In vitro phase II trial of recombinant interferon alpha-2 in gastrointestinal cancer

The antitumor effects of recombinant interferon alpha-2 (rIF) on clonogenic tumor cells were investigated in 29 cases of gastrointestinal cancer. An in vitro response (greater than or equal to 50% inhibition of tumor colony-forming units) was observed in 17% of the tumors, including 2 of 8 pancreatic, 2 of 6 gastric, and 1 of 10 colon cancer specimens. The relative efficacy of rIF in tissue cultures of pancreatic and gastric tumors was further substantiated by the resistance against simultaneously tested single conventional cytostatic drugs. Preliminary results of comparative studies of cloned interferon alpha-2 and human purified leukocyte interferon (hlIF) in 2 human colon cancer cell lines and 11 fresh tumor specimens suggest similar trends in terms of colony inhibition in individual assays. However, the interpatient differences indicate an overall superiority of the natural preparation (P less than 0.02).