High-Dose Intravenous Vitamin C Combined with Standard Therapy:
A Phase I Study in Metastatic Pancreatic Cancer
High-dose intravenous vitamin C (intravenous ascorbic acid) was initially studied on its own, but later early-phase clinical trials also began to evaluate its use alongside standard cancer medicines.
In patients with metastatic pancreatic cancer, one Phase I study assessed the safety and feasibility of intravenous ascorbic acid given together with gemcitabine and erlotinib.
What Did the Study Do?
The study enrolled 14 patients with stage IV metastatic pancreatic cancer. Its main purpose was to determine whether adding high-dose intravenous ascorbate to an existing cancer-drug regimen would introduce substantial additional toxicity.
14
Patients with Stage IV Metastatic Pancreatic Cancer
High-Dose Intravenous Ascorbate Added to an Existing Drug Regimen
Patients received intravenous ascorbic acid three times per week while also receiving gemcitabine and erlotinib. The planned study course lasted eight weeks.
The central question was still safety and feasibility, rather than whether the addition of vitamin C could improve pancreatic cancer outcomes.
Gemcitabine was one of the standard cancer medicines included in the study regimen.
Gemcitabine
Erlotinib was administered alongside gemcitabine as part of the combination regimen.
Erlotinib
Intravenous ascorbic acid was administered three times per week using a dose-escalation design.
Intravenous Ascorbate
How Was the Intravenous Vitamin C Dose Explored?
The study progressively increased the dose given at each infusion, allowing investigators to observe safety, tolerability, and pharmacokinetic changes at different dose levels.
50 g per infusion
75 g per infusion
100 g per infusion
8
Week Planned Study Course
The planned treatment period lasted approximately eight weeks.
9
Patients Completed Full Evaluation
Nine patients ultimately completed the full study course and both pre- and post-treatment imaging assessments.
What Did the Study Observe?
Multiple adverse events were recorded during the study. However, the investigators considered the serious events to be primarily related to progression of advanced pancreatic cancer or to gemcitabine and erlotinib, rather than to a clear additional toxicity from intravenous ascorbate.
Pharmacological Concentration and Clinical Benefit Remain Different Questions
The study showed that high-dose intravenous ascorbate could achieve high plasma concentrations within a combination regimen. Changes in plasma concentration alone, however, cannot establish improved tumour control or longer survival.
25.3–31.9
mmol/L · Plasma Level After a 100 g Infusion
Higher-Dose Infusions Produced Millimolar Plasma Concentrations
In patients receiving the higher infusion doses, intravenous ascorbic acid raised plasma vitamin C into the millimolar range.
Among patients receiving 100 g, post-infusion plasma concentrations were approximately 25.3–31.9 mmol/L, again demonstrating that intravenous administration can achieve pharmacological concentrations that are difficult to reach with conventional oral supplementation.
What Were the Imaging Results Among Patients Who Completed Assessment?
Nine patients completed the full treatment course and both pre- and post-treatment imaging. Under RECIST 1.0 criteria, the following outcomes were reported.
Stable Disease Cannot Be Directly Attributed to Intravenous Vitamin C
Patients were receiving gemcitabine and erlotinib at the same time, and the study did not include a randomised control group. Therefore, short-term disease stability cannot be attributed specifically to standard drugs, intravenous ascorbate, or any single component of the combination.
7 Patients with Stable Disease
Of the nine patients who completed imaging evaluation, seven were classified as having stable disease.
2 Patients with Progressive Disease
The remaining two patients were classified as having progressive disease.
How Should This Study Be Interpreted?
This was a very small Phase I open-label study. It should therefore be interpreted primarily as a safety and feasibility investigation, rather than as evidence of treatment efficacy.
The More Appropriate Conclusion Is a Safety Signal, Not Proof of Efficacy
In this small early-phase study, adding high-dose intravenous ascorbic acid to gemcitabine and erlotinib did not appear to produce obvious additional treatment-related toxicity and successfully achieved pharmacological plasma concentrations. However, the study was not sufficient to demonstrate improved tumour control or survival.
The sample was far too small to reliably determine effects on tumour control or survival.
Only 14 Patients
The number of patients available for complete pre- and post-treatment imaging comparison was even smaller.
Only 9 Completed Full Imaging Evaluation
There was no concurrent randomised group receiving gemcitabine and erlotinib alone for direct comparison.
No Randomised Control Group
What Did This Study Contribute to Later Research?
This study moved the research direction from simply asking whether high-dose intravenous vitamin C could be administered safely towards studying its use alongside standard cancer regimens.
The investigation no longer examined intravenous ascorbate in isolation, but began to assess its feasibility alongside standard cancer medicines.
From Single-Agent to Combination Research
The study provided early clinical information on whether adding high-dose intravenous ascorbate introduced substantial additional toxicity.
Added Early Combination-Safety Data
Later studies continued to investigate intravenous ascorbate with gemcitabine-based and other cancer regimens, examining safety, pharmacokinetics, and possible clinical signals.
Supported Further Pancreatic Cancer Research
The National Cancer Institute (NCI) continues to note that clinical findings from studies combining intravenous vitamin C with other cancer medicines have not been entirely consistent, and many studies have involved small patient populations.
Higher-quality and larger clinical trials are therefore still needed to determine the actual clinical value of this approach.
How Does BMS Clinic View This Evidence?
One important message from this study is that the use of high-dose intravenous vitamin C in patients with cancer needs to be evaluated within the context of the patient’s overall medical care, rather than considered in isolation.
If a patient is receiving chemotherapy, targeted therapy, or other cancer-care regimens, consideration of high-dose intravenous vitamin C should include a review of current medicines, cancer status, kidney function, G6PD status, and other individual risk factors.
BMS Clinic emphasises professional assessment based on current medical evidence and individual circumstances. If high-dose intravenous vitamin C is considered as part of supportive medical care, it should be evaluated alongside the patient’s existing cancer-care plan. Disease stability observed in an early Phase I study should not be interpreted as established clinical efficacy.
This page is provided for medical education and literature information purposes only. It is intended to help readers understand an early Phase I study of high-dose intravenous vitamin C combined with standard cancer therapy in metastatic pancreatic cancer and does not replace diagnosis, assessment, or personalised medical advice from a qualified healthcare professional.
The study discussed was a small Phase I clinical trial primarily designed to evaluate the safety and feasibility of intravenous ascorbic acid in combination with gemcitabine and erlotinib. The disease stability observed in some participants does not demonstrate that high-dose vitamin C itself can control pancreatic cancer, reduce tumour size, or prolong survival.
Patients with cancer considering high-dose intravenous vitamin C or other supportive medical approaches should first undergo appropriate assessment by a qualified healthcare professional based on their individual condition, current cancer treatment, kidney function, G6PD status, and other relevant risk factors.
Learn More About High-Dose Intravenous Vitamin C as Supportive Care
This Phase I study primarily evaluated the safety and feasibility of combining high-dose intravenous vitamin C with standard cancer treatment. It does not establish that intravenous vitamin C itself provides a confirmed tumour-control or survival benefit. Patients receiving chemotherapy, targeted therapy, or other cancer treatments should first undergo professional assessment based on their current medications, cancer status, kidney function, G6PD status, and other individual risk factors.
References
Monti DA, Mitchell E, Bazzan AJ, et al. Phase I evaluation of intravenous ascorbic acid in combination with gemcitabine and erlotinib in patients with metastatic pancreatic cancer. PLoS One. 2012;7(1):e29794.
National Cancer Institute. Intravenous Vitamin C (PDQ®) – Health Professional Version. Evidence review of intravenous vitamin C in people with cancer.