A phase I/II trial of oxidized autologous tumor vaccines during the watch and wait phase of chronic lymphocytic leukemia

Based on their activity in patients with advanced stage chronic lymphocytic leukemia (CLL), a phase I/II study was designed to evaluate the feasibility, safety, and efficacy of autologous vaccines made from oxidized tumor cells in patients with earlier stage CLL, and to determine an optimal schedule of injections. Eighteen patients (at risk for disease progression and with white blood cell counts between 15 and 100 x 10(6) cells/ml) were injected intramuscularly with 10 ml of oxidized autologous blood (composed mainly of CLL cells) either 12 times over 6 weeks (group 1), 12 times over 16 days (group 2), or 4 times over 6 weeks (group 3). Fourteen out of eighteen patients had Rai stage 0-II disease, while 4/18 had stage III-IV disease but did not require conventional treatment. Partial clinical responses, associated with enhanced anti-tumor T cell activity in vitro, were observed in 5/18 patients of whom three were in group 2. Stable disease was observed in six patients while disease progression appeared not to be affected in the remaining patients. Toxicity was minimal. Vaccination with oxidized autologous tumor cells appears worthy of further investigation and may be a potential alternative to a "watch and wait" strategy for selected CLL patients.