Report of the European Society of Cardiology Cardiovascular Round Table regulatory workshop update of the evaluation of new agents for the treatment of acute coronary syndrome: Executive summary.

Regulatory authorities interpret the results of randomized controlled trials according to published principles. The European Medicines Agency (EMA) is planning a revision of the 2000 and 2003 guidance documents on clinical investigation of new medicinal products for the treatment of acute coronary syndrome (ACS) to achieve consistency with current knowledge in the field. This manuscript summarizes the key output from a collaborative workshop, organized by the Cardiovascular Round Table and the European Affairs Committee of the European Society of Cardiology, involving clinicians, academic researchers, trialists, European and US regulators, and pharmaceutical industry researchers. Specific questions in four key areas were selected as priorities for changes in regulatory guidance: patient selection, endpoints, methodologic issues and issues related to the research for novel agents. Patients with ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) should be studied separately for therapies aimed at the specific pathophysiology of either condition, particularly for treatment of the acute phase, but can be studied together for other treatments, especially long-term therapy. Unstable angina patients should be excluded from acute phase ACS trials. In general, cardiovascular death and reinfarction are recommended for primary efficacy endpoints; other endpoints may be considered if specifically relevant for the therapy under study. New agents or interventions should be tested against a background of evidence-based therapy with expanded follow-up for safety assessment. In conclusion, new guidance documents for randomized controlled trials in ACS should consider changes regarding patient and endpoint selection and definitions, and trial designs. Specific requirements for the evaluation of novel pharmacological therapies need further clarification.

The European Medicines Agency's approval of new medicines for type 2 diabetes.

Since 2005, more than 40 new medicines for the treatment of type 2 diabetes have been introduced on the market. These consist of 15 new active substances establishing three new classes of non-insulin products, and several new or modified insulin products and combinations. The approval of these products in Europe is regulated via the centralized procedure at the European Medicines Agency. Demonstration of benefit with regard to improved glucose control remains the principal outcome required from confirmatory studies to demonstrate efficacy. For the majority of these new medicines approved since 2005, cardiovascular outcome trials have now been completed, and have invariably supported the cardiovascular safety of these products. In some of these trials additional important benefits have been observed, for instance, a reduction in major adverse cardiovascular events and improvement of renal outcome. The existing regulatory framework and the continuous adaption of regulatory requirements to emerging developments will continue to guide the approval of new products in the future.

EMA Review of Panobinostat (Farydak) for the Treatment of Adult Patients with Relapsed and/or Refractory Multiple Myeloma.

On August 28, 2015, a marketing authorization valid through the European Union was issued for panobinostat, in combination with bortezomib and dexamethasone, for the treatment of adult patients with relapsed and/or refractory multiple myeloma who have received at least two prior regimens including bortezomib and an immunomodulatory agent (IMiD).Panobinostat is an orally available histone deacetylase (HDAC) inhibitor that inhibits the enzymatic activity of HDAC proteins at nanomolar concentrations. HDAC proteins catalyze the removal of acetyl groups from the lysine residues of histones and some nonhistone proteins. Inhibition of HDAC activity results in increased acetylation of histone proteins, an epigenetic alteration that results in a relaxing of chromatin, leading to transcriptional activation. The recommended starting dose of panobinostat is 20 mg, taken orally in a cyclical manner for up to 48 weeks.The use of panobinostat in combination with bortezomib and dexamethasone was studied in a randomized, double-blind, placebo-controlled, multicenter phase III study (PANORAMA I) in 768 patients with relapsed or relapsed and refractory multiple myeloma who had received one to three prior lines of therapies. In the subgroup of patients who have received at least two prior regimens including bortezomib and an IMiD, there was a difference of 7.8 months in the progression-free survival in favor of the experimental arm (12.5 months for panobinostat + bortezomib + dexamethasone vs. 4.7 months for placebo + bortezomib + dexamethasone; hazard ratio = 0.47, 95% confidence interal 0.31-0.72; log-rank p value = .0003). The incidence of grade 3-4 adverse events suspected to be related to study drug was 76.9% vs. 51.2%, for the panobinostat and the placebo group, respectively. The most common side effects (grade 3-4) associated with panobinostat included diarrhea (18.9%), fatigue (14.7%), nausea (4.5%), vomiting (5.5%), thrombocytopenia (43.6%), anemia (7.9%), neutropenia (16.5%) and lymphopenia (8.1%).This article summarizes the scientific review of the application leading to regulatory approval in the European Union. The full scientific assessment report and product information, including the Summary of Product Characteristics, are available on the European Medicines Agency website (http://www.ema.europa.eu/ema/index.jsp?curl=pages/includes/medicines/medicines_landing_page.jsp&mid=). IMPLICATIONS FOR PRACTICE: Farydak was approved in the European Union in combination with bortezomib and dexamethasone, for the treatment of adult patients with relapsed and/or refractory multiple myeloma who have received at least two prior regimens including bortezomib and an immunomodulatory agent (IMiD). The addition of panobinostat to bortezomib and dexamethasone resulted in a clinically meaningful and statistically significant improvement of progression-free survival compared with bortezomib and dexamethasone, and an additional therapeutic option with a new mechanism of action was considered valuable. Although the toxicity associated with panobinostat combination was significant, at the time of the marketing authorization of panobinostat, it was considered that it was acceptable and that it should be left to the clinician and the patient to decide whether the panobinostat combination is the preferred treatment option or not.

