A Study of Abemaciclib (LY2835219) in Participants With Non-Small Cell Lung Cancer or Breast Cancer

Inclusion Criteria:

• Have a Stage IV diagnosis of 1 of the following: Part A: NSCLC (Kirsten rat sarcomamutant [KRAS mt], PD-L1+); Part B: NSCLC (squamous histology); Part C: metastaticbreast cancer (HR+, HER2-); or Part D: locally advanced or metastatic breast cancer (HR+, HER2-)

• Part A: must be chemotherapy naïve for metastatic NSCLC

• Part B: must have received at least 1 prior therapy containing platinum-basedchemotherapy for advanced/metastatic NSCLC

• Part C: must have previously received prior treatment with at least 1 but nomore than 2 chemotherapy regimens in the metastatic setting

• Part D: cannot have received endocrine therapy or chemotherapy as treatment inthe locoregionally recurrent or metastatic breast cancer disease setting. Note:Participants may be enrolled if they received prior (neo)adjuvant chemotherapyor endocrine therapy for localized disease.

• Are amenable to provide tumor tissue prior to treatment and provide tumor tissueafter treatment initiation (both mandatory).

• Have presence of measurable disease as defined by Response Evaluation Criteria inSolid Tumors (RECIST 1.1).

• Have a performance status (PS) ≤1 on the Eastern Cooperative Oncology Group (ECOG)scale.

• Have discontinued all previous treatments for cancer and recovered from the acuteeffects of therapy.

• Have an estimated life expectancy of ≥12 weeks.

• For Part D: Have postmenopausal status due to surgical/natural menopause or chemicalovarian suppression (initiated 28 days prior to Day 1 of Cycle 1) with agonadotropin-releasing hormone (GnRH) agonist such as goserelin or radiation-inducedovarian suppression.

Exclusion Criteria:

• Have a personal history of any of the following conditions: syncope of eitherunexplained or cardiovascular etiology, ventricular arrhythmia (including but notlimited to ventricular tachycardia and ventricular fibrillation), or sudden cardiacarrest. Exception: subjects with controlled atrial fibrillation for >30 days priorto study treatment are eligible.

• Have central nervous system (CNS) metastasis with development of associatedneurological changes 14 days prior to receiving study drug.

• Have corrected QT interval of >470 milliseconds on screening electrocardiogram (ECG).

• Have history of interstitial lung disease or pneumonitis.

• Have history of or active autoimmune disease, or other syndrome that requiressystemic steroids or autoimmune agents for the past 2 years.

• Have received a live vaccination within 30 days of study start.

• Have received prior treatment with an anti PD-1, anti-programmed death ligand 1 (PD-L1), or anti cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) agent.

• For Part D Only:

• Have initiated bisphosphonates or approved RANK ligand (RANK-L) targeted agents (for example, denosumab) <7 days prior to Cycle 1 Day 1.

• Are currently receiving or have previously received endocrine therapy forlocoregionally recurrent or metastatic breast cancer. Note: A participant maybe enrolled if she received prior (neo)adjuvant endocrine therapy (including,but not limited to anti-estrogens or aromatase inhibitors) for localizeddisease.

• Are currently receiving or have previously received chemotherapy forlocoregionally recurrent or metastatic breast cancer. Note: Participants may beenrolled if they received prior (neo)adjuvant chemotherapy for localizeddisease.