Safety Study of Itacitinib (INCB039110) in Combination With Gemcitabine and Nab-Paclitaxel in Subjects With Advanced Solid Tumors

Inclusion Criteria: * Histologically or cytologically confirmed solid tumor (Part 1) or pancreatic adenocarcinoma (Part 2) * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 1 * Received no more than 1 prior chemotherapy regimen for advanced or metastatic disease (not including neo-adjuvant and/or adjuvant therapy) (Part 1) * Received no prior chemotherapy for advanced or metastatic disease (Part 2 and Part 2a) * Adequate renal, hepatic, and bone marrow function without frequent blood product or hematopoietic growth factor support (eg use of erythropoietin or transfusions \> 2 units packed red blood cells every 3 months) * Ability to swallow and retain oral medication Exclusion Criteria: * Any known contraindications to the use of a required comedication (gemcitabine or nab-paclitaxel). * Evidence of uncontrolled brain metastases or history of uncontrolled seizures. * Ongoing radiation therapy and/or radiation therapy administered within 28 days of enrollment or ongoing radiotherapy-related toxicities. * Presence of ≥ Grade 2 neuropathy. * Inability to swallow food or any condition of the upper GI tract that precludes administration of oral medications. * Recent (≤ 3 months) history of partial or complete bowel obstruction. * Unwillingness to be transfused with blood components. * Known history of Hepatitis B or C infection or HIV infection