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T99-8                       Print Media:       301-827-6242
February 5, 1999            
                            Consumer Inquiries:888-INFO-FDA

FDA APPROVES NOVEL TREATMENT FOR RARE FORM OF CANCER

FDA today approved a new biologic treatment for cutaneous t-cell lymphoma, (CTCL), a rare slow-growing form of non-Hodgkin's lymphoma. The new biotechnology product, known as a "fusion protein," is approved to treat certain patients with advanced or recurrent CTCL, when other treatments have not worked.

The product, denileukin diftitox (trade name Ontak) is produced by genetically fusing protein from the diphtheria toxin to interleukin-2 (IL-2), a naturally occurring immune system protein. This stable, fusion protein targets cells with receptors for IL-2 on their surfaces, including malignant cells and some normal lymphocytes, resulting in cell death.

Approximately 60% of patients with CTCL were found to have tumors with these IL-2 receptors and only these patients have been shown to benefit from Ontak.

Approximately 1,000 people in the United States are diagnosed with CTCL each year. It often is a slowly progressive disease, causing itchy, dry skin patches that can develop into tumors in the skin and other organs.

Ontak was tested in a phase 3 clinical trial of 71 patients with advanced CTCL who had failed at least one other treatment, such as interferon, chemotherapy or radiation. In this study, 30% of the patients' tumors were reduced 50% or more, with the response lasting an average of 4 months. Ten percent of the patients achieved a complete clinical remission that lasted an average 9 months. Such complete remissions would not be expected in an untreated group.

Because Ontak also affects normal lymphocytes, which are infection-fighting cells, and because patients with CTCL are prone to infections, patients should be monitored carefully during treatment. Severe infections were reported in 23% of patients in the trial, although it is unclear whether Ontak was the cause. Other side-effects related to the intravenous infusion of Ontak include allergic reactions, flu-like symptoms and fluid retention that may lead to other complications.

FDA approved Ontak under its accelerated approval regulations that allow sponsors to demonstrate a product's effectiveness for serious and life-threatening illnesses using surrogate end-points, such as tumor reduction, provided that the end-points are likely indicators of clinical benefit. As part of the accelerated approval, the sponsor of Ontak has committed to conducting a placebo-controlled study to further assess the long-term safety and efficacy of the product.

Ontak will be marketed by Ligand Pharmaceuticals, San Diego, Calif., and manufactured by Seragen, Inc. of Hopkinton, Mass., a subsidiary of Ligand. Ontak was granted orphan drug status in 1996. Orphan status provides incentives to companies to develop products for in use in small patient populations.

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