Tumor necrosis factor-alpha (TNF alpha) enhances cisplatin cytotoxicity to ovarian carcinoma xenografts.

Antitumor effect was compared between administration schedule of once a day dosing of cisplatin (DDP) for 2 consecutive days (q40d) with or without TNF alpha. In two controls, TNF alpha or dilutor alone was administered. Against the ovarian carcinoma 2008 cells, DDP given at dose level of daily x 2 (3.5 mg/kg/day q40d) combined with TNF alpha (50 mu g/kg/day) schedule showed 6.08-fold tumor growth delay (TGD) (17.10+/-1.65; P<0.01), produced 3.17-fold greater cell kill [ratio of tumor volume of treated and control groups (T:C)=0.148; P<0.01] and resulted in longer survival [median survival (MS)=166; P<0.01] than DDP alone. These are superior to even high dose DDP (7.0 mg/kg/day x 2d) without TNF alpha administration schedule showing TGD=11.38 days T:C=0.271 and MS=97 days. High dose DDP (7.0 mg/kg/day q40d) with TNF alpha showed further DDP antitumor potency (TGD=29.74+/-2.08, P<0.01), however, this schedule showed only 2.56-fold TGD extension and no improvement was found in survival because of its severe toxicity. TNF alpha did not alter DDP induced systemic toxicity. These data indicate that optimal antitumor activity, tolerance and survival improvement occured on a schedule of low dose DDP combined with TNF alpha, and this has prompted the clinical evaluation of this administration schedule.