Demographic Diversity of Clinical Trials for Therapeutic Drug Products: A Systematic Review of Recently Published Articles, 2017-2022

The US Food and Drug Administration (FDA) encourages the use of enrollment practices that will lead to clinical trials that reflect the population most likely to use the therapeutic product (drug or biologic), if approved. In doing so, the benefit-risk profile of the product may be assessed more completely and offer patients and their health care providers a better understanding of the drug profile and greater confidence in clinical trial results. The objective of this systematic review was to assess recent literature on the demographic diversity of clinical trial participants, describe the methods used in defining clinical trial diversity, and address knowledge gaps to enhance clinical trial diversity. Our literature search initially yielded 246 articles. After applying our eligibility criteria, we conducted a full-text review and analyzed the contents of the 28 remaining articles in our systematic review. Eleven (39%) of the 28 articles used a reference standard to compare the participation of populations in clinical trials to assess diversity. The majority of the 28 articles reported on adult participants; only 5 included pediatric populations. Most articles found that women and minority populations were underrepresented in clinical trials. Some articles proposed solutions to improve clinical trial diversity; however, several did not comment on clinical trial diversity. Despite a growing emphasis on demographic diversity in research, certain populations continue to be underrepresented in clinical trials. There is a need to standardize the definition of diversity in clinical trials. Future research into effective enrollment approaches and appropriate reference standards could improve demographic diversity.

Thrombocytopenia including immune thrombocytopenia after receipt of mRNA COVID-19 vaccines reported to the Vaccine Adverse Event Reporting System (VAERS)

Background

The objective of this study is to assess cases of thrombocytopenia, including immune thrombocytopenia (ITP), reported to the Vaccine Adverse Event Reporting System (VAERS) following vaccination with mRNA COVID-19 vaccines.

Methods

This case-series study analyzed VAERS reports of thrombocytopenia after vaccination with Pfizer-BioNTech COVID-19 Vaccine or Moderna COVID-19 Vaccine.

Results

Fifteen cases of thrombocytopenia were identified among 18,841,309 doses of Pfizer-BioNTech COVID-19 Vaccine and 13 cases among 16,260,102 doses of Moderna COVID-19 Vaccine. The reporting rate of thrombocytopenia was 0.80 per million doses for both vaccines. Based on an annual incidence rate of 3.3 ITP cases per 100,000 adults, the observed number of all thrombocytopenia cases, which includes ITP, following administration of mRNA COVID-19 vaccines is not greater than the number of ITP cases expected.

Conclusions

The number of thrombocytopenia cases reported to VAERS does not suggest a safety concern attributable to mRNA COVID-19 vaccines at this time.

Venues for Meeting Sex Partners and Partner HIV Risk Characteristics: HIV Prevention Trials Network (HPTN064) Women's HIV Seroincidence Study (ISIS)

Identifying venues where women meet sexual partners, particular partners who increase women's risk of acquiring HIV, could inform prevention efforts. We categorized venues where women enrolled in HPTN 064 reported meeting their last three sex partners as: (1) Formal, (2) Public, (3) Private, and (4) Virtual spaces. We used multinomial logistic regression to assess the association between these venues and women's individual characteristics and reports of their partners' HIV risk characteristics. The 2099 women reported meeting 3991 partners, 51 % at Public, 30 % Private, 17 % Formal and 3 % at Virtual venues. Women meeting partners at Formal venues reported more education and condom use than women meeting partners at other venues. Fewer partners met through Formal venues had "high" risk characteristics for HIV than through other venues and hence may pose less risk of HIV transmission. HIV prevention interventions can help women choose partners with fewer risk characteristics across all venue types.

Complementary use of passive surveillance and Mini-Sentinel to better characterize hemolysis after immune globulin

BACKGROUND

Hemolysis after intravenous immune globulins (IGIVs) is a known complication, but expanding indications and recent manufacturing changes warrant ongoing postmarketing surveillance. Characterization of post-IGIV hemolysis to date has been limited to small case series.

STUDY DESIGN AND METHODS

We queried the Food and Drug Administration's (FDA) Adverse Event Reporting System (FAERS) from 2007 to 2014. All reported post-IGIV hemolysis cases were classified using a prespecified case definition and a case series analysis performed. We also conducted two assessments using FDA's Mini-Sentinel (MS) system to quantify the risk of hemolysis by six product indications and by IGIV formulation and evaluate the onset interval.

RESULTS

A total of 109 FAERS cases met our definition. For cases with available information, 83% (66/80) received IGIV doses of at least 2 g/kg, 98.1% (51/52) had non-O blood group, and 75% (64/85) of events occurred within 4 days of IGIV exposure. We identified 313,045 treatment episodes and 337 post-IGIV hemolytic events in MS from 2006 to 2014, with 72% occurring within 2 days. Rates of hemolysis were highest among patients with Kawasaki disease (KD) and immune thrombocytopenia (ITP). The risk among patients receiving nonlyophilized products was 2.3 times higher than that in patients receiving lyophilized products.

CONCLUSION

With the largest case series to date, FAERS data support that higher doses and non-O blood group are key risk factors. The incident rate of post-IGIV hemolysis is estimated at one per 1000 IGIV treatment episodes, with most occurring within 2 days of exposure. The risk is higher in patients with KD and ITP and after receipt of nonlyophilized IGIV.

