Gamma-Secretase Inhibitor RO4929097 and Gemcitabine Hydrochloride in Treating Patients With Advanced Solid Tumors

Inclusion Criteria: * Meets one of the following sets of criteria: * Histologically and/or cytologically confirmed solid malignancy * Metastatic or unresectable disease * Disease for which standard curative or palliative measures do not exist or are no longer effective * Histologically and/or cytologically confirmed adenocarcinoma of the pancreas (for patients in the expansion cohort) * Locally advanced or metastatic disease * No prior chemotherapy for advanced disease * Measurable disease, defined as ≥ 1 lesion that can be accurately measured in ≥ 1 dimension (longest diameter to be recorded) as ≥ 20 mm with conventional techniques or as ≥ 10 mm with spiral CT scan * No known brain metastases * ECOG performance status (PS) 0-1 (Karnofsky PS 60-100%) * Life expectancy \> 12 weeks * Hemoglobin ≥ 90 g/L (or ≥ 9 g/dL) * Leukocytes ≥ 3,000/mm\^3 * ANC ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Total bilirubin ≤ 1.25 times upper limit of normal (ULN) * AST/ALT ≤ 1.5 times ULN * Serum creatinine =\< ULN OR creatinine clearance ≥ 60 mL/min * No uncontrolled hypocalcemia, hypomagnesemia, hyponatremia, hypophosphatemia, or hypokalemia, defined as less than the lower limit of normal despite adequate electrolyte supplementation * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use two forms of adequate contraception (i.e., barrier contraception and one other method of contraception) for ≥ 4 weeks before, during, and for ≥ 12 months after completion of study treatment * Able to swallow medication * No malabsorption syndrome or other condition that would interfere with intestinal absorption * No uncontrolled concurrent illness including, but not limited to, any of the following: * Ongoing or active infection * Symptomatic congestive heart failure * Unstable angina pectoris * Cardiac arrhythmia other than chronic, stable atrial fibrillation * Psychiatric illness or social situations that would limit compliance with study requirements * No baseline QTc \> 450 msec (for male patients) or \> 470 msec (for female patients) * No history of risk factors for QT interval prolongation including, but not limited to, a family or personal history of any of the following: * Long QT syndrome * Recurrent syncope without known etiology * Sudden unexpected death * No history of torsade de pointes or other significant cardiac arrhythmias or the need for concomitant meds with known potential to prolong QT interval or antiarrhythmics * No diarrhea ≥ grade 2 not under control with standard anti-diarrhea medications * No serologic positivity for hepatitis A, B, or C * No history of liver disease or other forms of hepatitis or cirrhosis * No history of allergic reactions attributed to compounds of similar chemical or biologic composition to gamma-secretase inhibitor RO4929097 or to gemcitabine hydrochloride * Female patients may not donate ova during or after completion of study treatment * Male patients may not donate sperm during and for ≥ 12 months after completion of study treatment * Patients may not donate blood during and for ≥ 12 months after completion of study treatment * No other concurrent investigational or commercial agents or therapies administered with the intent to treat the patient's malignancy * Any number of prior therapies allowed * No prior therapy with a Notch inhibitor * At least 4 weeks since prior radiotherapy, chemotherapy, or systemic therapy (6 weeks if the last regimen included nitrosourea or mitomycin C) and recovered * Exceptions may be made for low-dose, non-myelosuppressive radiotherapy for symptomatic palliation * Patients in the expansion cohort must meet the following criteria: * No prior chemotherapy for advanced disease except for fluorouracil (with or without folinic acid) or gemcitabine hydrochloride given concurrently with radiotherapy as a "radiosensitizer" * At least 6 months since prior adjuvant gemcitabine hydrochloride * Prior radiotherapy for the management of local disease allowed provided \> 4 weeks have elapsed since the last radiation treatment and all toxicities have resolved * Patients who have had radiotherapy to their sole site of disease are eligible provided they have documented progression of that lesion before study registration * Recovered from side effects of previous systemic anticancer therapy to ≤ CTCAE grade 2 * No concurrent combination antiretroviral therapy for HIV-positive patients * No concurrent medications with narrow therapeutic indices that are metabolized by cytochrome P450 (CYP450), including warfarin sodium (Coumadin®) * No concurrent medications with known potential to prolong QT interval * No concurrent medications that are strong inducers/inhibitors or substrates of CYP3A4 * No concurrent medications or food that may interfere with the metabolism of gamma-secretase inhibitor RO4929097, including ketoconazole and grapefruit or grapefruit juice * No other concurrent investigational agents