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Vemurafenib and Obinutuzumab in Treating Patients with Previously Untreated Classical Hairy Cell Leukemia

Trial Status: Closed to Accrual

This phase II trial studies how well vemurafenib and obinutuzumab work in treating patients with previously untreated classical hairy cell leukemia. Vemurafenib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Obinutuzumab is a drug that targets a protein called CD20, which is found on the surface of B cells, the white blood cells that are affected by hairy cell leukemia. When obinutuzumab attaches to CD20, it directly destroys the B cells and makes them more visible to the immune system, which then helps them attack and destroy the cancerous B cells. Giving vemurafenib and obinutuzumab may help shrink the cancer in patients with previously untreated hairy cell leukemia.

Inclusion Criteria

  • Patients must be >= 18 years of age
  • Histologically confirmed classical HCL by the enrolling institution
  • Has not received any prior therapy for the disease
  • Absolute neutrophil count (ANC) =< 1.0
  • Hemoglobin (Hgb) =< 10.0 or
  • Platelet (PLT) =< 100K
  • Eastern Cooperative Oncology Group (ECOG) performance status of 0-2
  • Total bilirubin =< 1.5 times the upper limit of normal (ULN)
  • Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =< 2.5 x ULN
  • Serum creatinine =< 1.5 x ULN
  • Electrocardiogram (ECG) without evidence of clinically significant ventricular arrhythmias or ischemia as determined by the investigator and a rate-corrected QT interval (QTc, Bazett's formula) of < 480 msec
  • For women of childbearing potential, agreement to the use of two acceptable methods of contraception, including one barrier method, during the study and for 6 months after discontinuation of vemurafenib
  • For men with female partners of childbearing potential, agreement to use a latex condom and to advise their female partner to use an additional method of contraception during the study and for 6 months after discontinuation of vemurafenib
  • Negative serum pregnancy test within 7 days of commencement of treatment in women of childbearing potential

Exclusion Criteria

  • Have had previous treatment for HCL, including purine analogs, rituximab, and other investigational agents; previous treatment with transfusions and other supportive care such as granulocyte colony-stimulating factor (G-CSF) and erythropoietin are allowed
  • Known hypersensitivity to any of the study drugs
  • Clinically significant history of liver disease, including viral or other hepatitis, current alcohol abuse, or cirrhosis
  • Patients with uncorrectable electrolyte abnormalities with potassium (K) > ULN (upper limit of normal)
  • Patients with any active and uncontrolled infections (such as bacterial, fungal, and new or reactivated viral infections)
  • Presence of positive test results for hepatitis B virus (HBV), hepatitis B surface antigen (HBsAg) or hepatitis C (HCV) antibody * Patients who are positive for HCV antibody must be negative for HCV by polymerase chain reaction (PCR) to be eligible for study participation * Patients with occult or prior HBV infection (defined as positive total hepatitis B core antibody [HBcAb] and negative HBsAg) may be included if HBV deoxyribonucleic acid (DNA) is undetectable; these patients must be willing to undergo monthly DNA testing
  • Known infection with human immunodeficiency virus (HIV) or human T-cell leukemia virus 1 (HTLV-1)
  • Invasive malignancy that require active systemic chemotherapy or biologics that may cause significant drug-drug interaction with either vemurafenib or obinutuzumab
  • Malabsorption syndrome or other condition that precludes enteral route of administration
  • Patients with HCL variant (as defined by absence of expression of CD25)
  • Pregnant or lactating, or intending to become pregnant during the study


New Haven
Yale University
Contact: Scott Huntington
Phone: 203-200-4363


Dana-Farber Cancer Institute
Contact: Eric Stephen Winer
Phone: 617-632-6876

New Jersey

Basking Ridge
Memorial Sloan Kettering Basking Ridge
Contact: Jae Park
Phone: 646-608-3743
Memorial Sloan Kettering Monmouth
Contact: Jae Park
Phone: 646-608-3743
Memorial Sloan Kettering Bergen
Contact: Jae Park
Phone: 646-608-3743

New York

Memorial Sloan Kettering Commack
Contact: Jae Park
Phone: 646-608-3743
New York
Memorial Sloan Kettering Cancer Center
Contact: Jae Park
Phone: 646-608-3743
Memorial Sloan Kettering Nassau
Contact: Jae Park
Phone: 646-608-3743
West Harrison
Memorial Sloan Kettering Westchester
Contact: Jae Park
Phone: 646-608-3743


I. To determine the efficacy of vemurafenib in combination with obinutuzumab as assessed by complete response (CR) rates.


I. To assess the safety and tolerability of vemurafenib plus obinutuzumab in patients with previously untreated hairy cell leukemia (HCL).

II. To assess the efficacy of vemurafenib plus obinutuzumab based on duration of response and kinetics of minimal residual disease (MRD) response assessed by immunohistochemistry.

III. To determine the progression-free and overall survival of HCL patients treated with vemurafenib plus obinutuzumab.

IV. To assess the pharmacodynamics of vemurafenib and obinutuzumab via measurement of BRAF downstream targets (MEK, phosphorylated [p]-MEK, ERK, p-ERK) from the peripheral blood and/or bone marrow aspirate samples and by measurement of BRAFV600E allele burden by digital polymerase chain reaction (PCR).

V. To evaluate the potential mechanisms of resistance by assessing secondary BRAF mutations, signaling on the entire MAPK, PI3K and JAK-STAT pathways, and reactivation of MAPK pathways.


Patients receive vemurafenib orally (PO) twice daily (BID) on days 1-28 of all cycles. Beginning cycle 2, patients also receive obinutuzumab intravenously (IV) on days 1, 8, and 15 of cycle 2 and on day 1 of cycle 3 and 4. Treatment repeats every 28 days for up to 4 cycles of vemurafenib and for up to 3 cycles of obinutuzumab in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up at 4 weeks and every 2-3 months thereafter for 1 year.

Trial Phase Phase II

Trial Type Treatment

Lead Organization
Memorial Sloan Kettering Cancer Center

Principal Investigator
Jae Park

  • Primary ID 17-513
  • Secondary IDs NCI-2018-00285
  • ID NCT03410875