A Study of First-Line Olomorasib (LY3537982) and Pembrolizumab With or Without Chemotherapy in Patients With Advanced KRAS G12C-Mutant Non-small Cell Lung Cancer

Inclusion Criteria:

• Histologically or cytologically confirmed NSCLC with Stage IIIB-IIIC or Stage IVdisease, not suitable for curative intent radical surgery or radiation therapy.

• Part B and Safety Lead-In Part B: the histology of the tumor must be predominantlynon-squamous (in line with pemetrexed label).

• Must have disease with evidence of KRAS G12C mutation.

• Must have known programmed death-ligand 1 (PD-L1) expression

• Part A: Greater than or equal to (≥)50 percent (%).

• Part B: 0% to 100%.

• Part C: <50%.

• Must have measurable disease per RECIST v1.1.

• Must have an ECOG performance status of 0 or 1.

• Estimated life expectancy ≥12 weeks.

• Ability to swallow capsules.

• Must have adequate laboratory parameters.

• Contraceptive use should be consistent with local regulations for thoseparticipating in clinical studies.

• Women of childbearing potential must

• Have a negative pregnancy test.

• Not be breastfeeding during treatment

Exclusion Criteria:

• Have a documented additional validated targetable oncogenic driver mutation oralteration in genes such as epidermal growth factor receptor (EGFR), anaplasticlymphoma kinase (ALK), BRAF (V600E), human epidermal growth factor receptor 2 (HER2), MET (exon 14), ROS1, rearranged during transfection (RET), or neurotrophictyrosine receptor kinase (NTRK)1/2/3.

• Have had any of the following prior to randomization:

-- Prior systemic therapy (chemotherapy, immunotherapy, targeted therapy, orbiological therapy) for advanced or metastatic NSCLC.

--- 1 cycle of standard-of-care treatment prior to study enrollment will be allowedfor cases where immediate treatment is clinically indicated:

• Have known active central nervous system metastases and/or carcinomatous meningitis.

Exclusion Criteria for Participants receiving Pemetrexed and Platinum (Part B and Safety Lead-In Part B)

• Have predominantly squamous cell histology for NSCLC

• Only for participants with mild to moderate renal insufficiency: Unable to avoidaspirin, ibuprofen, or other nonsteroidal anti-inflammatory drugs (NSAIDs) two daysbefore (5 days for long acting NSAIDs), day of, and two days after administration ofpemetrexed

• Is unable or unwilling to take folic acid or vitamin B12 supplementation.