B-lymphocyte depletion with rituximab and β-cell function: two-year results

Area of Science:

• Immunology
• Endocrinology
• Clinical Medicine

Background:

• Rituximab, an anti-CD20 monoclonal antibody, previously showed a 1-year benefit in slowing beta-cell function decline in recent-onset type 1 diabetes mellitus (T1DM).
• Further investigation was needed to determine the persistence of rituximab's effect on beta-cell function in T1DM patients.

Purpose of the Study:

• To assess the long-term efficacy and persistence of rituximab's effect on beta-cell function in individuals with recent-onset T1DM.
• To evaluate the impact of rituximab on C-peptide levels, insulin dosage, and glycemic control over an extended follow-up period.

Main Methods:

• Eighty-one patients with recent-onset T1DM received rituximab or placebo infusions over 30 months.
• Mixed-meal tolerance tests (MMTT) were conducted every 6 months to measure serum C-peptide levels (AUC).
• Changes in C-peptide AUC, insulin dose, and HbA1c were analyzed to assess treatment effects.

Main Results:

• The decline in C-peptide levels was delayed by 8.2 months in the rituximab group compared to placebo.
• While overall C-peptide AUC, insulin dose, and HbA1c were similar at 30 months, a global test showed significantly larger C-peptide AUC means in the rituximab group over the entire follow-up (P = 0.03).
• B-lymphocyte recovery occurred by 18 months, with maintained IgG but depressed IgM levels.

Conclusions:

• Rituximab demonstrates a persistent effect in delaying the decline of beta-cell function in recent-onset T1DM.
• Despite the delay, rituximab does not appear to fundamentally alter the underlying pathophysiology of type 1 diabetes mellitus.
• The findings suggest that while immunotherapeutic approaches can modify disease progression, a cure for T1DM remains elusive.