Dose Escalation and Expansion Study of HM97662 in Advanced or Metastatic Solid Tumors

Inclusion Criteria: * Histologically and/or cytologically confirmed advanced or metastatic solid tumor who have failed/are intolerant to standard therapy. * Patients for dose-escalation part must have evaluable or measurable disease at baseline and the patients for randomized dose-ranging and dose-expansion part must have at least one measurable lesion at baseline by CT or MRI per Response Evaluation Criteria in Solid Tumor (RECIST v1.1). * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Life expectancy ≥ 3 months before starting HM97662. * Adequate renal function. * Adequate hematologic function. * Adequate liver function. * Males or females aged ≥ 18 years (or country's legal age of majority if the legal age was \> 18 years) at the time of informed consent. * For Dose-Ranging Part, documentation of an alteration in at least one of the genes of the SWI/SNF complex in tumor tissue (archival or newly obtained). Exclusion Criteria: * Prior exposure to valemetostat or other EZH1/2 dual inhibitor. * Known brain metastases that are untreated, symptomatic, or require therapy to control symptoms. * Patients currently taking medications that are known strong CYP3A inhibitors and strong or moderate CYP3A inducers. * Any prior treatment-related (i.e. chemotherapy, immunotherapy, radiotherapy) clinically significant toxicities that have not resolved to Grade ≤ 1 per CTCAE version 5.0 or prior treatment-related toxicities that are clinically unstable and clinically significant at time of enrollment. * Major surgery within 4 weeks before the first dose of study drug treatment in Cycle 1. * Females who are pregnant or breastfeeding. * Patients who have undergone an organ transplant.