Taking high-dose vitamin D3 alongside chemotherapy did not slow metastatic colorectal cancer in a phase 3 trial of 455 patients, closing a question that a smaller earlier study had left open and that many patients had acted on.
The SOLARIS randomized clinical trial, published in JAMA, reported median progression-free survival of 11.8 versus 10.3 months for the high-dose and standard-dose groups. The difference did not reach statistical significance, with a hazard ratio of 0.92 and a one-sided log-rank P value of .25, and there were no significant differences in objective response rate or overall survival.
