February 22, 2021

In a recent study published in Arthritis & Rheumatology, LRA-funded researcher Dr. Xian Zhang found that a low dose of the chemotherapy drug topotecan reduced the inflammation and kidney damage of lupus nephritis in mice with lupus. Topotecan was as effective as high doses of cyclophosphamide, another chemotherapy that’s currently used to treat severe lupus nephritis in people with SLE. The results suggest that topotecan may offer another treatment option for patients with lupus nephritis that causes fewer side effects than cyclophosphamide.

Dr. Zhang started his career in cancer research at the National Institutes of Health, studying the Fli-1 protein which had been shown to play a role in cancer.  When he joined the lab of Dr. Gary Gilkeson, a nationally recognized rheumatologist and leading lupus researcher, he started investigating the role of Fli-1 in lupus and inflammation development.

The chemotherapy drug cyclophosphamide is an U.S. Food and Drug Administration approved treatment for patients with severe lupus nephritis. However, it must be given in high doses, which means that some patients can experience major side effects like infertility and bladder damage. Many patients cannot continue taking cyclophosphamide due to these side effects and need additional treatment options.

Topotecan is another U.S. Food and Drug Administration approved chemotherapy drug that may help treat lupus nephritis. Topotecan acts by interfering with a molecule known as Fli-1 that is found inside of many immune cells, including B cells, which contribute to lupus nephritis. Fli-1 within B cells helps them produce proteins called antibodies to help the body fight microbes. But some antibodies cause the body to mistake normal human cells for microbes. This means that the immune system attacks and destroys healthy cells that the body needs to function. People with lupus and lupus nephritis have extra B cells that attack human cells.

Dr. Zhang’s research group previously discovered that topotecan could reduce inflammation in cells from lupus patients. However, it was not tested in people or animals with lupus nephritis. In this study, Dr. Zhang tested a low dose of topotecan in mice with lupus nephritis and compared it to cyclophosphamide. After treating mice with a low dose, he found that topotecan greatly reduced kidney injury and inflammation and improved the overall survival of the mice as well as cyclophosphamide. Another chemotherapy drug,  camptothecin, also effectively protected mice from kidney injury.

Dr. Zhang’s findings suggest that topotecan and camptothecin may be effective in treating lupus nephritis. He concluded that though more research is needed, both agents offer promising therapies for lupus nephritis with fewer side effects than cyclophosphamide.

“My research focus on Fli-1 and its influence on lupus is driven by my interest in helping develop new treatment solutions for patients with lupus, an autoimmune disease with no current cure. With the support of the LRA, we have demonstrated that certain existing FDA-approved drugs, at extremely low doses, can target Fli-1 and successfully treat lupus nephritis within mouse models, with very limited side effects. We hope that our research is able to pave the way for a future, safer and more effective therapeutic for lupus patients.”