A Study of Anti-PD-L1 Checkpoint Antibody (LY3300054) Alone and in Combination in Participants With Advanced Refractory Solid Tumors

Inclusion Criteria:

- Histologic or cytologic confirmation of advanced solid tumor.

- For LY3300054 + abemaciclib only: No participants with liver metastases. Participants
must have normal aspartate aminotransferase (AST), alanine aminotransferase (ALT),
total bilirubin, direct bilirubin.

- For LY3300054 + abemaciclib in HR+, HER- breast cancer:

- Express at least 1 of the hormone receptors [HR; estrogen receptor (ER) or
progesterone receptor (PR)] by immunohistochemistry (IHC) to fulfill the
requirement for HR+ disease on the primary tumor or metastatic lesion of the
breast cancer. ER and PR assays are considered positive if there is at least 1%
positive tumor nuclei in their sample as defined in the relevant American Society
of Clinical Oncology (ASCO)/College of American Pathologists (CAP) or local
guidelines.

- To fulfill the requirement of HER2- disease, a breast cancer must not
demonstrate, at initial diagnosis or upon subsequent biopsy, overexpression of
HER2 by either IHC or in-situ hybridization (ISH) as defined in the relevant
ASCO/CAP or local guidelines.

- Most recent HR and HER2 receptor testing should be used to determine eligibility.

- Have previously received prior treatment with at least 1 but no more than 3
chemotherapy regimens in the metastatic setting.

- Have AST, ALT, GGT, and AP that are ≤2.5x upper limit of normal (ULN) and normal
bilirubin (total and direct) regardless of liver involvement.

- For LY3300054 + merestinib in pancreatic cancer:

- Histologically or cytological confirmed diagnosis of metastatic or locally
advanced, unresectable pancreatic adenocarcinoma (excluding other pancreatic
malignancies for example, acinar cell carcinomas, adenosquamous carcinomas, and
neuroendocrine islet cell neoplasms).

- Have had disease progression, be refractory or intolerant to no more than 2 prior
systemic regimens.

- For LY3300054 + LY3321367 in PD-1/PD-L1-naive, MSI-H/MMR-deficient advanced solid
tumors:

- Have histologically or cytologically confirmed diagnosis of advanced solid tumor
AND shown to be MSI-H or MMR-deficient.

- For LY3300054 + LY3321367 in PD-1/PD-L1- resistant/refractory, MSI-H/MMR-deficient
advanced solid tumors:

- Have histologically or cytologically confirmed diagnosis of advanced solid tumor
AND shown to be MSI-H or MMR-deficient.

- Prior exposure to PD-1/PD-L1 agent regardless of response.

- For Phase 1b LY3300054 monotherapy or combination therapy, no prior treatment with a
PD-1 or PD-L1 agent is allowed.

- Exception: the LY3321367 combination in participants with PD-1/PD-L1-
resistant/refractory, MSI-H, where prior exposure to PD-1/PD-L1 agent required.

- For Phase 1a LY3300054 monotherapy or combination therapy, previous immunotherapy is
acceptable if the following criteria are met:

- Must not have experienced a toxicity that led to permanent discontinuation of
prior immunotherapy.

- Must have completely recovered or recovered to baseline prior to screening from
any prior adverse events (AEs) occurring while receiving prior immunotherapy.

- Must not have experienced a Grade ≥3 immune-related AE or an immune-related
neurologic or ocular AE of any grade while receiving prior immunotherapy.

- Must not have required the use of additional immunosuppressive agents other than
corticosteroids for the management of an AE, not have experienced recurrence of
an AE if re-challenged, and not currently require maintenance doses of >10
milligrams prednisone or equivalent per day.

- Have at least 1 measurable lesion assessable using standard techniques by Response
Evaluation Criteria in Solid Tumors (RECIST) v1.1.

- Have adequate organ function.

- Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG)
scale.

- Have an estimated life expectancy of ≥12 weeks, in the judgment of the investigator.

- Have submitted a tumor tissue sample, as follows:

- For participants entering the Phase 1a dose escalation: have submitted, if
available, the most recent archival tumor tissue sample.

- For those participating ONLY in Phase 1b expansions: Have submitted tumor tissue
sample from a newly obtained core or excisional biopsy for a tumor lesion
(preferred) or a recent biopsy taken with 3 months prior to study enrollment and
following the participants most recent prior systemic treatment and be willing to
undergo a biopsy procedure during the study treatment period for collection of
additional tumor tissue sample.

Exclusion Criteria:

- Have a serious concomitant systemic disorder including human immunodeficiency virus
(HIV), active hepatitis B virus (HBV), active hepatitis C virus (HCV), active
autoimmune disorder or disease requiring high dose of steroids.

- Have a bowel obstruction, history or presence of inflammatory enteropathy or extensive
intestinal resection or chronic diarrhea.

- Have evidence of interstitial lung disease that is symptomatic or may interfere with
the detection or management of suspected drug-related pulmonary toxicity or active,
noninfectious pneumonitis.

- Have an active infection requiring systemic therapy.

- Have moderate or severe cardiovascular disease.

- Have symptomatic or uncontrolled brain metastases, spinal cord compression, or
leptomeningeal disease requiring concurrent treatment.

- Have received a live vaccine within 30 days before the first dose of study treatment.

- Have a significant bleeding disorder or vasculitis or had a Grade ≥3 bleeding episode
within 12 weeks prior to enrollment.