LITESPARK-004 (MK-6482-004) phase 2 study of belzutifan, an oral hypoxia-inducible factor 2α inhibitor (HIF-2α), for von Hippel-Lindau (VHL) disease: Upd... Antitumor activity observed in the ongoing open-label phase 2 study, LITESPARK-004 (NCT03401788), led to the approval of ...