A phase I study to assess the safety, pharmacokinetics (PK), pharmacodynamics (PD) and antitumor activities of BAL101553, a novel tumor checkpoint controller (TCC), administered as 48-hour infusion in adult patients with advanced solid tumors.

Abstract

TPS2602 Background: BAL101553 (prodrug of BAL27862), is a novel TCC that promotes tumor cell death by modulating the spindle assembly checkpoint. BAL27862 has shown potent antitumor activity in diverse preclinical tumor models, including models refractory to standard therapies. In a completed Phase 1 study using 2-h IV infusions (Days 1, 8, 15, q28d, NCT01397929 , CDI-CS-001, Lopez et al. JCO 34, 2016 suppl; 2525) dose-limiting vascular effects were observed and appeared Cmax related. The recommended Phase 2 dose for 2-h IV BAL101553 is 30 mg/m2. Vascular toxicity was not observed in an ongoing study with oral BAL101553 (NCT02490800, CDI-CS-002) at daily doses up to 30 mg (QD). Preclinical data suggest that antiproliferative effects of BAL101553/27862 are driven by exposure (AUC); thus vascular toxicity and antitumor activity are mediated by different PK drivers. BAL27862 has a half-life of ~15 h. Based on PK-modeling, extending the infusion from 2 h to 48 h was expected to result in ~4-fold higher AUC at a given Cmaxlevel and thereby improve the therapeutic window. Methods: This is an ongoing multicenter, open-label, Phase 1 dose-escalation study (NCT02895360, CDI-CS-003/SAKK67/15) using a 3+3 design to determine the MTD, characterize dose-limiting toxicities and assess the PK, PD and antitumor activities of 48-h infusions of BAL101553 in consecutive 28-day cycles at a starting dose of 30 mg/m2 administered on Day 1, 8 and 15 (q28d). The dose escalation scheme foresees up to ~ 50% dose increments depending on observed toxicities. During cycle 2, patients receive 7 days oral (QD) BAL101553 (Day 15–21) instead of the weekly IV infusion to assess absolute oral bioavailability. Patients with histologically-confirmed advanced or recurrent solid tumors are eligible for enrollment. Adverse events are assessed using CTCAEv4; tumor response by RECIST 1.1 (every 2 cycles). PD assessments include optional tumor biopsies and circulating tumor cells. PK profiles are assessed during the first 2 cycles. Two dose cohorts (30 and 45 mg/m2) have completed without DLTs or signs of vascular toxicity. Clinical trial information: NCT02895360.