Peptide GAM immunoadsorption therapy in primary membranous nephropathy (PRISM): Phase II trial investigating the safety and feasibility of peptide GAM immunoadsorption in anti-PLA2 R positive primary membranous nephropathy.

INTRODUCTION: Membranous nephropathy (MN) is among the most common causes of nephrotic syndrome in adults worldwide. Most patients have primary MN (PMN), an autoimmune condition associated with the IgG anti-PLA2 R autoantibody. For patients with severe disease, standard of care continues to be a 6-month regime of rotating high dose steroids and immunosuppression that comes with a significant side-effect profile. Immunoadsorption is a relatively safe procedure for the extracorporeal removal of specific immunoglobulins without the need for medications.

DESIGN: This is a Phase II multi-centre, single arm prospective clinical trial carried out across Northwest region of the United Kingdom to assess the safety and clinical effectiveness of immunoadsorption therapy in PMN. 12 adult patients with biopsy proven MN, nephrotic range proteinuria and serum anti-PLA2 R antibody titers of more than 170 µ/mL will undergo 5 consecutive daily sessions of immunoadsorption. Primary outcome is the reduction of serum anti-PLA2 R antibodies at day 14. Secondary outcomes are the safety and tolerability of immunoadsorption therapy in patients with primary MN at all-time points, reduction of serum anti-PLA2 R levels, proteinuria and improvement in renal function. Quality of life and Cost-effectiveness of treatment will be assessed from a UK National Health Service perspective.

DISCUSSION: With proven efficacy in removing IgG antibodies and its use as a relatively safe treatment option in a multitude of conditions, immunoadsorption has the potential to offer patients with primary MN a more directed therapy free from the short and long-term side-effects generally seen in this condition.