Purpose

THIS STUDY IS CURRENTLY RECRUITING PATIENTS WITH ALVEOLAR SOFT PART SARCOMA ONLY AND IS NO LONGER RECRUITING PATIENTS WITH SYNOVIAL SARCOMA OR LEIOMYOSARCOMA. This study evaluates the safety and efficacy of AL3818 (anlotinib) hydrochloride in the treatment of metastatic or advanced alveolar soft part sarcoma (ASPS), leiomyosarcoma (LMS), and synovial sarcoma (SS). All participants with ASPS will receive open-label AL3818. In participants with LMS or SS, AL3818 will be compared to IV dacarbazine. Two-thirds of the participants will receive AL3818, one-third of the participants will receive IV dacarbazine.