Binimetinib for People With Relapsed/Refractory BRAF Wild Type Hairy Cell Leukemia and Variant

Eligibility Criteria

• * Histologically confirmed diagnosis of HCL or HCLv according to morphological and immunophenotypic criteria of WHO classification of lymphoid neoplasm. Participants should have at least one of the following indications for therapy:
• 1. Absolute neutrophil count (ANC) \<1 x10\^3/mcL
• 2. Hemoglobin \<10g/dL
• 3. Platelets\<100 x10\^3/mcL
• 4. Symptomatic splenomegaly
• 5. Enlarging HCL mass or bone lesion \> 2cm in short axis
• 6. Leukemia cell count \>5x10\^3/mcL
• * Refractory or relapsed disease - defined as either:
• * Refractory- no response or disease progression in less than or equal to 1 year following first-line treatment with a purine analog, or
• * Relapsed- having relapsed following treatment with at least 1 prior purine-analog treatments
• * Patients must be BRAF WT as confirmed from fresh bone marrow aspirate and/or peripheral blood sample, or lymph node/mass by the Laboratory of Pathology, NCI
• * Participants who are ineligible for, unable to obtain in a timely manner, cannot access, unwilling to undergo or have failed Moxetumomab Pasudotox trial at NCI
• * Age greater than or equal to 18 years
• * ECOG performance status less than or equal to 2 (Karnofsky greater than or equal to 60%).
• * Participants must have adequate organ and marrow function as defined below:
• * Total bilirubin less than or equal to 3x upper limit of normal (ULN), unless consistent with Gilbert s (ratio between total and direct bilirubin \> 5)
• * AST and ALT less than or equal to 3x ULN
• * Alkaline phosphatase \< 2.5x ULN
• * Serum creatinine less than or equal to 1.5 mg/dL or creatinine clearance greater than or equal to 60 mL/min/1.73 m\^2 for participants with creatinine levels above institutional normal calculated using eGFR
• * Serum albumin greater than or equal to 2 g/dL
• * Prothrombin time (PT)/International Normalized Ratio \< 2.5x ULN (If on warfarin, PT/INR \< 3.5x ULN; If on any other anticoagulation, Prothrombin time (PT) \< 2.5x ULN
• * Fibrinogen greater than or equal to 0.5x lower limit of normal
• * The effects of binimetinib on the developing human fetus are unknown therefore participants must use effective methods of contraception as directed below.
• * Females of childbearing potential (FOCBP) who are sexually active with a nonsterilized male partner must use a highly effective method of contraception and not donate ova prior to study entry and or the duration of study treatment and until 30 days after the last dose of binimetinib. Periodic abstinence, the rhythm method, and the withdrawal method are not acceptable methods of contraception. Females of childbearing potential are defined as those who are not surgically sterile (i.e., bilateral tubal ligation, bilateral oophorectomy, or complete hysterectomy) or those who are premenarchal or postmenopausal (defined as 12 months with no menses without an alternative medical cause). A highly effective method of contraception is defined as one that results in a low failure rate (i.e., less than 1% per year) when used consistently and correctly. Not all methods of contraception are highly effective. Female subjects must use a hormonal method in addition to a barrier method alone, to minimize the chance of pregnancy. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately.
• * Non-sterilized male participants who are sexually active with a female partner of childbearing potential must agree to use methods of contraception that are highly effective or acceptable, and not donate sperm from study entry until 90 days after the last dose of binimetinib.
• * Ability of subject to understand and the willingness to sign a written informed consent document.
• * Must co-enroll in study 10-C-0066: Collection of Human Samples to Study Hairy Cell and other Leukemias, and to Develop Recombinant Immunotoxins for Cancer Treatment
• * Participants who have had chemotherapy, immunotherapy or radiotherapy within 4 weeks prior to the start of study treatment.
• * Prior therapy with binimetinib.
• * Participants who are receiving any other investigational agents or have received an investigational agent within 14 days prior to the start of study treatment.
• * Participants who have undergone major surgery less than or equal to 6 weeks prior to start of study treatment or who have not recovered from side effects of such procedure.
• * Known hypersensitivity or contraindication to any component of binimetinib or its excipients.
• * Inability to swallow and retain study drug.
• * Is pregnant or breastfeeding or expecting to conceive within the projected duration of the study treatment, starting with the screening visit . Pregnant women are excluded from this study because binimetinib has 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 with binimetinib, breastfeeding should be discontinued if the mother is treated.
• * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, cardiac disfunction (details as below), uncontrolled pulmonary infection, pulmonary edema or psychiatric illness/social situations that would limit compliance with study requirements.
• * Evidence of active Hepatitis B Virus (HBV) or Hepatitis C Virus (HCV) infection.
• * Active second malignancy requiring treatment other than minor resection of indolent cancers like basal cell and squamous skin cancers.
• * Human immunodeficiency virus (HIV)-positive participants unless taking appropriate anti- HIV medications with a CD4 count of \> 200. Otherwise, there may be an increased risk of infections.
• * History of an allogeneic bone marrow or stem cell transplant.
• * Known history of acute or chronic pancreatitis
• * Impaired cardiovascular function or clinically significant cardiovascular disease including, but not limited to, any of the following:
• 1. History of acute coronary syndromes (including myocardial infarction, unstable angina, coronary artery bypass grafting, coronary angioplasty or stenting) \< 3 months prior to initiation of study therapy;
• 2. Congestive heart failure requiring treatment (New York Heart Association Grade greater than or equal to 2);
• 3. Left ventricular ejection fraction (LVEF) \< 50% as determined by Multigated Acquisition Scan (MUGA) or Transthoracic echocardiogram (TTE);
• 4. Uncontrolled hypertension defined as persistent systolic blood pressure greater than or equal to 160 mmHg or diastolic blood pressure greater than or equal to 100 mmHg despite current therapy;
• 5. History or presence of clinically significant cardiac arrhythmias (including resting bradycardia, uncontrolled atrial fibrillation or uncontrolled paroxysmal supraventricular tachycardia);
• 6. Triplicate average baseline QTcF interval greater than or equal to 480 ms.
• * Impairment of gastrointestinal function or disease which may significantly alter the absorption of study drug (e.g., active ulcerative disease, uncontrolled vomiting or diarrhea, malabsorption syndrome, small bowel resection with decreased intestinal absorption), or recent (less than or equal to 3 months) history of a partial or complete bowel obstruction, or other conditions that will interfere significantly with the absorption of oral drugs.
• * Concurrent neuromuscular disorder that is associated with elevated CK (e.g., inflammatory myopathies, muscular dystrophy, amyotrophic lateral sclerosis, spinal muscular atrophy).
• * History or current evidence of RVO or current risk factors for RVO (e.g., uncontrolled glaucoma or ocular hypertension, history of hyperviscosity or hypercoagulability syndromes); history of maculopathy or retinopathy for which there is an increased risk of