Brentuximab Vedotin in Treating Patients With Advanced Systemic Mastocytosis or Mast Cell Leukemia

Inclusion Criteria: * Written informed consent * Eastern Cooperative Oncology Group (ECOG) performance status of 0-3 * Life expectancy \> 12 weeks * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =\< 2.5 x upper limit of normal (ULN), if caused by ASM/MCL =\< 5 x ULN * Serum direct bilirubin =\< 1.5 x ULN; if considered related to ASM/MCL =\< 3 x ULN * Serum creatinine =\< 2.0 mg/dL * A diagnosis of systemic mastocytosis (SM) per 2008 World Health Organization (WHO) Criteria * Neoplastic mast cells must express CD30 by immunohistochemistry or flow cytometry * At least one of the eligible organ damage findings as defined by the international consensus response criteria * Females of childbearing potential and males who have partners of childbearing potential must agree to use an effective contraceptive method during the study and for 30 days following the last dose of study drug * Females of childbearing potential must have a negative serum or urine beta-human chorionic gonadotropin (hCG) pregnancy test result within 7 days prior to the first dose of SGN-35 * Females of non-childbearing potential are those who are postmenopausal greater than 1 year or who have had a bilateral tubal ligation or hysterectomy Exclusion Criteria: * Unwilling or unable to comply with the protocol * Any other concurrent severe known disease (except carcinoma in-situ) or concurrent severe and/or uncontrolled medical condition (e.g. uncontrolled diabetes, or active uncontrolled …