Patients on immunosuppressive therapy have an increased risk of infections. Since infections have a potential to trigger acute porphyric attacks vigilance is motivated regarding signs or symptoms of infection and/or possible symptoms of a porphyric attack. Side effects like nausea and vomiting may potentially be porphyrinogenic through reduction in carbohydrate intake.

Infections are common in patients using immunosuppressants and since infections might trigger an acute porphyric attack, vigilance regarding signs and symptoms of an infection and/ or a porphyric attack is recommended. Common adverse reactions of belimumab that can be confused with an acute porphyric attack are nausea and vomiting. These side effects may potentially be porphyrinogenic if leading to a decrease in carbohydrate intake.

Belimumab is not metabolized by cytochrome P450 enzymes. No pharmacokinetic porphyrinogenic effects are suspected.

Belimumab is a human IgG1-lambda monoclonal antibody specific for soluble human B Lymphocyte Stimulator protein.

Belimumab is used in the treatment of active, autoantibody-positive systemic lupus erythematosus in adults as an addition to standard therapy. It is administered as an intravenous infusion.

Belimumab is a protein for which the expected metabolic pathway is degradation to small peptides and individual amino acids by widely distributed proteolytic enzymes. Classical biotransformation studies have not been conducted (SPC, Keizer 2010).