12-O-TETRADECANOYLPHORBOL-13-ACETATE (TPA)-INDUCED INCREASE IN DEPRESSED WHITE BLOOD-CELL COUNTS IN PATIENTS TREATED WITH CYTOTOXIC CANCER CHEMOTHERAPEUTIC DRUGS

Fifty-two patients with solid tumors had depressed white blood cell an d neutrophil counts because of prior treatment with cytotoxic cancer c hemotherapeutic drugs. These patients were given one or more i.v, infu sions of 0.125-0.25 mg of 12-O-tetradecanoylphorbol-13-acetate (TPA), and this treatment increased the low white blood cell and neutrophil c ounts toward the normal range. The average white blood cell and neutro phil counts were 2.55 x 10(9)/liter and 1.76 x 10(9)/liter, respective ly, before treatment with TPA. After one or more i.v, infusions of TPA , the white blood cell and neutrophil counts increased to peak values of 5.92 x 10(9)/liter and 4.76 x 10(9)/liter, respectively, within a f ew days. Most patients had increased levels of white blood cells and n eutrophils by 24 hr after a single i,v. infusion of 0.25 mg TPA, Eleva ted levels were observed for at least 3 days. This study demonstrates that treatment with parenteral TPA is feasible with useful biological activity. Only mild and reversible side effects were observed.