After disappointing results achieved with older chemosensitivity tests such as the human
tumor clonogenic assay (
HTCA) during the 1980s, the last decade has seen a renaissance of the concept of individualized
chemotherapy in oncology, markedly stimulated by the development of newer nonclonogenic assays. These methods appear to be able to overcome major technical limitations associated with older assays, now allowing for successful testing of most of the
tumor specimens submitted. Currently, the
ATP-based
tumor chemosensitivity assay (
ATP-TCA) can be regarded as the most sophisticated assay to investigate both solid samples and effusions derived from patients with various organ
tumors. During the last 5 years, the
ATP-TCA has been used successfully to screen for novel
drug combinations for further clinical use in both ovarian and
breast cancer such as
mitoxantrone plus
paclitaxel (NT) and
treosulfan plus
gemcitabine (TG), respectively. Clinical trials that have been set up in heavily pretreated patients with recurrent ovarian or
breast cancer have convincingly confirmed the high activity of these combinations previously demonstrated in preclinical investigations using the
ATP-TCA. In a recent phase II trial performed in 59 patients with relapsed ovarian
carcinoma,
ATP-TCA-directed
therapy was able to triple the response rate and to double the survival time, compared with published empirical
chemotherapy regimes. Preliminary results with
ATP-TCA-directed
therapy in
breast cancer also evidenced promising response rates. These results have been confirmed by additional prospective clinical trials using other types of modern nonclonogenic assays. A phase III trial that is now actively recruiting patients with
platinum-refractory
ovarian cancer to verify the promising phase II studies will prove the further value of the
ATP-TCA as a predictor applicable in routine clinical oncology.