New research suggests vitamin D supplementation may help prevent immune checkpoint inhibitor (ICI)-induced colitis.
The study retrospectively analysed melanoma patients at Dana-Farber Cancer Institute in the US who received PD-1, CTLA-4, or combination ICIs between May 2011 to October 2017.
Clinical and laboratory characteristics associated with pathologically confirmed ICI colitis were evaluated and were externally validated in an independent cohort.
The discovery cohort included 213 patients of whom 37 developed ICI colitis (17%).
Vitamin D use was recorded in 66/213 patients (31%) before starting ICIs.
In multivariable regression analysis, vitamin D use conferred significantly reduced odds of developing ICI colitis (odds ratio [OR] 0.35; 95% CI 0.1-0.9).
These results were validated in the independent cohort (OR 0.46; 95% CI 0.2-0.9) of 169 patients of whom 49 developed ICI colitis (29%).
Pre-treatment neutrophil-to-lymphocyte ratio (NLR) ≥5 predicted reduced odds of colitis (OR 0.34; 95% CI 0.1-0.9), only in the validation cohort.
This is the first study to report that vitamin D intake is associated with reduced risk for colitis in patients being treated with ICIs. This finding is consistent with prior reports of prophylactic use of vitamin D in ulcerative colitis and graft-versus-host-disease.
However, larger prospective studies are needed to validate the findings.