New treatment for lymphoma
Patients with CD20-positive follicular B-cell non-Hodgkin’s lymphoma, who are unresponsive to rituximab or who have relapsed, may benefit from a new radioimmunotherapy product due to be launched in April.
Zevalin (Schering Health Care) is a monoclonal antibody (ibritumomab)
attached to a radioisotope (yttrium-90) by a linking agent (tiuxetan).
It is designed
to deliver radiation to lymphoma cells. It targets the CD20 antigen,
which are unique to B-cell lymphocytes.
Patients are pre-treated with an infusion of unlabelled rituximab seven
days before Zevalin treatment to remove normal cells carrying the CD20
antigen from the peripheral blood system. This prevents radioactivity
being distributed throughout the body by circulating lymphocytes. On
the eighth day Zevalin is given as a slow intravenous infusion, following
a second infusion of rituximab. Due to a crossfire effect, radiation
is also delivered to neighbouring malignant cells that cannot be reached
by antibodies.
In phase III trials 30 per cent of patients receiving Zevalin achieved
a complete response versus 16 per cent for rituximab alone (P=0.04),
and the overall response rate in patients treated with Zevalin was 80
per cent compared with 56 per cent for rituximab alone.
The radiation dose may result in secondary malignacies and the development
of hereditary defects, so it must be established whether the risks of
radiation are less than the risks from the disease itself.
Notice-board p379
Correction
Zevalin (ibritumomab tiuxetan) was launched by Schering Health Care, not Schering-Plough. |
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The
Pharmaceutical Journal