In vitro pharmacological purging of human bone marrow is enhanced by the use of lonidamine.

Lonidamine (LND), previously reported as a useful antitumor substance in combination with physical or chemical agents, has been studied for its capacity in increasing pharmacological elimination in vitro of residual tumor cells from human bone marrow. Different drugs were tested in association with LND against mixtures of human bone marrow and a tumor cell line, clonogenic human leukemic blast progenitors, and normal human bone marrow precursors. The results demonstrated that LND increased the efficacy of anthracycline derivatives (Adriamycin, Mitoxantrone) both on the tumor cell line and on the leukemic blast progenitors, while VP-16 or ASTA-Z 7654 was not affected by the same substance. The toxicity on normal stem cells reflected that of each drug and was not modified by the addition of LND. While a consistent dose-dependent CFU-GM reduction was observed immediately after treatment with the different drugs, a complete recovery was reached after 7 and 14 days of long-term marrow cultures. Because of the low toxicity and the efficacy demonstrated in association with certain agents in increasing tumor cell elimination in vitro, LND could play an important role in in vitro purging prior to autologous bone marrow transplantation.