New antibody delivers targeted radiation to non-Hodgkin's lymphoma

Main Category: Lymphoma / Leukemia / Myeloma
Article Date: 03 Apr 2004 - 0:00 PDT

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Schering Press Release - Brighton (UK) - A new and unique form of cancer treatment is launched today by Schering Health Care, to help fight non-Hodgkin's lymphoma (NHL), one of the fastest growing cancers in the world, with 8,450 new cases diagnosed in the UK every year.

The new drug, called Zevalin® (ibritumomab tiuxetan), is the first radioimmunotherapy product to made available in the UK with British clinicians amongst the first in Europe to use radioimmunotherapy in treating patients with NHL, specifically CD20 positive, follicular B-cell NHL patients who are refractory to or have relapsed following rituximab therapy.

Zevalin® is the first in class dual-action radioimmunotherapy, which combines the targeting ability of an anti-CD20 monoclonal antibody (ibritumomab) with the power of yttrium-90 radiation to destroy cancer cells.

The CD20 antigen is used as a target because it is expressed on more than 90% of B-cells in NHL, and has a stable cell surface expression. It is neither shed nor internalised upon antibody binding and is not found freely circulating in the plasma.

In clinical studies Zevalin® has shown high efficacy in patients with follicular NHL refractory to rituximab. The overall response rate was 74% with 15% of patients achieving a complete response.

Amongst the experts talking about the new treatment at the British Nuclear Medicine Society meeting in Brighton today, is Dr Tim Illidge from the University of Southampton School of Medicine, one of the UK pioneers of the new treatment. "Zevalin is an innovative new treatment option that will enhance the way we approach therapy for NHL. It provides a further useful therapeutic option for heavily pre-treated low grade lymphoma patients and may result in improved disease free survival and even overall survival", says Dr Illidge. The full treatment regimen with Zevalin® requires only two patient visits, on an out-patient basis. It begins with an infusion of rituximab seven days before the administration of Zevalin®. Rituximab is administered prior to Zevalin® to deplete circulating CD20+ B-cells, thereby optimising the biodistribution of radiolabelled Zevalin®.

On day eight the patient receives a second infusion of rituximab followed by a 10-minute intravenous injection of Zevalin® linked to the Yttrium-90 radioisotope. Only minimal safety precautions are needed, and the patient can be discharged from the hospital.

In other words, targeted radioimmunotherapy allows maximum destruction of lymphoma cells while minimising patient exposure. Lymphoma cells are radiation sensitive and the inner part of malignant cell clusters can be destroyed by Zevalin's beta radiation penetrating even bulky tumours where blood supply is poor.

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For further information please contact:

Aino Forsti
Direct Line: (UK)01444 465691
Direct Fax: (UK)01444 230146
E-mail: aforsti@schering.co.uk

Notes

About non-Hodgkin's Lymphoma

Non-Hodgkin's lymphoma (NHL) is a type of malignant disease that occurs within the lymphatic system. NHL is the fifth most common cancer after breast, prostate, lung, and colon.

It originates from lymphocytes, a type of white blood cells, which can be divided into two main types, B lymphocytes and T lymphocytes (also called B-cells or T-cells). In adults, approximately 85% of NHL cases are of B-cell origin.

The overall prevalence of NHL in the European Union is about 230,000, with an annual incidence of about 70,000. This incidence is currently increasing in Europe by four per cent per year.

Non-Hodgkin's lymphomas can be divided clinically into two general categories: indolent lymphomas, which tend to grow relatively slowly, and aggressive lymphomas, which grow more rapidly. Indolent lymphomas include most forms of follicular NHL and were formerly classified as "low-grade".

Although indolent lymphomas are usually not curable, patients often live for 10 years or more, but as their disease advances or transforms over time, they need effective treatment. Indolent NHL represents around 45-50% of all non-Hodgkin's lymphoma.

About Zevalin® Clinical Studies

Studies with Zevalin® confirmed high response rates and durable responses in relapsed or refractory follicular, or transformed B-cell non-Hodgkin's lymphoma patients:

* In a phase II study evaluating patients with follicular NHL who did not respond to or responded insufficiently to therapies with rituximab, (an anti-CD20 monoclonal antibody without radiation) treatment with Zevalin® resulted in response in 74% of the patients (according to the International Workshop response criteria (IWRC).

* A randomised and controlled phase III clinical study with 143 patients was designed to compare the Zevalin® radioimmunotherapy regimen with rituximab alone in patients with low-grade, follicular or transformed NHL. The pre-defined primary efficacy goal/endpoint was overall response rate to treatment (a standardised measure of tumour shrinkage). Thirty percent of patients receiving Zevalin® achieved a complete response which means disappearance of any evidence of the disease vs. 16% for rituximab (p=0.04). The overall response rate achieved in patients in the Zevalin® group was significantly higher than in the rituximab group (80% for Zevalin® vs. 56% for rituximab, p=0.002).

* Results based on long-term follow-up of responders from three clinical trials demonstrated Zevalin® therapy induced durable complete responses (the disappearance of disease) in patients with relapsed or refractory B-cell NHL. Median duration of complete response approached two years. A few patient responses have continued for as long as six years.

Schering AG, Germany is currently investigating the use of Zevalin® in the treatment of aggressive NHL (i.e. diffuse large B-cell lymphoma) and as consolidation therapy for follicular NHL in earlier disease stages.

About Radioimmunotherapy

Radioimmunotherapy combines the targeting abilities of monoclonal antibodies with the cancer-cell killing power of radiation. Monoclonal antibodies are very specific and can be designed to attach directly to antigens that appear on the surface of cells. The attachment of a radioisotope (an element that gives off radiation) to a targeting monoclonal antibody permits the delivery of radiation directly to lymphoma cells. Due to a crossfire effect, the radiation can also reach and destroy neighbouring malignant cells.

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