New strategies for the development of lipid-lowering therapies to reduce cardiovascular risk.

The very high occurrence of cardiovascular events presents a major public health issue, because treatment remains suboptimal. Lowering LDL cholesterol (LDL-C) with statins or ezetimibe in combination with a statin reduces major adverse cardiovascular events. The cardiovascular risk reduction in relation to the absolute LDL-C reduction is linear for most interventions without evidence of attenuation or increase in risk at low LDL-C levels. Opportunities for innovation in dyslipidaemia treatment should address the substantial risk of lipid-associated cardiovascular events among patients optimally treated per guidelines but who cannot achieve LDL-C goals and who could benefit from additional LDL-C-lowering therapy or experience side effects of statins. Fresh approaches are needed to identify promising drug targets early and develop them efficiently. The Cardiovascular Round Table of the European Society of Cardiology (ESC) convened a workshop to discuss new lipid-lowering strategies for cardiovascular risk reduction. Opportunities to improve treatment approaches and the efficient study of new therapies were explored. Circulating biomarkers may not be fully reliable proxy indicators of the relationship between treatment effect and clinical outcome. Mendelian randomization studies may better inform development strategies and refine treatment targets before Phase 3. Trials should match the drug to appropriate lipid and patient profile, and guidelines may move towards a precision-based approach to individual patient management. Stakeholder collaboration is needed to ensure continued innovation and better international coordination of both regulatory aspects and guidelines. It should be noted that risk may also be addressed through increased attention to other risk factors such as smoking, hypertension, overweight, and inactivity.

Independent academic Data Monitoring Committees for clinical trials in cardiovascular and cardiometabolic diseases.

Data Monitoring Committees (DMCs) play a crucial role in the conducting of clinical trials to ensure the safety of study participants and to maintain a trial's scientific integrity. Generally accepted standards exist for DMC composition and operational conduct. However, some relevant issues are not specifically addressed in current guidance documents, resulting in uncertainties regarding optimal approaches for communication between the DMC, steering committee, and sponsors, release of information, and liability protection for DMC members. The Heart Failure Association (HFA) of the European Society of Cardiology (ESC), in collaboration with the Clinical Trials Unit of the European Heart Agency (EHA) of the ESC convened a meeting of international experts in DMCs for cardiovascular and cardiometabolic clinical trials to identify specific issues and develop steps to resolve challenges faced by DMCs.The main recommendations from the meeting relate to methodological consistency, independence, managing conflicts of interest, liability protection, and training of future DMC members. This paper summarizes the key outcomes from this expert meeting, and describes the core set of activities that might be further developed and ultimately implemented by the ESC, HFA, and other interested ESC constituent bodies. The HFA will continue to work with stakeholders in cardiovascular and cardiometabolic clinical research to promote these goals.

New medicinal products for chronic heart failure: advances in clinical trial design and efficacy assessment.

