Directly relevant laboratory or animal data concerning the anticancer potential of the Gonzalez regimen are limited. Published animal studies focus on the role of pancreatic enzymes in cancer treatment rather than the regimen as a whole.
An animal study published in 1999 measured the ability of orally administered porcine pancreas preparation (PPP) to slow or halt the growth of cancer and to inhibit metastasis. Sixty Fischer F344 female rats were divided into five groups of 12 each. All groups were fed the same basic diet. After 5 days, R13762 transplantable rat mammary tumor was implanted into a mammary fat pad on each rat. The animals were maintained on their assigned diets for another 40 days. After the tumors had taken hold, two groups were given a high dose of PPP (20% by weight) and two groups were given a lower dose (2% by weight). The fifth group was used as a control and received no enzymes. In addition, one group from each of the PPP-dosed rat groups was also given a magnesium citrate supplement because magnesium is often given with PPP in clinical practice.
Results showed that PPP had no effect on tumor growth, and PPP alone did not show any significant effect on the amount of metastases. However, when the rate of metastases in the rats dosed at the 20% rate was compared with those dosed at 2%, it was noted that there was an increase in metastases in the rats given a higher dose of PPP. The lowest rate of metastases was seen in the rats given the 2% dose plus magnesium citrate.
In another study, the effects of porcine pancreatic enzyme (PPE) extracts on survival and tumor growth were examined in 5- to 6-week-old male beige X-linked immunodeficient mice. In the survival study, two groups of mice received pancreatic cancer cells AsPc1 injected into their pancreas. The treatment group (14 mice) received PPE in water at a dose of 400 mg/kg of body weight, which corresponds to the dose used in patients receiving the Gonzalez regimen. The control group (13 mice) was given only water. After death, the pancreas was removed and measured for volume and weight. The median survival rates for the treatment group and the control group were 43.5 days and 35 days, respectively. At day 35, the survival rates were 79% in the treatment group and 38% in the control group. In addition, the control mice showed reduced activity as compared with the treatment group, which showed normal activity and no signs of disease. In general, the size of tumors and the rate of invasion in the liver and peritoneum correlated with length of survival time.