A Study Evaluating Safety and Pharmacokinetics of ABBV-221 in Subjects With Advanced Solid Tumor Types Likely to Exhibit Elevated Levels of Epidermal Growth Factor Receptor

Inclusion Criteria:

- Eastern Cooperative Oncology Group (ECOG) performance status 0 or 2.

- Has a solid tumor likely to exhibit elevated levels of EGFR (e.g. head and neck
squamous cell carcinoma, non-small cell lung cancer, triple negative breast cancer
,colorectal carcinoma and glioblastoma multiforme).

- Has an archived, diagnostic tumor tissue available for analysis.

- Has adequate hematologic, renal, cardiac and hepatic function.

- Expanded Safety Cohort participants must have confirmed metastatic lung cancer and
progressed after receiving prior platinum-containing chemotherapy.

Exclusion Criteria:

- Previously received an EGFR-directed monoclonal antibody within the past 4 weeks.

- Has unresolved, clinically significant toxicities from prior anti-cancer therapy
defined as > Grade 1 on Common Terminology Criteria for Adverse Events.

- History of major immunologic reaction to any IgG containing agent.

- Any medical condition which in the opinion of the investigator places the participant
at an unacceptably high risk for toxicities.