Wyeth-Ayerst Pharmaceuticals, the pharmaceutical division of American Home Products Corporation (NYSE:AHP),announced today that the European Commission has designated Mylotarg™(gemtuzumab ozogamicin)as an "orphan medicinal product." The Commission decision follows a positive opinion adopted on 13 September 2000 by the Committee on Orphan Medicinal Products (COMP) of the European Agency for the Evaluation of Medicinal Products (EMEA).
"We anticipate that Mylotarg will become an important treatment option for European patients aged 60 and over with CD33-positive relapsed acute myeloid leukaemia (AML)," says L. Patrick Gage, Ph.D., President, Wyeth-Ayerst Research. "Its mechanism of action focuses on using antibody-antigen specificity to target delivery of potent chemotherapy to myeloid leukaemic cells. This compound represents the first product from Wyeth's promising oncology pipeline."
As a designated orphan medicinal product, Mylotarg will have access to the Commission's "centralised" procedure for assessment of the marketing authorisation application. Orphan medicinal products are intended to treat patients with rare life-threatening or very serious diseases for which no satisfactory method of treatment exists or where the product will be of significant benefit.
Orphan medicinal products do not automatically qualify for approval under "exceptional circumstances," but companies that sponsor orphan products receive incentives for bringing these products to the market and to the patient. Such incentives include the possibility of protocol assistance from the EMEA and fee reductions for all types of centralised marketing authorisation evaluation activities. If approved by the EMEA, Mylotarg would be the first product available in Europe from a new class of anticancer therapy known as "antibody-targeted chemotherapy." Mylotarg utilizes a patented linker technology with a novel potent anti-tumor antibiotic, calicheamicin.
Mylotarg is being developed jointly by Wyeth-Ayerst, a division of AHP, and Celltech Chiroscience, a research-based pharmaceutical company in the United Kingdom. At present, no other chemotherapeutic drugs are specifically approved for treating patients with relapsed AML.
About Acute Myeloid Leukaemia (AML)
AML is the most common type of acute leukaemia in adults. AML is characterised by a rapid accumulation of abnormal white blood cells in the blood and bone marrow, resulting in severe anaemia, infection, and haemorrhage during the course of the disease. Even with treatment, only about 20 percent of AML patients survive five years or more. Most treated AML patients have leukaemic relapses. Relapsed AML patients typically require prolonged hospitalisation, and their prognosis is generally poor.
About Mylotarg
Mylotarg is a recombinant humanised antibody linked with a potent anti-tumour antibiotic called calicheamicin, isolated by Wyeth-Ayerst researchers from a bacterium in caliche clay, a soil found in Texas, USA.
The antibody portion of Mylotarg binds specifically to the CD33 antigen, a glycoprotein commonly expressed by myeloid leukaemia cells. The anti-CD33 antibody was developed by the Fred Hutchinson Cancer Research Center in Seattle, Washington, USA, and was humanised by Celltech Group. The product received orphan drug status in the U.S. in November 1999, and was approved by the U.S. Food & Drug Administration in May 2000 as the first product in that country cleared specifically to treat relapsed AML patients.
Mylotarg should be administered under the supervision of a physician who is experienced in the use of cancer chemotherapeutic agents. Severe myelosuppression occurs when Mylotarg is used at recommended doses.
In clinical trials the adverse event profile for Mylotarg was consistent with the drug's targeted nature. No alopecia (hair loss) was seen. Additionally, no cardiotoxicity or cerebellar toxicity was reported. A low incidence(3%) of severe mucositis compared to 4-35% reported in the literature for other regimens and low incidence (28%) of severe infection compared to 29-65% reported in literature for other regimens were reported in the Mylotarg trials.
Patients being treated for leukaemia are at increased risk of developing opportunistic infections and bleeding. Patients treated with Mylotarg experienced anemia (47%), severe neutropenia (98%), and severe thrombocytopenia (99%).
Careful hematologic monitoring is required. Mylotarg can produce a postinfusion symptom complex of fever and chills, and less commonly hypotension and dyspnea during the first 24 hours after administration. Vital signs should be monitored during infusion and for four hours following infusion. Some patients developed severe liver function abnormalities, which were generally transient and reversible.
Caution should be exercised when administering Mylotarg to patients with hepatic impairment. Mylotarg may cause fetal harm when administered to a pregnant woman.
The most common adverse events reported were fever, chills, nausea, vomiting, thrombocytopenia, neutropenia, asthenia, diarrhea, abdominal pain, headache, stomatitis, dyspnea, epistaxis, and hypokalemia.
Wyeth-Ayerst Pharmaceuticals, a division of American Home Products Corporation, is a major research-oriented pharmaceutical company with leading products in the areas of women's health care, cardiovascular therapies, central nervous system drugs, musculoskeletal therapies, infectious disease, hemophilia, oncology, vaccines, and generic pharmaceuticals. American Home Products Corporation is one of the world's largest research-based pharmaceutical and health care products companies. It is a leader in the discovery, development, manufacturing and marketing of prescription drugs and over-the-counter medications. It is also a leader in vaccines, biotechnology and animal health care.
Celltech Group PLC (NYSE: CLL) is one of Europe's largest biopharmaceutical companies with a drug discovery capability of exceptional strength, including a leading position in antibody engineering. The merger with Medeva PLC in January, 2000 combined Celltech's late stage development pipeline with a profitable and cash-generating pharmaceutical business.