SUNSHINE: High-dose vitamin D boosts PFS in metastatic CRC

Receipt of chemotherapy and bevacizumab was generally similar between groups. “It is interesting to note that more patients receiving high-dose vitamin D discontinued treatment to undergo potentially curative surgery compared to those in the control arm, though this was not statistically different,” she noted.

In intent-to-treat analysis conducted at a median follow-up of 17-18 months, progression-free survival, the trial’s primary endpoint, was a median of 13.1 months in the high-dose group and 11.2 months in the low-dose group (P = .04). The difference in favor of high-dose vitamin D remained significant in multivariate analysis (hazard ratio, 0.67; P = .02).

The groups were statistically indistinguishable with respect to overall response rate, but the disease control rate was marginally better with high-dose versus low-dose vitamin D (96% vs. 84%, P = .05).

Rates of most grade 3 or 4 adverse events did not differ significantly between groups. However, diarrhea of these grades was less common in the high-dose vitamin D group (1% vs. 12%; P = .02). With respect to grade 3 or 4 events possibly related to the vitamin therapy, there was one case of hyperphosphatemia in the high-dose group and one case of kidney stones in the low-dose group.

Dr. Ng disclosed that she receives honoraria from Prime Oncology and Sage Publications; has a consulting or advisory role with Defined Health and Genentech/Roche; and receives research funding from Celgene, Genentech/Roche (institutional), Gilead Sciences, Pharmavite (institutional), and Trovagene.