A Study of PRT2527 in Participants With Advanced Solid Tumors

Prior treatment

• Treatment with strong inhibitors or inducers of CYP3A4
• Prior exposure to a CDK9 inhibitor
• have undergone major surgery within 2 weeks prior to Week 1 Day 1
• have had chemotherapy, biologic therapy, targeted therapy, immunotherapy, extended-field radiotherapy, or investigational agents within 5 half-lives or 28 days (whichever is shorter) prior to administration of the first dose of study drug on Week 1 Day 1.

Other illness

• Primary malignancies of the CNS, or uncontrolled CNS metastases, including impending spinal cord compression
• have impaired cardiac function or clinically significant cardiac disease
• History of another malignancy except for:
  • Curatively treated malignancy with no known active disease
  • Curatively treated non-melanoma skin cancer without evidence of disease
  • Curatively treated carcinoma in situ without evidence of disease

Lab values

• have a corrected QT interval \>480 msec from prior or baseline

• Tumor types under study
  • Selected sarcomas with a documented gene fusion
  • Castrate resistant prostate cancer (CRPC)
  • Hormone receptor positive (HR+), HER2 negative (HER2-) breast cancer
  • Non-small cell lung cancer (NSCLC)
  • MYC amplified solid tumors
• Must have measurable disease per RECIST 1.1; participants with CRPC or sarcoma may have nonmeasurable but evaluable disease
• Eastern Cooperative Oncology Group (ECOG) Performance Score of 0 or 1
• Adequate organ function
• Must provide tumor tissue sample to the central laboratory for biomarker analysis
• Participants must have recovered from the effects of prior cancer-related therapy, radiotherapy, or surgery to ≤ Grade 1