Prospective Observational Post-Marketing Study of Tafluprost for Glaucoma and Ocular Hypertension: Effectiveness and Treatment Persistence

INTRODUCTION

The aim of this study was to investigate the long-term intraocular pressure (IOP)-lowering effect and safety of tafluprost, a prostaglandin analogue, in actual clinical practice and to determine persistency of tafluprost as an indicator of its benefit-risk balance.

METHODS

This was a large-scale, post-marketing, multicenter, non-interventional, open-label, long-term study. Patients with glaucoma or ocular hypertension who initiated tafluprost treatment were registered and prospectively observed over a 2-year period in the real-world setting in Japan. Long-term IOP and safety data were collected.

RESULTS

Of the 4502 patients registered from 553 medical institutions, 4265 patients were analyzed. The majority of patients had normal-tension glaucoma (44.4%) and primary open-angle glaucoma (37.8%), and patients with ocular hypertension constituted 7.0%. Treatment patterns with tafluprost during the study period were as follows: naïve monotherapy (48.1%), switching monotherapy (18.4%), and concomitant therapy (33.5%). In all patients analyzed, mean IOP was significantly reduced from 18.6 ± 5.9 mmHg (month 0) to 15 mmHg or below throughout the 2-year observation period after initiation of tafluprost. Significant IOP-lowering effects were shown in various treatment patterns and disease types. Adverse reactions were observed in 795 patients (18.64%). Major adverse reactions included eyelid pigmentation, ocular hyperemia, eyelash changes, eyelid hypertrichosis, and iris hyperpigmentation. Kaplan-Meier curves showed that 84.6% and 76.1% of patients were persistent on tafluprost for 1 and 2 years, respectively, when discontinuation due to insufficient efficacy or adverse events was defined as a treatment failure event. Furthermore, among treatment-naïve patients (n = 2304), the persistency rates on tafluprost monotherapy were 77.0% for 1 year and 67.0% for 2 years.

CONCLUSION

Tafluprost showed significant long-term IOP-lowering effects regardless of treatment patterns or diagnosis, with minimum safety concerns in the actual clinical practice. The observed treatment persistence suggests that tafluprost can be used long term owing to its benefit-risk profile.

FUNDING

Santen Pharmaceutical Co., Ltd., Osaka, Japan.

Can Disproportionality Analysis of Post-marketing Case Reports be Used for Comparison of Drug Safety Profiles?

Clinical trials usually do not have the power to detect rare adverse drug reactions. Spontaneous adverse reaction reports as for example available in post-marketing safety databases such as the FDA Adverse Event Reporting System (FAERS) are therefore a valuable source of information to detect new safety signals early. To screen such large data-volumes for safety signals, data-mining algorithms based on the concept of disproportionality have been developed. Because disproportionality analysis is based on spontaneous reports submitted for a large number of drugs and adverse event types, one might consider using these data to compare safety profiles across drugs. In fact, recent publications have promoted this practice, claiming to provide guidance on treatment decisions to healthcare decision makers. In this article we investigate the validity of this approach. We argue that disproportionality cannot be used for comparative drug safety analysis beyond basic hypothesis generation because measures of disproportionality are: (1) missing the incidence denominators, (2) subject to severe reporting bias, and (3) not adjusted for confounding. Hypotheses generated by disproportionality analyses must be investigated by more robust methods before they can be allowed to influence clinical decisions.

Post-Marketing Survey of Adverse Events Following Ocriplasmin

BACKGROUND AND OBJECTIVE

To study the post-marketing safety profile of ocriplasmin (Jetrea; ThromboGenics, Iselin, NJ) as experienced by retinal physicians in the United States.

STUDY DESIGN/MATERIALS AND METHODS

Two thousand four hundred sixty-five retinal physicians were surveyed regarding their frequency of use of ocriplasmin and reports of ocular adverse events.

RESULTS

There were 270 respondents (11%) who reported treating 1,056 eyes with ocriplasmin. The reports of adverse events (AE) were as follows: acute decline in visual acuity (16.95%), development of submacular fluid or serous retinal detachment (10.23%), dyschromatopsia (9.09%), progression of vitreomacular traction to macular hole (8.71%), development of retinal detachment (2.65%), development of retinal tear (1.99%), development of afferent pupillary defect (1.80%), electroretinography abnormalities (0.57%), crystalline lens instability (0.38%), and vasculitis (0.28%).

