Moxetumomab Pasudotox for Advanced Hairy Cell Leukemia

Inclusion Criteria

• - INCLUSION CRITERIA: - Patients must have histologically confirmed hairy cell leukemia or hairy cell leukemia variant .with a need for therapy - Patients must be Pseudomonas-immunotoxin naive - Patients must have had at least 2 prior purine analogs, or at least 1 course of purine analog and 1 of either rituximab or BRAF inhibitor. - Men or women age greater than or equal to 18 years. - ECOG performance status less than or equal to 2. - Patients must have adequate organ function EXCLUSION CRITERIA - Patients who have had chemotherapy, immunotherapy or radiotherapy within 4 weeks prior to entering the study. - Patients who are receiving any other investigational agents. - Patients with known brain metastases should be excluded from this clinical trial - Patients with clinically significant ophthalmologic findings during screening - Pregnant or breastfeeding females. - Positive for Hepatitis B core antibody or surface antigen unless the patient is on Lamivudine or Entecavir and Hepatitis B Viral DNA load is less than 2000 IU/mL. - Active second malignancy requiring treatment other than minor resection of indolent cancers like basal cell and squamous skin cancers - HIV-positive patients unless taking appropriate anti-HIV medications with a CD4 count of greater than 200. - History of allogeneic bone marrow transplant. - Patients with history of both thromboembolism and known congenital hypercoagulable conditions. - Uncontrolled pulmonary infection, pulmonary edema. - Adequate oxygen saturation - Radioimmunotherapy within 2 years prior to enrollment in study. - Adequate hematologic function - Adequate lung function - Patients with history of thrombotic microangiopathy or thrombotic microangiopathy / hemolytic uremic syndrome - Patients with QTc interval (Friderica) elevation > 500 msec based on at least 2 separate 12-lead ECGs - Patient on high dose estrogen - Patients with clinical evidence of disseminated intravascular coagulation