Despite the availability of a number of different classes of therapeutic agents with proven efficacy in heart failure, the clinical course of heart failure patients is characterized by a reduction in life expectancy, a progressive decline in health-related quality of life and functional status, as well as a high risk of hospitalization. New approaches are needed to address the unmet medical needs of this patient population. The European Medicines Agency (EMA) is undertaking a revision of its Guideline on Clinical Investigation of Medicinal Products for the Treatment of Chronic Heart Failure. The draft version of the Guideline was released for public consultation in January 2016. The Cardiovascular Round Table of the European Society of Cardiology (ESC), in partnership with the Heart Failure Association of the ESC, convened a dedicated two-day workshop to discuss three main topic areas of major interest in the field and addressed in this draft EMA guideline: (i) assessment of efficacy (i.e. endpoint selection and statistical analysis); (ii) clinical trial design (i.e. issues pertaining to patient population, optimal medical therapy, run-in period); and (iii) research approaches for testing novel therapeutic principles (i.e. cell therapy). This paper summarizes the key outputs from the workshop, reviews areas of expert consensus, and identifies gaps that require further research or discussion. Collaboration between regulators, industry, clinical trialists, cardiologists, health technology assessment bodies, payers, and patient organizations is critical to address the ongoing challenge of heart failure and to ensure the development and market access of new therapeutics in a scientifically robust, practical and safe way.

Implications of a clinical medication review and a pharmaceutical care plan of polypharmacy patients with a cardiovascular disorder.

Background A clinical medication review, including patient involvement, is expected to improve pharmaceutical care. Objective To determine whether a clinical medication review followed by a pharmaceutical care plan decreases the number of potential drug-related problems (DRPs) and pharmaceutical care issues (PCIs) and leads to a positive effect on relevant clinical and laboratory parameters for elderly cardiovascular patients with multiple drug use. Setting Randomized controlled trial in eight primary care settings in the Netherlands. Method Elderly polypharmacy patients with a cardiovascular disorder were randomized into two groups. Intervention patients received a clinical medication review, followed by a pharmaceutical care plan developed in cooperation between these patients' pharmacists and general practitioners (GPs), and agreed to by the patients. Control patients received care as usual. Patient data were collected at the start of the study (t = 0) and after 1-year follow-up (t = 1). Main outcome measure Decrease in potential DRPs and pharmaceutical PCIs, improvement of clinical and laboratory parameters. Results 512 patients were included. An average of 2.2 potential DRPs and pharmaceutical PCIs were defined per patient in the intervention group. After 1-year follow-up, 47.2 % of potential DRPs and PCIs were resolved. In total, 156 care interventions were proposed (0.9/patient), 108 of which were implemented after 1 year (69.2 %). For control-group patients, a total of 47 proposed care interventions were documented for 255 patients (0.2/patient); after 1 year, 43 had been implemented (91.5 %). The study intervention (p < 0.001) and the number of medicines used (p = 0.030) had a significant effect on the number of interventions proposed. Small biochemical changes in cardiovascular risk factors did occur, but the differences were small and not considered clinically relevant. Conclusion The integrated use of a clinical medication review with a pharmaceutical care plan in a primary care setting supports the detection of and decrease in DRPs and pharmaceutical PCIs in almost half of the patients. Its benefit in terms of control of cardiovascular risk factors and safety parameters was relatively low. Risk stratification might be necessary to decide which patients might benefit most from this type of intervention.

The European Medicines Agency Review of Brentuximab Vedotin (Adcetris) for the Treatment of Adult Patients With Relapsed or Refractory CD30+ Hodgkin Lymphoma or Systemic Anaplastic Large Cell Lymphoma: Summary of the Scientific Assessment of the Committee for Medicinal Products for Human Use.

BACKGROUND: On October 25, 2012, a conditional marketing authorization valid throughout the European Union (EU) was issued for brentuximab vedotin for the treatment of adult patients with relapsed or refractory CD30+ Hodgkin lymphoma (HL) and for the treatment of adult patients with relapsed or refractory systemic anaplastic large cell lymphoma (sALCL). For HL, the indication is restricted to treatment after autologous stem cell transplantation (ASCT) or after at least two previous therapies when ASCT or multiagent chemotherapy is not a treatment option. MATERIALS AND METHODS: Brentuximab vedotin is an antibody-drug conjugate (ADC) composed of a CD30-directed monoclonal antibody (recombinant chimeric IgG1) that is covalently linked to the antimicrotubule agent monomethyl auristatin E (MMAE). Binding of the ADC to CD30 on the cell surface initiates internalization of the MMAE-CD30 complex, followed by proteolytic cleavage that releases MMAE. The recommended dose is 1.8 mg/kg administered as an intravenous infusion over 30 minutes every 3 weeks. RESULTS: Brentuximab vedotin as a single agent was evaluated in two single-arm studies. Study SG035-003 included 102 patients with relapsed or refractory HL. An objective response was observed in 76 patients (75%), with complete remission in 34 (33%). Study SG035-004 included 58 patients with relapsed or refractory sALCL. An objective response was observed in 50 patients (86%), with complete remission in 34 (59%). The most frequently observed toxicities were peripheral sensory neuropathy, fatigue, nausea, diarrhea, neutropenia, vomiting, pyrexia, and upper respiratory tract infection. CONCLUSION: The present report summarizes the scientific review of the application leading to approval in the EU. The detailed scientific assessment report and product information, including the summary of the product characteristics, are available on the European Medicines Agency website (http://www.ema.europa.eu). IMPLICATIONS FOR PRACTICE: Brentuximab vedotin was approved in the European Union for the treatment of adult patients with relapsed or refractory CD30+ Hodgkin lymphoma or systemic anaplastic large cell lymphoma. For Hodgkin lymphoma, brentuximab vedotin should only be used after autologous stem cell transplantation or following at least two prior therapies when transplantation or multiagent chemotherapy is not a treatment option. In two studies involving 160 patients, partial or complete responses were observed in the majority of patients. Although there was no information on the survival of patients treated in the studies at the time of approval, the responses were considered a clinically relevant benefit.