CONCLUSION

Although the frequency of some ocular AEs reported in this study are comparable to those reported in the phase 3 registration trials, additional phase 4 safety studies are warranted to better understand the pathophysiology and clinical relevance of ocular AEs of ocriplasmin.

Safety of Gadobutrol: Results From 42 Clinical Phase II to IV Studies and Postmarketing Surveillance After 29 Million Applications

OBJECTIVE

The aim of this study was to provide a systematic safety analysis of gadobutrol after more than 29 million applications in clinical routine.

MATERIALS AND METHODS

Forty-two clinical development phase II to IV studies on gadobutrol or comparator and the postmarketing safety surveillance database for gadobutrol (1998-2015) were analyzed. Adverse events (AEs) and drug-related AEs were evaluated in the clinical development database and spontaneous adverse drug reactions (ADRs) in the postmarketing database. Subgroup analyses were run on patients with special medical history and on patients of different age groups.

RESULTS

In the clinical development studies, 6809 and 2184 patients received gadobutrol or comparators, respectively. The incidence of drug-related AEs was 3.5% for both groups. With the exception of nausea (0.7% related cases in both groups), all other drug-related AEs were 0.3% or less in both groups. Hypersensitivity reactions were sporadic (<0.1%). Patients with history of allergies to contrast agents experienced slightly more drug-related AEs. No differences were seen between age groups.The overall reporting rate of ADRs from postmarketing surveillance was 0.05%. The most frequent ADRs were anaphylactoid/hypersensitivity reactions, nausea, vomiting, and dyspnea.For 3 single-agent reports of nephrogenic systemic fibrosis, using a conservative approach, association with gadobutrol could not be excluded.

CONCLUSIONS

Gadobutrol is well tolerated and has a favorable safety profile for patients of all age groups.

Impact of prescription drug monitoring programs and pill mill laws on high-risk opioid prescribers: A comparative interrupted time series analysis

BACKGROUND

Prescription drug monitoring programs (PDMPs) and pill mill laws were implemented to reduce opioid-related injuries/deaths. We evaluated their effects on high-risk prescribers in Florida.

METHODS

We used IMS Health's LRx Lifelink database between July 2010 and September 2012 to identify opioid-prescribing prescribers in Florida (intervention state, N: 38,465) and Georgia (control state, N: 18,566). The pre-intervention, intervention, and post-intervention periods were: July 2010-June 2011, July 2011-September 2011, and October 2011-September 2012. High-risk prescribers were those in the top 5th percentile of opioid volume during four consecutive calendar quarters. We applied comparative interrupted time series models to evaluate policy effects on clinical practices and monthly prescribing measures for low-risk/high-risk prescribers.

RESULTS

We identified 1526 (4.0%) high-risk prescribers in Florida, accounting for 67% of total opioid volume and 40% of total opioid prescriptions. Relative to their lower-risk counterparts, they wrote sixteen times more monthly opioid prescriptions (79 vs. 5, p<0.01), and had more prescription-filling patients receiving opioids (47% vs. 19%, p<0.01). Following policy implementation, Florida's high-risk providers experienced large relative reductions in opioid patients and opioid prescriptions (-536 patients/month, 95% confidence intervals [CI] -829 to -243; -847 prescriptions/month, CI -1498 to -197), morphine equivalent dose (-0.88mg/month, CI -1.13 to -0.62), and total opioid volume (-3.88kg/month, CI -5.14 to -2.62). Low-risk providers did not experience statistically significantly relative reductions, nor did policy implementation affect the status of being high- vs. low- risk prescribers.

CONCLUSIONS

High-risk prescribers are disproportionately responsive to state policies. However, opioids-prescribing remains highly concentrated among high-risk providers.

