Real-World Clinical Outcomes in Belimumab-Treated US African American and Hispanic Patients with Systemic Lupus Erythematosus: A Retrospective, Observational Study

Baseline Characteristics

In the OBSErve US study, 92 rheumatologists enrolled 501 patients with SLE; 123 (24.6%) were African American and 88 (17.6%) were Hispanic, of whom 69 (56.1%) and 43 (48.9%), respectively, continued to receive belimumab at Month 24. Of those patients who did not continue belimumab use over the 24 months, 26 (21.1%) African American and 23 (26.1%) Hispanic patients were lost to follow-up, and 28 (22.8%) and 22 (25.0%), respectively, discontinued belimumab (see Discontinuation of belimumab section below for more detail).

Baseline characteristics of the analyzed patients, including those who continued to receive belimumab at Month 24, are presented in Table 1. Our analyses focused on the 69 African American and 43 Hispanic patients who were receiving belimumab at 24 months. In the African American and Hispanic cohorts, most patients were female (88.4% and 95.3%) with mean (standard deviation [SD]) ages of 41.6 (12.5) and 42.2 (10.5) years, respectively (Table 1). Just under half of African American patients (n = 33, 47.8%) and over half of Hispanic patients (n = 25, 58.1%) had SLE for 1–5 years.

Table 1 Baseline demographics and disease characteristics of all African American (n = 123) and Hispanic (n = 88) patients with SLE in the OBSErve US study, and the subgroup who were receiving belimumab at 24 months (African American patients, n = 69; Hispanic patients, n = 43)

Among African American patients, none had mild SLE, 45 (65.2%) had moderate SLE, and 24 (34.8%) had severe disease at index. Among Hispanic patients, 1 (2.3%) had mild SLE, 31 (72.1%) had moderate disease, and 11 (25.6%) had severe SLE at index. In African American and Hispanic patients, mean (SD) assessment scores at index for PGA, SELENA-SLEDAI and PtGA were 75.4 (10.9) and 70.0 (16.2), 13.4 (3.2) and 11.3 (3.5), and 77.6 (11.7) and 72.5 (16.9), respectively. The most common clinical manifestation of SLE in African American patients at index was renal involvement/LN (data on biopsy-proven LN diagnosis/activity not collected) (n = 19, 27.5%), and the most common comorbidity was hypertension (n = 18, 26.1%) (Table 1). Among Hispanic patients at index, 14.0% (n = 6) had renal involvement/LN (data on biopsy-proven LN diagnosis/activity not collected), and the most common comorbidities were fibromyalgia (n = 10, 23.3%), osteoarthritis (n = 9, 20.9%) and hypertension (n = 9, 20.9%).

Reasons for Belimumab Initiation

The most common reasons for belimumab initiation for African American/Hispanic patients were lack of effectiveness of the previous treatment regimen (n = 54, 78.3%/n = 30, 69.8%), patient condition worsening (n = 46, 66.7%/n = 22, 51.2%) and to decrease corticosteroid use (n = 45, 65.2%/n = 30, 69.8%). Other reasons included poor tolerability of previous treatment regimen (n = 17, 24.6%/n = 16, 37.2%), patient request (n = 9, 13.0%/n = 6, 14.0%), previous treatment regimen being inconvenient (n = 1, 1.4%/n = 5, 11.6%) and drug-to-drug interactions with a previous medication (no patients/n = 2, 4.7%).

Overall Clinical Response

Among patients receiving belimumab at 24 months, 63 (91.3%) African American and 39 (90.7%) Hispanic patients had ≥ 20% improvement, and 12 (17.4%) and 5 (11.6%) patients, respectively, had ≥ 80% improvement in physician-assessed overall clinical response within the first 6 months post-index compared with 6 months pre-index. No patient experienced a lack of improvement (Fig. 1). The trend for improvement continued over the study period, with 81.2%/79.1%, 59.4%/86.0% and 44.9%/76.7% of African American/Hispanic patients having a ≥ 20% improvement and 7.2%/20.9%, 11.6%/18.6% and 10.1%/25.6% having a ≥ 80% improvement at 6–12, 12–18 and 18–24 months post-index, respectively (Fig. 1). Notably, a worse outcome was only reported for 0%/0%, 0%/2.3%, 2.9%/2.3% and 1.4%/0% of patients at 0–6, 6–12, 12–18 and 18–24 months post-index.

Fig. 1figure 1

Physician-assessed overall clinical improvement from index to Month 24 in a African American (n = 69) and b Hispanic (n = 43) patients who were receiving belimumab at 24 months

SLE Severity

The number of African American/Hispanic patients with severe disease, as assessed by physicians, decreased from 24 (34.8%)/11 (25.6%) at index to 2 (2.9%)/2 (4.7%) at Month 6, 1 (1.4%)/1 (2.3%) at Month 12, 1 (1.4%)/0 at Month 18 and 2 (2.9%)/0 at Month 24 (Fig. 2). Likewise, the number of patients with moderate disease decreased over the study period, with 45 (65.2%) and 31 (72.1%) African American and Hispanic patients respectively, having moderate SLE at index, falling to 15 (21.7%) and 8 (18.6%) patients at Month 24, while the number of patients with mild disease increased from none and 1 (2.3%) patient at index to 52 (75.4%) and 35 (81.4%) patients at Month 24 (Fig. 2).

