This is a first-in-human (FIH) multicenter, open-label, dose-escalation Phase 1 clinical trial to evaluate safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of D3S-003 in participants with advanced KRAS p.G12D mutant solid tumors.

Inclusion Criteria:

• Subjects must have histologically confirmed locally advanced, recurrent, or metastatic malignancy that has progressed following at least one line of standard therapy or where standard therapy has proven to be ineffective or intolerable or is considered inappropriate or when participation in a clinical trial of an investigational agent is considered a standard therapeutic option.
• Subjects must have documented presence of KRAS p.G12D mutation by a local test identified through tumor tissue or blood collected within the last 5 years.
• Subjects must have measurable disease per RECIST v1.1.
• Subject must have Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Subject must have adequate organ and marrow function within the screening period.

Exclusion Criteria:

• Participant has any prior treatment with a specific KRAS G12D inhibitor/degrader or pan RAS inhibitor/degrader.
• Subject has uncontrolled intercurrent illness, including but not limited to serious chronic gastrointestinal conditions associated with diarrhea, ongoing or active infections, uncontrolled or significant cardiovascular disease, autoimmune or inflammatory disorders or psychiatric illness/social situations that would limit compliance with study requirements, substantially increase risk of incurring adverse events (AEs), or compromise the ability of the subject to give written consent.
• Uncontrolled or untreated brain metastases
• Subject has active gastrointestinal disease or other that could interfere significantly with the absorption, distribution, metabolism, or excretion of oral therapy

NOTE: Other protocol inclusion/exclusion criteria may apply.