GDC-0973

To assess the efficacy of cobimetinib in patients with newly diagnosed and HMA- refractory chronic myelomonocytic leukemia (CMML). Overall response rate (ORR) is defined as the proportion of patients achieving complete remission, complete cytogenetic remission, partial remission, marrow response, and clinical benefit according to the 2015 MDS/MPN-IWG criteria. This was assessed from the dose of study medication to the decision to end treatment, up to 20 months.

Intracranial ORR is defined as the percentage of participants with either a complete response (CR) or a partial response (PR) in their intracranial disease based on two consecutive assessments \>= 4 weeks apart. Disease status for this endpoint will be determined by an Independent Review Committee (IRC) in accordance with Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) with modified measurability definition for intracranial lesions (\>= 0.5 cm by MRI) and allowing up to five intracranial target lesions. CR is defined as disappearance of all lesions. PR is defined as \>=30% decrease in tumor burden, in the absence of CR. The primary endpoint is analyzed on the BRAFV600 mutation positive (Cohort 2) only as the Sponsor had discontinued enrolment into Cohort 1. Data for Cohort 1 was not collected nor analyzed for this outcome measure.

Objective response rate was defined as the percentage of participants with a complete response (CR) or a partial response (PR) on two consecutive tumor assessments ≥4 weeks apart, as determined by the investigators using Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1). CR was defined as disappearance of all lesions. PR was defined as ≥30% decrease in the sum of diameters of target lesions, in the absence of CR, new lesions, and unequivocal progression in non-target lesions.

The safety profiles of Cobimetinib plus Niraparib and Cobimetinib plus Niraparib plus Atezolizumab will be evaluated in terms of number of patients reporting serious and non-serious AEs with severity graded according to National Cancer Institute - Common Terminology Criteria for Adverse Events (NCI - CTCAE v5.0)

The safety profiles of Cobimetinib plus Niraparib and Cobimetinib plus Niraparib plus Atezolizumabwill be evaluated in terms of number of patients reporting change from baseline in targeted clinical laboratory test results.

The efficacy profiles of Cobimetinib plus Niraparib and Cobimetinib plus Niraparib plus Atezolizumab will be evaluated in terms of investigator-assessed confirmed ORR, as determined using RECIST v1.1 in the Intention To Treat (ITT) population and in molecularly defined subgroups by loss of heterozygosity (LOH) status.

An AE was any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have to have a causal relationship with the treatment. An AE was therefore any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. New or pre-existing conditions which worsened during the study were also considered AEs.

ORR was defined as a stringent complete response (sCR), complete response (CR), very good partial response (VGPR), or partial response (PR) and was analyzed in the safety evaluable population and in the biomarker-selected sub-populations of t(11;14) and RAS mutations.

Dose-Limiting Toxicities (DLTs) were defined as cobimetinib-related adverse events occurring within the first 28 days of each administration of cobimetinib.

An AE is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including abnormal laboratory values or abnormal clinical test results), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as AEs.

A prior dose level was defined as an MTD/MAD if at a certain dose level, there were greater than or equal to (\>=) 2 out of 6 participants who had Dose Limiting Toxicities (DLTs).

Tumor assessment was performed using mINRC for Participants with Neuroblastoma.

Tumor assessment was performed using Response Assessment in Neuro-Oncology (RANO) criteria for participants with HGG and Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) for participants with LGG. While the data for LGG in the phase II cohort is presented separately in other parts of the record, it was also considered useful to combine the data for LGG from phase I and phase II, which was done here.

Tumor assessment was performed using RECIST v1.1 for Participants with All Other Tumours.

Tumor assessment will be performed using RANO criteria for LGG.

Tumor assessment was performed using mINRC for Participants with Neuroblastoma.

Tumor assessment was performed using RANO for participants with HGG and RECIST v1.1 for participants with LGG. While the data for LGG in the phase II cohort is presented separately in other parts of the record, it was also considered useful to combine the data for LGG from phase I and phase II, which was done here.

Tumor assessment was performed using RECIST v1.1 for Participants with All Other Tumours.

Tumor assessment was performed using RANO criteria for Participants with LGG.

DLTs include symptoms considered by the investigator to be possibly related to study drug.

An adverse event is any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product, regardless of causal attribution.

AESIs were graded per the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), v4.0. AESIs included the following: Grade ≥ 1 retinal vein occlusion; Grade ≥ 2 visual disturbances (including events suggestive of serous retinopathy); Grade ≥ 3 rash for \> 7 days; Grade ≥ 3 diarrhea for \> 3 days; Grade ≥ 2 left ventricular ejection fraction (LVEF) decrease; Grade 3 hepatotoxicity; any dose-limiting toxicity (DLT); cases of potential drug-induced liver injury that include an elevated alanine aminotransferase (ALT) or aspartate aminotransferase (AST) (AST \> 3 × baseline value \[and above the upper limit of normal, ULN\]) in combination with either an elevated bilirubin ( \> 2 × ULN) or clinical jaundice; or suspected transmission of an infectious agent by either study drug.

A SAE is any experience that: results in death, is life-threatening, requires in-patient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is medically significant.

