Phase 2 trial results warrant further study in a phase 3 trial.
Vitamin C boosts the activity of cellular proteins called TET enzymes that help control which genes are turned on or off. Because decreased function of TET enzymes is a common driver of certain forms of blood cancer, researchers tested the effects of vitamin C supplements in patients at risk of developing such malignancies. Results of the investigators' phase 2 clinical trial are published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.
The randomized, double-blind, placebo-controlled EVITA trial enrolled 109 patients in Denmark and the United States who had either a blood condition that can turn cancerous or a low-risk form of blood cancer. At the start of the trial, 55 patients were randomly assigned to receive oral vitamin C (1,000 mg/day) and 54 were assigned to receive placebo, for a total of 12 months.
Although the primary endpoint-growth rate of precancerous or cancerous cells-was similar between groups, participants who received vitamin C experienced changes in inflammatory signaling that aligns with better outcomes. Also, anemia, pneumonia, acute aseptic arthritis, and internal bleeding were less frequent (although gastrointestinal problems were more frequent) in patients taking vitamin C compared with those taking placebo.
At a median follow-up of 33.6 months (nearly 3 years) in the intention-to-treat population, 35 deaths were recorded, including 24 in the placebo group and 11 in the vitamin C group. An exploratory analysis of these data found that participants in the vitamin C group were more likely to survive during follow-up than those in the placebo group. This finding requires confirmation in a larger phase 3 clinical trial.
"The EVITA trial gives us a strong rationale to continue exploring if and how vitamin C might benefit people with certain pre-cancer or early-stage blood cancers. More work is needed but we are cautiously optimistic that these findings could inform future strategies to intercept leukemia development," said co-senior author Peter A. Jones, PhD, DSc (hon), of Van Andel Institute, in Grand Rapids, Michigan. Jones is co-leader of the Van Andel Institute-Stand Up To Cancer (VAI-SU2C) Epigenetics Dream Team, which led the EVITA trial.
"We are encouraged by our findings and what they ultimately could mean for people with these early-stage blood disorders. Although it is too soon to make recommendations based on our results, we are hopeful that a larger study will give us more definitive answers," added co-senior author Kirsten Grønbæk, MD, PhD, of Rigshospitalet, Copenhagen University Hospital in Denmark. Grønbæk is a longtime member of the VAI-SU2C Epigenetics Dream Team.
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