Scientists at UC Santa Barbara have discovered that patients with an inherited kidney disease may be helped by a drug that is currently available for other uses. The findings are published in this week’s issue of the Proceedings of the National Academy of Sciences.
Over 600,000 people in the U.S., and 12 million worldwide, are affected by the inherited kidney disease known as autosomal-dominant polycystic kidney disease (ADPKD). The disease is characterized by the proliferation of thousands of cysts that eventually debilitate the kidneys, causing kidney failure in half of all patients by the time they reach age 50. ADPKD is one of the leading causes of renal failure in the U.S.
“Currently, no treatment exists to prevent or slow cyst formation, and most ADPKD patients require kidney transplants or lifelong dialysis for survival,” said Thomas Weimbs, director of the laboratory at UCSB where the discovery was made. Weimbs is an associate professor in the Department of Molecular, Cellular and Developmental Biology, and in the Neuroscience Research Institute at UCSB.
Recent work in the Weimbs laboratory has revealed a key difference between kidney cysts and normal kidney tissue. They found that the STAT6 signaling pathway – previously thought to be mainly important in immune cells -is activated in kidney cysts, while it is dormant in normal kidneys. Cystic kidney cells are locked in a state of continuous activation of this pathway, which leads to the excessive proliferation and cyst growth in ADPKD.
Autosomal dominant polycystic kidney disease (ADPKD) is a genetic condition that causes multiple cysts to develop on the kidneys. Cysts are small sacs that are filled with fluid.
The symptoms of ADPKD tend not to begin until adulthood, usually between the ages of 30 and 60.
Symptoms can include:
* high blood pressure (hypertension)
* abdominal pain
* blood in the urine (haematuria)
The symptoms of ADPKD can range from mild to severe.
How common is ADPKD?
In general terms, ADPKD is uncommon as only 1 in every 1,000 people are born with the condition.
However, ADPKD is the most common genetic condition to affect the kidneys. It is estimated that around 50,000 people in the UK currently have ADPKD symptoms or will develop it at some time.
The drug Leflunomide, which is clinically approved for use in rheumatoid arthritis, has previously been shown to inhibit the STAT6 pathway in cells. Weimbs and his team found that Leflunomide is also highly effective in reducing kidney cyst growth in a mouse model of ADPKD.
For the treatment of moderate pain or moderately severe pain including arthralgia, headache, myalgia, dental pain following oral surgery such as extraction of impacted molars or chronic conditions such as low-back pain, bone pain and cancer-related pain.
- Adults: 100 mg/dose PO or 400 mg/day PO.
- Elderly >= 75 years: 100 mg/dose PO or 300 mg/day PO.
- Elderly 65 – 74 years: 100 mg/dose PO or 400 mg/day PO.
- Adolescents >= 16 years: 100 mg/dose PO or 400 mg/day PO.
- Adolescents 13 – 15 years: Maximum dosage has not been determined.
- Children: Maximum dosage has not been determined.
“These results suggest that the STAT6 pathway is a promising drug target for possible future therapy of ADPKD,” said Weimbs. “This possibility is particularly exciting because drugs that inhibit the STAT6 pathway already exist, or are in active development.”
University of California – Santa Barbara