A Study of PT0253 in Participants With KRAS G12D Mutated Advanced Solid Tumors

Active brain metastasis or carcinomatous meningitis. If participants have had brain metastases resected or have received radiation therapy, they may be eligible if: (1) study treatment begins at least 4 weeks from the end of brain-specific therapy, (2) residual neurological symptoms Grade less than or equal to (<=) 2, (3) currently on stable doses of corticosteroids, and (4) pre-study brain magnetic resonance imaging (MRI) documents no new/worsening brain lesions.

Malignancy treated with curative intent and with no known active disease present >=2 years before enrolment and felt to be at low risk for recurrence by the investigator

Basal or squamous cell carcinoma of the skin, in situ cervical cancer, early -stage endometrial cancer that has been definitively treated, superficial bladder cancer, Gleason 6/7 treated prostate cancer, and ductal carcinoma in situ or lobular carcinoma in situ of the breast.

Unresolved toxicities from prior anti-cancer therapies (Common Terminology Criteria for Adverse Events [CTCAE] grades >1), except for alopecia. Grade <=2 toxicities from prior anti-tumor therapies that are considered irreversible may be allowed, provided that they are not described in the exclusion criteria AND the investigator and medical monitor are in agreement to proceed.