Study of High-Dose Intravenous (IV) Vitamin C Treatment in Patients With Solid Tumors

Preclinical studies of pharmacologic doses of vitamin C (ascorbic acid, ascorbate) have shown significant anticancer effects in animal models and tissue culture investigations including cytotoxic effects in certain cancer cell lines at micromolar to millimolar concentrations.

Early clinical studies have shown that intravenous and oral doses of vitamin C may improve symptoms and prolong survival in terminal cancer patients. More recent double-blind placebo-controlled studies have shown that oral adminstration of vitamin C provides no benefit to cancer patients. Conversely, intravenous vitamin C administration raises plasma concentrations as high as 14 mM/L, and concentrations of 1-5 mM/L have been found to be selectively cytoxic to tumor cells in vitro.

The proposed Phase I trial with vitamin C should achieve millimolar concentrations of vitamin C that have been shown to kill tumor cells in vitro. The maximum tolerated dose (MTD), PK, possible drug accumulation with repeated dosing, quality of life, pain response, fatigue status, and hints of efficacy in patients with advanced cancer will be examined.

Inclusion criteria

• Primary histological diagnosis of advanced solid tumors (stage 3 and 4) and measurable disease.
• Disease must have progressed for which no available treatment provides clinical benefit.
• 18 years of age or older.
• No scheduled cancer therapy (chemotherapy, hormonal therapy, immune therapy, or radiation therapy) for three months after study entry, and the subject must have had their last therapy at least four (4) weeks prior to entry to this study.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2.
• Informed Consent - The patient must be willing and able to sign the informed consent prior to the start of the trial.
• Willingness to comply with the weekly phone calls between office visits.
• Willingness to undergo central line placement (e.g., port-a-catheter, central venous catheter, percutaneously inserted central catheter [PICC] line placement) and able to manage care of the entry site safely.
• Patients must be able to take food orally or have peg tube for feeding.
• Life expectancy of at least 3 months.

Exclusion criteria

• Glucose-6-phosphate dehydrogenase deficiency (G6PD) (a relative contraindication)
• Renal insufficiency as evidenced by serum creatinine of ≥ 1.3 mg/dl or evidence of oxalosis by urinalysis.
• Chronic hemodialysis.
• Iron overload (a ferritin > 500 ng/ml).
• Wilson's disease.
• Compromised liver function with evidence of complete biliary obstruction or have a serum bilirubin of 2.0 or liver function tests (AST > 63, ALT > 95) exceeding 1.5 x the upper limit of normal.
• Pregnant or lactating female.
• Current tobacco use.
• Evidence of significant psychiatric disorder by history or examination that would prevent completion of the study or preclude informed consent.
• Aspirin use exceeding 325 mg per day.
• Acetaminophen use exceeding 2 g per day.
• Brain metastases that have not responded to therapy.