KZR-261 in Subjects With Advanced Solid Malignancies

Inclusion Criteria: * Histologic or cytologic evidence of malignant solid tumor with advanced disease (except primary central nervous system \[CNS\] neoplasms), defined as cancer that is either metastatic or locally advanced and unresectable (and for which additional radiation therapy or other locoregional therapies are not considered to result in reasonable clinical benefit). * Disease that is resistant to or relapsed following available standard systemic therapy, or for which there is no standard systemic therapy or reasonable therapy in the Investigator's judgement likely to result in clinical benefit, or if such therapy has been refused by the subject. Documentation of the reason must be provided for subjects who have not received a standard therapy likely to result in clinical benefit. * Eastern Cooperative Oncology Group Performance Status score of 0 or 1. * Adequate baseline hematologic and organ function. * Willing to use contraception. Additional Inclusion for Part 2: Histologic or cytologic evidence of malignancy (melanoma/uveal melanoma, colorectal cancer, castration-resistant prostate cancer, mesothelioma). Exclusion Criteria: * Subjects who have participated in Part 1 dose escalation are not eligible to enroll in Part 2 dose expansion. * Persistent clinically significant toxicities from previous anticancer therapy (excluding alopecia). * Treatment with cytotoxic, biologic, or targeted therapies for advanced cancer within 14 days before administration of the s…