Similar Outcomes among African-Americans (AA) and Whites after Autologous Hematopoietic-Cell Transplantation (Auto HCT) for Multiple Myeloma (MM)
Authors: Hari Parameswaran , Majhail Navneet S. , Hassebroek Anna , Zhang Mei-Jie , Siddiqui Fareeha , Mehta Paulette 
Published: October 2019

Abstract
MM is the most common hematological malignancy among AA adults and AA have twice the incidence and mortality from MM compared to Whites (SEER data, 2007). Based on CIBMTR registration rates of Auto HCT and incidence rates for MM, AA patients have been shown to have significantly lower likelihood of receiving Auto HCT (age adjusted odds ratio 0.58) compared to White patients with MM. The characteristics of AA patients who undergo Auto HCT for MM and their post transplant outcomes have not been compared to that of White MM patients. We compared characteristics and post-transplant outcomes of AA (N=303) and White (N=1892) patients receiving a first Auto HCT for MM and reporting to the CIBMTR between 1995 and 2005. Recipients of tandem Auto HCT were excluded. Compared to Whites, AA were significantly younger (29% aged <50 yr vs 21%, p=0.002), had better performance status at Auto HCT (69% with KPS score ≥90 vs 61%, p=0.005) and had higher incidence of hypertension (47% vs 25%, p<0.001), diabetes mellitus (17 % vs 9%, p<0.001) and morbid obesity (38% vs 31%, p=0.01). Durie-Salmon stage, immunoglobulin subtype, renal function, number of prior chemotherapy regimens, response to chemotherapy and remission status at transplant were similar in both groups. Transplant was more likely to be performed later (>12 months from diagnosis) in AA (37% vs 28% in Whites, p<0.001). The proportion of AA receiving Auto HCT increased from 7% in 1995 to 17% in 2004. No significant differences were found between AA and Whites in overall survival (52% vs 47%, at 5 years), progression-free survival (19% vs 21%, at 5 years), non-relapse mortality (3% vs 5%, at 1 year), or relapse (72% at 5 years in both groups) after Auto HCT. In multivariate analyses adjusting for patient, disease and transplant-related variables, race did not impact overall survival, progression-free survival, non-relapse mortality, or relapse (Table 1). We conclude that despite increased pre-transplant co-morbidities and transplantation later in the course of disease, post-transplant outcomes are comparable among AA and White patients who undergo Auto HCT for MM. The lower transplant rates in AA and the differences in pre-transplant patient characteristics need further investigation to explore racial differences in patient referral and selection for Auto HCT.
Table 1: Multivariate analysis: African-Americans vs. Whites (reference group)
Outcome Relative Risk 95% CI P-value Overall survival 0.94 0.78–1.13 0.50 Progression-free survival 0.94 0.81–1.09 0.42 Non-relapse mortality 1.16 0.75–1.80 0.51 Relapse 0.92 0.78–1.08 0.31
Adjusted for age, gender, KPS score at transplant, comorbidities (hypertension, diabetes, obesity, smoking), renal function, immunoglobulin subtype, Durie-Salmon stage, number of previous chemotherapy regimens, response to chemotherapy, remission status, time since diagnosis and year of transplant