BAY-8002 is an orally available, potent and selective inhibitor of lactate transporter MCT1 (monocarboxylate transporter 1; SLC16A1) that potently inhibits bidirectional lactate transport. BAY-8002 exhibits antiproliferative activity in numerous cancer cell lines. BAY-8002 induces accumulation of lactate and significantly inhibits tumor growth in mice model. It does not cause tumor regression.