Risk of Preterm or Small-for-Gestational-Age Birth After Influenza Vaccination During Pregnancy: Caveats When Conducting Retrospective Observational Studies

Vaccines are increasingly targeted toward women of reproductive age, and vaccines to prevent influenza and pertussis are recommended during pregnancy. Prelicensure clinical trials typically have not included pregnant women, and when they are included, trials cannot detect rare events. Thus, postmarketing vaccine safety assessments are necessary. However, analysis of observational data requires detailed assessment of potential biases. Using data from 8 Vaccine Safety Datalink sites in the United States, we analyzed the association of monovalent H1N1 influenza vaccine (MIV) during pregnancy with preterm birth (<37 weeks) and small-for-gestational-age birth (birth weight < 10th percentile). The cohort included 46,549 pregnancies during 2009-2010 (40% of participants received the MIV). We found potential biases in the vaccine-birth outcome association that might occur due to variable access to vaccines, the time-dependent nature of exposure to vaccination within pregnancy (immortal time bias), and confounding from baseline differences between vaccinated and unvaccinated women. We found a strong protective effect of vaccination on preterm birth (relative risk = 0.79, 95% confidence interval: 0.74, 0.85) when we ignored potential biases and no effect when accounted for them (relative risk = 0.91; 95% confidence interval: 0.83, 1.0). In contrast, we found no important biases in the association of MIV with small-for-gestational-age birth. Investigators conducting studies to evaluate birth outcomes after maternal vaccination should use statistical approaches to minimize potential biases.

Post-Marketing Surveillance of Human Rabies Diploid Cell Vaccine (Imovax) in the Vaccine Adverse Event Reporting System (VAERS) in the United States, 1990‒2015

BACKGROUND

In 1980, human diploid cell vaccine (HDCV, Imovax Rabies, Sanofi Pasteur), was licensed for use in the United States.

OBJECTIVE

To assess adverse events (AEs) after HDCV reported to the US Vaccine Adverse Event Reporting System (VAERS), a spontaneous reporting surveillance system.

METHODS

We searched VAERS for US reports after HDCV among persons vaccinated from January 1, 1990-July 31, 2015. Medical records were requested for reports classified as serious (death, hospitalization, prolonged hospitalization, disability, life-threatening-illness), and those suggesting anaphylaxis and Guillain-Barré syndrome (GBS). Physicians reviewed available information and assigned a primary clinical category to each report using MedDRA system organ classes. Empirical Bayesian (EB) data mining was used to identify disproportional AE reporting after HDCV.

RESULTS

VAERS received 1,611 reports after HDCV; 93 (5.8%) were serious. Among all reports, the three most common AEs included pyrexia (18.2%), headache (17.9%), and nausea (16.5%). Among serious reports, four deaths appeared to be unrelated to vaccination.

CONCLUSIONS

This 25-year review of VAERS did not identify new or unexpected AEs after HDCV. The vast majority of AEs were non-serious. Injection site reactions, hypersensitivity reactions, and non-specific constitutional symptoms were most frequently reported, similar to findings in pre-licensure studies.

Electronic Health Data for Postmarket Surveillance: A Vision Not Realized

What has been learned about electronic health data as a primary data source for regulatory decisions regarding the harms of drugs? Observational studies with electronic health data for postmarket risk assessment can now be conducted in Europe and the US in patient populations numbering in the tens of millions compared with a few hundred patients in a typical clinical trial. With standard protocols, results can be obtained in a few months; however, extensive research published by scores of investigators has illuminated the many obstacles that prevent obtaining robust, reproducible results that are reliable enough to be a primary source for drug safety decisions involving the health and safety of millions of patients. The most widely used terminology for coding patient interactions with medical providers for payment has proved ill-suited to identifying the adverse effects of drugs. Directly conflicting results were reported in otherwise similar patient health databases, even using identical event definitions and research methods. Evaluation of some accepted statistical methods revealed systematic bias, while others appeared to be unreliable. When electronic health data studies detected no drug risk, there were no robust and accepted standards to judge whether the drug was unlikely to cause the adverse effect or whether the study was incapable of detecting it. Substantial investment and careful thinking is needed to improve the reliability of risk assessments based on electronic health data, and current limitations need to be fully understood.

