DISEASE CHARACTERISTICS:

• Diagnosis of T-cell-large granular lymphocyte (LGL) leukemia or natural killer (NK)-LGL leukemia associated with ≥ 1 of the following clinical manifestations:

  • Severe neutropenia (i.e., < 500/mm³)

  • Neutropenia associated with recurrent infections, meeting 1 of the following criteria:

    • One severe infection requiring hospitalization
    • At least 2 infections requiring antibiotic therapy

  • Symptomatic anemia with any of the following:

    • Significant fatigue with ECOG performance status 0-1
    • Dyspnea on exertion, but can walk one flight of stairs without stopping (< grade 1 respiratory symptoms)
    • Cardiac symptoms including worsening of angina or new onset of chest pain
  • Transfusion-dependent anemia

• T-cell-LGL leukemia must meet all of the following criteria:

  • CD3+ and CD57+ cells > 300/mm³ or CD8+ cells > 650/mm³ by phenotypic studies of peripheral blood
  • Evidence for clonal T-cell receptor gene rearrangement based on positive flow cytometric analysis, T-cell receptor (TCR)-γ chain polymerase chain reaction (PCR), TCR-Vβ PCR, or by Southern blot analysis
• NK-LGL leukemia must have CD56+ or CD16+ NK cells > 750/mm³ by phenotypic studies of peripheral blood

PATIENT CHARACTERISTICS:

• Life expectancy > 2 years
• ECOG performance status (PS) 0-2 OR Karnofsky PS 60-100%
• Bilirubin ≤ 2.0 mg/dL
• AST and ALT ≤ 2.5 times upper limit of normal
• Creatinine ≤ 2.0 mg/dL
• Not pregnant or nursing
• Fertile patients must use effective contraception prior to and during study
• Negative pregnancy test
• No history of allergic reactions attributed to compounds of similar chemical or biologic composition to tipifarnib
• No allergies to imidazoles (e.g., clotrimazole, ketoconazole, miconazole, econazole, fenticonazole, isoconazole, sulconazole, tioconazole, or terconazole)

• No uncontrolled concurrent illness including, but not limited to, any of the following:

  • Ongoing or active infection
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Cardiac arrhythmia
  • Psychiatric illness or social situations that would limit study compliance
• No other serious medical illness that would limit survival to < 2 years
• No other malignancy within the past 5 years except inactive nonmelanoma skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

• More than 1 month since prior methotrexate, cyclophosphamide, or cyclosporine
• At least 4 weeks since prior supportive growth factor therapy
• No concurrent antiretroviral therapy for HIV-positive patients
• No other concurrent investigational agents
• No prior tipifarnib or other inhibitors of MAPK signaling intermediates
• No other anticancer agents or therapies