High-Dose Vitamin D3 Fails to Improve Outcomes in Metastatic Colorectal Cancer, Phase 3 Trial Finds
核心洞察
A phase 3 trial (NCT04094688) of 455 patients found no statistically significant difference in progression-free survival between high-dose and standard-dose vitamin D3 added to chemotherapy for metastatic colorectal cancer (搜索).
High-dose vitamin D3 produced a median progression-free survival of 11.8 months versus 10.3 months for standard-dose, with similar overall survival (25.6 vs. 27.0 months) and response rates (51% vs. 44%).
The study demonstrated a safe, tolerable, and feasible high-dose vitamin D3 regimen, providing a rationale for future investigation.
A phase 3 clinical trial evaluating high-dose vitamin D3 (VD3) added to standard chemotherapy found no statistically significant improvement in outcomes for patients with metastatic colorectal cancer (搜索), according to findings published in the Journal of the American Medical Association (JAMA).
The trial (NCT04094688) enrolled 455 patients with treatment-naïve metastatic colorectal cancer (搜索). Patients received standard-of-care chemotherapy, consisting of modified FOLFOX6 (5-fluorouracil, leucovorin, oxaliplatin) or FOLFIRI (5-fluorouracil, leucovorin, irinotecan) plus bevacizumab every 2 weeks. One cohort of 228 patients received chemotherapy plus high-dose VD3, administered at 8,000 IU daily for two weeks followed by 4,000 IU daily. The remaining 227 patients received standard-dose VD3 (400 IU daily) with chemotherapy. VD3 administration continued until disease progression or intolerable toxicity.
Primary Efficacy Results
After an average follow-up of 20 months, the average progression-free survival (PFS) for patients receiving high-dose VD3 was 11.8 months, only slightly exceeding the 10.3 months observed in the standard-dose group. Overall survival rates remained similar between the two cohorts, at 25.6 months for high-dose versus 27.0 months for standard-dose. The objective response rate also did not differ significantly between treatment groups, at 51% for high-dose versus 44% for standard-dose.
The onset of treatment-related toxicities and adverse events did not differ significantly between groups.
Study Conclusions and Prior Rationale
The study concludes that adding high-dose VD3 to chemotherapy does not improve outcomes for metastatic colorectal cancer (搜索) compared to standard-dose VD3. However, the research provides new information that could prove useful in future studies, including the demonstration of a safe, tolerable, and feasible VD3 dosage and schedule.
This phase 3 trial built on earlier work: a 2019 phase 2 clinical trial (NCT01516216) that investigated combining chemotherapy with VD3 for metastatic colorectal cancer (搜索). That earlier study found that VD3, in both high-dose and standard-dose, yielded a slight but not significant difference in survival outcomes, though it showed an improved hazard ratio for high-dose VD3 plus chemotherapy compared to standard-dose VD3 plus chemotherapy, providing rationale for a more robust trial protocol.
Expert Perspectives
Ketan Thanki, MD, raised a key methodological concern about the trial design: "My first thought upon reading this paper was that current standard of care does not include routine supplementation, even at low dose, of vitamin D3 for patients undergoing chemotherapy for metastatic colorectal cancer (搜索). As a result, are we missing an effect of any degree of supplementation — whether low or high — by comparing low dose to high dose and not including an arm that includes no supplementation at all, unless a patient is already deficient at baseline or high risk for bone loss during chemotherapy?"
On the primary results, the study authors noted: "Unfortunately, the primary results of the study did not show statistically significant differences in progression-free survival between patients randomized to high-dose vitamin D compared to low-dose vitamin D. There were also no statistically significant differences in the response rates of these patients' cancers or in overall survival."
Regarding potential subgroup differences, an expert observed: "This is a great starting point to ask a question if left and right colon cancers respond differently to D3 supplementation, but is by no means an answer that they do. We know that right and left-sided colon cancers have very different tumor biology, so it is not a stretch to suggest that they may, and perhaps further studies will demonstrate that D3 is beneficial for one and not the other."