A Study Evaluating the Safety and Pharmacokinetics of Atezolizumab Administered in Combination With Hu5F9-G4 to Patients With Relapsed and/or Refractory Acute Myeloid Leukemia

Study Overview
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Brief Summary
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This Phase Ib study is designed to evaluate the safety and pharmacokinetics of atezolizumab when given in combination with Hu5F9-G4 to patients with relapsed or refractory (R/R) acute myeloid leukemia (AML).

Official Title
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A Phase Ib, Open-Label Study Evaluating the Safety and Pharmacokinetics of Atezolizumab (Anti-PD-L1 Antibody) Administered in Combination With Hu5F9-G4 to Patients With Relapsed and/or Refractory Acute Myeloid Leukemia

Conditions
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Acute Myeloid Leukemia

Intervention / Treatment
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* Drug: Atezolizumab
* Drug: Hu5F9-G4


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Life expectancy of at least 12 weeks Eastern Cooperative Oncology Group Performance Status 0-2 Documented and confirmed R/R AML per WHO classification, except acute promyelocytic leukemia, and lack of response to all therapies of known benefit Adequate end-organ function Negative HIV test at screening Negative hepatitis B surface antigen (HBsAg) test at screening Negative total hepatitis B core antibody (HBcAb) test at screening, or positive total HBcAb test followed by quantitative hepatitis B virus (HBV) DNA <500 IU/mL at screening Negative hepatitis C virus (HCV) antibody test at screening, or positive HCV antibody test followed by a negative HCV RNA test at screening Willingness and ability to provide pretreatment bone marrow aspirate and biopsy and agreement to provide subsequent bone marrow aspirates and biopsies during study treatment For women of childbearing potential: agreement to remain abstinent or use contraceptive methods, and agreement to refrain from donating eggs For men: agreement to remain abstinent or use contraceptive measures and agreement to refrain from donating sperm For women who are not postmenopausal or surgically sterile: requirement for a negative serum pregnancy test result within 14 days prior to initiation of study treatment Exclusion Criteria: Previous allogeneic hematopoietic stem cell transplant within 6 months prior to enrollment, active graft versus host disease, or requiring transplant-related immunosuppression Prior solid organ transplant Evidence of active central nervous system (CNS) involvement by leukemia Pregnancy or lactation or intention to become pregnant during the study or within 5 months after the final dose of atezolizumab and/or Hu5F9-G4, whichever is longer History of idiopathic pulmonary fibrosis, organizing pneumonitis, drug-induced pneumonitis, or idiopathic pneumonitis History of autoimmune disease. Patients with a history of autoimmune-related hypothyroidism who are on a stable dose of thyroid replacement may be eligible for this study. Patients with controlled Type 1 diabetes mellitus who are on a stable insulin regimen may be eligible for this study. Patients with eczema, psoriasis, lichen simplex chronicus, or vitiligo with dermatologic manifestations only are eligible for the study provided all of the following conditions are met: (1) Rash must cover <10% of body surface area, (2) Disease is well controlled at baseline and requires only low-potency topical corticosteroids, (3) No occurrence of acute exacerbations of the underlying condition that require psoralen plus ultraviolet A radiation, methotrexate, retinoids, biologic agents, oral calcineurin inhibitors, or high-potency or oral corticosteroids within the previous 12 months. Treatment with investigational therapy within 14 days prior to initiation of study drug Any approved AML-related therapy within 14 days prior to enrollment. Granulocyte colony-stimulating factor to treat neutropenic fever and/or infection is permitted. Hydroxyurea may be used throughout the trial to control peripheral blood blast counts in response to the first dose of study treatment and during the first 4 weeks of study treatment.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Atezolizumab + Hu5F9-G4<br>An initial safety evaluation will be performed in participants with relapsed AML. If atezolizumab in combination with Hu5F9-G4 is initially safe and tolerable in participants an additional cohort with R/R AML will be evaluated to further test the safety and anti-tumor activity. If dose-limiting toxicities (DLT) are observed in >=33% of participants in this initial cohort, a dose de-escalation cohort will be enrolled. If less than 33% of enrolled and dosed participants in any given cohort experience a DLT, an expansion cohort of 15 participants will be enrolled at the highest tolerated dose for this combination. If a dose de-escalation cohort is needed, an expansion cohort will be enrolled at the lower tolerated dose for this combination. | Drug: Atezolizumab<br>* Atezolizumab will be administered to participants by IV infusion at a fixed dose starting on Day 22 of Cycle 1. In subsequent cycles (Cycles 2 and beyond), IV atezolizumab will be given every 2 weeks (Q2W) on Days 8 and 22 of each 28-day cycle.