Phase II trial of a complex polyriboinosinic-polyribocytidylic acid with poly-L-lysine and carboxymethyl cellulose in the treatment of children with acute leukemia and neuroblastoma: a report from the Children's Cancer Study Group.

Therapeutic efficacy and toxicity were evaluated in 28 children with acute lymphoblastic leukemia, in ten with acute nonlymphoblastic leukemia (ANLL), and in 13 with metastatic neuroblastoma. All were refractory to standard chemotherapeutic agents and 25 were refractory to an investigational drug. The initial dose was 12 mg/m2/day and was based on an established maximal dose tolerated in adults. This dose was found to be intolerable in 5 of 5 children with leukemia. Similarly an initial dose of 9 mg/m2/day was intolerable in 4 of 5 patients with leukemia. The starting dose in the next 28 children with leukemia or neuroblastoma was 3 mg/m2. This drug was gradually increased to the highest tolerated dose by 3-mg/m2 increments. Fifteen children with acute lymphoblastic leukemia, 3 children with ANLL, and 2 children with neuroblastoma received the drug daily. Seven patients with ANLL and 7 patients with neuroblastoma received the drug biweekly. Seventeen patients with acute lymphoblastic leukemia, 6 patients with ANLL, and 5 patients with neuroblastoma had an adequate trial of the drug. An adequate trial was defined as a minimum of 5 weeks of therapy unless progressive disease developed. Side effects of the drug were striking and included fever, hypotension, myalgia, bone pain, arthralgia, arthritis, abdominal pain, liver toxicity, thrombocytopenia, and neurotoxicity. No complete remission occurred although interferon levels above 100 units/ml were induced in nearly 50% of the patients.