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A Phase II Efficacy Study of Roferon-A in Hairy Cell Leukemia

Phase 2
Not Enrolling
Hairy Cell Leukemia

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Trial Information

A Phase II Efficacy Study of Roferon-A in Hairy Cell Leukemia

This study began as an efficacy study of interferon alpha-2a in patients with hairy cell
leukemia. It was observed that most patients responded with interferon, but that very few
complete responses were being obtained. Studies being done elsewhere confirmed the low
complete remission rate. Once interferon was stopped, nearly uniform disease progression
requiring reinstitution of therapy was observed. There appears to be very few if any
patients who will not require further therapy after receiving 12 or 18 months of continuous
interferon treatment. Because of these findings, and in order to evaluate the safety and
efficacy of long-term recombinant interferon-alpha (IFN-Alpha) in patients with hairy cell
leukemia, we opted to administer interferon continuously to patients who were initially
responsive to this drug. Of the 53 evaluable patients (of the 56 entered on this study),
there was one complete remission, 41 partial remissions, 1 minor response, 9 patients with
stable disease and only 1 patient with disease progression. Fourteen patients continue to
receive interferon without interruption with a median duration of continuous interferon
treatment of 9.2 years. Thirty-four patients discontinued interferon for a variety of
reasons, the most common being the development of acquired interferon resistance in
association with interferon antibodies. The resistance to interferon was manifested early,
in the first 18 months of treatment, except in two cases. An important finding in this
study is the continued slow, but significant, hematologic improvement in absolute
granulocyte and platelet counts beyond 18 months of therapy, thereby indicating that
prolonged treatment results in continued benefit rather than the production of antibodies
with subsequent development of interferon resistance. Although it is clear from this study
that hairy cell leukemia can be controlled in the long-term with interferon, longer
follow-up will be necessary to determine if continuous therapy with interferon is better
than intermittent therapy. The optimal therapy for hairy cell leukemia remains open to
discussion. Although early reports suggested that 2-chlorodeoxyadenosine was curative,
additional studies with longer periods of follow up suggest that as many as 30% of patients
will relapse. This study provides the only instance where continuous long term treatment
with interferon has been evaluated. This provides an opportunity to evaluate the long term
toxicity of chronic interferon therapy, the long term efficacy of this treatment and to
evaluate the potential benefits of long term interferon in preventing second malignancies, a
complication noted in about 15% of patients treated in other fashions.

After their initial clinical evaluation, patients were given 3 million units of recombinant
IFN-Alpha subcutaneously daily for 4 to 6 months. In responding patients, maintenance
therapy was given at a dose of 3 million units subcutaneously 3 times per week. Responding
patients have continued on therapy indefinitely.

Inclusion Criteria

Age 18-70.

Patients must have morphologically identifiable hairy cells in peripheral blood and bone
marrow, or tissue biopsies with at least one of the following: 1) Positive stain for the
tartrate-resistant acid phosphatase 2) Electron microscopy compatible with hairy cells.

Patients must be ambulatory with an expected survival greater than 16 weeks and be willing
and able to give written informed consent.

Patients must have a disease that is assessable, defined by: 1) Pancytopenia 2) Bone
marrow leukemic infiltrate 3) Lymphadenopathy, splenomegaly, or hepatomegaly.

Patients must not require palliative chemotherapy, immunotherapy or hormonal therapy other
than the treatment prescribed in this protocol.

Patients must be tested for Hepatitis B surface antigen within one week of entry into this

No pregnant or lactating women. No fertile men and women, unless using effective

No patients with unstable angina. Patients with Class III or IV cardiovascular disease
may be entered only after medical clearance by a cardiology consultant.

No patients with severe intercurrent infection or patients having had surgery within the
past four weeks unless fully recovered.

No patients with impaired renal function (serum creatinine greater than 1.8).

No patients with impaired hepatic function (total bilirubin greater than 1.4).

No patients with serum calcium greater than 12 mg/dl.

No patients with a performance status less than or equal to 60% on the Karnofsky scale.

No patients who have had any prior (leukocyte or fibroblast) interferon therapy.

No patients unable to carry out the treatment program.

No patients less than 20,000 per cu mm platelets and clinical bleeding disorder; both must
be present for patient to be excluded.

Type of Study:


Study Design:

Endpoint Classification: Safety/Efficacy Study, Primary Purpose: Treatment


United States: Federal Government

Study ID:




Start Date:

January 1997

Completion Date:

April 2002

Related Keywords:

  • Hairy Cell Leukemia
  • Follow-Up Study
  • Relapse-Free Survival
  • Serum Soluble IL-2 Receptor
  • Hematologic Malignancy
  • Chronic Therapy
  • Leukemia
  • Leukemia, Hairy Cell



National Cancer Institute (NCI) Bethesda, Maryland  20892