Vitamin D tied to lower risk of immune checkpoint inhibitor-induced coltis

Last Updated: 2020-06-23

By Lisa Rappaport

(Reuters Health) - Melanoma patients treated with immune checkpoint inhibitors are less likely to develop drug-induced colitis when they also take vitamin D supplements, a new study suggests.

Researchers performed a retrospective analysis of data on a cohort of 213 melanoma patients treated with immune checkpoint inhibitors (ICI) at Dana Farber Cancer Institute between May 2011 and October 2017. Overall, 37 patients (17%) developed treatment-induced colitis.

A total of 66 patients (31%) used vitamin D prior to initiating ICI treatment, and they were less likely (OR 0.35) to develop ICI-induced colitis, the study team reports in Cancer.

"Since colitis is caused by inflammatory immune cells that are empowered when receiving immunotherapy, we hypothesized that Vitamin D can suppress or calm this bowel inflammation down," said senior study author Dr. Osama Rahma, of the Center for Immuno-Oncology at the Gastrointestinal Cancer Center at Dana-Farber Cancer Institute in Boston.

"Our results, if validated prospectively in clinical trials, could be practice-changing as practicing oncologists may consider using vitamin D in cancer patients who are at high risk to develop colitis when starting on immunotherapy," Dr. Rahma said by email.

Patients were considered to have used vitamin D if they took ergocalciferol or cholecalciferol, or multivitamins containing at least 400 IU of vitamin D. Vitamin D intake was divided into three dosage categories: no use, 1000 IU, and >1000 IU per day.

Researchers validated their findings in another group of 169 patients, of whom 49 (29%) developed ICI colitis. Vitamin D supplementation was also associated with a lower risk in this validation group (OR 0.46).

There are many biases with retrospective studies including small sample size and patient selection bias since those patients are treated in two major academic centers in Boston, Dr. Rahma said.

"In addition, we only looked at melanoma patients and studied the relationship between taking vitamin D and colitis rather than measuring the level of vitamin D in the blood," Dr. Rahma added.

Researchers are starting a new study to check the level of vitamin D using blood samples that are already collected from melanoma patients before starting immunotherapy, Dr. Rahma said.

"If the higher level of vitamin D correlates with lower risk of colitis we plan to propose a clinical trial testing the combination of immunotherapy and vitamin D or placebo in cancer patients with primary objective of preventing immune induced colitis." Dr. Rahma said.

Food alone may be insufficient to get melanoma patients enough of this nutrient to significantly lower their risk of treatment-induced colitis, said Dr. Michael Holick, a professor of medicine, physiology, and biophysics and molecular medicine at Boston University Medical Center who wasn't involved in the study.

"Patients with cancer are at extremely high risk of vitamin D deficiency and they can benefit by being supplemented with an adequate amount of vitamin D," Dr. Holick said by email. "This study demonstrates that this simple and inexpensive recommendation can reduce risk of an inflammatory complication associated with treating melanoma."

SOURCE: https://bit.ly/3dmptgJ Cancer, online June 22, 2020.