Phase 1/2a Study of RP-001 in Participants With Advanced Malignancies

Inclusion Criteria: * Male or female participants aged 18 years or older with advanced or metastatic cancer, which must be measurable per RECIST v1.1 and satisfy the following criteria: * Phase 1: Participants with solid tumors who are candidates for treatment with a taxane * Phase 2a: Participants with relapsed or refractory PDAC, or CRC. Exclusion Criteria: * 1\. Active infection requiring systemic anti-infective therapy within 28 days prior to first dose of RP-001. 2\. Cardiovascular disease, including: a. Unstable angina; b. symptomatic peripheral arterial vascular disease; c. Myocardial infarction within 6 months prior to RP-001 administration; d. New York Heart Association Class III or IV heart failure; e. Uncontrolled arrythmia; f. ECG abnormality that, in the opinion of the Investigator, increases the risks associated with participating in the trial. 3\. Concurrent systemic anti-cancer therapy other than luteinizing hormone-releasing hormone (LH-RH) agonists. 4\. Pregnancy, or breastfeeding. 5. Untreated central nervous system metastasis, or carcinomatous meningitis. 6. Any concurrent severe and/or uncontrolled medical or surgical condition which, in the opinion of the Investigator, may compromise the participant's involvement in the trial due to safety, compliance concerns or ability to evaluate response.