This proposed phase II trial will investigate weekly topotecan at a higher dose than was used in the previous trials in an attempt to achieve improved response rates and disease control without added toxicity. To help ameliorate the fatigue, planned rest weeks will be incorporated into the schedule. This trial will be the first clinical trial to evaluate a higher dose of weekly topotecan in the treatment of extensive-stage SCLC.

All patients will receive weekly topotecan.

Topotecan 6mg/m2 IV weekly x 6 consecutive weeks followed by a 2 week break. Cycles are repeated every 8 weeks, for 3 cycles. Restaging studies will be performed every cycle (or 8 weeks.)

Inclusion Criteria:

• Extensive small cell lung cancer with progression after one previous chemotherapy or chemotherapy/radiation therapy regimen
• Measurable or evaluable disease
• Able to perform activities of daily living with minimal assistance
• Adequate bone marrow, liver and kidney function
• May have received no more than 3 previous courses of radiation therapy
• Give written informed consent prior to study entry

Exclusion Criteria:

• Patients with limited stage disease
• History of a prior malignancy within three years
• Female patients who are pregnant or are breast feeding
• Significant history of uncontrolled cardiac disease
• Myocardial infarction or stroke within six months
• Symptomatic peripheral vascular disease
• CNS involvement
• Serious active infection or underlying medical condition