Inclusion Criteria:

          -  Documented informed consent by the participant

          -  Willingness to permit study team to obtain and use archival tissue, if already
             existing

          -  Eastern Cooperative Oncology Group (ECOG) performance status =< 2

          -  Life expectancy of > 3 months

          -  Histologic diagnosis of pancreatic carcinoma

          -  Unresectable disease

          -  Patients must not have received prior chemotherapy for disease with the following
             exceptions:

               -  Gemcitabine with or without capecitabine or fluorouracil, irinotecan, leucovorin,
                  and oxaliplatin (FOLFIRINOX) in the adjuvant setting if the recurrence is greater
                  than 6 months from the completion of chemotherapy

               -  Radiation sensitizing doses of 5-fluorouracil or capecitabine are allowed as part
                  of adjuvant treatment and recurrence must be documented >= 6 months from the
                  completion of chemotherapy

          -  Agreement by females and males of childbearing potential to use an adequate method of
             birth control (hormonal contraception is inadequate) or abstain from heterosexual
             activity for the course of the study through 30 days after the last dose of study
             medication

               -  Childbearing potential defined as not being surgically sterilized (men and women)
                  or have not been free from menses for > 1 year (women only)

          -  Absolute neutrophil count (ANC) >= 1,500/mm^3 (performed within 14 days prior to day 1
             of bosentan)

          -  Platelets >= 100,000/mm^3 (performed within 14 days prior to day 1 of bosentan)

          -  Total serum bilirubin =< 1.5 x upper limit of normal (ULN) (performed within 14 days
             prior to day 1 of bosentan)

          -  Aspartate aminotransferase (AST) =< 1.5 x ULN or =< 3 x ULN with liver metastases
             (performed within 14 days prior to day 1 of bosentan)

          -  Alanine aminotransferase (ALT) =< 1.5 x ULN or =< 3 x ULN with liver metastases
             (performed within 14 days prior to day 1 of bosentan)

          -  Creatinine clearance of >= 60 mL/min per 24 hour urine or the Cockcroft-Gault
             (performed within 14 days prior to day 1 of bosentan)

          -  Women of childbearing potential (WOCBP): negative urine or serum pregnancy test

               -  If the urine test is positive or cannot be confirmed as negative, a serum
                  pregnancy test will be required

        Exclusion Criteria:

          -  Dietary/herbal supplements

          -  Other investigational products

          -  Warfarin

          -  Cyclosporine A or rifampicin

          -  Glyburide; other hypoglycemic agents may be permitted

          -  Current or planned use of agents contraindicated for use with strong CYP3A4 inducers

          -  Strong inhibitors or inducers of CYP2C9

          -  Strong inhibitors or inducers of CYP3A

          -  Agent or agents that moderately inhibit both CYP2C9 and CYP3A (via a single
             concomitant agent, or co-administration of concomitant agents)

          -  Current or history of >= grade 2 peripheral neuropathy

          -  Issues with tolerating oral medication (e.g. inability to swallow pills, malabsorption
             issues, ongoing nausea or vomiting)

          -  Women who are or are planning to become pregnant or breastfeed

          -  Known allergy to eggs or any of the components within the study agents and/or their
             excipients

          -  No other prior malignancy is allowed except for the following: adequately treated
             basal cell or squamous cell skin cancer, in situ cervical cancer, adequately treated
             stage I or II cancer from which the patient is currently in complete remission, or any
             other cancer from which the patient has been disease free for three years

          -  Intercurrent or historic medical condition that increases subject risk in the opinion
             of the investigator. Eligibility may be revisited for intercurrent medical conditions
             once resolution/recovery is deemed adequate by the investigator (e.g. recovery from
             major surgery, completion of treatment for severe infection)

          -  Prospective participants who, in the opinion of the investigator, may not be able to
             comply with all study procedures (including compliance issues related to
             feasibility/logistics)