Understanding drug preferences, different perspectives.

AIMS: To compare the values regulators attach to different drug effects of oral antidiabetic drugs with those of doctors and patients. METHODS: We administered a 'discrete choice' survey to regulators, doctors and patients with type 2 diabetes in The Netherlands. Eighteen choice sets comparing two hypothetical oral antidiabetic drugs were constructed with varying drug effects on glycated haemoglobin, cardiovascular risk, bodyweight, duration of gastrointestinal complaints, frequency of hypoglycaemia and risk of bladder cancer. Responders were asked each time which drug they preferred. RESULTS: Fifty-two regulators, 175 doctors and 226 patients returned the survey. Multinomial conditional logit analyses showed that cardiovascular risk reduction was valued by regulators positively (odds ratio 1.98, 95% confidence interval 1.11-3.53), whereas drug choices were negatively affected by persistent gastrointestinal problems (odds ratio 0.24, 95% confidence interval 0.14-0.41) and cardiovascular risk increase (odds ratio 0.49, 95% confidence interval 0.27-0.87). Doctors and patients valued these effects in a similar manner to regulators. The values that doctors attached to large changes in glycated haemoglobin and that both doctors and patients attached to hypoglycaemia and weight gain also reached statistical significance. No group's drug choice was affected by a small absolute change in risk of bladder cancer when presented in the context of other drug effects. When comparing the groups, the value attached by regulators to less frequent hypoglycaemic episodes was significantly smaller than by patients (P = 0.044). CONCLUSIONS: Regulators may value major benefits and risks of drugs for an individual diabetes patient mostly in the same way as doctors and patients, but differences may exist regarding the value of minor or short-term drug effects.

Post-approval safety issues with innovative drugs: a European cohort study.

BACKGROUND: At time of approval, knowledge of the full benefit risk of any drug is limited, in particular with regards to safety. Post-approval surveillance of potential drug safety concerns is recognized as an important task of regulatory agencies. For innovative, often first-in-class drugs, safety knowledge at time of approval is often even less extensive and these may require tighter scrutiny post approval. OBJECTIVE: We evaluated whether more post-approval serious safety issues were identified for drugs with a higher level of innovation. METHODS: A cohort study was performed that included all new active substances approved under the European Centralized Procedure and for which serious safety issues were identified post-approval from 1 January 1999 to 1 January 2012. Serious safety issues were defined as issues requiring a Direct Healthcare Professional Communication to alert individual healthcare professionals of a new serious safety issue, or a safety-related drug withdrawal. Data were retrieved from publicly available websites of the Dutch Medicines Evaluation Board and the European Medicines Agency. The level of innovation was scored using a validated algorithm, grading drugs as important (A), moderate (B) or modest (C) innovations or as pharmacological or technological (pharm/tech) innovations. The data were analyzed using appropriate descriptive statistics and Kaplan-Meier analysis, with a Mantel-Cox log-rank test, and Cox-regression models correcting for follow-up duration, to identify a possible trend in serious safety issues with an increasing level of innovation. RESULTS: In Europe, 279 new drugs were approved between 1999 and 2011. Fifty-nine (21 %) were graded as important, 63 (23 %) moderate, or 34 (12 %) modest innovations and 123 (44 %) as non-innovative (pharm/tech), while 15 (25 %), 13 (21 %), 8 (24 %) and 17 (14 %) had post-approval safety issues, respectively (p = 0.06, linear-by-linear test). Five drugs were withdrawn from the market. The Kaplan-Meier-derived probability for having a first serious safety issue was statistically significant, log-rank (Mantel-Cox) p = 0.036. In the final adjusted Cox proportional hazard model there was no statistically significant difference in occurrence of a first serious safety issue for important, moderate and modest innovations versus non-innovative drugs; hazard ratios 1.76 (95 % CI 0.82-3.77), 1.61 (95 % CI 0.76-3.41)], and 1.25 (95 % CI 0.51-3.06), respectively. CONCLUSION: A higher level of innovation was not clearly related to an increased risk of serious safety issues identified after approval.

