Prevention and suppression of experimental allergic encephalomyelitis by an orally active leukocyte recruitment inhibitor, NPC 16570.

An orally active leukocyte recruitment inhibitor, NPC 16570 (N-[9H-fluoren-9-ylethoxycarbonyl]-4-aminobenzoic acid), was evaluated in experimental allergic encephalomyelitis (EAE) in rats. The mean time of disease onset in control animals was 12 +/- 1 days, with peak average clinical scores of 2.5 +/- 0.2, accompanied by perivascular infiltration of inflammatory cells into the CNS. Daily administration (p.o.) of NPC 16570 reduced the clinical severity (by 70%) at 10 and 30 mg/kg, and at 100 mg/kg, no clinical symptoms were detected. When NPC 16570 (100 mg/kg) treatment was initiated 7 days after EAE induction, the severity (75% inhibition) and duration of the disease were attenuated; 2 out of 6 animals showed no overt clinical symptoms and perivascular cell infiltration was prevented, suggesting potential utility in autoimmune diseases.