If African American patients with multiple myeloma (MM) are given equal access to treatments, they have outcomes that are as good as or better than white patients, according to a study published in Blood.
"MM constitutes 1.8% of malignancies in the United States, and its incidence is significantly higher among African Americans than whites," the authors, led by Nathanael Fillmore, MD, from the Veterans Affairs (VA) Boston Healthcare System and Brigham and Women's Hospital, explained, but recent studies have found substantial racial differences in survival, owing in part to minority patients having "limited access to novel therapies."
In this study, the authors reviewed data from more than 10,000 patients with MM who were treated in VA hospitals, a system that presumably offers equal access to all participants, to examine whether African Americans and whites with the diagnosis have different outcomes.
The study population included patients who were diagnosed with MM in the VA's health care system between 2000 and 2017. Of 15,717 identified patients (median age = 69.5 years; interquartile range [IQR] = 62.6-77.0 years), 3,254 were African American and 8,845 were white.
Across the entire population, median overall survival (OS) was 4.62 years, and median length of OS decreased with higher age at diagnosis, from 7.5 years among veterans diagnosed in their 40s to 5.9, 5.2, 3.5, and 2.6 years for those diagnosed in their 50s, 60s, 70s, and 80s, respectively (p<0.001).
Next, the researchers evaluated median OS between African American and white patients, finding that African American patients had significantly longer OS (5.07 years [IQR = 4.70-5.44 years] vs. 4.52 years [IQR = 4.38-4.65 years]; p<0.001).
"[Our findings raise] an important question about possible differences in disease biology."
â€”Nathanael Fillmore, MD
Based on the observation that African American patients are diagnosed with MM at a younger age – and that age at diagnosis affected outcome – the investigators then stratified patients by age at diagnosis (<65 and â‰¥65 years). Younger African American patients had a significantly longer OS compared with white patients, but this relationship was not observed in the older population:
- younger cohort: 7.07 years (IQR = 6.36-7.70 years) vs. 5.83 years (IQR = 95% CI 5.44-6.09 years; p<0.001)
- older cohort: 3.69 years (IQR = 3.45-4.05 years) vs. 4.04 years (IQR = 95% CI 3.9-4.19 years; p=0.63)
To clarify the role that access to novel therapies and hematopoietic cell transplantation (HCT) played in disparate outcomes, the investigators next looked at treatment data from participants' electronic health records. They observed no racial differences in overall use of novel agents at induction (including immunomodulatory drugs or proteasome inhibitors), with 82.5% of African American patients and 81.5% of white patients receiving a novel therapy (p<0.21).
There was a similar pattern in the most recent five-year period of the study, when both proteasome inhibitors and immunomodulatory drugs had become the standards of care. In addition, similar proportions of patients underwent HCT (10.1% of African American patients vs. 9.1% of white patients; p=0.09).
However, there was a significant difference in the type of treatment used: Bortezomib was used more frequently among African American patients, while thalidomide was used more frequently among white patients (TABLE). "Nevertheless, these differences do not account for the superior survival among younger African American patients," the authors noted. "African American patients had superior or equal survival to white patients in every treatment subgroup in the [younger group] and equal survival in the [older group]."
These findings raise "an important question about possible differences in disease biology," they added.
The authors report relationships with Takeda, Celgene, and Novartis.
Fillmore NR, Yellapragada SV, Ifeorah C, et al. With equal access, African American patients have superior survival compared to white patients with multiple myeloma: a VA study. Blood. 2019;133:2615-8.