The Additional Value of an E-Mail to Inform Healthcare Professionals of a Drug Safety Issue: A Randomized Controlled Trial in the Netherlands.

BACKGROUND: The usefulness and the impact of Direct Healthcare Professional Communications (DHPCs, or 'Dear Doctor letters') in changing the clinical behaviour of physicians have been debated. Changes in the current risk communication methods should preferably be based on the preferences of the healthcare professionals, to optimize the uptake of the message. OBJECTIVE: The aim of this study was to assess whether safety issues are communicated more effectively with an additional e-mail sent by the Dutch Medicines Evaluation Board (MEB) than with the DHPC only. METHODS: A randomized controlled trial was conducted amongst ophthalmologists and hospital pharmacists in the Netherlands, who were the target group of a DHPC that was issued for pegaptanib, a drug that is administered intra-ocularly in patients with macular degeneration. The intervention group (N = 110) received the pegaptanib DHPC, as well as the MEB e-mail. The control group (N = 105) received the traditional paper-based DHPC only. Two weeks later, the study population received an invitation to fill out an online questionnaire. Questions were asked about the respondents' knowledge and attitude regarding the pegaptanib issue, and any action they had consequently taken. Additional questions were asked about their satisfaction with the DHPC and the e-mail, and their preferred source of such information. RESULTS: Forty respondents (18.6%) completed the questionnaire. Eighty-one percent of the respondents in the intervention group (N = 21) and 47% of the control group (N = 19) correctly indicated that a serious increase in intra-ocular pressure could be caused by pegaptanib injections (Fishers' exact test, p = 0.046). Nine respondents in the intervention group versus none of the control group respondents indicated that they had taken action in response to the pegaptanib safety issue (Fishers' exact test, p = 0.01). The majority of both the intervention group and the control group confirmed that they would like to receive an MEB e-mail with safety information about drugs in the future (90 and 95 %, respectively). CONCLUSION: The results of this study indicate that an additional e-mail might strengthen the uptake of the safety information provided to healthcare professionals, who prefer to receive an e-mail from the MEB as a source of such information, as well as the DHPC. This study may serve as a starting point for new strategies to improve risk communication regarding safety issues associated with drugs and its impact on prescribing.

Risk perception of prescription drugs: results of a survey among experts in the European regulatory network.

BACKGROUND: Experts are perceived to be veridical and to focus only on objective data when evaluating risk. Only a few research studies have attempted to characterize the subjectivity in risk evaluation among experts. OBJECTIVE: The hypothesis of this study is that expert evaluation of a pharmaceutical drug can be partly explained by dimensions that describe the drug and by individual characteristics. DESIGN: Seventy-five medical assessors in 9 EU countries evaluated a list of 28 pharmaceutical drugs using 4 scales: risk, benefit, seriousness of harm, and patients' knowledge of the risk. They were also given a mock "clinical dossier" and asked to rate it on 8 dimensions: risk, benefit, worry, magnitude of the exposure, scientific knowledge of the risk, familiarity of the risk, ethical concerns, and risk acceptability. RESULTS: Female assessors perceived significantly higher benefits than men for a large number of the 28 drugs. Principal component analysis of the ratings for the clinical dossiers revealed 2 underlying components: seriousness of harm and scientific evidence. A regression model predicting the risk perception of the drug showed that the variables seriousness of harm (benefit, worry, magnitude of exposure, ethical concerns, and risk acceptability), years of regulatory experience, gender, and type of drug explained 54% of the variability among assessors. CONCLUSION: Assessors' view of the risks associated with pharmaceutical drugs is influenced by worry for patient safety, magnitude of patient exposure, and ethical concerns. These dimensions may influence their perceptions of benefit and risk acceptability. Senior assessors are more risk averse than junior assessors, and female assessors seem to be sensitive to the promise of benefit from medicines and consequently may be less risk averse than male assessors.

