Long-term retention rate, adverse event temporal patterns and rescue treatment strategies of mycophenolate mofetil in systemic sclerosis: insights from real-life.

Objectives: MMF is a mainstay for the treatment of SSc. The occurrence and implications of MMF-related adverse events (AEs) on drug retention rates in real life remain poorly defined. We aimed to determine the MMF retention rate and to investigate the causes and patterns of discontinuation, AEs and treatment options used after discontinuation.

Methods: SSc patients who started MMF treatment underwent a retrospective longitudinal assessment for up to 5 years. We documented the incidence, predictors and impacts of MMF treatment on gastrointestinal intolerance, infections, laboratory abnormalities and cancer. Rescue strategies implemented after MMF discontinuation were recorded.

Results: The 5-year MMF retention rate of 554 patients stood at 70.7%, and 19.6% of them stopped MMF due to AEs. One out of every four patients experienced a dose reduction or discontinuation of MMF due to AEs, with gastrointestinal intolerance being the predominant cause. The 5-year cumulative incidence rates for gastrointestinal intolerance, cancer, severe infections and laboratory toxicity leading to MMF discontinuation were 6.4%, 4.1%, 3.1% and 2.1%, respectively. Lower respiratory tract was the most affected, with bacteria being the predominant causative agent. Intestinal and pulmonary circulation involvement were tied to elevated AE rates and MMF discontinuation. The most common approaches post-MMF cessation were 'watch and wait' and switch to rituximab.

Conclusions: : MMF use in SSc appears to be limited by the occurrence of AEs, both in terms of persistence and dosing of the drug. Rescue options after MMF discontinuation are limited and many patients remain without immunosuppressant.