Fig. 2figure 2

Improvements in physician-assessed disease severity from index to Month 24 in a African American (n = 69) and b Hispanic (n = 43) patients who were receiving belimumab at 24 months. SLE, systemic lupus erythematosus

SELENA-SLEDAI, PGA and PtGA

SELENA-SLEDAI, PGA and PtGA were the most frequently used tools to assess disease severity, evaluated at index in 13 (18.8%) and 18 (41.9%), 28 (40.6%) and 12 (27.9%), and 20 (29.0%) and 10 (23.3%) African American and Hispanic patients, respectively, who were receiving belimumab at 24 months (Table 1). Use of these instruments decreased over the study period to 8 (11.6%) and 16 (37.2%) patients for SELENA-SLEDAI, 21 (30.4%) and 8 (18.6%) patients for PGA and 18 (26.1%) and 7 (16.3%) patients for PtGA at Month 24. Physicians did not use any tools to assess disease severity in 33 (47.8%) and 18 (41.9%) patients at index and 35 (50.7%) and 19 (44.2%) African American and Hispanic patients, respectively, at Month 24.

In African American patients, there was an improvement in mean (SD) SELENA-SLEDAI score of 8.8 (5.2) points at Month 24 versus index in the 8 patients with a SELENA-SLEDAI assessment at both of these time points (mean [SD] scores: 13.5 [3.4] at index, 4.8 [4.0] at Month 24). For the 21 patients with a PGA assessment at Month 24, mean (SD) PGA score was 29.5 (24.0); this equated to an improvement in mean (SD) PGA score of 47.0 (24.9) points at Month 24 versus the index value of 75.0 (12.0) (analyzed in the 20 patients with PGA assessments at both index and Month 24). Mean (SD) PtGA score was 35.3 (26.2) at Month 24 (n = 18 patients with a PtGA assessment at this time point), representing a 52.6 (16.4) mean (SD) point improvement at Month 24 versus index (mean [SD] score: 75.8 [12.9], calculated in the 14 patients with a PtGA assessment at both time points).

In Hispanic patients with a SELENA-SLEDAI assessment at index and Month 24 (n = 16, 37.2%), there was a mean (SD) SELENA-SLEDAI score improvement of 8.4 (4.5) points at Month 24 versus index (mean [SD] score at Month 24: 3.1 [2.8]; mean score at index: 11.6 [3.6]). For patients with a PGA assessment at index and Month 24 (n = 5, 11.6%), the mean (SD) PGA score improved by 43.0 (25.4) points at Month 24 versus index (mean [SD] score at index: 72.0 [5.9]), and among those patients with a PtGA assessment at index and Month 24 (n = 4, 9.3%), the PtGA score improved by 55.0 (9.1) points at Month 24 versus index (mean [SD] score at index: 76.3 [4.8]).

OCS Use

As noted above, the ability to decrease corticosteroid use was among the most common reasons for belimumab initiation; indeed, from index to Month 24, the number of patients receiving OCS, including high-dose OCS, and the mean daily OCS dose progressively decreased. Among African American and Hispanic patients, 57 (82.6%) and 35 (81.4%) received OCS at index, falling to 35 (50.7%) and 15 (34.9%) patients at Month 24, respectively (Fig. 3a, b). Similarly, the number of patients receiving OCS at a dose of > 7.5 mg/day decreased from 52 (75.4%) and 32 (74.4%) at index to 7 (10.1%) and 1 (2.3%) at Month 24 (Fig. 3a, b), and the mean (SD) dose of OCS decreased from 19.7 (12.8) mg/day and 18.8 (10.0) mg/day at index to 3.1 (3.2) mg/day and 1.6 (2.4) mg/day at Month 24 (Fig. 3c, d).

Fig. 3figure 3

Oral corticosteroid use and mean (SD) dose over the study period from index to Month 24 in a, c African American (n = 69) and b, d Hispanic (n = 43) patients who were receiving belimumab at 24 months. SD standard deviation

HCRU

The number of African American patients who required at least one unscheduled rheumatologist visit at 6 months pre-index and 18–24 months post-index decreased from 42 (60.9%) to 22 (31.9%), as did the mean number of unscheduled visits (from 2.4 to 1.6 visits) (Table 2). The number of Hispanic patients requiring at least one unscheduled rheumatologist visit at 6 months pre-index and 18–24 months post-index fell from 29 (67.4%) to 8 (18.6%), respectively (Table 2). In this cohort, the mean number of visits remained relatively stable throughout the study except for the last 6 months, almost doubling from a mean of 1.6 visits at months 12–18 to 3.1 visits at months 18–24.

Table 2 HCRU in African American (n = 69) and Hispanic (n = 43) patients with SLE who were receiving belimumab at 24 months

In African American patients, from 6 months pre-index to 18–24 months post-index, substantial reductions were observed in the number of patients with ≥ 1 emergency room visit (16 [23.2%] to 7 [10.1%]), hospitalizations (4 [5.8%] to 3 [4.3%]) and ancillary care services (10 [14.5%] to 3 [4.3%]), with mean numbers of emergency room visits and hospitalizations remaining relatively stable over the duration of the study (Table 2). In Hispanic patients, over the same period, there were reductions in the number of patients with ≥ 1 emergency room visit (3 [7.0%] to 2 [4.7%]) and ancillary care services (9 [20.9%] to 1 [2.3%]). One (2.3%) patient required a hospitalization at 0–6 months versus 2 (4.7%) patients at 6 months pre-index, with no patient hospitalized at 6–24 months post-index (Table 2).

Discontinuation of Belimumab

Over the study period, 28 (22.8%) African American and 22 (25.0%) Hispanic patients discontinued belimumab. The most common reasons for discontinuation in the former group were patient request (n = 13) and medication inefficacy (n = 7), and 2 patients discontinued belimumab due to an adverse event, while in the latter group, the most common reasons for discontinuation were loss to follow-up (n = 8) and loss of insurance or reimbursement (n = 7) (Table 3).

Table 3 Belimumab discontinuation rate and reasons for discontinuation in African American (n = 69) and Hispanic (n = 43) patients with SLE who were receiving belimumab at 24 months

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