Study to Evaluate the Safety and Efficacy of the Combination of Tirabrutinib and Idelalisib With and Without Obinutuzumab in Adults With Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL)

Study Overview
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Brief Summary
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The primary objective of this study is to determine the preliminary efficacy of the combination of tirabrutinib and idelalisib with obinutuzumab in adults with relapsed or refractory chronic lymphocytic leukemia (CLL). The study has a 6 participant per arm safety run-in to evaluate safety prior to the enrollment of subsequent participants. The treatment period is adaptive, with a duration of active treatment up to two years and a total follow-up on study for up to 30 days post end of treatment, or up to Week 25 should a participant discontinue treatment prior to Week 25 for reasons other than disease progression.

Official Title
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A Prospective, Open-Label, Multicenter, Phase 2 Trial to Evaluate the Safety and Efficacy of the Combination of Tirabrutinib (GS-4059) and Idelalisib With and Without Obinutuzumab in Subjects With Chronic Lymphocytic Leukemia

Conditions
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Chronic Lymphocytic Leukemia

Intervention / Treatment
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* Drug: Tirabrutinib
* Drug: Idelalisib
* Drug: Obinutuzumab


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Documentation of relapsed or refractory CLL Requiring treatment per modified International Workshop on CLL (IWCLL) 2008 criteria; individuals without radiographically measurable disease (defined as ≥ 1 lesion > 1.5 centimetre (cm) in diameter as assessed by computed tomography (CT) or magnetic resonance imaging [MRI]) must have bone marrow evaluation at screening Adequate hematologic function: platelet count ≥ 50 × 10^9/L, neutrophil count ≥ 1 × 10^9/L, hemoglobin ≥ 8 grams per decilitre (g/dL) unless lower values are directly attributable to documented bone marrow burden of CLL Creatinine clearance (CrCl) ≥ 50 milliliter per minute (mL/min) Total bilirubin ≤ 1.5× institutional upper limit of normal (ULN) unless attributed to Gilbert's syndrome and aspartate transaminase (AST)/alanine transaminase (ALT) ≤ 2.5 × ULN Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) ≤ 2 Absence of active human immunodeficiency virus (HIV), hepatitis B virus (HBV) infection, hepatitis C virus (HCV) infection, and cytomegalovirus (CMV) infection Satisfies the following criteria: For females of childbearing potential, willingness to abstain from sexual intercourse or use a protocol-specified method of contraception as described in the study protocol Males of reproductive potential who engage in sexual intercourse must agree to use protocol-specified method(s) of contraception as described in the study protocol Able to comply with study procedures and restrictions including mandatory prophylaxis for Pneumocystis jirovecii pneumonia (PJP) Key Exclusion Criteria: Known transformation of CLL (ie, Richter's transformation, prolymphocytic leukemia) Known central nervous system (CNS) involvement Progression on treatment with any inhibitor of Bruton's tyrosine kinase (BTK), spleen tyrosine kinase (SYK), phosphatidylinositol 3-kinase (PI3K), B-cell lymphoma 2 (BCL-2), or obinutuzumab. The treatment and disease response history of individuals with prior treatment with agents in these classes should be reviewed by the sponsor or the German CLL Study Group (GCLLSG) study office prior to enrollment to clarify sensitivity to these treatments. Any treatment for CLL other than corticosteroids for symptomatic management within 28 days of the start of study treatment Participation on a concurrent therapeutic clinical trial unless all treatment is complete with only ongoing surveillance Diagnosis of or concern for progressive multifocal leukoencephalopathy History of myelodysplastic syndrome or another malignancy other than CLL, except for the following: any malignancy that has been in complete remission for 3 years, adequately treated local basal cell or squamous cell carcinoma of the skin, cervical carcinoma in situ, superficial bladder cancer, asymptomatic prostate cancer without known metastatic disease and with no requirement for therapy or requiring only hormonal therapy and with normal prostate-specific antigen for ≥ 1 year prior to start of study therapy Active infection requiring systemic therapy Pregnant or nursing women (a negative pregnancy test is required for all women of childbearing potential within 7 days before start of treatment and monthly during therapy) Active autoimmune disease or the need for higher than prednisone 10 mg daily unless for management of CLL symptoms Treatment or prophylaxis for CMV within the past 28 days History of stroke or intracranial hemorrhage within 12 months of randomization; patients requiring therapeutic anticoagulation for any indication should be discussed with the GCLLSG cooperating physician and/or medical monitor prior to screening. Use of a strong CYP3A4 or a strong P-glycoprotein (P-gp) inducer within 2 weeks of first dose of study treatment or anticipated chronic use while on study Demonstration of corrected QT (QTc) interval > 450 milliseconds or requirement for ongoing treatment with concomitant medications that prolong the QT interval Note: Other protocol defined Inclusion/Exclusion criteria may apply.

