Vitamin C may offer unexpected benefits for people at risk of blood cancer, according to results from the phase 2 EVITA trial published in the journal Cancer. The randomized, double-blind, placebo-controlled study enrolled 109 participants in Denmark and the United States, all of whom had a blood disorder with potential to become cancerous or a low-risk form of blood cancer. Half took 1,000 mg of oral vitamin C daily; the other half received a placebo. Treatment lasted 12 months.
The trial's main goal was to see whether vitamin C slowed the growth of precancerous or cancerous cells. On that measure, the vitamin C and placebo groups were similar. However, researchers observed other differences: people taking vitamin C showed changes in inflammatory signaling linked to better outcomes and experienced fewer cases of anemia, pneumonia, acute aseptic arthritis, and internal bleeding. Gastrointestinal problems were more common in the vitamin C group.
At a median follow-up of 33.6 months, 35 participants had died—24 in the placebo group and 11 in the vitamin C group. An exploratory analysis indicated that those assigned to vitamin C were more likely to survive during follow-up. The authors emphasize that this is a preliminary finding and must be tested in a larger phase 3 trial before firm conclusions can be drawn.
The study was motivated by evidence that vitamin C can boost the activity of TET enzymes, which help regulate gene expression and are often less active in blood cancers. Co-senior author Peter A. Jones of Van Andel Institute said the results provide a strong rationale for further research, while co-senior author Kirsten Grønbæk of Rigshospitalet noted that it is too soon to make treatment recommendations based on these findings.