A Study of ABBV-181 in Participants With Advanced Solid Tumors

Inclusion Criteria:

- Participant must have an advanced solid tumor and must not be a candidate for surgical
resection or other approved therapeutic regimen known to provide clinical benefit. For
dose escalation, the participant may have been previously treated with a programmed
cell death 1 (PD-I) targeting agent. For dose expansion, the participant must be
PD-I/PD-L1 targeting agent naïve. For Combination, the participant must be have SCLC
with progressive disease and have failed platinum containing therapy and be PD-1/PD-L1
targeting agent naïve.

- Participant has an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0
to 2 for Monotherapy and 0 to 1 for Combination.

- Participants have adequate bone marrow, renal, hepatic and coagulation function.

- Participants must have measurable or evaluable disease per Response Evaluation
Criteria in Solid Tumors (RECIST) version 1.1 in the dose escalation portion of the
trial. Participants in the expansion cohort must have measurable disease per RECIST
version 1.1 or disease evaluable by assessment of tumor antigens.

Exclusion Criteria:

- Participant has received anticancer therapy including chemotherapy, immunotherapy,
radiation therapy, biologic, herbal therapy, or any investigational therapy within a
period of 5 half-lives, prior to the first dose of ABBV-181 or Rovalpituzumab
Tesirine.

- For Combination therapy, participant must not have had prior exposure to
Rovalpituzumab Tesirine or a pyrrolobenzodiazepine (PBD) based drug.

- Participant has unresolved adverse events greater than grade 1 from prior anticancer
therapy except for alopecia.

- Current or prior use of immunosuppressive medication within 14 days prior to the first
dose (with certain exceptions).

- History of primary immunodeficiency, bone marrow transplantation, chronic lymphocytic
leukemia, solid organ transplantation, or previous clinical diagnosis of tuberculosis.

- Confirmed positive test results for human immunodeficiency virus (HIV), or
participants with chronic or active hepatitis A, B or C. Subjects who have a history
of hepatitis B or C who have undetectable HBV DNA or HCV RNA are anti-viral therapy
may be enrolled.

- Participant has known history or inflammatory bowel disease, pneumonitis, or known
uncontrolled metastases to the central nervous system (CNS) (with certain exceptions).

- Participants with a history of or ongoing interstitial lung disease are also excluded.