Restorative activity of muroctasin on leukopenia associated with anticancer treatment.

The restorative effect of N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys(L18), muroctasin), a muramyl dipeptide derivative, was studied in patients with leukopenia associated with anticancer chemotherapy and radiation therapy. The drug was subcutaneously administered to 102 cancer patients in a single doses of 200 or 400 micrograms, and each dosage was given either every day for 6 days or every other day over a 5-day period. White blood cell (WBC) counts were made before, during and after treatment. MDP-Lys(L18) was most effective in patients receiving the drug every day and the 400 micrograms dose was somewhat superior to the 200 micrograms dose in augmenting the WBC population. Overall, the response to MDP-Lys(L18), in terms of the increase in number of WBCs, was good to excellent in 41.6% of patients. MDP-Lys(L18) was considerably more effective in patients with solid tumors than in those with hematological malignancies. The most common side effect was fever, which was dose-dependent, more pronounced with alternate-day dosing, and generally well controlled with antipyretics. The results of this study indicate that MDP-Lys(L18) is useful in improving the WBC count in leukopenic cancer patients treated with anticancer therapy. Considering the efficacy and side effect profiles together, it is suggested that 200 micrograms/day for 6 consecutive days is the optimal treatment regimen.