• Age \>= 18 years

• Histological or cytological documentation of metastatic adenocarcinoma of the biliary tract

• Patients with previously identified genetic aberrations that are associated with homologous recombinant repair pathway will be eligible \[e.g. somatic mutations in ATM, ATR, CHEK2, BRCA 1/2, RAD51, BRIP1, PALB2, PTEN, FANC, NBN, EMSY, MRE11, ARID1A\] or germline mutations in the above genes. Clinical Laboratory Improvement Act (CLIA)-certified assays including commercial tests (Foundation Medicine, Caris, Tempus) will be allowed

• Measurable disease

• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 to 2. (Form is available on the Academic and Community Cancer Research United \[ACCRU\] website)

• Life expectancy of \>= 16 weeks per estimation of investigator

• Absolute neutrophil count (ANC) \>= 1500/mm\^3 (obtained =\< 7 days prior to registration)

• Platelet count \>= 75,000/mm\^3 (obtained =\< 7 days prior to registration)

• Hemoglobin \>= 9.0 g/dL with no blood transfusion in the past 28 days (obtained =\< 7 days prior to registration)

• Total bilirubin =\< 1.5 x upper limit of normal (ULN) (obtained =\< 7 days prior to registration)

• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) =\< 2.5 x ULN (=\< 5 x ULN for subjects with liver involvement of their cancer) (obtained =\< 7 days prior to registration)

• Serum creatinine =\< 1.5 x ULN (obtained =\< 7 days prior to registration)

• Institutional normalized ratio (INR)/activated partial thromboplastin time (aPTT) =\< 1.5 x ULN (obtained =\< 7 days prior to registration)

⁃ Exception: Patients who are therapeutically treated with anticoagulant agents will be allowed to participate provided that no prior evidence of underlying abnormality in coagulation parameters exists. Close monitoring of at least weekly evaluations will be performed until INR/PTT is stable based on a measurement that is pre-dose as defined by the local standard of care

• Alkaline phosphatase limit =\< 2.5 x ULN (=\< 5 x ULN for patients with liver involvement of their cancer) (obtained =\< 7 days prior to registration)

• Creatinine clearance estimated of \>= 51 mL/min using the Cockcroft-Gault equation (obtained =\< 7 days prior to registration)

• Negative serum pregnancy test done =\< 28 days prior to registration and confirmed prior to treatment on day 1, for women of childbearing potential, postmenopausal women or women of childbearing potential with evidence of non-childbearing status.

⁃ Postmenopausal is defined as:

∙ Amenorrheic for 1 year or more following cessation of exogenous hormonal treatments

‣ Luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in the post-menopausal range for women under 50

‣ Radiation-induced oophorectomy with last menses \> 1 year ago

‣ Chemotherapy-induced menopause with \> 1 year interval since last menses

‣ Surgical sterilization (bilateral oophorectomy or hysterectomy)

• Provide informed written consent

• Willing to return to enrolling institution for follow-up (during the active monitoring phase of the study)

• Willing to provide blood and tissue for correlative purposes

• Hepatitis B virus surface antigen (HBsAg), anti-hepatitis B virus core antigen (anti-HBc) and hepatitis B virus surface antigen (anti-HBs)

• Patients with chronic HBV receiving any systemic anticancer therapy should receive antiviral prophylactic therapy through and for minimum 12 months following anticancer therapy

• Patients with past HBV undergoing other systemic anticancer therapies not clearly associated with a high risk of HBV reactivation should be monitored with HBsAg and alanine aminotransferase during cancer treatment (suggest every other cycle)