A Study of the Pan-KRAS Inhibitor LY4066434 in Participants With KRAS Mutant Solid Tumors

Inclusion Criteria:

• Have evidence of KRAS G12C, G12D, G12V, G12A, G12S, or G13D mutation in tumor tissueor circulating tumor DNA

• Histological or cytologically proven diagnosis of a locally advanced, unresectable,and/or metastatic solid tumor cancer

• Have measurable disease per RECIST 1.1

• Have an ECOG performance status of ≤1

• Must not be pregnant and/or planning to breastfeed during the trial or within 180days of the last dose of trial intervention

• Must be able to swallow tablets

• Participants with asymptomatic or treated CNS disease may be eligible

Exclusion Criteria:

• Have known active CNS metastases and/or carcinomatous meningitis

• Have any unresolved toxicities from prior therapy greater than NCI CTCAE Version 5.0Grade 1 at the time of starting trial treatment, except for alopecia, hearing loss,peripheral neuropathy and ongoing endocrinopathies controlled on appropriatereplacement therapy

• Have significant cardiovascular disease defined as unstable angina or acute coronarysyndrome, history of myocardial infarction, known left ventricular ejection fractionor heart failure, uncontrolled or symptomatic arrhythmias.

• Have known active hepatitis B virus (HBV), hepatitis C virus (HCV) or untreated HIVinfection

• Have other active malignancy unless in remission with life expectancy greater than 2years.

• Have active uncontrolled systemic bacterial, viral, fungal, or parasitic infection

• Have history of non-infectious pneumonitis/interstitial lung disease that receivedsteroids or has current clinically significant pneumonitis/interstitial lung disease