This is a first in human, open-label, sequential dose escalation and expansion Phase 1 study of NKTR-214 in adult patients with locally advanced or metastatic solid tumors.

Inclusion Criteria:

• Histologically confirmed diagnosis of a locally advanced or metastatic solid tumor.
• Received 1 or 2 prior lines of therapy.
• Life expectancy >12 weeks.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1.
• Measurable disease per RECIST v1.1.
• Demonstrated adequate organ function within 14 days of treatment initiation.
• Subjects must be recovered from the effects of any prior chemotherapy, immunotherapy, other prior system anticancer therapy, radiotherapy or surgery.
• Women of childbearing potential must agree to use highly effective methods of birth control.
• All participants must agree to use double barrier contraception during study participation and for at least 2 months after the last dose of study drug.
• Additional criteria may apply.

Exclusion Criteria:

• Use of an investigational agent or an investigational device within 28 days before administration of first dose of NKTR-214.
• Females who are pregnant or breastfeeding.
• Participants who have an active autoimmune disease requiring systemic treatment within the past 3 months or have a documented history of clinically severe autoimmune disease that requires systemic steroids or immunosuppressive agents.
• Active central nervous system (CNS) metastases.
• Prior surgery or radiotherapy within 14 days of therapy.
• Participants who have had < 28 days since the last chemotherapy, immunotherapy, biological therapy, or < 14 days from approved tyrosine kinase inhibitor (TKI) therapy (sunitinib, sorafenib, vemurafenib, dabrafenib, cobimetinib), or systemic or inhaled steroid therapy at doses greater than 10mg of prednisone or equivalent before administration of the first dose of study medication.
• Participants' inability to adhere to or tolerate protocol or study procedures.
• Additional criteria may apply.