Race, ethnicity may influence response to non-TNF inhibitor biologics in RA patients
medwireNews: Findings from a large real-world rheumatoid arthritis (RA) study suggest that non-tumor necrosis factor (TNF) inhibitor biologics are associated with lower disease activity than TNF inhibitors among Black and Asian patients, as well as those with non-Hispanic ethnicity.
As reported at the EULAR 2021 Virtual Congress, the researchers used the American College of Rheumatology’s RISE registry to evaluate longitudinal disease activity in 16,448 people with RA who were treated with either a TNF inhibitor or an alternative biologic or targeted synthetic DMARD, including abatacept, rituximab, tocilizumab, and tofacitinib.
A total of 59.7% of patients included in the study were White, while 8.3% were Asian, 1.8% were Black, and 30.2% were of other or mixed race or unknown. Most patients (86.4%) were of non-Hispanic or non-Latino ethnicity.
Milena Gianfrancesco (University of California, San Francisco, USA) reported that in the overall study population, there was no significant difference in average CDAI score at the 1-year follow-up in the TNF inhibitor and non-TNF inhibitor groups, at 8.84 and 7.99 points, respectively (average treatment effect [ATE]=0.85).
However, when patients were categorized by race, TNF inhibitors were associated with significantly higher disease activity at 1 year than non-TNF inhibitors in Black and Asian patients, but not in White patients.
Specifically, mean CDAI scores among Black people were 13.91 points in the TNF inhibitor group versus 7.83 points in the non-TNF inhibitor group (ATE=6.08), and the corresponding scores were 6.54 versus 2.74 points among Asian people (ATE=3.80).
The team also identified differences in treatment response when patients were analyzed according to ethnicity. In non-Hispanic people, TNF inhibitors were associated with a significantly higher mean CDAI score at 1 year than non-TNF inhibitors (8.92 vs 7.63 points), but the opposite was seen in Hispanic people, with significantly lower scores in those given TNF inhibitors (5.69 vs 8.33 points).
“These analyses are aimed to be hypothesis-generating and they warrant follow-up and replication, ideally in additional external datasets,” said Gianfrancesco.
Noting that the study focused particularly on patient groups “traditionally underrepresented in clinical trials,” she concluded that “it is feasible to use this data to simulate trials that traditionally may be underpowered or impractical.”
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