Can high dose, intravenous Vitamin C prolong life for patients with metastatic prostate cancer?

Prostate cancer is the most common cancer (excluding skin cancer) in men in Denmark and the Unites States. When metastatic disease is present cure is no longer possible. The main treatment at this stage is castration, either surgical or medical, ending the patients testosterone production and causing a temporary regression in disease activity.

Eventually, the cancer will progress, usually within 2 years from the castration, with a more aggressive course and a survival of 2-3 years.

The current treatment option for the patients, who have undergone castration and have disease progression, is chemotherapy with only limited gains in quality of life and survival.

This clinical study is a phase 2 study to evaluate the effects of high dose intravenous vitamin c in subjects with early castration resistant prostate cancer.

Primary endpoint:

• Prostate specific antigen (PSA) changes after 12 to 20 weekly vitamin c infusions

Secondary endpoints:

• Bone metastases changes after 12 to 20 weekly vitamin c infusions
• Changes in bone specific alkaline phosphates, oxidative DNA-damage, PINP, NTX after 12 to 20 weekly vitamin c infusions
• RNA-expression changes in prostatic tumor tissue after 12 to 20 weekly vitamin c infusions
• RNA-expression changes in lymphocytes after 12 to 20 weekly vitamin c infusions

Tertiary endpoints:

• Pharmacokinetics of vitamin c in the elderly cancer patients

Methods and material:

• 80 subjects are included (efficacy evaluation when 20 subjects have been evaluated for extension arm)
• Each subject receives a weekly infusion of 60 grams vitamin c (in the form of ascorbate) for 12 to 20 weeks

Vitamin C for palliative treatment:

Intravenous vitamin C has been used since the 1970's for terminally ill cancer patients claiming big increases in survival time. The efficacy of the drug is questioned and no randomized, controlled trial of Vitamin C's efficacy on cancer patients survival has been made.

Recent results from in vitro and xenograft studies in mice has shown some promise for vitamin c as a cytotoxic agent against cancer cells.

The following parameters are recorded for baseline:

• Biomarkers (PSA, bALP, NTX, PINP)
• Routine blood work (hgb, creatinine, p-vitamin c etc.)
• Radio nucleotide bone scintigraphy
• Prostate biopsies for later microarray (Affymetrix ST1.0)
• Urine samples 8-oxo-guanine(for oxidative DNA-damage measurements)

These parameters are repeated after treatment, usually after 12 to 26 weeks after the first vitamin c infusion.

Inclusion Criteria:

• Castration resistant metastatic prostate cancer (bony or visceral metastases)
• Gleason sum > 6
• PSA > 10 ng/ml
• ECOG < 3
• Prior orchidectomy or LHRH antagonist/agonist treatment
• Must give informed content

Exclusion Criteria:

• Synchronous active cancer (skin cancer excluded)
• Prior chemotherapy
• History of oxalate renal stones
• Glucose-6-phosphate dehydrogenase deficiency
• Impaired renal function (creatinine > 200micromoles/L
• Haemochromatosis
• Cardiac disease (NYHA > 2, CSS > 2, recent AMI (less than 6 months)
• Recent major surgery (less than 4 weeks before inclusion and more than 2 days of admittance time)
• Prior intended curative treatment of prostate cancer