A Study of Prexasertib (LY2606368) With Chemotherapy and Radiation in Participants With Head and Neck Cancer

The primary purpose of Parts A and B of this study is to determine a recommended dose level
of prexasertib (an inhibitor of checkpoint kinase 1[Chk-1]) in combination with cisplatin and
radiation therapy (Part A) or cetuximab and radiation therapy (Part B) in participants with
locally advanced head and neck cancer.

Inclusion Criteria:

- Must be able to comply with the treatment plan and follow-up schedule

- Must have diagnosis of head and neck squamous cell carcinoma of the oropharynx
(tonsil, base of tongue, soft palate, or oropharyngeal walls), hypopharynx, or larynx

- Have adequate organ function

- If participant is of reproductive potential, must agree to use medically approved
contraceptive precautions during the study and for six months following the last dose
of study drug

- If the participant is a female of childbearing potential, must have had a negative
serum or urine pregnancy test within 14 days of the first dose of study drug and must
not be breast feeding

Exclusion Criteria:

- Must not have taken an unapproved drug as treatment for any indication within the last
28 days prior to starting study treatment

- Must not have received any of the following prior therapies or treatments: systemic
therapy for the study cancer, radiation therapy to the head and neck region, or
curative-intent surgery in the head and neck region

- Have evidence of a distant metastatic disease

- Must not have an active symptomatic fungal, bacterial or viral infection, including
human immunodeficiency virus (HIV) or Hepatitis A, B, or C

- Must not have a serious heart condition, such as congestive heart failure, unstable
angina pectoris, or heart attack within the last three months

- Must not have a family history of long corrected QT interval (QTc) syndrome

- Must not have known allergic reaction against any of the components of the study
treatment