Key Inclusion Criteria:  Patients must meet the following criteria to enroll in this study:  Documented diagnosis of ovarian cancer, endometrial cancer, colorectal cancer, gastric cancer, gastroesophageal junction cancer, triple negative breast cancer, non-small cell lung cancer, or cholangiocarcinoma No other meaningful life-prolonging therapy option available Must provide archival tumor tissue or a newly obtained tumor biopsy specimen prior to the first dose of ELU001 for folate receptor alpha (FRα) expression analysis Adequate organ function Measurable disease, or in the absence of measurable disease, non-measurable disease as per Response evaluation criteria in solid tumors (RECIST) v1.1 Part 1: Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2; Part 2: ECOG performance status of 0 or 1. Recovered from previous surgeries Agree to highly effective contraception, not to get pregnant, or for men, not father a child during study participation  Key Exclusion Criteria:  Patients who meet any of the following are not eligible to enroll in this study:  Active or ongoing eye disorders Taken any treatments that use the protein folate receptor alpha or FRα to work Taken any other experimental treatments History of significant cardiac issues or other cancers within 3 years. Significant anemia, significant neutropenia, or significant thrombocytopenia (e.g., not enough platelets in your blood - platelets held stop bleeding in your body) Detectable viral load for HIV (human immunodeficiency virus), hepatitis B or C. If you are pregnant. Part 1: Cannot have active autoimmune diseases such as rheumatoid arthritis, SLE (systemic lupus erythematosus), ulcerative colitis, Crohn's Disease, MS (multiple sclerosis), ankylosing spondylitis, thyroiditis that require treatments that suppress your immune system. Part 1: if your cancer has spread to your brain. Part 2: You can have cancer that has spread to your brain but there are exceptions. The cancer in your brain cannot be causing any symptoms, it cannot be larger than 3 cm, there can be no evidence on a scan that shows your brain tissue has shifted from its expected position inside the skull (called "herniation") or be bleeding in the skull or brain itself (called "hemorrhage").