A phase II combination trial with recombinant human tumor necrosis factor and gamma interferon in patients with colorectal cancer.

Recombinant human tumor necrosis factor (TNF) is a cytotoxic monokine with immunomodulatory functions. Gamma interferon (g-IFN) synergizes with TNF in many ways. We therefore conducted a Phase I/II combination trial with TNF and g-IFN at an immunomodulatory dose level in 16 patients with colorectal cancer. TNF (50 micrograms/m2 in a 30 min infusion) and g-IFN (100 micrograms in subcutaneous injections) were administered daily Monday through Friday for 4 weeks. Two cases of major toxicity, one acute renal failure and one case of severe thrombocytopenia, led to discontinuation of study medication in these patients. Toxicities in remaining patients were manageable with conservative treatment. Changes in laboratory values included leukopenia, anemia and thrombocytopenia. Alterations in lipid metabolism and changes in serum levels of acute phase proteins were observed. Increase in both total lymphocytes and a Leu 11 positive subpopulation, as well as an induction of measurable interleukin 2 serum levels in a subgroup of patients, were noted. Response results of 14 evaluable patients were one patient with a mixed response, 4 with stable disease and 9 with disease progression. Median survival was 23.5 weeks with only one patient alive after 71 weeks. Therefore the drug combination of TNF/g-IFN in the chosen regimen cannot be recommended for the treatment of patients with colorectal cancer.