Eligibility Details:  
        Inclusion Criteria:
          -  Patients must have histologically or cytologically confirmed pancreatic adenocarcinoma
             that is metastatic or unresectable or recurrent
          -  Only subjects with positive mesothelin expression (Ventana mesothelin [MSLN]-
             immunohistochemistry [IHC]; Negative=H-score =< 10) are eligible. This is to be
             performed centrally. For dose escalation cohorts, patients with mesothelin expression
             in >= 5% of tumor cells are eligible. For dose expansion, patients must have moderate
             or strong tumor mesothelin expression defined as >= 30% of tumor cells with mesothelin
             expression of 2+/3 on immunohistochemical staining
          -  Patients must have received and either progressed or been intolerant to at least 1
             systemic therapy
          -  Life expectancy of at least 3 months
          -  Eastern Cooperative Oncology Group (ECOG) performance status score 0-1 (Karnofsky >=
             80%)
          -  Prior anti-cancer treatments are permitted (i.e. chemotherapy, including gemcitabine
             and nab-paclitaxel; radiotherapy; hormonal, or immunotherapy with the exception of
             anti-CTLA4, anti-PD1/PD-L1, and combination of anti-CTLA4 and anti-PD1/PD-L1)
             providing toxicity (except for alopecia) related to prior anti-cancer therapy and/or
             surgery have either resolved, improved to baseline or G1
          -  At least one (1) measurable lesion at baseline by computed tomography (CT) or magnetic
             resonance imaging (MRI) as per RECIST version (v)1.1; measurable disease is a
             requirement in both dose escalation phase and dose expansion phase
               -  Note: Measurable lesions may be in an irradiated field as long as there is
                  documented progression and the lesion(s) can be reproducibly measured
          -  At least one lesion safely accessible for biopsy unless medically contraindicated;
             biopsies are mandatory both in dose escalation and in dose expansion; in dose
             escalation and in expansion the following biopsies are optional: at baseline and at
             progression; biopsy could be: core needle or excisional or punch biopsy. Irradiated
             lesions can be biopsied if tumor growth is confirmed
          -  Patients must have archival tumor tissue for mesothelin expression and correlative
             biomarker studies; subjects must consent to provide tumor blocks or slides and the
             availability of the tissue must be confirmed prior to subjects receiving study
             medication; if an archived tumor specimen is unavailable or unsuitable for correlative
             biomarker studies, a pre-treatment fresh tumor biopsy is required
          -  Women of childbearing potential (WOCBP) must have a negative serum or urine pregnancy
             test (minimum sensitivity 25 IU/L or equivalent units of HCG) within 24 hours of study
             enrollment or randomization; WOCBP must agree to appropriate methods of contraception
             for the duration of treatment and for 6 months after completion of treatment; males
             who are sexually active with a partner of childbearing potential must agree to
             appropriate methods of contraception for the duration of treatment plus 7 months
             post-treatment completion; for all male patients, prior to treatment, advice should be
             sought for conserving sperm due to the chance of irreversible infertility as a
             consequence of treatment; genetic consultation is recommended if the patient wishes to
             have children after ending treatment; the investigator or a designated associate is
             requested to advise the patient how to achieve highly effective birth control
               -  Highly effective (failure rate of less than 1% per year) contraception methods
                  include:
                    -  Combined (estrogen and progesterone containing: oral, intravaginal,
                       transdermal) and progesterone-only (oral, injectable, implantable) hormonal
                       contraception associated with inhibition of ovulation
                    -  Intrauterine device (IUD) or intrauterine hormone-releasing system (IUS)
                    -  Bilateral tubal occlusion or vasectomized partner (provided that partner is
                       the sole sexual partner and has received medical assessment of the surgical
                       success)
                    -  Sexual abstinence (reliability to be evaluated in relation to the duration
                       of the clinical trial and the preferred and usual lifestyle of the patient)
               -  Male patients with a female partner of childbearing potential must use a condom
                  and ensure that an additional form of contraception is also used during treatment
                  plus 7 months post-treatment completion.
