In a study to be presented by Tyan et al at the upcoming 2020 ASCO-SITC Clinical Immuno-Oncology Symposium (Abstract 89), researchers found that vitamin D intake may be associated with reduced risk of colitis among patients being treated with immune checkpoint inhibitors.

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Retrospective Analysis

In the single-center study, researchers performed a retrospective analysis of 213 patients with melanoma who were treated with an immunotherapy from 2011 to 2017. Patients either receive a programmed cell death protein 1 inhibitor, a cytotoxic T-lymphocyte–associated protein 4 inhibitor, or a combination of the two agents.

Researchers used clinical and laboratory characteristics of pathologically confirmed immune checkpoint inhibitor–associated colitis to perform their analysis, and external validation was performed on an independent cohort.

Findings

Thirty-seven patients (17%) in the cohort developed immune checkpoint inhibitor–associated colitis. Patients treated with ipilimumab alone or in combination with nivolumab were more likely to develop immune checkpoint inhibitor–associated colitis than patients treated with pembrolizumab.

Thirty-one percent of patients reported using vitamin D before beginning treatment with immunotherapy. Patients who used vitamin D had reduced odds of developing immune checkpoint inhibitor–associated colitis (odds ratio [OR] = 0.35, 95% confidence interval = 0.1–0.9). In the validation cohort, these results were confirmed. A neutrophil/lymphocyte ratio of 5 or less before treatment was also predictive of reduced odds of developing colitis (OR = 0.34, 95% CI = 0.1–0.9)—but only is the discovery cohort.

The authors concluded, “This is the first study to report that among patients treated with immune checkpoint inhibitors, vitamin D intake is associated with reduced risk for immune checkpoint inhibitor–[associated] colitis. This finding is consistent with prior reports of prophylactic use of vitamin D in ulcerative colitis and graft-vs-host disease. This observation should be validated prospectively in future studies.”

Disclosure: For full disclosures of the study authors, visit coi.asco.org.