The goal of this study is to provide continuation therapy with TH-302 to patients with soft tissue sarcomas who obtained response or stabilization of disease with prior treatment on TH-CR-406/SARC021 protocol. After written informed consent has been obtained and eligibility has been established, patients will receive the study drug as part of the continuation study. Patients will receive treatment on study as long as they have clinical benefit and do not experience unacceptable toxicity.