Proper dosing helps manage side effects with Bexxar

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Proper Dosing Can Provide Better Safety for Bexxar

Bexxar, a radio-conjugated monoclonal antibody,

delivers a radioactive iodine compound to B-cell

lymphocytes in persons with B-cell cancers. There is

a risk, however, of serious side effects in over- and

under-dosing. Three studies were presented at this

year's American Society for Clinical Oncology (ASCO)

meeting in San Francisco detailing the use of

Patient-Optimized (PO) dosing with Bexxar

(tositumomab and iodine I-131 tositumomab) for

patients with low-grade non-Hodgkin's lymphoma. This

provides treatment with a good estimate of side

effects for each patient.

In studies at the University of Nebraska, Omaha,

Bexxar was given using PO. Doses were calculated for

each individual patient based upon the amount of tumor

in the body and bone marrow. This provides an

estimate of how well the drug is cleared from the

body. This resulted in low incidences of Grade IV

thrombocytopenia and neutropenia, which were two and

16 percent, respectively. Patients with reduced

baseline blood count, bone marrow involvement or

extensive prior treatment were at greater risk of side

effects, but even in these subgroups, the incidences

of Grade IV thrombocytopenia and Grade IV neutropenia

were never greater than 5 and 28 percent,

respectively. Researchers concluded that even in

these higher risk groups, no patients were exposed to

unacceptable risks.

See: http://www.corixa.com/default.asp?pid=release_year & year=2001

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