Study of Onvansertib in Combination With FOLFIRI and Bevacizumab or FOLFOX and Bevacizumab Versus FOLFIRI and Bevacizumab or FOLFOX and Bevacizumab for First-Line Treatment of Metastatic Colorectal Cancer in Adult Participants With a KRAS or NRAS Mutation

Inclusion Criteria:

* Histologically confirmed metastatic colorectal cancer.
* Documented KRAS or NRAS mutation.
* No previous systemic therapy in the metastatic setting.
* Participants must be willing to submit archival tissue or undergo fresh biopsy.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
* Women of childbearing potential must use contraception or take measures to avoid pregnancy.
* Imaging computed tomography (CT) or magnetic resonance imaging (MRI) of chest/abdomen/pelvis and other scans as necessary to document all sites of disease performed within 28 days prior to the first dose of onvansertib.
* Must have acceptable organ function

Exclusion Criteria:

* Concomitant KRAS or NRAS and BRAF-V600 mutation or microsatellite instability high/deficient mismatch repair.
* Prior treatment with a VEGF inhibitor, including bevacizumab or biosimilars.
* Previous oxaliplatin treatment within 12 months prior to randomization, when arm open.
* Known dihydropyrimidine dehydrogenase (DPD) deficiency.
* Anticancer chemotherapy or biologic therapy administered within 28 days prior to the first dose of study drug.
* Untreated or symptomatic brain metastasis.
* Gastrointestinal (GI) disorder(s) that would significantly impede the absorption of an oral agent.
* Unable or unwilling to swallow study drug.
* Uncontrolled intercurrent illness.
* Known hypersensitivity to fluoropyrimidine or leucovorin, irinotecan, or oxalipatin.
* Abnormal glucuronidation of bilirubin; known Gilbert's syndrome.
* Use of strong CYP3A4 or CYP2C19 inhibitors or strong CYP3A4 inducers.
* QTc \>470