Placebo-Controlled Study of Perifosine + Single Agent Chemotherapy for Metastatic Cancer Patients

This is an exploratory phase 2, randomized placebo-controlled trial with stratification for disease and chemotherapy type. If there is any evidence of improved time to progression in any tumor type with any of the drugs to be evaluated, the initial study or component(s) of the study will be expanded to increase the certainty that this is an effect of perifosine. If there is compelling evidence of benefit from this study, a phase 3 trial will be conducted to obtain proof of principle. Primary Study Objectives: To determine the time to tumor progression when receiving single agent chemotherapy (capecitabine) in combination with perifosine in comparison to patients receiving single agent chemotherapy (capecitabine) alone (i.e., with placebo). Secondary Study Objectives: * To determine the toxicity of single agent chemotherapy in combination with perifosine. * To compare the time to progression of chemotherapy in combination with placebo to historical experience. * Overall survival will also be evaluated.