[In vitro predictive activity assay of agents based on dynamic cellular morphological findings--clinical application]

The antitumor activity and mode of action of antitumor agents were assayed by a new method which takes a relatively short time for evaluation. The method was clinically applied to patients with malignant lymphoma or acute leukemia for estimating drug sensitivity. Fresh malignant cells were obtained from patients' bone marrow, lymph nodes, or peripheral blood using Lymphoprep methods in 26 patients with these malignant disorders. Each sample (5 X 10(5) cells/ml) was cultured in the medium with RPMI 1640 supplemented with 10% of FCS and 20% of patients' own sera containing every antitumor agent at predetermined concentrations for 30 minutes. Each sample was again cultured for another 72 hours at 37 degrees C in a 5% CO2 humidified atmosphere after rinsing. Microscopic observation was periodically carried out using a specially devised observation chamber with an inverted immersion microscope for 72 hours. Morphological changes of 200 to 300 cells of each sample were described according to morphological criteria. Of these, irreversible changes in number were considered to be indicative of antitumor activity of the agent tested. More than 50% cellular damage was categorized as effective and more than to 50% reduction of leukemia cells or decrease in size of lymph nodes the same degree in malignant lymphoma were considered to be clinically effective. Forty-four assay runs in 26 patients were done, and on 31 occasions were shown to be coincident. We conclude that this in vitro method is fully applicable for predicting the effectiveness of an agent to be clinically administered regardless of the various controversial problems to be solved.