Phase I clinical trial of an MAF-containing lymphoblastoid cell line supernatant

A preliminary Phase I evaluation of macrophage activating factor (MAF) derived from the partially purified supernatant of human RPMI-1788 lymphoblastoid cell line was performed in 4 parts in 39 patients with advanced cancer. The first two parts used subcutaneous routes of administration and the second two parts used a 4-h intravenous infusion method. Individual doses ranged from 0.1 ml (1.7 mg protein) to 100 ml (1,700 mg protein). Subcutaneous dose was limited by the volume of administered material, and an attempt to use a concentrate of the supernatant resulted in severe local skin reactions. Larger doses given intravenously were well tolerated. Resultant toxicity was mild and consisted of transient fever and chills. One patient with malignant melanoma had a complete response of a 3-cm skin metastasis; one patient with breast cancer had disappearance of a skin nodule while visceral disease progressed; and one patient with histiocytic lymphoma had resolution of a conjunctival lesion. Treatment in many patients was associated with an increase in absolute peripheral lymphocytes. In the high-dose intravenous group, a statistically significant increase in the phagocytic index of peripheral blood leukocytes was noted. Lymphoblastoid MAF appears to be relatively safe to administer and has promise both as an antitumor agent and in the treatment of other altered immune conditions.