Gemcitabine and Cisplatin With Ivosidenib or Pemigatinib for the Treatment of Unresectable or Metastatic Cholangiocarcinoma

PRIMARY OBJECTIVE: I. To evaluate the safety, tolerability, maximum tolerated dose (MTD) and/or recommended phase 2 dose, gemcitabine and cisplatin in combination with either ivosidenib or pemigatinib. SECONDARY OBJECTIVES: I. To evaluate median and progression free survival (PFS) for 6 months per investigator assessment. II. To evaluate the rate of overall survival (OS) in patients treated with gemcitabine and cisplatin in combination with either ivosidenib or pemigatinib. III. To describe the overall toxicity and adverse events profile associated with gemcitabine and cisplatin in combination with either ivosidenib or pemigatinib. IV. To determine the best response profile per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria in patients treated with gemcitabine and cisplatin in combination with either ivosidenib or pemigatinib. CORRELATIVE RESEARCH OBJECTIVE: I. To measure plasma 2-hydroxglutarate (2-HG) levels =\< 21 days prior to registration and at cycle 4 day 1 (+/- 2 days). OUTLINE: This is a dose de-escalation study. Patients are assigned to 1 of 2 arms. ARM A (IDH1 GENE MUTATION): Patients receive ivosidenib orally (PO) on days 1-21, cisplatin intravenously (IV) on days 1 and 8, and gemcitabine IV on days 1 and 8. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. ARM B (FGFR2 GENE ALTERATION): Patients receive pemigatinib PO on days 1-21, cisplatin IV on days 1 and 8, and gemcitabine IV on days 1 and 8. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days and then every 6 months for up to 3 years.