中小市值行业深度报告：IgA肾病专题：潜在需求庞大，耐赋康放量确定性高

Investment Rating - The report maintains an "Outperform" rating for the industry [1]. Core Insights - IgA Nephropathy (IgAN) is a prevalent primary glomerular disease with a high patient base and progression risk, particularly affecting young adults aged 16-35, with a male-to-female ratio of 2:1 to 6:1 [1][2]. - The incidence of IgAN in China is approximately 54.3%, significantly higher than the global average, with an estimated 1.3 million diagnosed patients and around 5 million total patients [1][30]. - The report highlights the complexity of IgAN's pathogenesis, which is linked to mucosal immune abnormalities and the overproduction of Gd-IgA1, leading to kidney damage through complement activation [36][37]. - Current treatment options are limited, with only two approved drugs, but the market demand is substantial, driving the development of numerous innovative therapies in clinical trials [2][4]. Summary by Sections 1. Overview of IgAN - IgAN is characterized by the deposition of IgA-dominant immune complexes in the mesangial area of the glomeruli, leading to various clinical manifestations such as hematuria and proteinuria [1][34]. - The disease has a high progression risk, with 20-40% of patients progressing to end-stage renal disease (ESRD) within 20 years [30]. 2. Pathogenesis of IgAN - The pathogenesis involves a "four-hit" model, starting with mucosal immune dysregulation and leading to the formation of nephritogenic immune complexes that cause glomerular injury [36][38]. - Genetic susceptibility and environmental factors contribute to the disease's onset and progression [36]. 3. Diagnosis and Treatment - Kidney biopsy is the gold standard for diagnosing IgAN, and treatment focuses on reducing proteinuria and delaying renal failure [1][3]. - Current guidelines recommend supportive therapy for low-risk patients, with the consideration of medications like ACE inhibitors and SGLT2 inhibitors [1][3]. 4. Innovative Drug Development - The report discusses the focus on innovative drugs targeting mucosal immunity and complement pathways, with several candidates in clinical trials showing promise in reducing proteinuria and preserving kidney function [2][4]. - Notable drugs include Nefopam and Sparsentan, with the latter having received full approval in the US and EU [2][4].