RARE Daily

FDA Approves First Drug to Decrease Urine Protein in the Rare Kidney Disease IgAN

December 16, 2021

The U.S. Food and Drug Administration granted accelerated approval to Swedish biotech Calliditas’ Tarpeyo delayed release capsules to reduce proteinuria (increased protein levels in the urine) in adults with primary immunoglobulin A (IgA) nephropathy at risk of rapid disease progression.

Photo: Renée Aguiar-Lucander, CEO of Calliditas

“Tarpeyo represents an FDA approved product to help these patients who are at risk of rapid disease progression,” said Renée Aguiar-Lucander, CEO of Calliditas. “

The FDA noted that it has not been established whether Tarpeyo (budesonide) slows kidney function decline in patients with IgA nephropathy.

IgA nephropathy, also known as Berger’s disease, is a rare kidney disease that occurs when IgA (a type of antibody) deposits build up in the kidneys, causing inflammation that damages kidney tissues. The deposits can cause the kidneys to leak blood and protein into the urine. IgA nephropathy complications can include high blood pressure and chronic kidney disease, which can sometimes progress to kidney failure. 

The effect of Tarpeyo on proteinuria was assessed in a randomized, double-blind study in research participants with IgA nephropathy, reduced kidney function, and proteinuria who were taking a stable dose of maximally tolerated renin-angiotensin system (RAS) inhibitor therapy. Participants were assigned to receive either Tarpeyo 16 mg once daily or a placebo for nine months, followed by a two-week tapering (weaning) period of either Tarpeyo 8 mg once daily or a placebo.

The primary endpoint was the percentage reduction in urine protein-to-creatinine ratio (UPCR) at nine months compared to the beginning of the study. The UPCR is a method to estimate daily protein excretion in the urine, with a lower number indicating less protein. At nine months, research participants receiving Tarpeyo had an average 34 percent reduction in UPCR, whereas participants receiving the placebo had an average 5 percent reduction in UPCR. 

As a condition of the accelerated approval, an ongoing study of Tarpeyo must be completed to confirm that the medication slows kidney function decline in patients with IgA nephropathy.  

People who have allergic reactions to budesonide or any ingredients in Tarpeyo must not take the medication. Serious hypersensitivity reactions, including anaphylaxis (a severe, life-threatening allergic reaction) have occurred. 

Tarpeyo is a corticosteroid and can cause side effects similar to other corticosteroids, which include hypercortisolism (high levels of the cortisol hormone) and adrenal suppression (not able to produce enough cortisol). Patients with moderate to severe liver impairment may be at increased risk of these side effects. 

Tarpeyo is an immunosuppressant. As such, patients should not take Tarpeyo if they have untreated infections. It may also decrease the immune response to some vaccines. The most common side effects of Tarpeyo are high blood pressure; swelling in the lower legs and hands; muscle spasms; acne; skin irritation; weight increase; difficulty breathing; face swelling; indigestion; fatigue; and excess hair, often around the nose and mouth. 

Author: Rare Daily Staff

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