A phase I study of 3-day topotecan and cisplatin in elderly patients with small-cell lung cancer

A phase II study of topotecan and cisplatin with sequential thoracic radiotherapy in elderly patients with small-cell lung cancer: Okayama Lung Cancer Study Group 0102

PURPOSE

The treatment outcome in elderly patients with limited-disease small-cell lung cancer (LD-SCLC) remains poor. We carried out a phase II trial of split topotecan and cisplatin (TP) therapy and sequential thoracic radiotherapy for elderly LD-SCLC patients as a follow-up to our previous phase I trial.

METHODS

In total, 30 patients aged 76 years or older, with untreated LD-SCLC were enrolled. Four courses of topotecan (1.0 mg/m(2), days 1-3) and cisplatin (20 mg/m(2), days 1-3) were administered, followed by thoracic radiotherapy (1.8 Gy/day, total of 45 Gy). The primary end point was the overall response rate (ORR).

RESULTS

The trial was terminated early with 22 patients because of slow accrual. Their median age was 79 years. The median number of courses of chemotherapy administered was three, and the actual completion rate of the entire treatment course was 41 %. The ORR was 68 % with a 95 % confidence interval of 47-89 % (15/22 cases). The median progression-free survival and overall survival were 9.1 and 22.2 months, respectively. The main toxicity was myelosuppression, with grades 3-4 neutropenia (96 %), thrombocytopenia (50 %), and febrile neutropenia (32 %).

CONCLUSIONS

This regimen produced a favorable survival outcome, despite moderate-to-severe toxicity profiles. Further efforts are necessary to define an optimal regimen for elderly patients with limited SCLC.

Recent advances with topotecan in the treatment of lung cancer

Topotecan is a semisynthetic derivative of camptothecin that specifically targets topoisomerase I. It has well-established antineoplastic properties and has been successfully combined with other antineoplastic agents with activity dependent on DNA disruption, such as cisplatin and etoposide. Topotecan is indicated for the treatment of small cell lung cancer (SCLC) sensitive disease after failure of first-line chemotherapy and metastatic ovarian carcinoma after failure of initial or subsequent chemotherapy. Since the approval of topotecan for the second-line treatment of SCLC, studies have been conducted in the first-line setting. Recent studies demonstrate the utility of i.v. topotecan in combination with cisplatin for untreated SCLC. Further, an oral formulation of topotecan is currently under investigation and may provide added convenience for patients. Oral topotecan has been studied in the first- and second-line settings for both SCLC and non-small cell lung cancer (NSCLC). Three recent phase III trials have demonstrated the activity of oral topotecan. In the first study of chemotherapy-naïve patients with extensive-disease SCLC, oral topotecan plus cisplatin provided efficacy and safety similar to those of etoposide plus cisplatin. In a second study of patients with relapsed SCLC, treatment with oral topotecan showed a statistically significant and clinically meaningful longer overall survival time and improvement in dyspnea and quality of life compared with best supportive care alone in all prognostic groups. Finally, in previously treated patients with NSCLC, single-agent oral topotecan was shown to be noninferior in 1-year survival rate relative to the current standard of i.v. docetaxel. In future studies, oral topotecan will represent a good candidate for combination therapy with other i.v. or oral chemotherapy agents, monoclonal antibodies, and small molecule tyrosine kinase inhibitors.

Topotecan in the management of cervical cancer

Topotecan, a semisynthetic camptothecin, exerts its cytotoxic effect through inhibition of DNA topoisomerase I. Single-agent topotecan has demonstrated activity against persistent, metastatic and recurrent cancer of the uterine cervix. When combined with cisplatin in Phase II trials, further improved response rates have been reported. The cisplatin/topotecan doublet subsequently proved to be the first regimen in a series of multiple Phase III studies to demonstrate improved disease-free and overall survival in this setting compared with cisplatin alone, thus leading to its third indication by both the US FDA and the European Medicines Agency in 2006. This survival advantage was achieved at the expense of an increase in grade 3-4 hematologic toxicity; however, there was no difference in patient-reported quality of life between the cisplatin/topotecan doublet and single-agent cisplatin. This article reviews the pharmacology of topotecan and its evolution as an active agent in advanced and metastatic cervical cancer that is not amenable to cure with surgery or radiotherapy.