Results from the multicenter double-blind randomized phase III SOLARIS trial (Alliance A021703) showed that the addition of high-dose vitamin D3 to standard treatment did not improve progression-free survival vs standard-dose vitamin D3 in patients with untreated metastatic colorectal cancer. The investigators, led by Kimmie Ng, MD, MPH, and colleagues at Dana-Farber Cancer Institute, Boston, presented their findings at the European Society for Medical Oncology (ESMO) Congress 2024 (Abstract LBA26).
Study Details
More than 450 patients received standard chemotherapy plus bevacizumab and were randomly assigned to high-dose or standard-dose vitamin D3. After a median 20-month follow-up, Dr. Ng’s team observed no additional concerning side effects or toxicities with the addition of high-dose vitamin D3. However, the addition of high-dose vitamin D3 to standard treatment did not delay the progression of cancer more so than standard-dose vitamin D3.
The researchers did, however, note a potential benefit for high-dose vitamin D3 for patients with left-sided disease (ie, in the descending colon, sigmoid colon, or rectum). They stated that this finding requires further investigation.
Additional Perspective
The SOLARIS trial was inspired by previous research suggesting that higher levels of vitamin D in the blood are associated with improved survival for patients with metastatic colorectal cancer and that the addition of high-dose vitamin D3 to standard therapy could potentially improve progression free survival. The SOLARIS results suggest, however, that high-dose vitamin D3 cannot be recommended as a treatment for patients with untreated metastatic colon cancer.
Disclosure: Funding for the study was provided by the National Cancer Institute and Pharmavite. The study authors reported no conflicts of interest.
