Phase 1/2a study of once daily oral BAL101553, a novel tumor checkpoint controller (TCC), in adult patients with progressive or recurrent glioblastoma (GBM) or high-grade glioma.

Abstract

2025 Background: BAL101553 (prodrug of BAL27862) is a novel TCC that promotes tumor cell death by modulating the spindle assembly checkpoint. BAL27862 is a lipophilic, small molecule shown in rodents to penetrate the brain (brain/plasma ratio around unity), with promising antitumor activity in orthotopic preclinical GBM models as monotherapy or in combination with radiotherapy (RT) with or without temozolomide. In this ongoing study (NCT02490800, CDI-CS-002), daily oral BAL101553 was initially examined in solid-tumor patients, with an MTD of 16 mg/d and DLTs of G4 hyponatremia and G2 hallucinations (Lopez 2018, JCO 36, 2018, suppl. A2530). Subsequently the study was expanded by including a separate cohort of patients with progressive or recurrent GBM or high-grade glioma (Ingles Garces 2017, JCO 35, 2018, suppl. TPS2601). Methods: Patients with histologically-confirmed GBM or high-grade glioma, with progressive or recurrent disease after prior RT with/without chemotherapy, received once-daily oral BAL101553 (28-day cycles) in a 3+3 dose-escalation design to determine the maximum tolerated dose (MTD). Adverse events were assessed by CTCAE v4.03 grade (G), and tumor response by RANO every two cycles. Pharmacokinetics (PK) were evaluated on Day 1 of Cycles 1 and 2. Results: In the ongoing study, 23 pts (13M/10F; median age 50 y), median (min–max) number of prior regimens = 2 (1–5), received doses of 8, 15, 20, 25 or 30 mg oral BAL101553 once daily. One DLT of reversible G2 depression and fatigue occurred at 20 mg. Both mean Cmax and AUC increased with dose between 8 and 30 mg. The PK exposure in GBM patients was lower than for solid tumor patients, in particular at 20 and 25 mg. At 25 mg/d (n = 3), one patient with IDH-mutated GBM had a partial response (63% area reduction per RANO) and continues on study > 8 months, and another patient had stable disease for 5 months. At 15–20 mg/d, stable disease was observed in 3/10 patients. Conclusions: The current data in patients with GBM or high-grade glioma suggest that BAL101553 is well tolerated at dose levels above the MTD established in patients with advanced solid tumors, and shows indications of clinical activity. Clinical trial information: 02490800.