Japanese Research for Patients With Non-metastatic Castration Resistant Prostate Cancer - Enzalutamide

The purpose of this study is to investigate the efficacy and safety of enzalutamide in patients with non-metastatic castration resistant prostate cancer. The total duration of the study will be 5 years. All patients will receive enzalutamide 160 mg (four 40 mg capsules) orally once daily. The treatment will be started at Visit 0 within one week after enrollment. Visit 1 is at 2 weeks after the treatment started; clinical assessments are conducted on adverse events and the Japanese version of the Functional Assessment of Cancer Therapy-Prostate (FACT-P) scales. Patients who are considered to be adequate by the investigator can continue the treatment with 12-week cycle visit (counted from initial dose) until patients meet withdrawal criteria. Patients will be followed up at 2 and 3 years after enrollment and at 3 years after the last participant enrollment. The end of the study is defined as follow-up assessment date at 3 years after the last participant enrollment. Patients will primarily be assessed by prostate-specific antigen (PSA) progression-free survival (PFS).


Eligibility Criteria:
Inclusion Criteria:

1. Patients with histologically or cytologically confirmed prostate cancer
2. Patients with history of radical prostatectomy or radiation therapy for radical treatment
3. Patients who receive continuous androgen deprivation therapy using both gonadotropin-releasing hormone (GnRH) agonist and antagonist, or using surgical castration
4. Patients with serum testosterone 1.73 nmol/L (0.50 ng/dL) or less
5. Patients with history of bicalutamide or flutamide at any time after first recurrence confirmed since radical treatment completed
6. Patients with 3 increased PSA test results which measured consecutively at least one week apart during androgen deprivation therapy
7. Patients with serum PSA 1 micrograms/L (1 ng/mL) or more
8. Patients with no confirmed remote metastasis after diagnosis of prostate cancer (excluding lymph nodes metastasis with a minor axis of less than 15 mm which considered to be nonmeasurable in the Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1)
9. Patients with asymptomatic prostate cancer
10. Patients with the Eastern Cooperative Oncology Group (ECOG) performance status 0-1
11. Patients with life expectancy of at least 12 months
12. Patients who have signed written informed consent to participate in this study

Exclusion Criteria:

1. Patients with history of any chemotherapy (including estramustine phosphate sodium hydrate (JAN)) or treatment with enzalutamide or abiraterone acetate
2. Patients with history of steroid usage as treatment for prostate cancer
3. Patients with history of 5-alpha-reductase inhibitor, estrogen or steroidal antiandrogen within past 4 weeks prior to initial administration of enzalutamide
4. Patients with history of malignant tumor other than prostate cancer within past 3 years
5. Patients with history of seizure or predisposing disease of seizure
6. Patients with severe liver dysfunction
7. Patients with a previous history of hypersensitivity to any component of drugs which will be administered in this study
8. Patients who considered to be inappropriate for the study participation by the investigator.