High-Dose Vitamin D3 Fails to Extend Progression-Free Survival in Untreated Metastatic Colorectal Cancer
In the SOLARIS phase 3 trial, 455 patients with previously untreated metastatic colorectal cancer were randomized to high-dose vitamin D3 plus standard chemotherapy with bevacizumab or standard-dose vitamin D3. High-dose vitamin D3 did not improve progression-free survival (11.8 vs 10.3 months), objective response rate, or overall survival, though there was a signal suggesting left-sided tumors may benefit. The regimen was well tolerated with similar adverse events between groups. The findings do not support routine use of high-dose vitamin D3 in unselected patients and warrant further investigation in targeted subgroups.
