As mentioned earlier, a weekly regimen of topotecan has allowed for more convenient administration over more prolonged and more complex administration schedules. The current study will evaluate the tolerability of a weekly intravenous schedule of topotecan in combination with a standard dose of pegylated liposomal doxorubicin in advanced solid tumors. Due to the addition of the pegylated liposomal doxorubicin to a weekly schedule of topotecan, Pharmacokinetics data will also be obtained.