Is Vitamin C an Epigenetic Interception Strategy in Pre-Leukemic Disease?

Patients with clonal cytopenia of undetermined significance (CCUS) and lower-risk myeloid neoplasms are often managed with active surveillance, and few options exist to change their risk of progression. The phase 2 EVITA trial (NCT03682029) randomly assigned 109 patients with CCUS or lower-risk myeloid malignancies to 1000 mg of oral vitamin C daily or placebo for 12 months. Supplementation did not significantly slow clonal growth, but a post hoc analysis showed an overall survival (OS) signal favoring vitamin C (HR, 0.35; 95% CI, 0.17-0.71; P = .0025).¹

CancerNetwork® spoke with Peter A. Jones, PhD, DSc (hon), distinguished professor at Van Andel Institute, co-leader of the Van Andel Institute–Stand Up To Cancer (SU2C) Epigenetics Dream Team, and co-senior author of the EVITA trial, about the science behind the study and where the research goes next. He began by explaining the disconnect between the trial’s primary end point and its survival findings. He also recounted the early laboratory observation and TET2 biology that set the study in motion.

Jones then discussed vitamin C’s role as an epigenetic cofactor in cancer interception, and why the trial was too small to show which patients benefit most. He concluded by outlining the translational end points a phase 3 trial will need to address.

CancerNetwork: Although the EVITA trial did not show a significant change in clonal growth rates, it demonstrated favorable shifts in inflammatory cytokines and a marked OS signal. How do you explain this divergence, and could vitamin C be acting primarily through TET2-mediated epigenetic reprogramming rather than direct clonal clearance?

Jones: It is very important to realize that the clonal growth rate measurements were made after 1 year of treatment from enrollment. Survival was measured much later; thank heavens, a lot of people did quite well. We do not know what happened to the clonal growth rate at the end of the observation period. I wish we had measured that, but we did not. There is a disconnect there that one needs to be aware of. The measurements were made after the first year, but the effect was seen many years afterward, and we do not know what happened in the patients [in the interim].

The other thing [to note] is that the trial is highly [science backed]. If I could reminisce a bit: in my first faculty job as a junior faculty member, I made an observation that If you added vitamin C to cultures that had been treated with a chemical carcinogen, immediately or soon after that treatment, you could completely block the emergence of a malignant cell in the culture dish. These experiments are easy to do because cultures normally do not contain vitamin C. It took a long time for us to realize that this may have implications for patients, which is why our SU2C Epigenetics Dream Team pursued this trial.

It was based on 2 [important] facts. First, many patients with these conditions are vitamin C deficient. Second, the TET2 enzyme is required for the demethylation of DNA, which cells need in order to differentiate. We have known for many years that the DNA methylation pattern, which generally suppresses gene activity, changes during development. It was only after Anjana Rao, PhD, discovered the TET enzymes that we finally had a way to see whether this might be relevant to the effect on transformation.² Those findings allowed us to start this trial, along with the realization that enhancers require demethylation to function.³ Enhancers are areas of DNA that control when genes are switched on and off. Putting 2 and 2 together, it was a perfect situation to see whether we could impact human health and, in fact, the progression of the disease.

You have highlighted this work as a model for cancer interception, intervening in pre-leukemic states such as CCUS before overt malignant transformation occurs. How does low-dose oral vitamin C function as an epigenetic priming strategy, and could it sensitize high-risk clones to secondary therapies or prevent inflammatory clonal expansion?

It is quite possible that would be the case. Vitamin C is a powerful epigenetic drug, which is not generally realized. Interception means catching the cancer before it develops. These people have a mutation that we know increases the probability that they might get Frank [scurvy]. We also know that changes in enhancer methylation are important in differentiation. What we think is happening is that the drug works because it is an essential cofactor.

When vitamin C’s importance in human health was first discovered, it was found that it could prevent scurvy. That is thought to be the world’s first randomized clinical trial. It was conducted by James Lind, who put 2 sailors on vitamin C [citrus fruit], 2 on this, and 2 on that. The sailors on vitamin C ended up nursing the other ones, so it was a pretty convincing clinical trial. No statistics needed.

It was only later that we realized vitamin C is not just for collagen. Collagen requires vitamin C to be deposited and wrapped up properly, and [a lack of vitamin C] is what causes scurvy. However, vitamin C is involved in at least 60 other enzymes, which was not realized at the time. One of those is the TET enzymes, which require vitamin C. That is why we thought this would make a lot of sense.

Did your biomarker analyses reveal whether patients carrying specific TET2 loss-of-function mutations or higher baseline variant allele frequencies derived a more pronounced epigenetic or clinical benefit from supplementation?

The problem is that in such a short, small trial, we are not able to answer that. We only had 109 patients and, quite frankly, never expected to see such a strong increase in OS. There is not enough there to slice and dice, so I cannot answer that. If we do a bigger trial, we should be able to.

As your team prepares to move these findings into a definitive phase 3 trial, what translational end points will be essential to prove the epigenetic mechanism of action?

I am a DNA methylation guy; I have been working in that field since 1980, so I am very interested in DNA methylation. Obviously, the most important thing is whether we get the same increase in OS. That is the number one question.

However, we are experts in the measurement of DNA methylation, and you might even think of these conditions as DNA methylation diseases. These particular pathways are mostly impactful in blood cell disorders; they do not seem to be as important in solid tumors. These conditions are dependent on DNA methylation.

The bottom line is that we will be sampling patients and isolating distinct blood stem cells and blood cells for detailed DNA methylation analysis. We already know that TET2, which is probably the most important enzyme, requires vitamin C to work efficiently. The goal would be to see whether a bigger study could answer some of the questions you just asked, such as what the impact of different TET2 mutations is.

References

1. Mikkelsen SU, Al-Mousawi A, Puglisi AM, 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 randomized, placebo-controlled trial. Cancer. 2026;132(19):e70549. doi:10.1002/cncr.70549
2. Tahiliani M, Koh KP, Shen Y, et al. Conversion of 5-methylcytosine to 5-hydroxymethylcytosine in mammalian DNA by MLL partner TET1. Science. 2009;324(5929):930-935. doi:10.1126/science.1170116
3. Tulstrup M, Soerensen M, Hansen JW, et al. TET2 mutations are associated with hypermethylation at key regulatory enhancers in normal and malignant hematopoiesis. Nat Commun. 2021;12(1):6061. doi:10.1038/s41467-021-26093-2