Abstract: PO1730
Time to CD20 B-Cell Return After Rituximab in Patients with Antineutrophil Cytoplasmic Antibody Vasculitis
Session Information
- Glomerular Diseases: Vasculitis and TMA
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
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 subjects | 109 |
| 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.