Primary Membranous Nephropathy (pMN)
Primary Membranous Nephropathy (pMN) is a serious and progressive kidney disease. It occurs when the body’s immune system makes autoantibodies that mistakenly attack protein found in the kidneys. These autoantibodies form immune complexes that build up in the glomeruli—the tiny filters in the kidneys—causing inflammation and kidney damage.
Kidney damage causes protein to leak out of the blood and build up in the urine, resulting in nephrotic syndrome. Patients often experience severe swelling, fatigue, discomfort, reduced mobility, weight gain, and elevated blood pressure and cholesterol. This damage can ultimately lead to kidney failure.
In many patients, the immune system targets a specific protein on kidney cells called PLA2R (phospholipase A2 receptor). Doctors now often test for antibodies to PLA2R to help diagnose pMN, track treatment progress or assess prognosis.
pMN management is primarily focused on achieving complete remission of proteinuria as this has been definitively correlated to improved outcomes.
Unmet need
The unmet need in pMN is significant. Despite being a serious kidney disease, there are currently no approved therapies. Rituximab is often used off-label as a first-line treatment, but 20-40% of patients are refractory, highlighting a clear need for more effective, disease-modifying options.
~70k patients in
the US alone
Untreated, ~30% progress to
end-stage renal disease within
10 years and another 30% develop
chronic kidney disease
Zero approved
therapies
How budoprutug may be able to help
B cell-depleting therapies such as budoprutug are a promising potential treatment approach for pMN because they work to eliminate the problematic B cells that produce disease-causing autoantibodies.
Budoprutug targets CD19, which has broad expression across many types of B cells, including autoantibody producing cells.
A completed budoprutug Phase 1b study in pMN patients demonstrated proof of concept and a favorable safety profile, and a Phase 2 study is currently ongoing.
Support and Resources
If you or a loved one have been diagnosed with pMN, you are not alone. Below are nonprofit advocacy organizations and communities that offer information and support for patients and caregivers.
Seferiana’s Story
Seferiana’s pMN journey began in 2016 when a shocking diagnosis disrupted her active lifestyle and marathon training. Although Seferiana has faced treatment challenges, she has also found strength in community and discovered her voice as an advocate. Today she serves on the Kidney Health Initiative Patient and Family Partnership Council, where she helps shape future treatments and support for patients like her.
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