Cladribine and Rituximab in Treating Patients With Hairy Cell Leukemia

This phase II trial studies the side effects and how well cladribine and rituximab work in treating patients with hairy cell leukemia. Drugs used in chemotherapy, such as cladribine, work in different ways to stop the growth of cancer cells either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Immunotherapy with monoclonal antibodies, such as rituximab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving cladribine together with rituximab may kill more cancer cells.

PRIMARY OBJECTIVES: I. To demonstrate the efficacy in achieving complete response of combination of cladribine administered intravenously over 2 hours for 5 days followed by rituximab weekly for 8 weeks in patients with untreated or previously treated hairy cell leukemia. II. To examine the efficacy of rituximab to eradicate minimal residual disease (MRD) after cladribine therapy (as assessed by immunophenotyping of bone marrow and peripheral blood). III. To examine the effect of addition of rituximab to cladribine on the long term disease-free (DFS) and overall survival (OS) (as compared with historical controls). IV. To evaluate potential predictors of outcome including molecular and flow evaluations of MRD, as well as other potential molecular predictors such as v-raf murine sarcoma viral oncogene homolog B1 (BRAF). OUTLINE: Patients receive cladribine intravenously (IV) over 2 hours once daily (QD) on days 1-5 and rituximab IV once weekly for 8 weeks beginning on day 28 in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for 1 year.

Patients receive cladribine IV over 2 hours QD on days 1-5 and rituximab IV once weekly for 8 weeks beginning on day 28 in the absence of disease progression or unacceptable toxicity.

ABP 798, BI 695500, C2B8 Monoclonal Antibody, Chimeric Anti-CD20 Antibody, CT-P10, IDEC-102, IDEC-C2B8, IDEC-C2B8 Monoclonal Antibody, MabThera, Monoclonal Antibody IDEC-C2B8, PF-05280586, Rituxan, Rituximab ABBS, Rituximab Biosimilar ABP 798, Rituximab Biosimilar BI 695500, Rituximab Biosimilar CT-P10, Rituximab Biosimilar GB241, Rituximab Biosimilar IBI301, Rituximab Biosimilar JHL1101, Rituximab Biosimilar PF-05280586, Rituximab Biosimilar RTXM83, Rituximab Biosimilar SAIT101, rituximab biosimilar TQB2303, rituximab-abbs, RTXM83, Truxima

Defined as the absence of hairy cells in the bone marrow or the presence of less than 1 percent atypical cells and the disappearance of all evidence of hairy cell leukemia on physical examination. Monitored using the method of Thall, Simon, Estey as extended by Thall and Sung.

Efficacy of rituximab in eradication of minimal residual disease after cladribine therapy, assessed by immunophenotyping of bone marrow and peripheral blood

The method of Thall, Simon, Estey as extended by Thall and Sung will be used for efficacy and safety monitoring.

Inclusion Criteria: Age 18 years and older Diagnosis of hairy cell leukemia (HCL) established by bone marrow examination Patients with relapsed disease are eligible if they have had no more than one prior therapy Women of child-bearing potential must use birth control (oral contraceptive, barrier, abstinence or any other acceptable method) for the duration of the study Performance status =< 3 Creatinine less than or equal to 2.0 unless related to the disease Bilirubin less than or equal to 3.0 Transaminases less than or equal 3 x upper limit of normal unless related to the disease No prior investigational agent in the 4 weeks prior to initiation of therapy Exclusion Criteria: Unable or unwilling to sign the consent form Known infection with human immunodeficiency virus (HIV), hepatitis B or C Presence of active infection Presence of central nervous system (CNS) metastases New York Heart Association classification III or IV heart disease Prior chemotherapy (last 4 weeks)

Ravandi F, O'Brien S, Jorgensen J, Pierce S, Faderl S, Ferrajoli A, Koller C, Challagundla P, York S, Brandt M, Luthra R, Burger J, Thomas D, Keating M, Kantarjian H. Phase 2 study of cladribine followed by rituximab in patients with hairy cell leukemia. Blood. 2011 Oct 6;118(14):3818-23. doi: 10.1182/blood-2011-04-351502. Epub 2011 Aug 5.