Phase II Study of BL22 Immunotoxin in Patients With Cladribine-Resistant Hairy Cell Leukemia

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Alternate Title

BL22 Immunotoxin in Treating Patients Previously Treated With Cladribine for Hairy Cell Leukemia

Basic Trial Information

PhaseTypeStatusAgeSponsorProtocol IDs
Phase IITreatmentCompleted18 and overNCI, Pharmaceutical / IndustryNCI-04-C-0014
NCI-6048, 6048, NCT00074048



  1. Determine the response rate in patients with cladribine-resistant hairy cell leukemia treated with BL22 immunotoxin.


  1. Determine the response duration in patients treated with this drug.
  2. Determine the safety of this drug in these patients.
  3. Determine the pharmacokinetics of this drug in these patients.
  4. Correlate BL22 blood levels and toxicity of this drug with the development of neutralizing antibodies in these patients.

Entry Criteria

Disease Characteristics:

  • Histologically confirmed hairy cell leukemia
  • CD22-positive disease by fluorescence-activated cell sorting with anti-CD22 antibody
  • Meets at least 1 of the following indications for treatment:
    • Absolute neutrophil count less than 1,000/mm3
    • Hemoglobin less than 10 g/dL
    • Platelet count less than 100,000/mm3
    • Absolute lymphocyte count greater than 20,000/mm3
    • Symptomatic splenomegaly
  • Meets 1 of the following response criteria:
    • No response
    • Complete response (CR) or partial response (PR) less than 2 years in duration after the last course of prior cladribine
    • CR or PR less than 4 years in duration after a second or later course of prior cladribine

Prior/Concurrent Therapy:

    Biologic therapy

  • No prior BL22 immunotoxin
  • More than 12 weeks since prior monoclonal antibody therapy


  • See Disease Characteristics
  • More than 4 weeks since prior systemic cytotoxic chemotherapy

    Endocrine therapy

  • More than 4 weeks since prior systemic steroids (except stable doses of prednisone no greater than 20 mg/day)


  • Not specified


  • Not specified


  • No other concurrent investigational agents

Patient Characteristics:


  • 18 and over

    Performance status

  • ECOG 0-2

    Life expectancy

  • Not specified


  • See Disease Characteristics


  • AST and ALT no greater than 2.5 times upper limit of normal (ULN)
  • Bilirubin no greater than 2.2 mg/dL
  • Albumin at least 3.0 g/dL


  • Creatinine no greater than 1.4 mg/dL


  • Creatinine clearance at least 50 mL/min


  • No symptomatic congestive heart failure
  • No unstable angina pectoris
  • No cardiac arrhythmia


  • Not pregnant or nursing
  • Negative pregnancy test
  • Fertile patients must use effective contraception
  • No serum that neutralizes more than 75% of the activity of 1 µg/mL of BL22 immunotoxin using a bioassay
  • No ongoing or active infection
  • No psychiatric illness or social situation that would preclude study compliance
  • No other concurrent uncontrolled illness that would preclude study participation

Expected Enrollment


A total of 20-45 patients will be accrued for this study within 3 years.


Primary Outcome(s)

Response rate

Secondary Outcome(s)

Duration of response
Correlation of BL22 blood levels and toxicity with the development of neutralizing antibodies


Patients receive BL22 immunotoxin IV over 30 minutes on days 1, 3, and 5 followed by rest.

Patients are then evaluated at 8 weeks. Patients achieving complete hematologic remission are followed. All other patients continue to receive BL22 immunotoxin as above on days 1, 3, and 5. Treatment repeats every 4 weeks for up to a total of 16 courses in the absence of disease progression or unacceptable toxicity. Patients achieving CR without minimal residual disease (MRD) receive 2 courses beyond CR. Patients achieving CR with MRD receive 4 courses beyond CR.

Patients are followed every 4 months for 1 year, every 6 months for 1 year, and then annually thereafter.

Published Results

Kreitman RJ, Stetler-Stevenson M, Margulies I, et al.: Phase II trial of recombinant immunotoxin RFB4(dsFv)-PE38 (BL22) in patients with hairy cell leukemia. J Clin Oncol 27 (18): 2983-90, 2009.[PUBMED Abstract]

Related Publications

Matsushita K, Margulies I, Onda M, et al.: Soluble CD22 as a tumor marker for hairy cell leukemia. Blood 112 (6): 2272-7, 2008.[PUBMED Abstract]

Trial Contact Information

Trial Lead Organizations

Cambridge Antibody Technology

Robert Kreitman, MD, Protocol chair
Ph: 301-496-6947

Related Information

Web site for additional information

Registry Information

Official TitlePhase II Trial Of BL22 Immunotoxin In Hairy Cell Leukemia
Trial Start Date2003-10-27
Trial Completion Date2010-08-18
Registered in ClinicalTrials.govNCT00074048
Date Submitted to PDQ2003-10-22
Information Last Verified2007-10-23

Note: The purpose of most clinical trials listed in this database is to test new cancer treatments, or new methods of diagnosing, screening, or preventing cancer. Because all potentially harmful side effects are not known before a trial is conducted, dose and schedule modifications may be required for participants if they develop side effects from the treatment or test. The therapy or test described in this clinical trial is intended for use by clinical oncologists in carefully structured settings, and may not prove to be more effective than standard treatment. A responsible investigator associated with this clinical trial should be consulted before using this protocol.