<br>* Other names: Tecentriq;Drug: Hu5F9-G4<br>* Two priming doses of 1 mg/kg of Hu5F9-G4 will be administered to participants by continuous IV infusion on Days 1 and 4 of Cycle 1, followed by loading doses of 15 mg/kg IV on Day 8 and 30 mg/kg IV on Day 11. Starting on Day 15 of Cycle 1, Hu5F9-G4 maintenance will be given by IV infusion at a dose of 30 mg/kg once a week (QW) of each 28-day cycle. Dosing for de-escalation, if needed: Hu5F9-G4 will be given as two priming doses of 1 mg/kg IV on Days 1 and 4, followed by loading doses of 10 mg/kg IV on Day 8 and 15 mg/kg on Day 11. Starting on Day 15, maintenance treatment with Hu5F9-G4 will be given by IV infusion at a dose of 15 mg/kg once a week (QW).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With Adverse Events | Percentage of participants with at least one adverse event. | Up to approximately 13 months after first participant enrolled | 
| Complete Remission (CR) | The CR rate is assessed as the percentage of participants who achieve a CR, complete remission with incomplete platelet recovery (CRp), complete remission with incomplete hematologic recovery (CRi), or complete remission with partial hematologic recovery (CRh) (as defined by the IWG 2003 and ELN 2010 criteria) after up to six cycles of combination therapy. | Up to approximately 3 months after first participant enrolled | 
| Duration of Response (DOR) | DOR is defined as the time from the initial response (CR, CRp, CRi, CRh, or partial remission [PR]) to the time of disease progression or death, whichever occurs first | Up to approximately 3 months after first particpant enrolled | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum Concentrations of Atezolizumab | C=cycle (cycle=28 days) ; D=day; PTFI=prior to first infusion; TDV=treatment discontinuation visit; UTA=up to approximately; M=month | C1 D22 PTFI of Hu5F9-G4 and atezolizumab, and 30 minutes after atezolizumab infusion; C2 D8 PTFI; C2 D22 PTFI; C3 D22 PTFI; C4 D22 PTFI; C8 D22 PTFI; C12 D22 PTFI; C16 D22 PTFI; TDV (up to C16 D21);120 days after final dose of atezolizumab (UTA 37M) | 
| Serum Concentrations of Hu5F9-G4 | C=cycle (cycle=28 days); D=Day; PTFI=prior to first infusion; H=hour; AEOI=after end of infusion; TDV=treatment discontinuation visit; UTA=up to approximately; M=months; E=every; T=thereafter | C1D1 PTFI&1H AEOI; C1D8 PTFI,&1H AEOI; C1D11 PTFI,&1H AEOI; C1D22 1H AEOI; C2D1 PTFI,&1H AEOI; C2D8 PTFI; C3D1 PTFI,&1H AEOI; C5D1 PTFI; C7D1 PTFI, C9D1 PTFI; C11D1 PTFI; C13D1 PTFI; C15D1 PTFI; C17D1&D1 E 2C T PTFI(UTA 37M);TDV(up to C16D21)(UTA 37M) | 
| Objective Response Rate | Objective response rate is defined as the percentage of participants with a partial remission (PR) or better (i.e., CR + CRp + CRi + CRh+ PR). | Up to approximately 3 months after first participant enrolled | 
| Event-Free Survival | Event-free survival is defined as the time from study entry to the date of induction treatment failure or relapse from CR, CRp, CRh, CRi, or death from any cause. | Up to approximately 3 months after first participant enrolled | 
| Leukemia-Free Survival | Leukemia-free survival is defined (only for participants achieving a CR, CRp, CRh, or CRi) as the time from the date of achievement of remission (CR, CRp, or CRi) until the date of relapse from CR, CRp, CRh, CRi, or death from any cause. | Up to approximately 3 months after first participant enrolled | 
| Overall Survival | Overall survival is defined as time from study entry to the date of death from any cause. | Up to approximately 13 months after first participant enrolled | 
| Progression-Free Survival | Progression-free survival (Investigator) is defined as the time from the first day of study treatment to disease progression or death, whichever occurs first. | Up to approximately 3 months after first participant enrolled | 
| Rate of Transfusion Independence | Rate of transfusion independence is defined as the percentage of participants who achieve transfusion independence (i.e., achieving any continuous 56-day window without requiring platelet or RBC transfusions) at any time during study treatment. | Up to approximately 3 months after first participant enrolled | 
| Duration of Transfusion Independence | Duration of transfusion independence is defined as the number of consecutive days of transfusion independence, measured from 1 day after the last transfusion to disease progression or subsequent transfusion. | Up to approximately 3 months after first participant enrolled | 
| Incidence of Anti-Drug Antibodies (ADAs) Against Atezolizumab During the Study Relative to the Prevalence of ADAs at Baseline |  | Baseline up to approximately 37 months | 
| Incidence of ADAs Against Hu5F9-G4 During the Study Relative to the Prevalence of ADAs at Baseline |  | Baseline up to approximately 37 months |