Influence of race/ethnicity on response to lupus nephritis treatment: the ALMS study

Abstract

Objective: To compare the efficacy and safety of mycophenolate mofetil (MMF) and intravenous cyclophosphamide (IVC) as induction treatment for lupus nephritis (LN), by race, ethnicity and geographical region.

Methods: A total of 370 patients with active Class III-V LN received MMF (target dose 3.0 g/day) or IVC (0.5-1.0 g/m(2)/month), plus tapered prednisone, for 24 weeks. Renal function, global disease activity, immunological complement (C3 and C4) and anti-dsDNA levels are the outcomes that were assessed in this study.

Results: MMF was not superior to IVC as induction treatment (primary objective). There were important pre-specified interactions between treatment and race (P = 0.047) and treatment and region (P = 0.069) (primary endpoint). MMF and IVC response rates were similar for Asians (53.2 vs 63.9%; P = 0.24) and Whites (56.0 vs 54.2%; P = 0.83), but differed in the combined Other and Black group (60.4 vs 38.5%; P = 0.03). Fewer patients in the Black (40 vs 53.9%; P = 0.39) and Hispanic (38.8 vs 60.9%; P = 0.011) groups responded to IVC. Latin American patients had lower response to IVC (32 vs 60.7%; P = 0.003). Baseline disease characteristics were not predictive of response. The incidence of adverse events (AEs) was similar across groups. Serious AEs were slightly more prevalent among Asians.

Conclusions: MMF and IVC have similar efficacy overall to short-term induction therapy for LN. However, race, ethnicity and geographical region may affect treatment response; more Black and Hispanic patients responded to MMF than IVC. As these factors are inter-related, it is difficult to draw firm conclusions about their importance.

Trial registration: ClinicalTrials.gov NCT00377637.

Fig. 1

Percentage of patients achieving the primary efficacy endpoint, by race and treatment group (A), where Black is a subset of the Other racial group; and percentage of patients achieving the primary efficacy endpoint, by region and treatment group (B) (intent-to-treat populations).

Fig. 2

Percentage of patients reporting AEs, by race and treatment group. Patients could experience more than one AE. Any infection includes lower and upper respiratory tract plus any other infections. Any AE includes infections plus other AEs. Groups of AEs are not exclusive. Values on the y-axis represent a cumulative percentage; for example, the value for any AE represents the total percentage of patients with lower and upper respiratory tract infection, any other infection plus any other AE.

Fig. 3

Effects of race and region on the incidence of infectious AEs. The asterisk indicates P-value for factor, obtained from a logistic regression analysis of all patients modelling infectious AEs with a main effect for factor.