Intraperitoneal recombinant alpha 2-interferon for 'salvage' immunotherapy in persistent epithelial ovarian cancer

Fourteen patients with epithelial ovarian cancer were treated with intraperitoneal (i.p.) administration of alpha-recombinant interferon (rIFN-alpha 2) after documentation of persistent disease at second-look laparotomy and combination chemotherapy. After therapy, 11 patients had a surgical re-evaluation which confirmed 4 complete responses (36%), 1 partial response (9%), and disease progression in 6 (55%). Five of 7 patients (71%) with minimal residual disease (MRD, i.e. less than 5 mm) had a surgically-documented response, whereas there was none in the 4 patients whose tumors were greater than or equal to 5 mm. Fever greater than or equal to 38 degrees C was seen in 58%, greater than or equal to 39.0 degrees C in 18%; nausea and vomiting in 37%, and abdominal pain in 22%. There was no consistent alteration in peripheral WBC's during treatment, while i.p. monocytes and lymphocytes showed a significant boost on day 1 after each dose of rIFN-alpha 2. Natural killer (NK) lymphocyte cytotoxicity was elevated in the i.p. cavity fluid obtained from most patients on day 1 after treatment, while blood NK values showed considerable variability. Pharmacokinetic studies showed i.p. levels of rIFN-alpha 2 were 30-1000 times blood levels. I.p. rIFN-alpha 2 may act by increasing concentrations of drug and augmenting regional host cells in patients with MRD ovarian cancer.