[Recommendations for the study and evaluation of gender differences in clinical trials in Spain]

Systematic review of gender bias in clinical trials of monoclonal antibodies for the treatment of multiple sclerosis

INTRODUCTION

This article analyses the presence of gender bias in clinical trials of monoclonal antibodies used to treat multiple sclerosis.

MATERIAL AND METHODS

We performed a systematic review of controlled clinical trials of 4 monoclonal antibodies used to treat multiple sclerosis (natalizumab, rituximab, alemtuzumab, and ocrelizumab). We searched the PubMed/MEDLINE database for articles published in English before March 2020. The study was conducted in accordance with the relevant international recommendations.

RESULTS

The search identified 89 articles, 55 of which met the inclusion criteria. Of all patients included in these trials, 64.6% were women. The lead authors of 10 of the studies were women. Fifteen of the 55 studies included a sex-based analysis of the primary endpoint. Only 8 articles discussed the results separately for men and for women.

CONCLUSIONS

The clinical trials of these 4 monoclonal antibodies present a significant gender bias. In most cases, the primary and secondary endpoints are not analyzed according to patient sex, despite the fact that international recommendations include this as a minimum requirement for ensuring scientific validity and obtaining appropriate results for extrapolation to the wider population.

Gender bias in clinical trials of biological agents for severe asthma: A systematic review

Asthma is one of the most common chronic diseases characterized by sex disparities. Gender bias is a well-documented issue detected in the design of published clinical trials (CTs). International guidelines encourage researchers to analyze clinical data by sex, gender, or both where appropriate. The objective of this work was to evaluate gender bias in the published CTs of biological agents for the treatment of severe asthma. A systematic review of randomized controlled CTs of the biological agents (omalizumab, benralizumab, reslizumab, mepolizumab or dupilumab) for the treatment of severe asthma was conducted. The literature search was performed using PubMed and EMBASE without language restrictions. This study followed the corresponding international recommendations. We identified a total of 426 articles, of which 37 were finally included. Women represented 60.4% of patients included. The mean percentage of women in these trials was 59.9%, ranged from 40.8% to 76.7%. The separate analysis by sex of the main variable was only performed in 5 of the 37 publications included, and none of the trials analyzed secondary variables by sex. Only 1 of the articles discussed the results separately by sex. No study included the concept of gender in the text or analyzed the results separately by gender. The proportion of women included in CTs was higher compared to publications of other disciplines, where women were under-represented. The analysis of the main and secondary variables by sex or gender, even the discussion separately by sex, was insufficient. This gives rise to potential gender bias in these CTs.

Systematic review of gender bias in vortioxetine clinical trials

This paper evaluates gender bias in the published clinical trials of Vortioxetine. We conducted a systematic review of controlled clinical trials of Vortioxetine for the treatment of depression. The literature search was performed using MEDLINE and following the corresponding international recommendations. We identified 42 articles, of which 23 were included. The proportion of women ranged from 47%-75% and the percentage of women included in the 10,404 total patients sample was 65%. The separate analysis of the main variable between the subpopulations of men and women was only carried out in 3/23 publications included. In contrast, 6/23 trials analyzed secondary variables separated by sex. No trials discussed the results separately by sex. The proportion of women included was slightly higher than that in clinical trials of other antidepressants. However, the analysis of the main result or secondary variables by sex, as well as discussing the results separately by sex, are scarce. This gives rise to gender bias in these works.

Systematic review of gender bias in clinical trials of monoclonal antibodies for the treatment of multiple sclerosis

INTRODUCTION

This article analyses the presence of gender bias in clinical trials of monoclonal antibodies used to treat multiple sclerosis.

MATERIAL AND METHODS

We performed a systematic review of controlled clinical trials of 4 monoclonal antibodies used to treat multiple sclerosis (natalizumab, rituximab, alemtuzumab, and ocrelizumab). We searched the PubMed/MEDLINE database for articles published in English before March 2020. The study was conducted in accordance with the relevant international recommendations.

RESULTS

The search identified 89 articles, 55 of which met the inclusion criteria. Of all patients included in these trials, 64.6% were women. The lead authors of 10 of the studies were women. Fifteen of the 55 studies included a sex-based analysis of the primary endpoint. Only 8 articles discussed the results separately for men and for women.

CONCLUSIONS

The clinical trials of these 4 monoclonal antibodies present a significant gender bias. In most cases, the primary and secondary endpoints are not analyzed according to patient sex, despite the fact that international recommendations include this as a minimum requirement for ensuring scientific validity and obtaining appropriate results for extrapolation to the wider population.

Gender bias in clinical research, pharmaceutical marketing, and the prescription of drugs

This thesis is part of the studies of gender bias in health which together with the paradigm of evidence-based medicine shares the empirical assumption that there are inaccuracies in medical practice, in addition to a lack of rigour and transparency. It worked with the distinction between the concepts of sex and gender and between the concepts of sex-related differences and gender inequalities, in terms of applying a gender perspective in the study design and the subsequent analysis. This PhD review presents the research process conducted in Spain, which can provide an example for future research. Study I described a review of 58 clinical trials (CTs) of etoricoxib to assess its compliance with the Recommendations of Evaluation of Gender Differences in the Clinical Evaluation of Drugs. In Study II, key informants from professions related to different areas in drug development and pharmacovigilance held a working meeting to reach a consensus document on recommendations for the study and evaluation of gender differences in CTs in Spain. In Study III, the websites of the eight best-selling hormone replacement therapy drugs in Spain on Google first page of results were analysed. In Study IV, a logistic regression analysis was performed to compare analgesic prescription by sex in regions with a higher or lower Gender Development Index (GDI) than the Spanish average. Gender biases identified in this thesis limited the legitimacy of medicine, which is not based on the best possible evidence. The results also demonstrate the existence of inequalities between men and women that are not due merely to biological differences, but are gender inequalities stemming from the social differences that exist between both sexes.

Sex as a variable in medicines assessment reports for licensing in the European Union. Can gender bias be excluded?

PURPOSE

To analyse publically available official reports on the evaluation of European Union (EU) registration of new medicines (aimed at diseases affecting both sexes) in order to address the possibility of gender bias.

METHODS

Descriptive study reviewing two types of assessment reports corresponding to different EU registration procedures: European Public Assessment Reports (EPARs) for the centralised procedures (399 reports considered from 2001 to 2002 and 2008 to 2009) and Mutual Recognition or Decentralised Public Assessment Reports (MPARs) for the mutual recognition and decentralised procedures (2,704 reports, totality until 2009-inclusive).

RESULTS

Two hundred and twenty-four EPARs fulfilled the study criteria. It can be deduced from those EPARs that women participated in at least one clinical trial in 215 (78.5 %) of the reports. In 49(17.9 %) of the EPARs, the study population is explicitly evaluated according to sex, ten (3.6 %) presenting results disaggregated by sex. Most sex-related differences are in safety and pharmacokinetics; six of the 22 cases (72.7 %) of safety differences and nine of the 23 cases (60.9 %) of pharmacokinetic differences are not discussed. In relation to MPARs, only 2,704 out of 15,621 registries (17 %) were published, which casts doubts on the representativity of the available reports. Those published reflect less participation by women than in the EPARs.

CONCLUSIONS

From the incomplete sex-related data made public, it is difficult to conclude on the existence of gender bias in the evidence used for the evaluation of new medicines. It certainly cannot be excluded. It is therefore recommended that compliance with existing guidance for publication of reports is increased, so as to transparently reassure on the issue.