Initiatives to identify and mitigate medication errors in England

In response to the EU Directive on Pharmacovigilance, the National Health Service (NHS) in England and the Medicines and Healthcare Products Regulatory Agency (MHRA) in the UK have formed a partnership to work together to simplify and increase medication error reporting, improve data report quality, maximise learning and guide practice to minimise harm from medication errors by sharing incident data. This initiative will facilitate implementation of new requirements for medication error reporting and reduce the need for duplicate data entry by frontline staff. The initiative is also intended to provide new types of feedback from the National Reporting and Learning System run by the NHS England and from the Yellow Card Scheme run by the MHRA and to improve learning at the local level by clarifying medication safety roles and identifying key safety contacts to allow better communication between local and national levels. Finally, the partnership has established a new National Medication Safety Network to provide a forum for discussing potential and recognised safety issues, and for identifying trends and actions to improve the safe use of medicines. This article describes the initiative, the structure of which may act as a template for other countries.

Correlation between Drug Market Withdrawals and Socioeconomic, Health, and Welfare Indicators Worldwide

The relationship between the number of withdrawn/restricted drugs and socioeconomic, health, and welfare indicators were investigated in a comprehensive review of drug regulation information in the United Nations (UN) countries. A total of of 362 drugs were withdrawn and 248 were restricted during 1950-2010, corresponding to rates of 12.02 ± 13.07 and 5.77 ± 8.69 (mean ± SD), respectively, among 94 UN countries. A socioeconomic, health, and welfare analysis was performed for 33 OECD countries for which data were available regarding withdrawn/restricted drugs. The gross domestic product (GDP) per capita, GDP per hour worked, health expenditure per GDP, and elderly population rate were positively correlated with the numbers of withdrawn and restricted drugs (P < 0.05), while the out-of-pocket health expenditure payment rate was negatively correlated. The number of restricted drugs was also correlated with the rate of drug-related deaths (P < 0.05). The World Bank data cross-validated the findings of 33 OECD countries. The lists of withdrawn/restricted drugs showed markedly poor international agreement between them (Fleiss's kappa = -0.114). Twenty-seven drugs that had been withdrawn internationally by manufacturers are still available in some countries. The wide variation in the numbers of drug withdrawals and restrictions among countries indicates the need to improve drug surveillance systems and regulatory communication networks.

Continuous versus group sequential analysis for post-market drug and vaccine safety surveillance

The use of sequential statistical analysis for post-market drug safety surveillance is quickly emerging. Both continuous and group sequential analysis have been used, but consensus is lacking as to when to use which approach. We compare the statistical performance of continuous and group sequential analysis in terms of type I error probability; statistical power; expected time to signal when the null hypothesis is rejected; and the sample size required to end surveillance without rejecting the null. We present a mathematical proposition to show that for any group sequential design there always exists a continuous sequential design that is uniformly better. As a consequence, it is shown that more frequent testing is always better. Additionally, for a Poisson based probability model and a flat rejection boundary in terms of the log likelihood ratio, we compare the performance of various continuous and group sequential designs. Using exact calculations, we found that, for the parameter settings used, there is always a continuous design with shorter expected time to signal than the best group design. The two key conclusions from this article are (i) that any post-market safety surveillance system should attempt to obtain data as frequently as possible, and (ii) that sequential testing should always be performed when new data arrives without deliberately waiting for additional data.

The monitoring medicines project: a multinational pharmacovigilance and public health project

The Monitoring Medicines project (MM), funded by the FP-7 EU framework, was carried out between 2009 and 2013 by a consortium of 11 partners. The objectives were to support and strengthen consumer reporting of adverse drug reactions (ADRs); expand the role and scope of national pharmacovigilance centres concerning medication errors; promote improved use of pharmacovigilance data; and develop methods to complement spontaneous reporting. The work was organised into four themes: patient reporting; medication errors; drug dependence, counterfeit and substandard medicines and clinical risk estimation; and active and targeted spontaneous pharmacovigilance. MM differed from some other major pharmacovigilance initiatives by having participants from developing countries in Asia and Africa and in leaning towards public health and communicable diseases. MM brought together stakeholders including WHO, drug regulators, pharmacovigilance centres, consumers, public health and disease specialists and patient safety networks. Resources and methodologies developed directly by, or with support from, MM include electronic systems/tools for consumer ADR reporting and cohort event monitoring; publication by WHO of handbooks on consumer reporting, medication errors and pharmacovigilance for TB medicines; methodologies for detecting drug dependence and substandard or counterfeit medicines in ADR databases; and a database on HIV treatment risks with a risk assessment tool. MM enabled stakeholders to achieve more than if they had worked alone in pursuit of patient safety.

