Bexxar Highly Effective As First-Line Treatment for Patients With Non-Hodgkin's Lymphoma

Study Shows Radioimmunotherapy Produces Durable, Ongoing Remissions of

Three Years or More

May 22, 2000, 01:00 ET from University of Michigan Comprehensive Cancer Center

    NEW ORLEANS, May 22 /PRNewswire/ -- A radioimmunotherapy known as Bexxar
 produced tumor shrinkage in 97 percent of 76 previously untreated patients
 with advanced-stage, low-grade non-Hodgkin's lymphoma (NHL) in a new study at
 the University of Michigan Comprehensive Cancer Center.
     Most notably, 76 percent of patients achieved a complete remission, with
 no sign of cancer.  In addition, 84 percent of the 37 patients with evidence
 of lymphoma at the molecular level at the start of the trial achieved
 molecular remission for as long as three years with the treatment.  Molecular
 remissions were determined by a rigorous use of polymerase chain reaction, or
 PCR, technology, arguably the most sensitive cancer detection method available
     The promising results, from the first completed study of a first-line,
 stand-alone radioimmunotherapy for cancer, were presented today at the meeting
 of the American Society of Clinical Oncology by Mark S. Kaminski, M.D., U-M
 professor of hematology/oncology and co-director of the U-M's
 leukemia/lymphoma and bone marrow transplant programs.
     "We are extremely excited by these findings, which showed remarkable
 response rates and molecular remissions ongoing beyond three years," says
 Kaminski.  "Molecular remissions are seldom seen with chemotherapy in
 low-grade lymphoma, and appear to coincide with prolonged, durable responses.
 Furthermore, these results demonstrate the potential of this treatment as an
 effective and well-tolerated first-line, single-agent treatment for low-grade
 lymphoma, a disease without a known cure."
     The Phase II study, conducted entirely at the U-M, enrolled 76 patients
 with previously untreated, advanced-stage, low-grade follicular lymphoma.  The
 study was designed to evaluate the safety and efficacy of Bexxar as an NHL
 treatment given alone and as the first treatment approach.
     Patients received a trace dose, followed one to two weeks later with a
 therapeutic dose.  No further treatment was given.  This is in contrast with
 what patients would have experienced if given chemotherapy treatment, which is
 commonly repeated every three to four weeks for several months.
     Patients tolerated Bexxar treatment well.  Moderate, reversible low blood
 counts were seen, but no patients required hematologic supportive care.
 Sixty-two percent of patients developed human anti-mouse antibodies (HAMA).
 About two-thirds of these patients experienced flu-like symptoms lasting less
 than one-week.
     Virtually all patients -- 74 of 76 - responded in some way to treatment.
 An impressive number of patients (58) achieved a complete response.  About 70
 percent of those patients are projected to continue to be disease-free for at
 least three years.
     PCR analyses were conducted to test for detectable signs of disease in
 bone marrow among all patients before and after therapy.  Of the 37 patients
 who had molecular signs of the cancer before treatment, 31 achieved molecular
 remissions when measured again later.  About 75 percent of those 31 patients
 are projected to remain in remission for at least three years.
     A remission is usually measured by a patient's disease-free status based
 on the absence of symptoms through examination and medical imaging.  Molecular
 remissions are based on tests at the DNA level to see if the disease has been
 eradicated.  The PCR assay can detect one cancerous cell among a million
 normal cells; in non-Hodgkin's lymphoma the test looks for aberrant cells in
 the bone marrow and blood and can demonstrate how completely the disease has
 been destroyed by treatment.
     Bexxar is a radioimmunotherapy that combines a monoclonal antibody
 attached to the radioisotope iodine 131.  It attaches to a protein found only
 on the surface of the blood's B-cells, including those turned malignant in
 non-Hodgkin's lymphoma patients.  The compound is believed to work through a
 combination of immune system activity involving the monoclonal antibody and
 the effects from the radiation released by the iodine 131.  Through this
 targeted approach, the tumor cells receive a greater concentration of the
 therapeutic radiation while minimizing radiation exposure to normal tissues.
     The original studies in the therapeutic development of Bexxar, or Iodine I
 131 tositumomab, were done at the U-M by Kaminski and his colleague Richard
 Wahl, M.D., professor of nuclear medicine and radiology.  The therapy is now
 being jointly developed by Coulter Pharmaceutical, Inc. and SmithKline
     Non-Hodgkin's lymphoma is a form of cancer that affects the blood and
 lymphatic tissues.  The sixth leading cause of cancer death in the U.S., NHL
 also has the second fastest growing incidence rate of all cancers.  According
 to the National Cancer Institute, nearly 300,000 Americans have NHL, among
 them 140,000 with the low-grade or transformed low-grade forms of the disease.
 In more than 30 years, the survival rates of low-grade NHL patients have not
 changed, and patients continue to die from the disease or complications
 associated with current treatments.

SOURCE University of Michigan Comprehensive Cancer Center