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Abstract: PO1730

Time to CD20 B-Cell Return After Rituximab in Patients with Antineutrophil Cytoplasmic Antibody Vasculitis

Session Information

Category: Glomerular Diseases

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Huizenga, Noah, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Laliberte, Karen A., Massachusetts General Hospital, Boston, Massachusetts, United States
  • Zonozi, Reza, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Rosenthal, Jillian, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Jeyabalan, Anushya, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Cortazar, Frank B., Massachusetts General Hospital, Boston, Massachusetts, United States
  • Niles, John, Massachusetts General Hospital, Boston, Massachusetts, United States
Background

Rituximab (RTX) has been shown to be an effective maintenance treatment for ANCA vasculitis. However, the optimal dosing regimen is not well-defined. We analyzed data from the MAINTANCAVAS trial (NCT02749292) to determine time to CD20 B cell return in patients who were treated with ≥ 2 years of continuous B cell depletion and subsequently randomized into the trial and dosed for B cell return or a rising ANCA titer.

Methods

All patients in the MAINTANCAVAS trial were included. Patients were enrolled after ≥ 2 years of continuous B cell depletion. B cells were measured at 3-month intervals with a ± 2 week window. Days to B cell return were calculated as the time from the last rituximab dose (1000 mg) to date of first detectable CD20 B cells by flow cytometry. Kaplan Meier curves were produced for each round of B cell depletion.

Results

We analyzed data from 109 patients. Median (IQR) duration of B cell depletion was 280.0 (272.0 – 363.0) days until first episode of recovery (Table 1). >80% of subjects had B cell return by 1 year and <10% had B cell return prior to 6 months (Figure 1). Median (IQR) duration of B cell depletion was 265.0 (247.0 – 354.5) days for patients who received a second round of rituximab (Table 1).

Conclusion

This data suggests that after 2 years, maintenance RTX dosing can be extended beyond 6 months for many patients. Further analysis is needed to determine optimal dosing based on B cell return vs ANCA titer and the associated adverse event profiles and RTX utilization.

Table 1. Demographics and B cell depletion duration (median (IQR)).
# of subjects109
Male
Female
57
52
Hispanic or Latino
Not Hispanic or Latino
Black or African American
Asian
1
108
2
3
MPO
PR3
59
50
<3 years on Rituxan
>3 years on Rituxan
52
57
Initial B cell depletion duration
Second episode duration
280.0 (272.0 - 363.0)
265.0 (247.0 - 354.5)

Figure 1. Kaplan-Meier for B cell depletion.