Using 'big data' to validate claims made in the pharmaceutical approval process

Big Data in the healthcare setting refers to the storage, assimilation, and analysis of large quantities of information regarding patient care. These data can be collected and stored in a wide variety of ways including electronic medical records collected at the patient bedside, or through medical records that are coded and passed to insurance companies for reimbursement. When these data are processed it is possible to validate claims as a part of the regulatory review process regarding the anticipated performance of medications and devices. In order to analyze properly claims by manufacturers and others, there is a need to express claims in terms that are testable in a timeframe that is useful and meaningful to formulary committees. Claims for the comparative benefits and costs, including budget impact, of products and devices need to be expressed in measurable terms, ideally in the context of submission or validation protocols. Claims should be either consistent with accessible Big Data or able to support observational studies where Big Data identifies target populations. Protocols should identify, in disaggregated terms, key variables that would lead to direct or proxy validation. Once these variables are identified, Big Data can be used to query massive quantities of data in the validation process. Research can be passive or active in nature. Passive, where the data are collected retrospectively; active where the researcher is prospectively looking for indicators of co-morbid conditions, side-effects or adverse events, testing these indicators to determine if claims are within desired ranges set forth by the manufacturer. Additionally, Big Data can be used to assess the effectiveness of therapy through health insurance records. This, for example, could indicate that disease or co-morbid conditions cease to be treated. Understanding the basic strengths and weaknesses of Big Data in the claim validation process provides a glimpse of the value that this research can provide to industry. Big Data can support a research agenda that focuses on the process of claims validation to support formulary submissions as well as inputs to ongoing disease area and therapeutic class reviews.

[A prevalence study to monitor the consumption of antibiotics]

Following the second Antibiotics Plan, in association with the hospital hygiene operational team, the hospital pharmacy department of the Desgenettes military teaching hospital led a study into the prevalence of the prescribing of antibiotics in December 2011. The study highlighted the trends in prescriptions and assessed the effectiveness of corrective or preventive actions implemented following the first prevalence study of 2006, in particular the multidisciplinary antibiotherapy coordination meetings.

"First-wave" bias when conducting active safety monitoring of newly marketed medications with outcome-indexed self-controlled designs

Large health care databases are used extensively for pharmacoepidemiologic studies. Unique methodological issues arise when applying self-controlled designs (i.e., using within-person comparisons) for active surveillance of newly marketed drugs. We use 3 examples to illustrate bias related to population-level exposure time trends when using outcome-indexed self-controlled (i.e., case-crossover) designs for active surveillance and evaluate the ability of the case-time-control design to adjust for bias from population-level exposure time trends. We mimicked active surveillance by conducting sequential analyses after market entry for 3 medications and outcomes (valdecoxib for myocardial infarction (MI), aripiprazole for MI, and telithromycin for acute liver failure) using Medicaid Analytic eXtracts (from all 50 US states, 2000-2006). The case-crossover exposure odds ratio (EOR) in the months immediately following valdecoxib market entry implausibly suggested a 12-fold higher risk of MI during exposed time relative to unexposed time; among age-, sex-, and time-matched controls, the corresponding EOR of 4.5 indicated strong population-level exposure time trends. Over subsequent monitoring periods, case-crossover EORs rapidly dropped to 1.4. Adjustment for bias from population-level exposure time trends with the case-time-control analysis resulted in more consistent associations between valdecoxib and MI across sequential monitoring periods. Similar results were observed in each example. Strong population-level exposure time trends can bias case-crossover studies conducted among "first-wave" users of newly marketed medications. Suggested strategies can help assess and adjust for population-level exposure time trends.

