The primary purpose of the study is to assess the objective response rate (ORR) of E7090 by Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 based on independent imaging review (IIR) in participants with unresectable cholangiocarcinoma with FGFR2 gene fusion who failed gemcitabine-based combination chemotherapy.

Inclusion Criteria:

1. Participants with a histologically or cytologically diagnosis of intrahepatic or perihilar cholangiocarcinoma who agree to provide archival tumor sample or residual biopsy sample, or agree with tumor biopsy.

2. Participants who have confirmed FGFR2 gene fusion of tumor by fluorescence in situ hybridization (FISH) in central laboratory. FGFR2 gene fusion confirmed by the same FISH assay in another test/study will be discussed with the sponsor and agreed on a case by case basis.

3. Participants with surgically unresectable or advanced/metastatic disease who have received at least one prior chemotherapy including gemcitabine-based combination chemotherapy (example: gemcitabine and cisplatin)

   a. Prior adjuvant chemotherapy is allowed if relapse was within 6 months after last administration.

4. Measurable disease meeting the following criteria:

   1. At least 1 lesion of >=1.0 centimeter (cm) in the longest diameter for a non-lymph node or >=1.5 cm in the short-axis diameter for a lymph node that is serially measurable according to RECIST 1.1 using computerized tomography/magnetic resonance imaging (CT/MRI).
   2. Lesions that have had external beam radiotherapy (EBRT) or locoregional therapies such as radiofrequency (RF) ablation must show evidence of progressive disease based on RECIST 1.1 to be deemed a target lesion.

5. Corrected serum calcium less than or equal to (<=) upper limit of normal (ULN).

6. Phosphate <=ULN.

7. Participants with Performance Status (PS) score of 0-1 established by Eastern Cooperative Oncology Group (ECOG).

8. Participants who are expected to survive for 3 months or longer after starting administration of the investigational drug.

9. Washout period required from the end of prior treatment to the start of E7090 administration will be as follows

   1. Antibody and other investigational drugs : >=4 weeks
   2. Prior chemotherapy (except small-molecule targeted therapy), surgical therapy, radiation therapy：>=3 weeks
   3. Endocrine therapy, immunotherapy, small-molecule targeted therapy: >=2 weeks

Exclusion Criteria:

1. Participants with brain or subdural metastases are not eligible, unless they have completed local therapy and have discontinued the use of corticosteroids for this indication for at least 4 weeks before starting treatment in this study. Any signs (example: radiologic) or symptoms of brain metastases must be stable for at least 4 weeks before starting study treatment.

2. Concomitant active infection requiring systemic treatment (except hepatitis B or C virus-infected participants who are under anti-viral treatment).

3. Participants who test positive for human immunodeficiency virus (HIV antibody) at Screening 2.

4. Child-Pugh score B or C.

5. Moderate or severe ascites extending from the pelvis to the liver surface.

6. Following ocular disorders

   1. Current evidence of Grade 2 or higher corneal disorder
   2. Current evidence of active macula disorder (example: age-related macular degeneration, central serous chorioretinal disease)

7. Participants whose toxicity of previous treatment has not recovered to Grade 1 or lower per Common Terminology Criteria for Adverse Events (CTCAE v4.03), except for alopecia, infertility and the adverse events listed in inclusion criteria.

8. Participants with prior therapy targeting FGFR2.

9. Participants who need the use of drugs or foods that strongly inhibits or induces the metabolizing enzyme cytochrome P450 (CYP) 3A4 during study treatment (there must be a time interval of >= 7 days since the final use of these drugs or foods by the start of study treatment).

Eisai's data sharing commitment and further information on how to request data can be found on our website http://eisaiclinicaltrials.com/.