Inclusion Criteria:

1. Histologically confirmed melanoma with metastases and has no received any systemic
treatment within 1 month

2. Evidence of mutations and/or copy number increases of KIT with laboratory examination
documented from either primary or metastatic tumor site

3. ECOG performance status 0, 1, or 2

4. Estimated life expectancy of 6 months or greater

5. Age 18 years or older, male of female

6. At least one measurable site of disease

7. Adequate organ function

8. Willingness and ability to comply with scheduled visits, treatment plans, laboratory
tests, and other study procedures

Exclusion Criteria:

1. Melanoma from primary sites other than acral or mucosal melanoma

2. Received systemic anti-cancer therapy within 1 month before enrollment for metastatic
disease

3. Diagnosis of any second malignancy within the last 5 years, except for adequately
treated basal cell carcinoma, squamous cell skin cancer, or in situ cervical cancer

4. Severe and/or uncontrolled concomitant medical diseases

5. pregnant or childbreeding women

6. Known hypersensitivity to imatinib

7. Current treatment on another clinical trial