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
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Tirabrutinib + Idelalisib<br>Tirabrutinib 80 mg (4 x 20 mg tablets/2 x 40 mg tablets/1 x 80 mg tablet) once daily + idelalisib 100 mg (1 x 100 mg tablet) once daily for up to 104 weeks. | Drug: Tirabrutinib<br>* Tablets administered orally<br>* Other names: GS-4059;Drug: Idelalisib<br>* Tablets administered orally<br>* Other names: CAL-101;|
| Experimental: Tirabrutinib + Idelalisib + Obinutuzumab<br>Tirabrutinib 80 mg (4 x 20 mg tablets/ 2 x 40 mg tablets/ 1 x 80 mg tablet) once daily + idelalisib 100 mg (1 x 100 mg tablet) once daily for up to 104 weeks + obinutuzumab 100 mg on Day 1, 900 mg on Day 1 or 2, and 1000 mg subsequently for up to 8 doses on Day 1 of Weeks 2, 3, 5, and then every 4 weeks through Week 21. | Drug: Tirabrutinib<br>* Tablets administered orally<br>* Other names: GS-4059;Drug: Idelalisib<br>* Tablets administered orally<br>* Other names: CAL-101;Drug: Obinutuzumab<br>* Administered intravenously<br>* Other names: GA101;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of Complete Response/Complete Remission (CR), as Assessed by Investigator Using Modified International Workshop on Chronic Lymphocytic Leukemia (IWCLL) 2008 Criteria at Week 25 | Rate of CR per modified IWCLL 2008 criteria at Week 25 was defined as the percentage of participants who achieved CR/complete remission with incomplete recovery of the bone marrow (CRi) at Week 25. CR: meeting following criteria and no disease related symptoms: no lymphadenopathy > 1.5 cm/hepatomegaly/splenomegaly; lymphocytes < 4000/μL; bone marrow sample must be normocellular with 30% lymphocytes and no B-lymphoid nodules; platelets > 100,000/µL; hemoglobin > 11 g/dL; and neutrophils > 1500/µL. CRi: CR criteria (no lymphadenopathy > 1.5 cm/hepatomegaly/splenomegaly; lymphocytes < 4000/μL; bone marrow [hypocellular] with 30% lymphocytes and no B-lymphoid nodules), persistent anemia/thrombocytopenia/neutropenia unrelated to CLL but related to drug toxicity. | Week 25 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of CR With Bone Marrow Minimal Residual Disease (CR/BM MRD) Negativity, as Assessed by the Investigator Using the Modified IWCLL 2008 Criteria at Week 25 | Rate of CR/BM MRD at Week 25 was defined as percentage of participants who achieved CR/CRi per modified IWCLL 2008 criteria and also achieved BM MRD negativity at Week 25. CR: meeting following criteria and no disease related symptoms: no lymphadenopathy > 1.5 cm/hepatomegaly/splenomegaly; lymphocytes < 4000/μL; bone marrow sample must be normocellular with 30% lymphocytes and no B-lymphoid nodules; platelets > 100,000/µL; hemoglobin > 11 g/dL; and neutrophils > 1500/µL. CRi: CR criteria (no lymphadenopathy > 1.5 cm/hepatomegaly/splenomegaly; lymphocytes < 4000/μL; bone marrow [hypocellular] with 30% lymphocytes and no B-lymphoid nodules), persistent anemia/thrombocytopenia/neutropenia unrelated to CLL but related to drug toxicity. MRD response was assessed with four-color-flow cytometry (FACS) and MRD negativity was defined as one CLL cell per 10,000 leukocytes [0.01%], ie,<10^-4 and participants were defined as MRD negative if their disease burden was below this threshold. | Week 25 | 
| Rate of CR With Peripheral Minimal Residual Disease (CR/PB MRD) Negativity, as Assessed by the Investigator Using the Modified IWCLL 2008 Criteria at Week 25 | Rate of CR/PB MRD at Week 25 was defined as the percentage of participants who achieved CR/CRi per modified IWCLL 2008 criteria and also achieved PB MRD negativity at Week 25. CR: meeting following criteria and no disease related symptoms: no lymphadenopathy > 1.5 cm/hepatomegaly/splenomegaly; lymphocytes < 4000/μL; bone marrow sample must be normocellular with 30% lymphocytes and no B-lymphoid nodules; platelets > 100,000/µL; hemoglobin > 11 g/dL; and neutrophils > 1500/µL. CRi: CR criteria (no lymphadenopathy > 1.5 cm/hepatomegaly/splenomegaly; lymphocytes < 4000/μL; bone marrow [hypocellular] with 30% lymphocytes and no B-lymphoid nodules), persistent anemia/thrombocytopenia/neutropenia unrelated to CLL but related to drug toxicity. MRD response was assessed with FACS and MRD negativity was defined as one CLL cell per 10,000 leukocytes [0.01%], ie,<10^-4 and participants were defined as MRD negative if their disease burden was below this threshold. | Week 25 | 
| Overall Response Rate (ORR), as Assessed by the Investigator Using the Modified IWCLL 2008 Criteria at Week 25 | ORR was assessed based on modified IWCLL 2008 criteria and was defined as percentage of participants achieving a CR, CRi, partial remission (PR; including nodular partial response [nPR]), and PR with lymphocytosis (PR-L). CR and CRi: meeting all the criteria that have been defined in Outcome measures 1, 2 and 3. PR: ≥ 2 of these: ≥ 50% decrease in lymphocytes, lymphadenopathy, size of liver, size of spleen, and 50% decrease in bone marrow infiltrates; and ≥ 1 of these: neutrophils > 1500/μL or ≥ 50% increase from Baseline, platelets ≥ 100,000/µL or ≥ 50% increase from Baseline, hemoglobin >11 g/dL or ≥ 50% increase from Baseline. PR-L: meeting PR criteria; however, a lymphocytosis related to treatment may be present. nPR: All criteria for a CR/CRi were fulfilled, but the bone marrow showed lymphoid nodules. | Week 25 | 
| Percentage of Participants Experiencing Any Treatment-Emergent Adverse Events (AEs) and Treatment-Emergent Serious Adverse Events (SAEs) | Treatment-emergent AEs are defined as 1 or both of the following: Any AEs with an onset date on or after the study drug start date and no later than 30 days after permanent discontinuation of study drug Any AEs leading to discontinuation of study drug A SAE is defined as an event that, at any dose, resulted in any of the following: death, life-threatening, in-patient hospitalization or prolongation of existing hospitalization, persistent or significant disability/incapacity, a congenital anomaly/birth defect, or a medically important event or reaction. | First dose date up to the last dose date (maximum: 105 weeks) plus 30 days |