A Phase 1b/2, Open-Label, Dose Escalation and Expansion Study Evaluating the Safety and Efficacy of Entospletinib (GS-9973) With Vincristine and Dexamethasone in Adult Subjects With Relapsed or Refractory Acute Lymphoblastic Leukemia (ALL)

Monotherapy Lead-In (Day -7 to Day -1): Entospletinib (ENTO) 200 mg tablet orally twice daily as a single agent. Induction (two 28-day cycles): ENTO 200 mg twice daily continuously in combination with vincristine (VCR) 0.5 mg intravenously (IV) on Days 1, 8, 15, and 22 of each cycle; dexamethasone (DEX) 20 mg twice daily orally on Days 8-11 and Days 22-25 (Cycle 1) and on Days 1-4 and Days 15-18 (Cycle 2); and central nervous system (CNS) prophylaxis per institutional standards on Day 28 of each cycle. Maintenance (up to 36, 28-day cycles): Participants who achieved a complete remission (CR) received stem cell transplant (SCT) (if eligible) per investigator's discretion; others who obtained clinical benefit (ie, at least a partial response \[PR\]) after induction were offered maintenance therapy with ENTO 200 mg twice daily continuously in combination with VCR 0.5 mg on Day 1 of each cycle and DEX (20 mg daily or 10 mg twice daily) on Days 1-4 and Days 15-18 of each cycle.

Monotherapy Lead-In (Day -7 to Day -1): ENTO 400 mg tablet orally twice daily as a single agent. Induction (two 28-day cycles): ENTO 400 mg twice daily continuously in combination with VCR 0.5 mg IV on Days 1, 8, 15, and 22 of each cycle; DEX 20 mg twice daily orally on Days 8-11 and Days 22-25 (Cycle 1) and on Days 1-4 and Days 15-18 (Cycle 2); and CNS prophylaxis per institutional standards on Day 28 of each cycle. Maintenance (up to 36, 28-day cycles): Participants who achieved a CR received SCT (if eligible) per investigator's discretion; others who obtained clinical benefit (ie, at least a PR) after induction were offered maintenance therapy with ENTO 400 mg twice daily continuously in combination with VCR 0.5 mg on Day 1 of each cycle and DEX (20 mg daily or 10 mg twice daily) on Days 1-4 and Days 15-18 of each cycle.

Monotherapy Lead-In (Day -7 to Day -1): ENTO 400 mg tablet orally twice daily as a single agent. Induction (two 28-day cycles): ENTO 400 mg twice daily continuously in combination with VCR 1.0 mg IV on Days 1, 8, 15, and 22 of each cycle; DEX 20 mg twice daily orally on Days 8-11 and Days 22-25 (Cycle 1) and on Days 1-4 and Days 15-18 (Cycle 2); and CNS prophylaxis per institutional standards on Day 28 of each cycle. Maintenance (up to 36, 28-day cycles): Participants who achieved a CR received SCT (if eligible) per investigator's discretion; others who obtained clinical benefit (ie, at least a PR) after induction were offered maintenance therapy with ENTO 400 mg twice daily continuously in combination with VCR 1.0 mg on Day 1 of each cycle and DEX (20 mg daily or 10 mg twice daily) on Days 1-4 and Days 15-18 of each cycle.

Monotherapy Lead-In (Day -7 to Day -1): ENTO 400 mg tablet orally twice daily as a single agent. Induction (two 28-day cycles): ENTO 400 mg twice daily continuously in combination with VCR 2.0 mg IV on Days 1, 8, 15, and 22 of each cycle; DEX 20 mg twice daily orally on Days 8-11 and Days 22-25 (Cycle 1) and on Days 1-4 and Days 15-18 (Cycle 2); and CNS prophylaxis per institutional standards on Day 28 of each cycle. Maintenance (up to 36, 28-day cycles): Participants who achieved a CR received SCT (if eligible) per investigator's discretion; others who obtained clinical benefit (ie, at least a PR) after induction were offered maintenance therapy with ENTO 400 mg twice daily continuously in combination with VCR 2.0 mg on Day 1 of each cycle and DEX (20 mg daily or 10 mg twice daily) on Days 1-4 and Days 15-18 of each cycle.