Testing the Combination of the Anti-Cancer Drugs Temozolomide and M1774 to Evaluate Their Safety and Effectiveness

Inclusion Criteria: * Patients must have histologically or cytologically confirmed diagnosis of metastatic advanced cancer. * In dose escalation, any solid tumor patients with either O6-methylguanine DNA methyltransferase (MGMT) promoter hypermethylation positivity on testing / pre-screening of archival tissue OR an extracranial solid tumor where TMZ is considered a standard of care per National Comprehensive Cancer Network (NCCN) guidelines (neuroendocrine tumor, small cell lung cancer, melanoma or soft tissue sarcoma). The tumor lesion must be safely accessible to a mandatory biopsy. Patients with MGMT promoter hypermethylated colorectal cancer must be mismatch repair proficient / microsatellite stable. * In phase 2, only patients with mismatch repair proficient / microsatellite stable colorectal cancer that have MGMT promoter hypermethylation positivity on pre-screening of archival tissue will be eligible. * In dose escalation, patients must have progressed after treatment with all available therapies including immunotherapies for metastatic disease that are known to confer clinical benefit, or are intolerant to treatment, or refuse standard treatment. Patients may not have previously received temozolomide or an ataxia telangiectasia and rad3-related (ATR) inhibitor. * For patients with mismatch repair proficient / microsatellite stable colorectal cancer in the phase 2 portion, patients must have received prior therapy with 1 or more systemic therapies in the metastatic s…