                    -  Note: a woman is considered WOCBP, i.e. fertile, following menarche and
                       until becoming postmenopausal unless permanently sterile; permanent
                       sterilization methods include but are not limited to hysterectomy, bilateral
                       salpingectomy and bilateral oophorectomy
               -  A postmenopausal state is defined as no menses for 12 months without an
                  alternative medical cause; a high follicle stimulating hormone (FSH) level in the
                  postmenopausal range may be used to confirm a postmenopausal state in women not
                  using hormonal contraception or hormonal replacement therapy; a man is considered
                  fertile after puberty unless permanently sterile by bilateral orchiectomy
          -  Leukocytes >= 3,000/mcL
          -  Absolute neutrophil count (ANC) >= 1500/mcL
          -  Platelets >= 100,000/mcL
          -  Hemoglobin >= 9 g/dL
               -  Patients must have not had a transfusion in the 2 weeks preceding this hemoglobin
                  (Hb) measurement
          -  Total bilirubin =< institutional upper limit of normal (ULN)
          -  Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase
             [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT])
             =< 3 x institutional ULN
          -  Creatinine =< institutional ULN OR glomerular filtration rate (GFR) >=60 mL/min/1.73
             m^2 unless data exists supporting safe use at lower kidney function values, no lower
             than 30 mL/min/1.73 m^2
          -  Albumin >= 2.5 mg/dL
          -  Ability to understand and the willingness to sign a written informed consent document
        Exclusion Criteria:
          -  Participation in another clinical study with an investigational product during the
             last 28 days or 5 half-lives prior to study day 1, whichever is shorter; concurrent
             enrollment in a non-interventional clinical study or the follow-up period of an
             interventional study is allowed
          -  Untreated central nervous system (CNS) metastatic disease, leptomeningeal disease, or
             cord compression; subjects with previously treated brain metastases may participate
             provided they are stable (without evidence of progression by imaging for at least six
             weeks prior to the first dose of trial treatment and any neurologic symptoms have
             returned to baseline), have no evidence of new or enlarging brain metastases, and are
             not using steroids for at least 14 days prior to trial treatment
          -  Evidence of uncontrolled, active infection, requiring parenteral anti-bacterial,
             anti-viral or anti-fungal therapy (washout: 7 days prior to cycle 1 day 1 [C1D1])
          -  Patients are prohibited from receiving the following therapies during the screening
             and treatment phase of this trial:
               -  Antineoplastic systemic chemotherapy or biological therapy
               -  Radiation therapy
                    -  Note: Radiation therapy to a symptomatic solitary lesion or to the brain may
                       be considered on an exceptional case by case basis after consultation with
                       Cancer Therapy Evaluation Program (CTEP); the patient must have clear
                       measurable disease outside the radiated field; administration of palliative
                       radiation therapy will be considered clinical progression for the purposes
                       of determining progression free survival (PFS)
               -  Live vaccines within 30 days prior to the first dose of trial treatment and while
                  participating in the trial; examples of live vaccines include, but are not
                  limited to, the following: measles, mumps, rubella, chicken pox, yellow fever,
                  rabies, Bacillus Chalmette-Guérin (BCG), typhoid (oral) vaccine, and intranasal
                  influenza vaccines (e.g., Flu-Mist)
          -  Current or prior use of systemic immunosuppressive medication (except corticosteroids
             at physiological doses, not exceeding 10 mg prednisone-equivalent day) within 10 days
             before the first dose of study medication; intranasal, inhaled, topical, or local
             steroid injections are allowed; steroids as premedication for hypersensitivity
             reactions (i.e. CT scan premedication) are allowed
          -  Any major surgery within 4 weeks of study drug administration
          -  Concomitant second malignancies (except adequately treated squamous cell carcinoma
             [SCC] or basal cell carcinoma [BCC] skin cancers or in situ bladder, breast or
             cervical cancers) within the last 3 years prior to study entry
          -  Uncontrolled or significant cardiovascular disease, including but not limited to
             ongoing or active symptomatic congestive heart failure, uncontrolled hypertension,
             unstable angina pectoris, unstable cardiac arrhythmia
          -  National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE)
             version (v)5 >= grade (G)2 peripheral neuropathy (sensory or motor)
          -  Patients with corneal epitheliopathy and at the discretion of the ophthalmologist any
             other eye disorder
               -  Note: Low grades of superficial punctate keratitis, within the range seen in the
                  normal population, should not lead to the exclusion of the patient
          -  Active or prior documented inflammatory bowel disease (i.e. ulcerative colitis)
          -  Active or prior documented autoimmune disease within the past 2 years
               -  Note: subjects with vitiligo, Grave's disease, psoriasis not requiring systemic
                  treatment or hypothyroidism (i.e. following Hashimoto syndrome) stable on hormone
                  replacement are not excluded
          -  Recent history or current evidence of bleeding disorder (i.e. any CTCAE G >= 2
             hemorrhage/bleeding event within 28 days before the start of treatment)
          -  Active human immunodeficiency virus (HIV), hepatitis B or C infection; HIV-positive
             patients on antiretroviral therapy with undetectable viral load will not be excluded
             from the trial; subjects with treated hepatitis B or C with unquantifiable viral loads
             and no organ compromise are not excluded
          -  Any condition that, in the opinion of the investigator, would interfere with
             evaluation of study treatment or interpretation of patient safety or study results
          -  Pregnant women are excluded from this study because of the potential for teratogenic
             or abortifacient effects; because there is an unknown but potential risk for adverse
             events in nursing infants secondary to treatment of the mother, breastfeeding should
             be discontinued for at least 6 months after last dose of study drugs; these potential
             risks may also apply to other agents used in this study; should a patient become
             pregnant or suspect she is pregnant while she is participating in this study, the
             patient should inform the treating physician immediately
          -  Participants who have had prior organ transplants (i.e. renal, lung, heart) due to the
             potential for increased rejection with immunotherapy
          -  Patients taking strong CYP3A4 inhibitors or strong CYP3A4 inducers within 2 weeks
             before the start of study treatment are excluded; consumption of grapefruit or its
             juice, and other fruit/juices which are strong CYP3A4 inhibitors within 2 weeks of
             study treatment is also not permitted; examples of strong CYP3A4 inhibitors include
             the following: indinavir, ritonavir, clarithromycin, itraconazole, ketoconazole,
             nefazodone, and saquinavir; examples of strong CYP3A4 inducers include the following:
             carbamazepine, rifampin, phenytoin, St. John's wort, and phenobarbital; these lists
             are not exhaustive