Pancreatic, gastric, and colorectal cancers have all been shown to overexpress the gastrin gene and to be sensitive to the trophic effects of the gastrin in animal models. The hypothesis of this study is that G17DT will elicit specific and high-affinity antibodies that will bind gastrin-17, thus preventing the trophic activity of cancer cells.

Inclusion Criteria:

• Histologically verified adenocarcinoma of the colon or rectum

• Recurrent/ metastatic disease not amenable to curative surgery and/or radiotherapy

• measurable/ evaluable lesions

• Life expectancy > 3 months

• Karnofsky index > 50% or WHO performance rating of 0-2

• Biochemical markers:

  • renal function < 25% above upper limit of normal range (creatinine, 140 imol/1 unless malignant involvement proven)
  • liver function < 25% above upper limit of normal range (bilirubin ~25 mcmol/1 unless malignant involvement proven)

• Haematological status:

  • haemoglobin, 11 g/ dl
  • WBC, 4 X 109/1
  • platelets, 100 x 109/l

• Written consent

Exclusion Criteria:

• Other concomitant malignant disease except treated basal cell carcinoma of the skin or cancer of the uterine cervix stage 0-1
• H 2 receptor antagonist or proton pump inhibitor therapy
• Previous gastric surgery (including vagotomy)
• Active uncontrolled infection
• Autoimmune disorders
• Anticancer treatment within the last three months unless progression of the disease occurred in the interim
• Women of child-bearing age
• Patient is a poor medical risk because of non-malignant systemic disease
• Previous radiotherapy to all measurable or evaluable lesions.