The purpose of this study is to learn about the effects of a new study drug, called SGR-3515 that may be a treatment for advanced solid tumors.

SGR-3515-101 is a phase 1, first-in-human, single agent, dose-escalation study designed to evaluate the safety, tolerability, dose limiting toxicities, pharmacokinetics, pharmacodynamics, and preliminary anti-tumor activity of SGR-3515 and to identify the maximum tolerated dose, recommended phase 2 dose and schedule of SGR-3515, in participants with advanced solid tumors hypothesized to be sensitive to Wee1/Myt1 inhibition and any solid tumors with designated molecular perturbation relevant to DNA damage repair pathway, including but not limited to CCNE1 amplification.

Inclusion Criteria:

• Diagnosis of advanced/metastatic solid tumor
• Measurable disease per RECIST version 1.1
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Participant must understand and sign an Informed Consent Form (ICF) prior to any study-related assessments/procedures
• Adequate bone marrow and organ function
• Women of child-bearing potential (WOCBP) or males must agree to use highly effective contraception for the duration of study and for 90 days after the last dose of study drug

Exclusion Criteria

• Participants with primary Central Nervous System (CNS tumors).
• Participant has received prior systemic anti-cancer treatments or other investigational agents ≤ 21 days of first dose of study drug, or 5 half-lives, whichever is shorter
• Participant who has received definitive local control radiation (any dose greater than 50 Gy) < 42 days prior to the first dose of study drug.
• Participant who has received major surgeries ≤ 21 days prior to first dose of study drug
• Participants who have not recovered to Grade 1 or baseline levels from toxicity or adverse events related to prior treatment for their cancer, excluding Grade 2 alopecia, peripheral neuropathy and ototoxicity.
• Participant who has another clinically significant invasive malignancy, as determined by the investigator, ≤ 2 years prior to the first dose