in 4.7% cases and hypotension (systolic blood pressure less than 90 mm Hg) occurred in 9.8% of cases. When compared with the results of the Göteborg and MIAMI trials of metoprolol, it appears that there is no appreciable increase in mortality or morbidity when metoprolol is used in the community practice of acute coronary care.

Prescribing of noncontraceptive estrogens and progestins in the United States, 1974-86

This paper describes changes in the prescribing of noncontraceptive estrogens and progestins, using data from pharmaceutical marketing surveys. The number of estrogen prescriptions decreased from 1975 to 1980, and then increased through 1986. Progestin use has increased since 1982; concomitant use of estrogens and progestins increased over time and was common in 1986. The trends suggest that the use of estrogens, particularly the combined use of estrogens and progestins, will continue to increase.

Postmarketing surveillance methodologies

This article describes and discusses the strengths and limitations of the major pharmacoepidemologic methodologies employed in postmarketing drug surveillance and describes the current status of the U.S. surveillance system. The main methodologies employed in postmarketing drug surveillance include controlled clinical trials, observational epidemiologic studies (cohort, case-control, cross-sectional), demographic methods, drug utilization surveys, spontaneous reports, and automated databases linking medications and disease. Examples of pharmacoepidemiologic studies using each of these methodologies are presented. When a question arises about the efficacy and/or safety of a marketed drug, typically a mixture of these study methodologies is employed. The article concludes with a brief discussion of the role of the Food and Drug Administration, pharmaceutical manufactures, and academic institutions in initiating and conducting postmarketing drug studies.

The use of combined estrogen-progestin replacement therapy

The evaluation of innovations which use old technology poses different problems than does the evaluation of new technologies. The main necessity is the targeting of its use rather than the technology itself. The need to evaluate the extent of use and its problems is illustrated by the example of progestin use among menopausal and postmenopausal women in the United States. There progestins are not officially approved for use in menopause, even though they have been on the market for a long time with other indications. Estrogen-replacement therapy was widely used from the early 1960s until 1975, when the claim that estrogens cause endometrial cancer notably decreased their use. The use of estrogens increased again in the early 1980s, and one reason for this revival was the claim that progestins offered protection against endometrial cancer. When recommendations for combined estrogen-progestin therapy have been made, other health effects have been ignored. Two consensus conferences as well as the drug control authority have recommended against combined estrogen-progestin therapy until further research is completed. Absence of good research, specialization in medicine, and advantages for prescribers and the drug industry may have contributed to the wide use of this unassessed treatment. Possible solutions for prevention of the diffusion of these kinds of innovations are discussed.

The contribution of epidemiology to the study of drugs

Epidemiology is concerned with the distribution of disease and health in human populations. Drugs are one of the factors that influence such a distribution. Pharmacoepidemiology can be defined as the application of epidemiologic knowledge, methods, and reasoning to the study of the effects (beneficial and adverse) and uses of drugs in human populations. Pharmacoepidemiology aims to describe, explain, control, and predict the effects and uses of pharmacologic treatment modalities in a defined time, space, and population. The present article is an introduction to the contributions of epidemiology to the study of drugs.

Benefit-risk assessment of investigational drugs: current methodology, limitations, and alternative approaches

Development of investigational drugs is a process integrated traditionally into four overlapping phases. The goal is to introduce new therapies to clinical medicine by assessing benefits and risks associated with administering the new drug. Benefit assessment is performed with respect to the disease for which the drug may comprise an effective treatment. In contrast, safety assessment is relatively standardized across many pharmacologic classes of agents. For purposes of benefit-risk assessment, investigational drugs are developed to provide benefit in three major disease categories: acute, episodic, and chronic. Benefit assessment is the major focus of conventional methodologies. Inherent limitations of risk assessment produced by conventional approaches are illustrated by the historical inability to detect toxicities of various drugs until large patient populations have been treated, typically after the drug is marketed. Alternative approaches to overcome these limitations include assessment of safety in studies specifically designed to optimize such evaluation and more extensive safety testing of investigational drugs in patient subgroups at higher risk. Such approaches serve the interest of patients, physicians, and developers by facilitating the development of new therapies by providing a more complete benefit-risk assessment prior to initial marketing of the drug.