A randomised, double-blind, placebo-controlled Phase II trial found that daily oral vitamin C supplementation was associated with reduced mortality among patients with precancerous or low-risk malignant blood conditions. However, it did not meet its primary efficacy endpoint. The findings from the EVITA trial are published in Cancer.
The trial enrolled 109 patients in Denmark and the United States with either clonal cytopenia of undetermined significance or a lower-risk myeloid malignancy, conditions associated with an increased risk of progressing to blood cancer, including leukaemia. Participants were randomly assigned to receive 1,000 mg per day of oral vitamin C or placebo for 12 months.
The rationale for the trial is biological: vitamin C is known to enhance the activity of TET enzymes, cellular proteins that regulate gene expression by controlling DNA methylation. Reduced TET enzyme function is a recognised driver of certain blood cancers, making vitamin C a plausible candidate for intercepting disease progression.
The primary endpoint, the growth rate of precancerous or cancerous cells, did not differ significantly between the two groups. However, participants receiving vitamin C showed changes in inflammatory signalling consistent with more favourable outcomes and experienced lower rates of anaemia, pneumonia, acute aseptic arthritis, and internal bleeding compared with the placebo group, though gastrointestinal side effects were more frequent.
At a median follow-up of 33.6 months, 35 deaths were recorded overall: 24 in the placebo group and 11 in the vitamin C group. An exploratory survival analysis found a higher likelihood of survival in the vitamin C group, though the authors emphasise that this finding requires confirmation in a larger Phase III trial before any clinical recommendations can be made.
Source: Source: Jones PA, Grønbæk K et al. Oral vitamin C supplementation in patients with clonal cytopenia of undetermined significance or lower-risk myeloid malignancies: Results from EVITA, a phase 2 randomised placebo-controlled trial. Cancer (2026). DOI: 10.1002/cncr.70549
