Praxis Medical Insights

IgG4-related disease (IgG4-RD) has a high relapse rate of at least 60% after cessation of treatment, particularly in patients with multiorgan involvement, necessitating continued immunosuppressive therapy 1
The British Society of Gastroenterology strongly recommends that all patients with IgG4-related sclerosing cholangitis (IgG4-SC), including those with multiorgan involvement, should be considered for continued immunosuppressive therapy 1
Emerging evidence from case series suggests that >95% of patients with IgG4-RD respond to biological therapy using anti-CD20 monoclonal antibodies such as rituximab 1
Rituximab is considered the preferred treatment for patients whose disease flares on withdrawal of steroids, particularly in those with multisystem disease 1

Clinical Response and Treatment Pattern

This patient has been receiving rituximab since 2018 with documented "good control" and "good response with relief of symptoms" 2
The patient's most recent evaluation indicates "IgG remains controlled" with "no evidence of active disease" following rituximab treatment 2
The current treatment pattern of rituximab every 8-9 months has been effective in maintaining disease control 2
The patient's last dose was in May 2025, with the current request being for a single 1000mg IV dose, consistent with the established effective treatment regimen 2

For IgG4-related disease with sclerosing cholangitis, European guidelines recognize three maintenance regimens after disease relapse, including "rituximab induction with or without maintenance rituximab (e.g., 2 infusions of 1,000 mg rituximab 15 days apart every 6 months)" 2
Rituximab has shown great efficacy in treating IgG4-RD that flares on withdrawal of steroids or fails to respond to first- or second-line treatment 1
Rituximab administration should include appropriate premedication to minimize infusion reactions 3