A Study of LY4337713 in Participants With FAP-Positive Solid Tumors

Inclusion criteria

• Must have clinical or imaging evidence of fibroblast activation protein (FAP) expression per local assessment
• Must have histologically or cytologically confirmed diagnosis of one of the following:

• Adenocarcinoma of the pancreas
• Hormone receptor (HR)-positive human epidermal growth factor 2 (HER2)-negative breast cancer
• HER2-positive breast cancer
• Triple negative breast cancer (TNBC)
• Platinum-resistant or refractory ovarian cancer (including ovarian carcinosarcoma)
• Other solid tumors

• Gastric cancer (adenocarcinoma)
• Colorectal cancer (CRC)
• Esophageal cancer (squamous cell carcinoma or adenocarcinoma)
• Cholangiocarcinoma
• Must have received prior treatments as indicated below:

• Phase 1a

• Adenocarcinoma of the pancreas: Participants must have received at least 1, but no more than 2 prior regimens for locally advanced unresectable or metastatic disease.
• HR-positive HER2-negative breast cancer: Participants must have received less than or equal to (≤)5 prior lines of treatment for advanced or metastatic disease, which must include a cyclin-dependent kinase 4/6 inhibitor.
• HER2-positive breast cancer: Participants must have received at least 2 lines of HER2-targeted therapy, which should include at least 1 antibody-drug conjugate (ADC) for metastatic disease (if locally available).
• TNBC: Participants must have received at least 2 lines of therapy for metastatic disease.
• Platinum-resistant or refractory ovarian cancer: Participants must have received or after at least 1 platinum-based therapy.
• Other solid tumors (gastric cancer, CRC, esophageal and cholangiocarcinoma): Participants must have received greater than or equal to (≥)1 prior line of systemic therapy for advanced or metastatic disease; including prior line(s) in combination with immunotherapy or vascular endothelial growth factor inhibitor.
• Phase 1b:

• Participants must have advanced or metastatic solid tumors and have received ≥1 prior line of therapy.
• Must have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 to 1.
• Measured creatinine clearance ≥60 milliliters per minute (mL/min)

Exclusion criteria

• Have known active central nervous system (CNS) metastases or carcinomatous meningitis.
• Have significant cardiovascular disease
• Have prolongation of the corrected QTcF >470 milliseconds (msec) during screening. QTcF is calculated using Fridericia's Formula: QTcF = QT/(RR0.33)
• Have evidence of ongoing and untreated urinary tract obstruction
• Had previous hemi- or total-body radiation.
• Had previous adoptive T-cell therapy (e.g., chimeric antigen receptor T-cell [CAR-T therapy, T-cell receptor [TCR] therapy, etc.)
• Unable to lie flat during, or otherwise tolerate, single photon emission computed tomography (SPECT), positron emission tomography (PET), computed tomography (CT) or magnetic resonance imaging (MRI).