Healthcare professionals' self-reported experiences and preferences related to direct healthcare professional communications: a survey conducted in the Netherlands.

BACKGROUND: In Europe, Direct Healthcare Professional Communications (DHPCs) are important tools to inform healthcare professionals of serious, new drug safety issues. However, this tool has not always been successful in effectively communicating the desired actions to healthcare professionals. OBJECTIVE: The aim of this study was to explore healthcare providers' experiences and their preferences for improvement of risk communication, comparing views of general practitioners (GPs), internists, community pharmacists and hospital pharmacists. METHODS: A questionnaire was developed and pilot tested to assess experiences and preferences of Dutch healthcare professionals with DHPCs. The questionnaire and two reminders were sent to a random sample of 3488 GPs, internists and community and hospital pharmacists in the Netherlands. Descriptive statistics were used to describe demographic characteristics of the respondents. Chi squares, ANOVAs and the Wilcoxon signed rank test were used, when appropriate, to compare healthcare professional groups. RESULTS: The overall response rate was 34% (N = 1141, ranging from 24% for internists to 46% for community pharmacists). Healthcare providers trusted safety information more when provided by the Dutch Medicines Evaluation Board (MEB) than by the pharmaceutical industry. This was more the case for GPs than for the other healthcare professionals. Respondents preferred safety information to be issued by the MEB, the Dutch Pharmacovigilance Center or their own professional associations. The preferred alternative channels of drug safety information were e-mail, medical journals and electronic prescribing systems. CONCLUSIONS: Safety information of drugs does not always reach healthcare professionals through DHPCs. To improve current risk communication of drug safety issues, alternative and/or additional methods of risk communication should be developed using electronic methods and medical journals. Moreover, (additional) risk communication coming from an independent source such as the MEB should be considered. Special effort is needed to reach GPs.

Impact of safety-related regulatory action on clinical practice: a systematic review.

BACKGROUND: After market approval, new serious safety issues are regularly identified for drugs that lead to regulatory action to inform healthcare professionals. However, the effectiveness of these safety-related regulatory actions is under question. We currently lack a comprehensive overview of the effects of these drug safety warnings on clinical practice to resolve the debate about their effectiveness. OBJECTIVE: The aim of this systematic review is to provide an overview of studies that assessed the impact of safety warnings. STUDY SELECTION: A systematic search was performed for articles assessing the impact of Direct Healthcare Professional Communications or 'Dear Doctor' letters, Black Box Warnings and Public Health Advisories on clinical behaviour published between January 1996 and January 2010. The following variables were extracted: publication year, country, name of the drug, safety issue, specific safety warning (Direct Healthcare Professional Communication/Black Box Warning/Public Health Advisory), effect (intended/unintended) of the safety warning, outcome measure and study design. Papers were checked for several quality aspects. Study data were summarized using descriptive analyses. RESULTS: A total of 50 articles were identified. Two articles assessed two different drugs and were therefore counted twice (n = 52). Thirty-three articles described the impact of safety warnings issued for three drugs and drug groups, i.e. third-generation oral contraceptives, cisapride and selective serotonin reuptake inhibitors. The remaining 19 articles described a broad variety of 14 drugs and drug groups. Twenty-five studies applied an interrupted time series design, 23 a controlled or uncontrolled before/after design, and four articles applied both. None of the articles could rule out the influence of confounding factors. The intended effects were reported in 18 (72%) of the 25 before/after analyses, whereas only 11 (41%) of the 27 interrupted time series analyses reported an impact. Only two (8%) of the before/after analyses against 11 (41%) of the interrupted time series analyses reported mixed impacts. When unintended effects were assessed in case of selective serotonin reuptake inhibitors and third-generation oral contraceptives, these were almost always present: in 19 of 22 and 4 of 5 articles, respectively. Our review shows that safety-related regulatory action can have some impact on clinical practice but firm conclusions are difficult to draw. Evidence is primarily based on three drugs and drug groups. Almost half of the studies had inadequate before/after designs and the heterogeneity in analyses and outcome measures hampered the reporting of overall effect sizes. Studies with adequate interrupted time series design reported a more mixed impact of safety warnings than before/after studies. Furthermore, this review shows the relevance of considering not only the intended but also the unintended effects of safety warnings. CONCLUSIONS: There is a clear need for further research with appropriate study designs and statistical analyses, with more attention to confounding factors such as media coverage, to understand the impact of safety-related regulatory action.