Inclusion Criteria:

• histologically confirmed advanced solid tumors
• measurable or evaluable disease
• age ≥18 years
• written informed consent
• ECOG performance status of 0-1

Exclusion Criteria:

• Prior treatment with romidepsin or gemcitabine
• Prior chemotherapy treatment within 3 weeks prior to the first day of treatment or prior treatment with an investigational agent within 4 weeks prior to the first day of treatment. Patients must have recovered from all therapy-related toxicities (CTC grade ≤ 1)
• Prior radiotherapy within 4 weeks prior to the first day of treatment. Patients who have not fully recovered or whose acute toxicity related to prior radiotherapy has not returned to baseline are ineligible.
• Prior surgery within 3 weeks prior to the first day of treatment, excluding surgical biopsies and port placements
• Concomitant use of any other anti-cancer therapy
• Concomitant use of any investigational agent
• Use of any investigational agent within 4 weeks of study entry
• Any known cardiac abnormalities, including congenital QT syndrome, myocardial infarction, CAD, CHF, chronic hypertension:
• Serum potassium <4.0 mmol/L or serum magnesium <2.0 mg/dL (electrolyte abnormalities can be corrected with supplementation to meet inclusion criteria)
• Concomitant use of drugs that may cause a prolongation of the QTc
• Concomitant use of CYP3A4 inhibitors
• Clinically significant active infection
• Known infection with human immunodeficiency virus (HIV), hepatitis B, or hepatitis C
• Inadequate bone marrow or other organ function as evidenced by:
• Hemoglobin <9 g/dL (Transfusions and/or erythropoietin are permitted.)
• Absolute neutrophil count (ANC) ≤1.5 x 109 cells/L
• Platelet count <100 x 109 cells/L or platelet count <75 x 109 cells/L if bone marrow disease involvement is documented
• Total bilirubin >2.0 x upper limit of normal (ULN)
• Aspartate transaminase/serum glutamic oxaloacetic transaminase (AST/SGOT) and alanine transaminase/serum glutamic pyruvic transaminase (ALT/SGPT) >2.0 x ULN or >3.0 x ULN in the presence of demonstrable liver metastases
• Serum creatinine >2.0 x ULN
• Patients who are pregnant or breast-feeding
• Any significant medical or psychiatric condition that might prevent the patient from complying with all study procedures