[Interpretation of contemporary positioning of traditional Chinese medicine injections and analysis of key problems]

According to the current situations and development of (TCMIs), the author of the article reveals the scientific connotation of TCMIs in theory, preparations and clinic application, and points out that TCMIs are an innovative and breakthrough of conventional dosage forms of traditional Chinese medicines, the combination of traditional theory and modern technology as well as a type of modern dosage form with the characteristics of traditional Chinese medicines, which conforms to the principle of including the essence and excluding the wastes for traditional Chinese medicine preparations, meets the demands for quick-acting of traditional Chinese medicines and guides one of the development orientation of traditional Chinese medicines. In the meantime, an analysis was also made on key issues, such as adverse reactions of TCMIs, modern clinical application, special drug delivery route and diversity of components and ingredients.

Ranolazine refractory angina registry: 1-year results

Patients with refractory angina (RA) have limited therapeutic options and significant limitations in their quality of life. Ranolazine is approved for patients with chronic stable angina but has not been studied in patients with RA. The Ranolazine Refractory Angina Registry was designed to evaluate the safety, tolerability, and effectiveness in RA patients. In a dedicated RA clinic using an extensive prospective database, 100 patients were enrolled. Angina class, medications, major adverse cardiac events including death, myocardial infarction, and revascularization were obtained at 1, 6, and 12 months. Overall 43% of patients had a ≥2 class improvement in angina. At 1 year, 57% patients remained on ranolazine (91.2%; 500 mg BID), including 58% with a ≥2 class improvement in angina. Reasons for discontinuation included: side effects (n = 16), major adverse cardiac events (n = 10), cost (n = 5), ineffective (n = 6), cost and ineffective (n = 3), and unknown (n = 3). In conclusion, ranolazine is an effective antianginal therapy in patients with RA; still at 1 year only 57% of patients remained on ranolazine because of side effects, suboptimal effectiveness, cost, or progression of disease.

Gluten content of barium sulfate suspensions used for barium swallows in patients with celiac disease

PURPOSE

To determine the availability and accuracy of information provided by hospitals, imaging centers, and manufacturers regarding gluten in barium sulfate suspensions.

METHODS

A total of 105 facilities were contacted via telephone to determine the gluten content of the contrast media used in those facilities. Manufacturers were contacted and their Web sites reviewed to determine the gluten content of their barium products.

RESULTS

Thirty-nine percent of the hospitals and 52% of the imaging centers were not aware of the gluten content of the contrast media they used. Twenty-nine-and-a-half percent of the respondents provided the correct gluten content. The manufacturers noted that 5 products were tested and confirmed gluten free, 1 product was not tested but described as gluten free, 1 product's gluten content depended upon its flavor, and 1 product was reported to contain gluten.

DISCUSSION

Clinicians caring for patients with celiac disease or patients who choose to restrict their gluten consumption must ensure that the barium sulfate suspension ingested is gluten free.

CONCLUSION

It can be difficult to determine the gluten content of barium sulfate, as a majority of radiology departments and imaging centers did not know whether the product they use is gluten free. Educating staff members and improving product labeling would benefit the quality of care provided to patients with celiac disease.

Tocilizumab in rheumatoid arthritis: a case study of safety evaluations of a large postmarketing data set from multiple data sources

OBJECTIVES

To evaluate the magnitude of serious adverse events (SAEs) observed in postmarketing reports of tocilizumab (TCZ) for rheumatoid arthritis (RA) in relation to SAEs observed in TCZ clinical trials and external epidemiology data.

METHODS

A total of 64,000 patient-years (PY) of TCZ exposure was needed to determine, with 90% power, whether rates of SAEs of interest (eg, death, hepatic, gastrointestinal, and cardiovascular) were ≥50% higher (agreed with the Food and Drug Administration) than expected. Reporting rates were calculated for spontaneously reported SAEs, open-label or unblinded postmarketing clinical trials (phase 3b/4), and a Japanese postmarketing surveillance program in the global postmarketing safety database. Event rates were calculated for the registrational placebo-controlled trials and long-term extension data. External comparators for anti-tumor necrosis factor (aTNF)-treated RA patients were derived from a US-based health care insurance claims database or published literature.

