Safety and Clinical Pharmacology of GDC-0068 in Combination With Docetaxel, Fluoropyrimidine Plus Oxaliplatin, Paclitaxel, or Enzalutamide in Participants With Advanced Solid Tumors

This is an open-label, multicenter, Phase Ib, dose-escalation study designed to assess the safety, tolerability, and pharmacokinetics of oral ipatasertib (GDC-0068) administered in combination with either docetaxel (Arm A), or oxaliplatin, leucovorin, 5-fluorouracil (5-FU) (mFOLFOX6 chemotherapy) (Arm B), or paclitaxel (Arm C), in participants with advanced or metastatic solid tumors for which standard therapy either does not exist or has proven ineffective or intolerable. Arm D will assess the safety, tolerability, and pharmacokinetics of ipatasertib administered in combination with enzalutamide in participants with metastatic castration-resistant prostate cancer (CRPC). There will be two stages within each arm of this study: a dose-escalation stage (Stage 1) and a cohort-expansion stage (Stage 2). In Stage 1, approximately 3 to 6 cohorts in Arms A and B and 1 to 2 cohorts in Arms C and D will be evaluated to determine the maximum tolerated dose (MTD) of ipatasertib in a given combination. Additional participants will be enrolled in Stage 2 (cohort expansion), to further characterize the safety and tolerability of ipatasertib in these combinations and to confirm a potential recommended Phase II dose of ipatasertib for each regimen.

NOTE: Arms A, B, and C are closed.


Eligibility Criteria:
Inclusion Criteria:

* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at screening
* Histologically or cytologically documented advanced or metastatic solid tumors for which established therapy either does not exist or has proven ineffective or intolerable
* Life expectancy greater than or equal to (\>=) 12 weeks
* Adequate hematologic and end organ function
* For female participants of childbearing potential and male participants with partners of childbearing potential, agreement (by participant and/or partner) to use highly effective forms of contraception and to continue its use for the duration of the study and for 4 months after last dose of study treatment (for females) and 6 months after last dose of study treatment (for males)

Exclusion Criteria:

* Prior anti-cancer therapy that fulfills the following criteria: a total of more than three (Arms A and B) or two (Arms C and D) prior cytotoxic chemotherapy regimens, high-dose chemotherapy requiring stem-cell support, and irradiation to \>=25 percent (%) of bone marrow-bearing areas
* Treatment with chemotherapy, hormonal therapy (except hormone replacement therapy, oral contraceptives, or gonadotropin-releasing hormone (GnRH) agonists or antagonists for prostate cancer), immunotherapy, biologic therapy, radiation therapy (except palliative radiation to bony metastases), or herbal therapy as cancer therapy within 4 weeks prior to initiation of ipatasertib. Exceptions are kinase inhibitors approved by local regulatory authorities, which may be used within 2 weeks prior to initiation of ipatasertib, provided that any clinically-relevant drug-related toxicity has completely resolved and prior approval is obtained from the Medical Monitor
* Palliative radiation to bony metastases within 2 weeks prior to initiation of ipatasertib
* History of Type 1 or Type 2 diabetes requiring regular medication
* Grade \>= 2 heart failure or history of unstable angina
* History of clinically significant ventricular arrhythmias or active ventricular arrhythmia requiring medication
* For Arm D only: History of seizure, unexplained loss of consciousness, transient ischemic attack within 12 months of enrollment, cerebral vascular accident, and any brain metastases