Laboratory abnormalities were graded per the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), v4.0. SGPT/ALT - serum glutamic-pyruvic transaminase/alanine aminotransferase; SGOT/AST - serum glutamic oxaloacetic transaminase/aspartate aminotransferase

DLT is defined as 1 of the following toxicities considered by the investigator to be related to study treatment: a) Grade 3 nausea, vomiting or diarrhea that resolved to Grade less than or equal to (≤) 1 within 7 days, b) Grade 3 rash or photosensitivity that resolved to Grade ≤2 within 7 days, c) Grade 3 cutaneous squamous cell carcinoma (cuSCC) that was subsequently resected, d) Grade greater than or equal to (≥) 3 fatigue or hyperuricemia that resolved to Grade ≤2 within 7 days, e) Grade 3 fever, f) Grade 3 or 4 elevation of serum creatine phosphokinase (CPK) levels, which is asymptomatic, deemed by the investigator to be clinically insignificant and that returned to Grade ≤2 during the 14-day cobimetinib treatment holiday, g) Grade ≥3 febrile neutropenia, h) Grade ≥4 neutropenia (absolute neutrophil count \[ANC\] less than \<500/microliter \[μL\]), i) Grade ≥4 thrombocytopenia, j) Grade ≥4 anemia, k) Grade ≥3 elevation of total bilirubin, hepatic transaminase or alkaline phosphatase.

The highest dose level(s) at which fewer than one-third of participants experienced a DLT was declared the MTD. DLT is defined as 1 of the following toxicities considered by the investigator to be related to study treatment: a) Grade 3 nausea, vomiting or diarrhea that resolved to Grade ≤1 within 7 days, b) Grade 3 rash/photosensitivity that resolved to Grade ≤2 within 7 days, c) Grade 3 cuSCC that was subsequently resected, d) Grade ≥3 fatigue/hyperuricemia that resolved to Grade ≤2 within 7 days, e) Grade 3 fever, f) Grade 3 or 4 elevation of serum CPK levels, which is asymptomatic, deemed to be clinically insignificant and returns to Grade ≤2 during the 14-day cobimetinib treatment holiday, g) Grade ≥3 febrile neutropenia, h) Grade ≥4 neutropenia (ANC \<500/ μL), i) Grade ≥4 thrombocytopenia, j) Grade ≥4 anemia, k) Grade ≥3 elevation of total bilirubin, hepatic transaminase or alkaline phosphatase.

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes.

Adverse events (AE) were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) v3.0. DLT was defined as either of the following occurring during the Study Treatment Period. The occurrence of a drug-related AE that, in the opinion of the cohort review committee (CRC), was of potential clinical significance such that further dose escalation would expose participants in higher dose cohorts to risk of irreversible medical harm or require medical treatment to avoid irreversible medical harm or non-hematologic toxicity * Grade 3 or 4 events, including Grade 3 nausea and/or vomiting and/or Grade 3 diarrhea, despite prophylaxis and/or treatment Hematologic toxicity * Grade 4 thrombocytopenia * Grade 4 neutropenia of greater than or equal to (≥) 4 days' duration * Grade 4 neutropenia of any duration with fever or documented infection

AEs were graded according to the NCI-CTCAE v3.0. A DLT was determined from clinical findings during the Study Treatment Period (Cycle 1, Days 1). MTD was defined as the dose at which no DLTs were observed. DLT was defined as either of the following occurring during the Study Treatment Period. The occurrence of a drug-related AE that, in the opinion of the CRC, was of potential clinical significance such that further dose escalation would expose participants in higher dose cohorts to risk of irreversible medical harm or require medical treatment to avoid irreversible medical harm or non-hematologic toxicity * Grade 3 or 4 events, including Grade 3 nausea and/or vomiting and/or Grade 3 diarrhea, despite prophylaxis and/or treatment Hematologic toxicity * Grade 4 thrombocytopenia * Grade 4 neutropenia of greater than or equal to (≥) 4 days' duration * Grade 4 neutropenia of any duration with fever or documented infection

AEs were graded according to NCI-CTCAE v3.0. A DLT was the basis for determining MTD in Stage 1A participants. The participants of Stage 1A are dose-escalation cohorts, starting at the MTD of the 21/7 schedule, were treated on a 14/14 schedule to determine the MTD. A DLT was defined as either of the following occurring during the Study Treatment Period: Occurrence of a drug-related AE that, in the opinion of the CRC, was of potential clinical significance such that further dose escalation would expose participants to risk of irreversible medical harm; Nonhematologic toxicity: Grade 3 or 4 events, including Grade 3 nausea and/or vomiting and/or Grade 3 diarrhea, despite prophylaxis and/or treatment; Hematologic toxicity: Grade 4 thrombocytopenia. Grade 4 neutropenia of more than 4 days' duration; Grade 4 neutropenia of any duration with fever or documented infection. AEs (Grade 3 or higher) for which a clinical cause unrelated to cobimetinib was evident was not considered DLTs.

Cmax is defined as the maximum plasma concentration achieved after administration of cobimetinib on Day 1, Cycle 1 in Stage 1 and was measured as nanograms per milliliter (ng/mL).

The area under the concentrations-time curve (AUC0-24) was calculated with the measured data points from the time of administration of cobimetinib up to 24 h after administration by the trapezoidal formula. AUC 0-24 is the truncated AUC over a 24-hour sampling interval. The concentration-time curve is the result of time points of blood sampling and its measured concentration of free cobimetinib in the blood samples. AUC is measured as hours times nanograms per milliliter (h\*ng/mL).

Tmax is defined as the time to reach Cmax during stage 1 at Day 1 Cycle 1.