Rituximab Stabilizes Pulmonary Function in Patients With Systemic Sclerosis Association ILD

New data continues to support the use of rituximab in stabilizing pulmonary function for patients with systemic sclerosis (SSc) associated interstitial lung disease (ILD).

A team, led by Dr. Kelly Morgan, Department of Rheumatology, Fiona Stanley Hospital,identified whether rituximab stabilized or improved pulmonary function in patients with systemic sclerosis associated interstitial lung disease at 12 months.

The Study

In the retrospective analysis, the investigators examined 13 patients with systemic sclerosis associated interstitial lung disease at 2 tertiary centers. Each participant had disease progression, despite conventional therapy and received rituximab between 2008-2019. The baseline characteristics of the patient population was representative of patients with systemic sclerosis associated interstitial lung disease.

The team compared baseline percentage forced vital capacity (FVC) and percentage diffusing capacity of carbon monoxide (DLCO) to 1 year post first dose of rituximab. They also calculated the mean and median change in FVC percentage and DLCO percentage.

For patients with available data, the investigators compared the FVC percentage and DLCO percentage 2 years and 1 year prior to rituximab treatment with the change 12 months post treatment.

The results show all patients showed stability in pulmonary function testing at the 1 year mark following rituximab treatment. The mean FVC percentage was 57.18 (±16.93 SD) prior to rituximab and 59.75 (±18.83 SD) 12 months post rituximab (P = 0.07).

In addition, the mean DLCO percentage increased from 37.10 (±18.41 SD) prior to rituximab to 38.03 (± 19.83) following rituximab and the mean change in DLCO percentage was 0.93 (±5.05 SD) (P = 0.53).

The data for the 2 years prior to rituximab treatment, the mean percentage of FVC and DLCO declined by 9.25 and 9.66, respectively.

“This case series suggests that rituximab may stabilize PFTs, and delay deterioration, in patients with progressive SSc-ILD,” the authors wrote. “These findings add to the growing body of evidence suggesting a role for rituximab in the treatment of SSc-ILD.”

A Rituximab Biosimilar

Earlier this week, the US Food and Drug Administration (FDA) has approved rituximab-arrx (RIABNI), a new biosimilar to rituximab (RITUXAN) for the treatment of adult patients with moderate to severe rheumatoid arthritis in combination with methotrexate.

The treatment is earmarked for patients who have not had an adequate response to 1 or more tumor necrosis factor (TNF) antagonist therapies.

Rituximab-arrx is a CD20-directed cytolytic antibiotic with no clinically meaningful differences in safety or efficacy to rituximab based on the data from a randomized, double-blind, comparative clinical study.

In the trial, investigators compared the efficacy, safety, pharmacokinetics, and immunogenicity of rituximab-arrx and rituximab reference product in patients with moderate to severely active rheumatoid arthritis.

There were 311 patients included in the trial.

The investigators sought a primary efficacy endpoint of the change in disease activity score 28 using C-reactive protein DAS28-CRP) from baseline at week 24. The results were within the predefined equivalence margin showing equivalence in clinical efficacy between the 2 treatments. Safety, pharmacokinetics, and immunogenicity were also similar between the 2 treatments.

The study, “Rituximab treatment for systemic sclerosis associated interstitial lung disease – A case series of 13 patients,” was published online in the Internal Medicine Journal.