Vitamin D May Help Prevent a Common Side Effect of Anti-Cancer Immunotherapy

New research published in CANCER indicates that taking vitamin D supplements may help prevent a potentially serious side effect of a revolutionary form of anti-cancer therapy

Vitamin D
Immune checkpoint inhibitors help the immune system recognize and fight cancer cells. Although these treatments have helped many patients and prolonged their lives, they can cause side effects such as colitis, an inflammatory reaction in the colon.

"Colitis induced by immune checkpoint inhibitors can limit the use of these drugs, resulting in discontinuation of treatment. While this is one of the most common and serious side effects of immunotherapy, there is a lack of understanding of the risk factors that could be modified to prevent colitis," said Dr. Osama Rahma of the Dana-Farber Cancer Institute and Harvard Medical School in Boston.

Dr. Rahma and his colleagues conducted a study to determine whether taking vitamin D supplements could reduce the risk of colitis in patients receiving immune checkpoint inhibitors to treat their cancer. The team chose this strategy because previous studies have shown that vitamin D can affect the immune system in autoimmune disorders and inflammatory bowel disease.

This study included information on 213 melanoma patients who received immune checkpoint inhibitors between 2011 and 2017. Thirty-seven (17%) of these patients developed colitis. Sixty-six patients in this study (31%) took vitamin D supplements before starting treatment with immune checkpoint inhibitors.

65% less likely to develop colitis
Patients who took vitamin D were 65% less likely to develop colitis after adjusting for confounding factors. These results were validated in another group of 169 patients, 49 (29%) of whom developed colitis. In this validation group, vitamin D use was associated with a 54% reduction in the risk of developing colitis.

"Our findings on the relationship between vitamin D intake and colitis risk reduction could have an impact on treatment if validated in future prospective studies," said Dr. Rahma. "Vitamin D supplementation should be further tested to determine whether it can be a safe, readily available and cost-effective approach to preventing gastrointestinal toxicity of immunotherapy and increasing the effectiveness of treatment with immune checkpoint inhibitors in cancer patients.