Under-Representation of Black Patients with Multiple Myeloma in Studies Supporting International Myeloma Working Group Guidelines

INTRODUCTION

Multiple myeloma (MM) is more common in Black persons when compared to non-Hispanic Whites. Black patients with MM suffer from various disparities that are well established and include lower use of novel therapies, autologous stem cell transplantation and under-representation in clinical trials. The International Myeloma Working Group (IMWG) published their first consensus guideline in 2003 and they continue to produce consensus guidelines for the myeloma community that are widely used. Our study aimed to assess the racial composition of supporting trials used by IMWG to publish their guidelines.

METHODS

We performed a cross sectional study that included all IMWG publications up to July 2022. References cited in each publication were extracted. Each reference was reviewed, and the following data were extracted: study type, number of patients, the year of the study, location (U.S. alone vs. global), and ethnic/racial composition. Review articles, comments, editorials, case reports, and animal-based studies were excluded. Analysis was done using R statistical software version 4.0.5 (R Project for Statistical Computing)

RESULTS

A total of 59 IMWG publications with 3956 references were reviewed, of which 1211 were duplicates and 54 were un-accessible. Of the remaining 2691 articles, 644 were review articles, editorials, comments, case reports/series, and animal-based studies. References (n=2047) included in our final analysis of which 39% (n=804) were clinical trials, 35% were observational studies, 20% were diagnostic and or genetic testing-based studies, 3% were population-based analysis and 3% were classified as others. Only 10.4% of included references (n=213/2047) reported race/ethnicity of studied patients. Total number of patients in all referenced studies were 5,747,920 with only 2.6% (n=150,790) black patients. Clinical trials (n=804) included data on 189,244 patients with only 8.8% (n=71/804) of included clinical trials reporting on race/ethnicity. The proportion of black patients enrolled in the clinical trials that reported race/ethnicity was 1.7% (n=3156) and 1.6% in the observational studies.

Of the trials referenced and done exclusively in the US, 41 out of 282 (14.5%) reported race/ethnicity with a total number of patients of 38,050 of which 2493 (6.5%) were black patients. Proportion of Black patients in studies that included multiple sites (with at least one U.S. site) reported race as black in only 5.1% of included patients. Of all the references cited by the guidelines and done exclusively outside of the U.S., there was only one study only that included only black patients.

CONCLUSIONS

IMWG guidelines were based mainly on studies that did not include sufficient number of Black patients. This was evident not only in clinical trials but also in other types of supporting studies including observational studies. With better understanding of different MM disease biology in different racial/ethnic groups, it is important to improve reporting of race in clinical trials and observational studies. Guidelines should consider inclusion of observational studies with more black patients to allow for better reflection of disease prevalence, clinical characteristics and/or outcomes.

Schinke:Janssen: Honoraria. van Rhee:GlaxoSmithKline: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy; Janssen Pharmaceuticals: Research Funding; Bristol Myers Squibb: Research Funding; EUSA Pharma: Consultancy.