The results of a small clinical trial found that a novel drug called cemdisiran is safe in humans and potentially effective for treating IgA nephropathy. The findings, published in the
Clinical Journal of the American Society of Nephrology, could lead to additional studies and eventually a new, approved therapy for patients affected by this rare form of kidney disease.
IgA nephropathy occurs when a person’s body produces too many abnormal immune proteins, which can accumulate in the kidneys. This accumulation stimulates production of additional immune proteins associated with inflammation, called C5, which can damage the kidneys and impair their function over time.
For these reasons, researchers have been interested in finding ways to inhibit or reduce the amount of C5 that people with IgA nephropathy produce. “The idea is if you can inhibit C5, you may stop the inflammation effect in the kidneys,” explains Dr. Sean Barbour, a researcher with the University of British Columbia’s Division of Nephrology, and Medical Lead, BC Renal Glomerulonephritis (GN) Registry.
The newly developed drug, cemdisiran, can be injected under the skin just once a month, meaning patients could administer it themselves from home. It works via small molecules that specifically inhibit the body’s ability to produce C5.
Barbour, a leading expert of IgA nephropathy, partnered with other international experts to lead a small, phase II trial of cemdisiran. They recruited 31 patients, half of whom were treated with the drug and the other half of whom were given their standard care.
The results confirmed cemdisiran is safe in humans, resulting in no major, short-term side effects. About 40% of people given the drug experienced mild redness or irritation at the injection site, which is a common side effect for many drugs that are injected under the skin.
As well, the preliminary results suggest cemdisiran is beneficial for kidney health. Patients who were given the drug had an overall 37% decrease in protein levels in their urine (proteinuria) after eight weeks, compared to those who did not receive the drug. Protein in the urine is an indicator of kidney health, and lower protein levels reflect better kidney health.
Barbour notes that most treatments currently approved for IgA nephropathy, such as steroids, work by suppressing the overall function of the immune system, which can involve serious side effects (e.g., increased risk of infection). However, cemdisiran offers a more targeted approach, only suppressing a very specific part of the immune system that causes IgA nephropathy.
“With cemdisiran, you are actually treating the disease by reducing gene expression for C5, so it’s an exciting therapy in that way,” says Barbour, noting that this is the first drug of its kind using this mechanism - called a small interfering RNA – for the treatment of IgA nephropathy.
Importantly, these positive, preliminary results could lead to additional studies and potentially approval of cemdisiran as a therapy for people living with IgA nephropathy.
