Clinical Study on the Safety and Tolerability of Macitentan in Combination With Dose-dense Temozolomide in Patients With Recurrent Glioblastoma

This is an open-label, single arm, Phase 1 study to assess the safety and tolerability of macitentan in combination with dose-dense temozolomide in adult patients with recurrent glioblastoma or gliosarcoma. The study is composed of three parts. A Phase 1 Dose Escalation Period with a traditional 3+3 design will determine the maximum tolerated dose of macitentan in combination with dose-dense temozolomide. A Phase 1b Period will expand the safety and tolerability data of two doses of macitentan and dose-dense temozolomide selected from the Dose Escalation Period and explore efficacy. An Ancillary Study will further evaluate the effects of macitentan on biomarkers in brain tumor tissue. The study is planned to have a minimum duration of 12 months. The study will end when all patients (excluding those prematurely withdrawn or lost to follow-up) in each part of the study have completed a visit at month 12 and 30 days of safety follow-up.