Intravenous administration of high-dose vitamin C in addition to chemotherapy improves survival in patients with pancreatic cancer

Results from a randomized phase 2 clinical trial show that adding high-dose intravenous vitamin C to chemotherapy doubles overall survival in patients with advanced metastatic pancreatic cancer from eight to 16 months.

“Pancreatic cancer is an extremely dangerous disease with a very poor outcome for patients. The median survival with treatment is eight months, without treatment less, and the five-year survival rate is negligible. When we started the study, we thought success would be reached if we achieved a 12-month survival rate, but we doubled the overall survival rate to 16 months. The results were so compelling to show the benefit of this therapy on patient survival that we decided to terminate the study early”.

Joe Cullen, MD, professor of surgery and radiation oncology at the University of Iowa and senior author of the study.

The findings, published in the November issue of Redox Biology, mark another success for high-dose intravenous vitamin C administration, which has overcome many hurdles in nearly 20 years of researchers’ persistent attempts to prove its benefits for cancer patients.

Increased survival rate, improved quality of life

In the study, 34 patients with stage 4 metastatic pancreatic cancer were randomized to receive standard chemotherapy (gemcitabine and nab-paclitaxel) or chemotherapy combined with high-dose vitamin C infusions. Results showed that median overall survival was 16 months for patients receiving chemotherapy plus vitamin C, compared with eight months for patients receiving chemotherapy alone. In addition, disease progression-free survival increased from four to six months.

Vitamin C supplementation not only increased overall survival, but also made patients feel better after treatment. They experienced fewer side effects and tolerated the treatment more easily.

The new study is not the only evidence of the benefits of including intravenous vitamin C in cancer treatment. Earlier this year, the results of another phase 2 clinical trial involving patients with glioblastoma, a deadly form of brain cancer, were published. That study also showed a significant increase in survival when high-dose intravenous vitamin C was added to standard treatment with chemotherapy and radiation.

A third phase 2 trial in non-small cell lung cancer is still ongoing, with results expected within a year. All three trials were funded by a grant from the National Cancer Institute (NCI).

“The NCI funding was incredibly important for us to get these Phase 2 trials underway and get these really encouraging results. Our goal is to show that adding high doses of intravenous vitamin C, which is a very inexpensive drug that is also well tolerated, can improve the treatment of those cancers that are among the deadliest in the U.S. population,” said Cullen.

The long journey to clinical trials

Research scientists have spent decades studying the anti-cancer effects of high doses of vitamin C administered intravenously. Their work revealed a critical difference between intravenous and oral administration of vitamin C. Intravenous administration of vitamin C produces very high levels in the blood that cannot be achieved with oral administration. These high concentrations lead to unique chemical reactions within cancer cells that make them more vulnerable to chemotherapy and radiation therapy.

Cullen notes that despite skepticism about vitamin C as a cancer treatment, the results he and his colleagues have obtained, from basic scientific research to understand the biological mechanisms at work to various clinical trials, have been very encouraging and robust.

At each step of the process, the treatment methodology continued to improve. Scientists conducted studies on cells, and it worked. It also worked very well on mice. Then the researchers did phase 1 trials, which were very promising. So the progress was just phenomenal. For example, in one phase one trial in pancreatic cancer, where scientists used high doses of vitamin C along with radiation therapy, three participants have now lived for nine years, well beyond the typical survival range.