This study tests a treatment called SNP-ACTH (1-39) Gel for people with a kidney disease known as primary membranous nephropathy (PMN). This disease affects the tiny filters in the kidneys. The study is in two parts to find the best dose and compare its effects to another drug called rituximab. In the first part, 16 patients will receive different doses of SNP-ACTH Gel for a year. In the second part, 132 patients will either take the best dose of SNP-ACTH Gel or rituximab for a year. Doctors will check patient progress at different times to decide the best dose for the second part.

• Patients will need regular visits over 24 months for the study.
• Participants must have certain health conditions, like kidney function tests, to join.
• There might be risks, such as reactions to the treatment, and participants cannot have certain health issues like diabetes.