Phase I-II trials of poly IC stabilized with poly-L-lysine

Poly IC, stabilized with poly-L-lysine and carboxymethyl cellulose (poly ICLC), resists hydrolysis by primate serum (unlike the parent compound), induces high levels of serum interferon, and is effective in acute viral infections of subhuman primates. In a phase I-II clinical trial, poly ICLC was given iv in 15 daily doses of 0.5-27.0 mg/m2 to 19 patients with various solid tumors and to six patients with acute leukemia (1-65 years of age). At least three complete trials were conducted at each of six dose levels. Toxic reactions included fever (in 100% of trials), nausea (44%) hypotension (28%), thrombocytopenia and leukopenia (68%), erythema (12%), and polyarthralgia plus myalgia (16%). Hypotension and arthralgia-myalgia were related to dose level and/or magnitude of interferon induction, but other toxic manifestations were not. Poly ICLC induced significant serum interferon levels in 76% of trials, and the correlation between dose and peak interferon titer was linear. The maximum tolerated dose for all patients at a given drug dose was 12 mg/m2; at this dose, the mean peak interferon titer was 1940 reference units/ml. At a dose of 18 mg/m2, the mean peak interferon titer was 4473 reference units/ml, but severe myalgia and arthralgia were intolerable in at least half of the patients, and most had significant hypotension. At a dose of 27 mg/m2, one patient had acute renal failure. At high doses, iv poly ICLC also induced interferon in the cerebrospinal fluid.