Phase II trial of paclitaxel shows antitumor activity in patients with previously treated germ cell tumors

A trial of paclitaxel was conducted in patients with previously treated germ cell tumors (GCT). As the identification of new agents in GCT may be compromised by restricting entry criteria to heavily pretreated patients, an alternative trial design was used in which eligibility was restricted to patients with limited prior therapy.

Patients were eligible if their prior therapy was limited to one cisplatin-based regimen or < or = six cycles of prior cisplatin-based therapy. Paclitaxel 250 mg/m2 was administered by continuous infusion over 24 hours every 21 days. The dose of paclitaxel was modified for each patient based on toxicity. Granulocyte colony-stimulating factor (G-CSF) 5 micrograms/kg/d was administered during nadir periods.

Thirty-one patients were treated; eight patients (26%) achieved a partial (n = 5) or a complete (n = 3) response. Responses were achieved in patients who had failed to respond to treatment with cisplatin, ifosfamide, and etoposide, and in patients with poor prognostic features, ie, mediastinal primary tumor site and patients with a best prior response of an incomplete response to cisplatin therapy. One complete responder remains continuously free of disease at 13+ months and one of the five patients who achieved a partial response remains progression-free at 14+ months.

Paclitaxel has antitumor activity in GCT and warrants continued study in combination chemotherapy. Phase I/II trials will address its role in combination with cisplatin and ifosfamide and as a part of dose-intensive therapy. Furthermore, the study showed that a trial design in which eligibility criteria limits prior therapy was feasible, resulted in the identification of antitumor activity in a new agent, and may be considered in future trials for other promising new agents in GCT.