A Phase 1a/b Study Investigating the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Preliminary Antitumor Activity of PRMT5 Inhibitor BGB-58067 Alone and in Combination With Anticancer Agents in Patients With Advanced Solid Tumors

Inclusion Criteria: * Participants must sign the ICF and be capable of giving written informed consent * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 or Karnofsky Performance Scale (KPS) ≥ 70 * Life expectancy ≥ 3 months * Evidence of homozygous loss of MTAP or lost MTAP expression in the tumor tissue * Able to provide tumor sample to meet the minimum tissue requirement for central MTAP deficiency testing * Participants with histologically or cytologically confirmed advanced, metastatic, or unresectable solid tumors, whose diseases have progressed or recurred after receiving standard systemic therapy or radiotherapy, or for whom standard systemic therapy is not available or tolerated, or would be unlikely to tolerate or derive clinically meaningful benefit from appropriate standard treatment in the opinion of the investigator; participants with advanced, metastatic, or unresectable solid tumors who have not received prior systemic treatment or have received one cycle of standard-of-care therapies will be enrolled in selected cohorts * Adequate organ function Exclusion Criteria: * Prior treatment with any methylthioadenosine (MTA)-cooperative PRMT5 inhibitor or methionine adenosyltransferase 2a (MAT2A) inhibitor * Active leptomeningeal disease or symptomatic spinal cord compression * Uncontrollable pleural effusion, pericardial effusion, or ascites requiring frequent drainage * Any malignancy ≤ 2 years before first dose of study drug except for the specific cancer under investigation in this study and any locally recurring cancer that has been treated curatively * Significantly impaired pulmonary function * Clinically significant infections * Serologically active hepatitis B or C infection * Known HIV infection. Participants with treated HIV infection may be included in Phase 1b if they meet certain criteria * High cardiovascular risk factors * QTcF \> 470 ms based on the screening triplicate 12-lead ECG records and/or a history of additional risk factors for torsade de pointes (eg, heart failure, hypokalemia, or a family history of Long QT Syndrome) * Toxicities (because of prior anticancer therapy) that have not recovered to baseline or stabilized * Participants who are unable to swallow or with disease/procedure significantly affecting gastrointestinal function * Female participants who are pregnant or are breastfeeding * Concurrent participation in another therapeutic clinical study (participation in observational or noninterventional studies is allowed) Note: Other protocol defined Inclusion/Exclusion criteria may apply.