Active vitamin D metabolites, including 25-hydroxyvitamin D (25D) and 1,25-dihydroxyvitamin D (1,25D), have potent immunomodulatory effects that attenuate acute kidney injury (AKI) in animal models. We conducted a phase 2, randomized, double-blind, multiple-dose, 3-arm clinical trial comparing oral calcifediol (25D), calcitriol (1,25D), and placebo among 150 critically ill adult patients at high-risk of moderate-to-severe AKI. The primary endpoint was a hierarchical composite of death, kidney replacement therapy (KRT), and kidney injury (baseline-adjusted mean change in serum creatinine), each assessed within 7 days following enrollment using a rank-based procedure. Secondary endpoints included new or progressive AKI and a composite of KRT or death. Hypercalcemia was the key safety endpoint. We also performed RNA sequencing on circulating CD14+ monocytes collected immediately prior to randomization and two days later. The global rank score for the primary endpoint was similar among calcifediol (n = 51) vs. placebo (n = 49) treated patients (P = 0.85) and for calcitriol (n = 50) versus placebo-treated patients (P = 0.58). Secondary endpoints also occurred at similar rates across groups. Hypercalcemia occurred in one patient in the calcifediol group (1.7%), one patient in the calcitriol group (2.0%), and none of the patients in the placebo group. Compared to placebo, calcitriol upregulated more individual genes and pathways in circulating monocytes than did calcifediol, including pathways involving interferon (IFN)-α, IFN-γ, oxidative phosphorylation, DNA repair, and heme metabolism. Treatment with calcifediol or calcitriol in critically ill adults upregulated multiple genes and pathways involving immunomodulation, DNA repair, and heme metabolism, but did not attenuate AKI. gov (NCT02962102). NIH/NIDDK grant K23DK106448 (Leaf) and NIH/NHLBI grant R01HL16687 (Kim).
Leaf et al. (Tue,) studied this question.