This is a first in human (FIH), Phase 1, dose escalation and expansion study in select solid tumors. This study includes 2 parts: a Dose Escalation and Backfill portion (Part A) and a Dose Expansion portion (Part B).

This is a FIH, Phase 1, open-label, multicenter, multiple-dose, dose escalation and expansion study. This study includes 2 parts: a Dose Escalation and Backfill portion (Part A) and a Dose Expansion portion (Part B). NEOK001 is a bispecific B7-H3 x ROR1 exatecan antibody-drug conjugate (ADC) that will be administered intravenously once every cycle.

Key Inclusion Criteria:

• Participants must have locally advanced or metastatic disease in a select tumor type, for which no standard therapy is available.
• Participants must have at least 1 measurable target lesion based on RECIST v1.1.
• Participants must have Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Participants must have adequate hematologic, hepatic, and renal function.
• Participants should have available archived tumor tissue from their most recent biopsy.

Key Exclusion Criteria:

• Participant's most recent systemic anti-cancer treatment was an ADC with a topoisomerase 1-inhibitor payload component.
• Participants with known symptomatic central nervous system (CNS) metastases or any evidence of leptomeningeal disease or evidence of unstable CNS metastases, even if asymptomatic.
• Participants with a known history of interstitial lung disease (ILD) requiring steroid treatment, or for whom suspected ILD cannot be ruled out by imaging at screening.
• Participants with clinically severe pulmonary compromise due to intercurrent pulmonary illness and/or pulmonary disorder requiring supplemental oxygen or any prior pneumonectomy.
• Participants with a QT interval corrected for heart rate using Fridericia's formula (QTcF) ≥ 470 msec.