Systematic vitamin D supplementation is associated with improved outcomes and reduced thyroid adverse events in patients with cancer treated with immune checkpoint inhibitors: results from the prospective PROVIDENCE study.

BACKGROUND: Hypovitaminosis D can have a negative prognostic impact in patients with cancer. Vitamin D has a demonstrated role in T-cell-mediated immune activation. We hypothesized that systematic vitamin D repletion could impact clinical outcomes in patients with cancer receiving immune-checkpoint inhibitors (ICIs). METHODS: We planned a prospective observational study (PROVIDENCE) to assess serum vitamin D levels in patients with advanced cancer receiving ICIs (cohort 1 at treatment initiation, cohort 2 during treatment) and the impact of systematic repletion on survival and toxicity outcomes. In an exploratory analysis, we compared the clinical outcomes of cohort 1 with a control cohort of patients followed at the participating centers who did not receive systematic vitamin D repletion. RESULTS: Overall, 164 patients were prospectively recruited in the PROVIDENCE study. In cohort 1, consisting of 101 patients with 94.1% hypovitaminosis (≤ 30 ng/ml) at baseline, adequate repletion with cholecalciferol was obtained in 70.1% at the three months re-assessment. Cohort 2 consisted of 63 patients assessed for vitamin D at a median time of 3.7 months since immunotherapy initiation, with no patients having adequate levels (> 30 ng/ml). Even in cohort 2, systematic supplementation led to adequate levels in 77.8% of patients at the three months re-assessment. Compared to a retrospective control group of 238 patients without systematic vitamin D repletion, PROVIDENCE cohort 1 showed longer overall survival (OS, p = 0.013), time to treatment failure (TTF, p = 0.017), and higher disease control rate (DCR, p = 0.016). The Inverse Probability of Treatment Weighing (IPTW) fitted multivariable Cox regression confirmed the significantly decreased risk of death (HR 0.55, 95%CI: 0.34-0.90) and treatment discontinuation (HR 0.61, 95%CI: 0.40-0.91) for patients from PROVIDENCE cohort 1 in comparison to the control cohort. In the context of longer treatment exposure, the cumulative incidence of any grade immune-related adverse events (irAEs) was higher in the PROVIDENCE cohort 1 compared to the control cohort. Nevertheless, patients from cohort 1 experienced a significantly decreased risk of all grade thyroid irAEs than the control cohort (OR 0.16, 95%CI: 0.03-0.85). CONCLUSION: The PROVIDENCE study suggests the potential positive impact of early systematic vitamin D supplementation on outcomes of patients with advanced cancer receiving ICIs and support adequate repletion as a possible prophylaxis for thyroid irAEs.

Vitamin D Supplementation and Disease-Free Survival in Stage II Melanoma: A Randomized Placebo Controlled Trial.

Patients with newly resected stage II melanoma (n = 104) were randomized to receive adjuvant vitamin D3 (100,000 IU every 50 days) or placebo for 3 years to investigate vitamin D3 protective effects on developing a recurrent disease. Median age at diagnosis was 50 years, and 43% of the patients were female. Median serum 25-hydroxy vitamin D (25OHD) level at baseline was 18 ng/mL, interquartile range (IQ) was 13-24 ng/mL, and 80% of the patients had insufficient vitamin D levels. We observed pronounced increases in 25OHD levels after 4 months in the active arm (median 32.9 ng/mL; IQ range 25.9-38.4) against placebo (median 19.05 ng/mL; IQ range 13.0-25.9), constantly rising during treatment. Remarkably, patients with low Breslow score (<3 mm) had a double increase in 25OHD levels from baseline, whereas patients with Breslow score ≥3 mm had a significantly lower increase over time. After 12 months, subjects with low 25OHD levels and Breslow score ≥3 mm had shorter disease-free survival (p = 0.02) compared to those with Breslow score <3 mm and/or high levels of 25OHD. Adjusting for age and treatment arm, the hazard ratio for relapse was 4.81 (95% CI: 1.44-16.09, p = 0.011). Despite the evidence of a role of 25OHD in melanoma prognosis, larger trials with vitamin D supplementation involving subjects with melanoma are needed.

Vitamin D in melanoma: Controversies and potential role in combination with immune check-point inhibitors.

The role of vitamin D in melanoma is still controversial. Although several Authors described a correlation between vitamin D deficiency and poor survival in metastatic melanoma patients, clinical trials exploring the effects of vitamin D supplementation in this clinical setting were mostly inconclusive. However, recent evidence suggests that vitamin D exerts both anti-proliferative effects on tumor cells and immune-modulating activities, that have been widely explored in auto-immune disorders. On the one hand, vitamin D has been shown to inhibit T-helper17 lymphocytes, notoriously involved in the pathogenesis of immune-related adverse events (iAEs) which complicate immune-checkpoint inhibitor (ICI) treatment. On the other hand, vitamin D up-regulates PDL-1 expression on both epithelial and immune cells, suggesting a synergic effect in combination with ICIs, for which further investigation is needed.