Record ID: MS-N089
Family: Nutrition and supplements
Clinical question: Does oral vitamin C slow clonal growth or improve outcomes in clonal cytopenia of undetermined significance (CCUS) or lower-risk myeloid malignancies?
Evidence label: Randomized phase II; negative primary endpoint with exploratory signal
Evidence at a glance
Benefit: No difference in the prespecified clonal-growth endpoint. Fewer serious adverse events and longer overall survival were secondary or exploratory observations.
Certainty: Low for clinical benefit. The trial was modest in size and was not designed to establish survival.
Risk: The studied 1,000 mg/day regimen appeared tolerable, but kidney disease, kidney-stone risk, iron overload and treatment interactions still warrant review.
Cancer control: The study does not establish prevention of leukemia, delayed progression or improved survival.
What was studied
The 2026 EVITA trial randomized 109 adults in Denmark and the United States (55 vitamin C, 54 placebo). Participants had CCUS or lower-risk myeloid malignancies and were not receiving anticancer therapy. They took oral vitamin C 1,000 mg/day or placebo for 12 months. The primary endpoint was median clonal growth rate; the trial is registered as NCT03682029.
The primary analysis included 98 participants with paired mutation measurements. Eighty-seven completed the treatment period. This was oral supplementation, not intravenous pharmacologic ascorbate, and it addresses a different clinical question from pancreatic-cancer infusion studies.
What the results mean
The primary endpoint was negative: the between-group difference in median clonal growth rate was −0.016 (95% CI −0.096 to 0.064; P=.70). This is the result that should lead interpretation.
Serious adverse events occurred in 18 of 55 participants assigned vitamin C (33%) and 30 of 53 evaluable placebo participants (57%). Overall survival favored vitamin C in an exploratory analysis (HR 0.35, 95% CI 0.17–0.71; P=.0025). Because survival was not the primary endpoint and event counts were limited, that striking estimate may be unstable and needs prospective confirmation.
Limits and uncertainty
The paper reports baseline diagnostic reclassification and protocol deviations, and clonal-growth analysis was unavailable for some participants. The trial was too small to settle leukemia transformation or mortality.
Biological effects on cytokines and plasma vitamin C do not substitute for a clinical endpoint. The authors call for a phase III trial.
Safety and practical context
“Vitamin C” is not one interchangeable exposure: food intake, oral tablets and intravenous pharmacologic doses have different pharmacology and risks. People with kidney disease, recurrent oxalate stones, glucose-6-phosphate dehydrogenase deficiency or iron-overload disorders should discuss supplementation with the hematology team.
Do not use this result to defer marrow evaluation, molecular monitoring or indicated myeloid-disease treatment.
Questions for the care team
- Was I represented by CCUS or a lower-risk myeloid subgroup in EVITA?
- Which endpoint matters most for my situation: clonal growth, blood counts, transformation or survival?
- Could kidney function, iron status or medicines change the safety of 1,000 mg/day?
- Is there a confirmatory trial or monitored study rather than self-treatment?
Sources
- EVITA phase II randomized trial (Cancer, October 1, 2026; PMID 42764731)
- ClinicalTrials.gov record NCT03682029
Funding and conflicts
The article reports multiple academic and grant-supported affiliations. Disclosed professional relationships included work or consulting for GlaxoSmithKline, AbbVie, Geron, Taiho Oncology and Zymo Research; the remaining authors reported no conflicts. Funding details should be checked in the full article.
Last literature search: October 21, 2026
Record appraised: October 21, 2026
This educational record is not individualized medical advice. Research doses and schedules are not personal prescriptions; do not delay or replace evidence-based cancer care.