Persons at high risk for HIV infection in Kisumu, Kenya: identifying recruitment strategies for enrolment in HIV-prevention studies

A combination of in-depth interviews ( n = 38) and surveys ( n = 203) were used to (1) identify strategies to recruit persons at high risk for HIV infection; (2) determine whether one strategy was more successful than others; and (3) describe motivators and barriers to participation in HIV-prevention studies. From in-depth interviews, four main recruitment strategies were identified: (1) use of a person with specific knowledge of a target population (link person mobilization); (2) use of co-workers or contemporaries (peer mobilization); (3) use of group or association leaders (leader mobilization); and (4) contacting persons by study staff directly (staff contact mobilization). The odds of inconsistently using condoms during sex were greater among those recruited using the peer mobilization (adjusted odds ratio [AOR] = 3.59; 95% confidence interval [CI] = 1.35–9.54) and the leader mobilization strategies (AOR = 2.76; 95% CI = 1.04–7.38) compared with the link person mobilization strategy. The main motivators for taking part in an HIV research study were receiving HIV-prevention education, HIV information or counselling, and receiving compensation for study participation. The main barriers were fear of lack of confidentiality and HIV testing concerns. Using evaluated strategies to recruit persons at high risk for HIV infection and addressing barriers to participation will improve the conduct and outcome of HIV-prevention studies.

Sporadic paediatric diarrhoeal illness in urban and rural sites in Nyanza Province, Kenya

OBJECTIVE

Investigate differences in the infectious aetiology, health seeking behaviour, and provider practices with regard to diarrhoeal illness among children presenting to urban versus rural clinics in Western Kenya.

DESIGN

Laboratory-based, passive surveillance.

SETTING

The urban portion of the study was conducted at the paediatric outpatient clinic of Nyanza Provincial Hospital in Kisumu. The rural portion of the study was conducted at four outpatient clinics in the Asembo Bay community approximately 20 kilometers west of Kisumu.

SUBJECTS

Children aged less than five years presenting to medical facilities for the treatment of diarrhoea from October 2001-October 2003 at the urban site and May 1997-April 2003 for the rural sites.

RESULTS

Among the 1303 urban and 1247 rural specimens collected, 24% of specimens yielded a bacterial pathogen (24% urban, 25% rural). Campylobacter was the predominant bacterial pathogen (17% urban, 15% rural), followed by Shigella and nontyphoidal Salmonella (both 4% urban and 5% rural). In both communities, susceptibilities of these pathogens to the most commonly prescribed antibiotics was low (< or = 50%); 70% of all episodes of diarrhoea were prescribed antibiotic treatment. Urban health practitioners prescribed fewer antibiotics, chose drugs more likely to be effective, and were more likely to prescribe oral rehydration therapy for bloody diarrhoea.

CONCLUSION

Most characteristics of diarrhoeal disease and their causes were similar in paediatric patients presenting to urban and rural clinics. Urban providers were more compliant with WHO recommendations.

Recognition of multiple antibody epitopes throughout Borrelia burgdorferi p66, a candidate adhesin, in patients with early or late manifestations of Lyme disease

Antibody responses to p66, a candidate integrin ligand of Borrelia burgdorferi, were studied in 79 patients with early or late manifestations of Lyme disease. The central portion of p66 was previously shown to contain all of the information required for specific recognition of beta3-chain integrins, but work by others had suggested that the C-terminal portion of the protein contains a single surface-exposed, immunodominant loop. In examining antibody responses to full-length p66 and to three overlapping fragments of the protein, we found that the majority of Lyme disease patients had immunoglobulin M (IgM) and/or IgG responses to p66 and that, particularly early in the disease, epitopes throughout p66 were recognized. Among patients with later manifestations of the illness, antibody responses to the C-terminal portion of the protein were more prominent. These results demonstrate that Lyme disease patient sera recognize epitopes throughout p66.

Characterization of a candidate Borrelia burgdorferi beta3-chain integrin ligand identified using a phage display library

The spirochaetal agents of Lyme disease, Borrelia burgdorferi (sensu lato) bind to integrins alphaIIbbeta3, alphavbeta3 and alpha5beta1 in purified form and on the surfaces of human cells. Using a phage display library of B. burgdorferi (sensu stricto) DNA, a candidate ligand for beta3-chain integrins was identified. The native B. burgdorferi protein, termed p66, is known to be recognized by human Lyme disease patient sera and to be expressed on the surface of the spirochaete. We show here that recombinant p66 binds specifically to beta3-chain integrins and inhibits attachment of intact B. burgdorferi to the same integrins. When expressed on the surface of Escherichia coli, this protein increases the attachment of E. coli to a transfected cell line that expresses alphavbeta3, but not to the parental cell line, which expresses no beta3-chain integrins. Localization of p66 on the surface of B. burgdorferi, the ability of recombinant forms of the protein to bind to beta3-chain integrins and the fact that p66 and B. burgdorferi bind to beta3-chain integrins in a mutually exclusive manner make p66 an attractive candidate bacterial ligand for integrins alphaIIbbeta3 and alphavbeta3.