RESULTS

The global postmarketing safety database provided 65,099 PY of TCZ exposure; the aTNF external comparator population provided 53,360 PY. Spontaneous reporting rates per 100 PY (95% confidence interval) were 8.3 (8.1, 8.5) SAEs, 0.39 (0.34, 0.44) deaths, 0.06 (0.04, 0.08) serious hepatic events, 0.15 (0.12, 0.18) serious gastrointestinal events, 0.09 (0.07, 0.12) serious myocardial infarctions, 0.15 (0.12, 0.18) serious strokes, and 0.07 (0.05, 0.09) cardiac deaths in the global postmarketing safety database. These were of similar magnitude to corresponding rates from registrational clinical trials, the aTNF external comparator population, and published literature.

CONCLUSIONS

SAE rates observed among postmarketing TCZ users were similar to those of various comparison populations. Predetermined design of studies to compare postmarketing AEs using multiple data sources is a useful strategy that can be applied to other medications.

Postmarket safety in Canada: are significant therapeutic advances and biologics less safe than other drugs? A cohort study

OBJECTIVES

Examine the probability of new active substances (NASs) approved in Canada between 1 January 1997 and 31 March 2012 acquiring a serious postmarket safety warning.

DESIGN

Cohort study.

DATA SOURCES

Annual reports of the Therapeutic Products Directorate and the Biologic and Genetic Therapies Directorate; evaluations of therapeutic innovation from the Patented Medicine Prices Review Board and Prescrire International; MedEffect Canada website.

INTERVENTIONS

Postmarket regulatory safety warning or withdrawal from market due to safety reasons.

PRIMARY AND SECONDARY OUTCOME MEASURES

Compare the probability of acquiring a postmarket safety warning in Canada in four different groups of drugs: (1) traditional medications versus biologics; (2) medications that offer significant new therapeutic benefits versus those that do not. Determine how well the type of review that an NAS received from Health Canada predicted the product's postmarket therapeutic value.

RESULTS

The probability of a traditional NAS acquiring a serious safety warning and/or being withdrawn was 29.9% (95% CI 21.8% to 40.2%) vs 27.3% (95% CI 18.2% to 39.7%) for an NAS of biological origin (p=0.47, log-rank test). For medications that were significant therapeutic advances the probability was 40.2% (95% CI 24.5% to 60.9%) vs 33.9% (95% CI 26.4% to 42.7%) for those that were not (p=0.18, log-rank test). Health Canada was 77.4% accurate in predicting the therapeutic importance of an NAS.

CONCLUSIONS

There was no difference in postmarket regulatory safety action between traditional medications and biologics and no difference between drugs with significant therapeutic benefits and those without. Although these results draw on Canadian data, they are likely to be relevant internationally. Further research should assess whether the current level of premarket safety evaluation is acceptable.

How safe are new drugs? Market withdrawal of drugs approved in Canada between 1990 and 2009

BACKGROUND

Studying drugs withdrawn from the market for safety reasons can help in evaluating the strengths and weaknesses of the pre- and post-market safety evaluation systems. This study considered 2 questions: Has there been a change over time in the percentage of new drugs that are eventually withdrawn because of safety reasons? How long are new drugs on the market before their serious safety problems are recognized?

METHODS

All drugs approved between 1 January 1990 and 31 December 2009 and subsequently withdrawn for safety reasons (until 1 October 2013) were identified, and the generic name, date of approval, and date of withdrawal were recorded. The total number of drugs approved over the same period was obtained from annual Health Canada reports. The percentages of new active substances approved in the 5-year periods 1990-1994, 1995-1999, 2000-2004, and 2005-2009 and eventually withdrawn were compared using the χ(2) test. The time between approval and withdrawal was calculated in days.

RESULTS

Of the 528 new drugs approved over the period of interest, a total of 22 (4.2%) were eventually withdrawn. Between 3.9% and 4.4% of the drugs approved in each 5-year period were eventually withdrawn (χ(2) = 0.04, p = 0.99 for difference among 5-year periods). The median time between approval and withdrawal was 1271 days (interquartile range 706-2876).

INTERPRETATION

One explanation for the finding of no difference in the percentage of drugs approved in the four 5-year periods that were eventually withdrawn is the lack of any change in the rigour of the premarket evaluation system and the postmarket surveillance systems. The 1271-day median time between Notice of Compliance and withdrawal emphasizes the need to be particularly cautious in prescribing new drugs early in their life cycle.