Patients With NMOSD Who Switch From Rituximab to Eculizumab Report Fewer Comorbidities and Hospitalizations

Data sourced from the IQVIA PharMetrics Plus United States database suggest that among patients with aquaporin-4 immunoglobulin G-positive (AQP4+) neuromyelitis optica spectrum disorder (NMOSD) who switched their treatment from rituximab to eculizumab (Soliris; Alexion Pharmaceuticals), there is a significant reduction in hospitalization, days hospitalized, and reported comorbidities.¹

The investigators, including Adrian Kielhorn, MBA, the senior director of Global Health Economics Outcomes Research at Alexion Pharmaceuticals, and colleagues presented the data in a poster at MSMilan 2023, the joint ECTRIMS-ACTRIMS meeting, held October 11-13, in Milan, Italy. They concluded that the results were consistent with the recognized clinical benefit of eculizumab as relapse preventing treatment in AQP4+ NMOSD, although the assessment was limited in sample size and in patient population, as the database only included those with commercial insurance.

“Limited data are available on outcomes among patients with AQP4+ NMOSD switching from treatment with off-label rituximab to eculizumab, which is FDA-approved for AQP4+ NMOSD. This retrospective claims analysis captures the impact of switching on hospitalizations and comorbidities in adult patients with AQP4+ NMOSD in the United States,” Keilhorn et al wrote, adding in conclusion that “the use of a control group confirmed that the majority of the observed benefits can be associated with eculizumab and not other external factors.”

In total, the analysis included a switch group (n = 20) and a control group (n = 525), both of which had mean ages of about 45 years (switch, 45.3 years [SD, 11.2]; control, 45.5 years [SD, 13.7]), and were less than 20% men (switch, n = 3 [15%]; control, n = 102 [19.4%]). All patients included were compiled from a pool of 424 individuals with continuous enrollment of 6 months pre- and post-switch date—the switch group had a mean time of 180.9 days (SD, 85.3) since their last rituximab infusion to their first dose of eculizumab. The mean number days from rituximab initiation to either switch or reference date was 363.3 (SD, 370.1) for the switch group and 365 (SD, 0) for the control group.

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All told, among those in the switch group, there was a 97.5% reduction in the number of total days spent in the hospital—defined as all-cause hospitalization—after switching to eculizumab, down from 200 in the 6 months before the switch to just 5 in the 6 months after the switch. In comparison, the control group reported 554 days spent in hospital in the 6 months prior to their reference date and 481 days in the 6 months after reference date, a reduction of 13%. The difference in the survival distributions with all-cause hospitalization was statistically significant (P = .01).

All-cause hospitalizations claims decreased as well for those who switched to eculizumab, from 9 (45%) prior to the switch to 2 (10%) after the switch (P = .013), and the mean number of hospitalizations decreased from 22 (1.1 per patient) to 2 (0.1 per patient) from the preswitch period to the postswitch period. The mean duration of hospitalization was significantly decreased from 8.5 weeks to 2.5 weeks in the switch group as well (P <.001).

“One of the 2 patients with hospitalizations posttreatment switch had discontinued eculizumab ~7.5 weeks before the hospitalization event; the other patient’s hospitalization was due to a surgical procedure. Both patients resumed their eculizumab treatment some time after the hospitalization ended,” Keilhorn et al wrote.

The total number of documented comorbidities was also significantly reduced in the switch group (96% reduction; 6 months prior, n = 127 [6.4 per patient]; 6 months post, n = 5 [0.25 per patient]), and the total number of patients with comorbidities was reduced by 78% (6 months prior, n = 9 [45% of cohort]; 6 months post, n = 2 [10% of cohort]). Comparatively, in the control group, the number of patients with comorbidities remained mostly stable (6 months prior, n = 53 [10% of cohort]; 6 months post, n = 49 [9% of cohort]; 8% reduction), as did the total number of comorbidities reported (6 months prior, n = 424; 6 months post, n = 402; 5% reduction).

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REFERENCE
1. Lee J, Kielhorn A, Fam S, Riser E, Flanagan E. Switching from rituximab to eculizumab in patients with AQP4+ NMOSD in the United States: Impact on hospitalisations and comorbidities. Presented at: MSMilan; October 11-13, 2023; Milan, Italy. POSTER P358.