A Study of RO5503781 as a Single Agent or in Combination With Cytarabine in Participants With Acute Myelogenous Leukemia

Study Overview
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Brief Summary
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This Phase 1/1b, open-label study will evaluate the safety and pharmacokinetics of escalating doses of RO5503781 as a single agent or in combination with cytarabine in participants with acute myelogenous leukemia. In Part 1, RO5503781 will be administered in escalating doses as a single agent, and in Part 2, RO5503781 will be administered in combination with cytarabine. An optional Part 3 in which RO5503781 will be administered with cytarabine and anthracycline may be considered . In Part 4, the safety and pharmacokinetic profile of an optimized formulation of RO5503781 in combination with cytarabine will be assessed.

Official Title
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A Multi-Center, Open-Label, Phase 1/1b Study of Escalating Doses of RO5503781 Administered Orally as 1) a Single Agent, 2) In Combination With Cytarabine, or 3) With Cytarabine and Anthracycline and 4) Assessing PK and Safety of New Optimized Formulation of RO5503781 With Cytarabine in Patients With Acute Myelogenous Leukemia (AML)

Conditions
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Myelogenous Leukemia, Acute

Intervention / Treatment
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* Drug: RO5503781 MBP
* Drug: RO5503781 SDP
* Drug: Idarubicin
* Drug: Daunorubicin
* Drug: Cytarabine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Documented/confirmed acute myelogenous leukemia (AML), except for acute promyelocytic leukemia Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2 in Part 1 and Part 2, participants enrolled in the extension/tail portion, Part 3 and Part 4 must have an ECOG performance status of 0 or 1 All non-hematological adverse events of any prior chemotherapy, surgery or radiotherapy must have resolved to National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE) Grade less than or equal to (</=) 2 prior to starting therapy Adequate hepatic and renal function Willing to submit the blood sampling and bone marrow sampling required by protocol Additional inclusion criteria for Parts 1-4 may apply. Exclusion Criteria: Participants receiving any other investigational or commercial agents or therapies administered with the intention to treat their malignancy within 14 days of first receipt of study drug, with the exception of hydroxyurea as defined in protocol History of allergic or toxic reactions attributed to cytarabine (Part 2) or history of allergic reactions to components of the formulated product Current evidence of central nervous system (CNS) leukemia Participants with severe and/or uncontrolled medical conditions or other conditions that could affect their participation in the study Participants with evidence of electrolyte imbalance greater than or equal to (>/=) Grade 2 which cannot be corrected prior to study initiation Pregnant or breastfeeding women Human immunodeficiency virus (HIV) - positive participants receiving anti-retroviral therapy Participants who refuse to potentially receive blood products and/or have a hypersensitivity to blood products Additional exclusion criteria for Parts 1-4 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: Part 1: RO5503781<br>Participants will receive RO5503781 alone in escalating doses on Days 1 to 5 of each 28-day cycle until disease progression or unacceptable toxicity. | Drug: RO5503781 MBP<br>* Participants will receive RO5503781 tablets daily (current formulation) containing microprecipitated bulk powder (MBP) at a starting dose of 400 milligrams (mg).<br>|
