This clinical trial is focused on studying a condition called Lupus Nephritis, which is a type of kidney inflammation caused by an autoimmune disease known as Systemic Lupus Erythematosus. The study is testing a new treatment called Zetomipzomib (KZR-616), which is a small molecule designed to inhibit the immunoproteasome, a part of the immune system that can contribute to inflammation. The purpose of the study is to evaluate the effectiveness and safety of Zetomipzomib in patients with active forms of Lupus Nephritis, specifically Class III or IV, with or without Class V, and pure Class V.

Participants in the study will receive either Zetomipzomib or a placebo, which is a substance with no active medication. The study will compare the outcomes of those receiving Zetomipzomib to those receiving the placebo. The treatment will be administered as a subcutaneous injection, which means it is injected under the skin. The study will last for about a year, during which participants will have regular check-ups to monitor their health and the effects of the treatment.

Throughout the study, the main goal is to see how many patients achieve a complete renal response, which means their kidney function improves significantly. The study will also look at other outcomes, such as partial renal response and changes in disease activity. This research aims to provide new insights into treating Lupus Nephritis and potentially offer a new treatment option for patients with this condition.