Etoposide single-agent chemotherapy for solid tumors

Relationship between diagnosis-specific activity of cytotoxic drugs in fresh human tumour cells ex vivo and in the clinic

The aim of this investigation was to evaluate the relationship between the disease-specific activity of cytotoxic drugs in the clinic and in fresh human tumour cells from patients, as detected by a non-clonogenic cytotoxicity assay. The activity of 18 different cytotoxic drugs in fresh human tumour cells ex vivo was analysed in up to 15 samples from each of 13 different diagnoses using the fluorometric microculture cytotoxicity assay (FMCA). For each drug and diagnosis, relative activity indices (RAIs) were calculated, defined as the fraction of samples within the diagnosis having a survival index (SI) less than the median SI for the drug in all tested samples. Clinical response rates for the drug in the same diagnoses were collected from published phase II trials and were compared with the RAIs using Spearman's rank correlation (Rho) and Pearson's correlation coefficient (R). Correlation coefficients could be calculated for 12 drugs. The coefficients varied between 0.02 and 0.92 (Rho) and between 0.07 and 0.91 (R), but for most drugs the correlation between RAI and clinical response rates was good, with Rho > 0.6 and R > 0.7. Weak correlations were observed for cyclophosphamide and vincristine (Rho = 0.32 and 0.16, respectively), which might be due to old clinical data, and for paclitaxel (Rho = 0.02), which perhaps could be explained by in vitro activity of the solvent, Cremophor EL. The 18 drugs were also categorised according to their suggested clinical use in solid or haematological tumours, and were then compared regarding the activity in solid compared with haematological tumours ex vivo, expressed as the ratio between the number of responders among solid and haematological tumours (S/H ratio). The mean ex vivo S/H ratios in the group of drugs registered for use in haematological tumours was only 0.09 and was significantly different (P = 0.05) from the mean S/H ratios for the drugs used in both haematological and solid tumours (0.31) and in solid tumours only (0.47). Furthermore, the FMCA could identify the 50% most and least sensitive diagnoses with respect to clinical phase II activity with 74% (78/106) correct classifications. The results indicate that the relative activity of cytotoxic drugs in different diagnoses may be detected by the FMCA. Thus, 'phase II trials ex vivo' using non-clonogenic cytotoxicity assays might be used to make clinical trials more effective by targeting trials to diagnoses in which a new agent is most likely to be active.

Case report of successful use of VP-16 in nasopharyngeal carcinoma

We report the use of VP-16 as a single agent for the treatment of nasopharyngeal carcinoma. Our patient, a 16-year-old Black Haitian male, had complete clinical and radiographic response to VP-16. The remission continued for 14 months. The patient experienced minimal toxicity. We believe that the good response, excellent compliance, and minimal toxicity experienced by our patient should encourage more trials of VP-16 as upfront therapy for patients with nasopharyngeal carcinoma.

Clinical trial of etoposide (VP-16) in children with recurrent malignant solid tumors. A phase II study from the Pediatric Oncology Group

Etoposide (VP-16), 150 mg/M2, given intravenously daily for 3 days every 3 weeks resulted in 3 complete responses and 6 partial responses in 154 patients with a spectrum of recurrent malignant solid tumors. There was evidence of disease control in an additional 37 patients (27 mixed responses and 10 stable disease). These responses occurred primarily in patients with Ewing's sarcoma, Hodgkin's disease, neuroblastoma and rhabdomyosarcoma. Most of the patients had every extensive prior therapy; however prior therapy with teniposide (VM-26), the congener of VP-16, did not seem to preclude responses to the latter drug. Myelosuppression was the principal form of toxicity. Neutropenia characterized by absolute neutrophil counts of 0.5 to 0.9 x 10(9)/L occurred in one-half of the patients, and thrombopenia with platelet counts of less than 25 to 49 x 10(9)/L in one-fourth. These results demonstrate a favorable therapeutic index for VP-16 in several recurrent childhood solid tumors, supporting its use as a component of primary therapy for these diseases.

Etoposide (VP-16-213) plus cis-diamminedichloroplatinum as salvage therapy in advanced epithelial ovarian cancer

Twenty-two patients with advanced epithelial ovarian cancer were treated with etoposide and cis-platinum. Each had failed one to three regimens of combination chemotherapy including cis-platinum-based combinations. Prior total cis-platinum doses ranged from 50 to 1600 mg/m2 with a median of 440 mg/m2. One of 18 evaluable patients had a complete response lasting 8 months, 1 had a partial response lasting 3 months, 8 had stable disease for a mean of 5.6 months, and 8 had progressive disease. The 4 unevaluable patients had undetectable clinical disease for a mean of 6.7 months. Bone marrow suppression was seen in 4 of 22 patients; two of whom had serious sequelae. The poor objective response rate (9.1%) seen with this combination in patients heavily pretreated with cis-platinum is similar to that seen for single agent etoposide in patients pretreated with alkylating agents. The difficulty of obtaining a good objective response in the face of prior cis-platinum-based combination chemotherapy failure is again verified.

Etoposide in prostatic cancer: experimental studies and phase II trial in patients with bidimensionally measurable disease

Etoposide, a semisynthetic derivative of podophyllotoxin, was evaluated concurrently in vitro against a human derived hormone-resistant cell line, PC-3, and in vivo in bidimensionally measurable hormone-resistant human prostatic cancer. In vitro, a dose-response relationship was observed, with 74% inhibition at 10 micrograms/ml (1 h incubation) and greater than 99% inhibition at 90 micrograms/ml, both in the range of clinically achievable concentrations. In vivo, 1 PR (5%, 95% confidence limits 0-12%) of 18+ months was observed in 20 adequately treated patients. The results confirm the limited role of etoposide in hormone-refractory disease and the need for new model systems for evaluation of potential chemotherapeutic compounds in this disease.

Phase II trial of VP-16-213 in advanced ovarian carcinoma

We have reevaluated the effectiveness of VP-16-213 in advanced ovarian carcinoma. Twenty-five patients with measurable disease were treated for 3 days every 2 weeks with an escalating dose of the oral preparation. Twenty-two percent of 23 evaluable patients responded including one complete response. The median duration of response was 20 weeks and median survival 32 weeks. Toxicity was mild. The response rate observed is relatively high in patients pretreated with cis-platinum. VP-16-213 deserves further study, especially in combination with cis-platinum.