Ruxolitinib for the Treatment of T-Cell Large Granular Lymphocytic Leukemia

Inclusion Criteria: * Age 18 or older and able to swallow pills * Diagnosis of T-LGLL defined as: LGL cell population meeting diagnostic criteria (defined as CD3+CD8+ cell population \>650/mm3 or CD3+CD8+CD57+ population \>500/mm3 or LGL cell population with other immunophenotype that includes co-expression of CD3+, CD8+, CD57+ with \>500 cells/mm3 and the presence of a clonal T-cell receptor (within 1 month of diagnosis or relapse). This also includes patients with rare T-LGLL variants include CD4+ T-LGLL, and gamma/delta T-LGLL which can be CD4- and CD8-), though patients still must have the presence of a clonal T-cell receptor within 1 month of diagnosis or relapse. Note: patients with MDS-like T-LGLL may be included with PI approval even if CD3+CD8+ cell population is \< 650/mm\^3, though +TCR is required. Natural-Killer (NK) LGL is also permitted, provided there is a clonal NK-cell population noted with \> 500 cells/mm\^3 * Untreated T-LGLL or failed at least one line of frontline therapy; * Patients must be off treatment for at least 14 days or 5 half-lives, whichever is longer * Require Treatment for T-LGLL (one or more required) * Symptomatic anemia with hemoglobin \< 10 g/dL * Transfusion-dependent anemia * Neutropenia with absolute neutrophil count (ANC) \< 500/mm\^3 * Neutropenia with ANC \< 1500/mm\^3 with recurrent infections * Platelet count \> 50 x 10\^9/L. Platelet transfusion may be utilized to meet inclusion criteria, as long as the platelet count …