| Experimental: Part 2: RO5503781 + Cytarabine<br>Participants will receive RO5503781 in escalating doses on Days 1 to 5 and cytarabine on Days 1 to 6 of each 28-day cycle until disease progression or unacceptable toxicity. | Drug: RO5503781 MBP<br>* Participants will receive RO5503781 tablets daily (current formulation) containing microprecipitated bulk powder (MBP) at a starting dose of 400 milligrams (mg).<br>Drug: Cytarabine<br>* Parts 2 and 4: Participants will receive cytarabine 1000 milligrams per meter squared (mg/m^2) intravenous (IV) infusion daily. Part 3: Participants will receive cytarabine 100-200 mg/m^2 IV infusion daily.<br>|
| Experimental: Part3:RO5503781+Cytarabine+Anthracycline<br>Participants will receive RO5503781 on Days 1 to 5, cytarabine on Days 1 to 7, and anthracycline (daunorubicin or idarubicin) on Days 1 to 3 of each 28-day cycle until disease progression or unacceptable toxicity. | Drug: RO5503781 MBP<br>* Participants will receive RO5503781 tablets daily (current formulation) containing microprecipitated bulk powder (MBP) at a starting dose of 400 milligrams (mg).<br>Drug: Idarubicin<br>* Idarubicin will be administered as per standard clinical practice.<br>Drug: Daunorubicin<br>* Daunorubicin will be administered as per standard clinical practice.<br>Drug: Cytarabine<br>* Parts 2 and 4: Participants will receive cytarabine 1000 milligrams per meter squared (mg/m^2) intravenous (IV) infusion daily. Part 3: Participants will receive cytarabine 100-200 mg/m^2 IV infusion daily.<br>|
| Experimental: Part 4: Optimized RO5503781 + Cytarabine<br>Participants will receive optimized RO5503781 formulation on Days 1 to 5 and cytarabine on Days 1 to 6 of each 28-day cycle until disease progression or unacceptable toxicity. | Drug: RO5503781 SDP<br>* Participants will receive RO5503781 tablets daily (new optimized formulation) containing spray-dried powder (SDP) at recommended dose(s) for development from Phase 1b to Phase 3.<br>Drug: Cytarabine<br>* Parts 2 and 4: Participants will receive cytarabine 1000 milligrams per meter squared (mg/m^2) intravenous (IV) infusion daily. Part 3: Participants will receive cytarabine 100-200 mg/m^2 IV infusion daily.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximum Tolerated Dose (MTD) and/ or Recommended Phase 2 Dose (RP2D) of RO5503781 |  | Day 1 up to Day 42 | 
| Proportion of Participants with Dose-Limiting Toxicities (DLTs) |  | Day 1 up to Day 42 | 
| Safety: Proportion of Participants with Adverse Events (AEs) and Serious Adverse Events (SAEs) |  | Baseline up to approximately 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pharmacokinetics: Maximum Observed Plasma Concentration (Cmax) (in Micrograms per Milliliters [mcg/mL]) of RO5503781, Cytarabine,1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cycle (Cy) 1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacokinetics: Time to Reach Maximum Plasma Concentrations (Tmax) in hours of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description). | 
| Pharmacokinetics: Terminal Half-Life (t1/2) (in hours) of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacokinetics: Area Under Plasma Concentration-Time Curve Over One Dosing Internal (AUCtau) (in mcg*hour/mL) of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacokinetics: Area Under Plasma Concentration-Time Curve From 0 to the Last Measurable Concentration (AUClast) (in mcg*hour/mL) of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacokinetics: Area Under Plasma Concentration-Time Curve From 0 to Infinity (AUCinf) (in mcg*hour/mL) of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacokinetics: Apparent Oral Clearance (CL/F) (in liters/hour) of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacokinetics: Apparent Volume of Distribution (V/F) (in liters) of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy 1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacokinetics: Apparent Elimination Rate Constant (kel) (in 1/hour) of RO5503781, Cytarabine, 1-beta-D-Arabinofuranosyluracil, Daunorubicin, Daunorubicinol, Idarubicin, and Idarubicinol | Timeframe for RO5503781: Predose (0 hour [Hr]), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy 1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) Timeframe for cytarabine, 1-beta-D-arabinofuranosyluracil (cytarabine metabolite): Parts 2,4: Predose (0Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Days 1, 5; Predose (0Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15; Part 3: Predose (0 Hr) on Cy1 Day 1; Predose (0 Hr), 1, 2, 3, 4, 6, 10 Hr Postdose on Cy1 Day 5; Cy1 Day 6 (Cy=28days) Timeframe for daunorubicin, daunorubicinol (daunorubicin metabolite), idarubicin, and idarubicinol (idarubicin metabolite): Part 3: Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr Postdose on Cy 1 Days 1, 5; Predose (0 Hr) on Cy1 Day 2; Cy1 Day 6 (Cy length=28 days) | Predose (0 Hr) on Cy 1 Day 1 up to Cy 1 Day 15 (Cy length=28 days) (detailed timeframe for individual drug is provided in outcome measure description) | 
| Pharmacodynamics: Macrophage Inhibitory Cytokine-1 (MIC1) Serum Levels |  | Predose (0 Hr), and 1, 2, 3, 4, 6, 10 Hr postdose on Cy 1 Days 1, 5; predose (0 Hr) on Cy1 Day 2; Cy1 Day 6; Cy 1 Days 8, 9, 15 (Parts 1, 2, 4 only) (Cy length=28 days) | 
| Pharmacodynamics: Proportion of Participants With Tumor Suppressor Protein 53 (p53) Mutation, as Assessed by Gene Sequencing and/or Research-Use AmpliChip p53 Test |  | Predose (0 Hr), and 6 Hr postdose on Cy 1 Days 1, 5; predose (0 Hr) on Cy 1 Day 2; Cy 1 Day 6; at disease progression/relapse (up to approximately 3.25 years) | 
| Pharmacodynamics: Murine Double Minute-2 (MDM2) Messenger Ribonucleic Acid (mRNA) Expression, as Assessed by Quantitative Real Time Polymerase Chain Reaction (RT-PCR) |  | Predose (0 Hr), and 6 Hr postdose on Cy 1 Days 1, 5; predose (0 Hr) on Cy 1 Day 2; Cy 1 Day 6; at disease progression/relapse (up to approximately 3.25 years) | 
| Proportion of Participants With Complete Remission (CR) as best response during study and follow up period, as Assessed Using Bone Marrow and Hematological Examinations |  | Day 1 of each treatment cycle starting from Cy 2 up to 28 days after last dose of RO5503781 (approximately 3.25 years); additionally, every 2 months for participants with CR from occurrence of CR to 1 year (overall up to approximately 3.25 years) | 
| Proportion of Participants With Complete Remission Without Platelet Recovery (CRp) as best response during study and follow up period as Assessed Using Bone Marrow and Hematological Examinations |  | Day 1 of each treatment cycle starting from Cy 2 up to 28 days after last dose of RO5503781 (approximately 3.25 years); additionally, every 2 months for participants with CRp from occurrence of CRp to 1 year (overall up to approximately 3.25 years) | 
| Proportion of Participants With Complete Remission With Insufficient Recovery of Peripheral Counts (CRi) or Morphologic Leukemia Free State (MLFS) as Best Response During Study and Follow Up as Assessed Using Bone Marrow and Hematological Examinations |  | Day 1 of each treatment cycle starting from Cy 2 up to 28 days after last dose of RO5503781 (approximately 3.25 years); additionally, every 2 months for participants with CRi from occurrence of CRi to 1 year (overall up to approximately 3.25 years) | 
| Proportion of Participants With Partial Response (PR) as Best Response During Study and Follow Up Period, as Assessed Using Bone Marrow and Hematological Examinations |  | Day 1 of each treatment cycle starting from Cy 2 up to 28 days after last dose of RO5503781 (approximately 3.25 years); additionally, every 2 months for participants with PR from occurrence of PR to 1 year (overall up to approximately 3.25 years) | 
| Proportion of Participants With Hematologic Improvement (SD/HI) as Best Response During Study and Follow Up Period, as Assessed Using Bone Marrow and Hematological Examinations |  | Day 1 of each treatment cycle starting from Cy 2 up to 28 days after last dose of RO5503781 (approximately 3.25 years); additionally, every 2months for participants with SD/HI from occurrence of SD/HI to 1 year (overall up to approximately 3.25years) | 
| Proportion of Participants With Disease Progression as Best Response During Study and Follow Up Period |  | Baseline up to approximately 3.25 years |