EU/3/00/005

On 18 October 2000, orphan designation (EU/3/00/005) was granted by the European Commission to Wyeth Europa Limited, United Kingdom, for gemtuzumab ozogamicin for the treatment of acute myeloid leukaemia.

What is acute myeloid leukaemia? 

Acute myeloid leukaemia is a disease in which cancer cells are found in the blood and the bone marrow. The bone marrow is the spongy tissue inside the large bones in the body. Normally, the bone marrow makes cells called “blasts” that mature into several different types of blood cells that have specific functions in the body. These include red cells, white cells and platelets. Red blood cells carry oxygen and other materials to all tissues of the body. White blood cells fight infection. Platelets make the blood clot. When leukaemia develops, the bone marrow produces large numbers of abnormal blood cells. There are several types of leukaemias. In myeloid leukaemia blasts that are developing into white blood cells called granulocytes are affected. These blasts do not mature but multiply abnormally and accumulate in the bone marrow. Then, they are also found in the blood. Leukaemia can be acute (when it develops quickly with many blasts). Acute myeloid leukaemia is life-threatening.

What are the methods of treatment available?

Treatment for leukaemia is complex and depends on a number of factors including the type of leukaemia, the extent of the disease and whether the leukaemia has been treated before. It also depends on the age, the symptoms, and the general health of the patient. The primary treatment of acute myeloid leukemia is chemotherapy (using drugs to kill cancer cells). Several products were authorised for the condition in the Community at the time of submission of the application for orphan drug designation. Gemtuzumab ozogamicin, also known as mylotarg, could be of potential significant benefit for the treatment of acute myeloid leukaemia. The assumption will have to be confirmed at the time of marketing authorisation. This will be necessary to maintain the orphan status.

What is the estimated number of patients affected by the condition?

According to the information provided by the sponsor, acute myeloid leukaemia was considered to affect about 25,000 persons in the European Union.

 

*Disclaimer: The number of patients affected by the condition is estimated and assessed for the purpose of the designation, for a European Community population of 377,000,000 (Eurostat 2001) and may differ from the true number of patients affected by the condition. This estimate is based on available information and calculations presented by the sponsor at the time of the application.

How is this medicinal product expected to act?

Antibodies are proteins in the body that target and link specific structures on the surface of foreign bodies, such as bacteria or cancer cells. CD33 is a protein found on the surface of acute myeloid leukaemia cells. Gemtuzumab ozogamicin is an antibody chemically linked to a specific compound that recognises and binds specifically to the CD33 protein. Following the binding, the cancer cells itself transforms the compound linked to the antibody into a type of toxic substance, which might lead to the destruction of the cancer cell.

What is the stage of development of this medicinal product?

The effects of gemtuzumab ozogamicin were evaluated in experimental models. At the time of submission of the application for orphan designation, clinical trials in patients with acute myeloid leukaemia were ongoing. Gemtuzumab ozogamicin was marketed in the United States for the treatment of patients with CD33 positive acute myeloid leukaemia in first relapse who are 60 years of age or older and who are not considered candidates or cytotoxic chemotherapy, at the time of submission. Orphan designation of Gemtuzumab ozogamicin was granted in the United States for the same indication and in Japan for patients with relapsed or refractory acute myelogenous (myeloid) leukaemia. According to Regulation (EC) No 141/2000 of 16 December 1999, the Committee for Orphan Medicinal Products (COMP) adopted on 13 September 2000 a positive opinion recommending the grant of the above-mentioned designation.

Opinions on orphan medicinal products designations are based on the following cumulative criteria

• the seriousness of the condition, 
• the existence or not of alternative methods of diagnosis, prevention or treatment and
• either the rarity of the condition (considered to affect not more than five in ten thousand persons in the Community) or the insufficient return of development investments.

Designated orphan medicinal products are still investigational products which were considered for designation on the basis of potential activity. An orphan designation is not a marketing authorisation. As a consequence, demonstration of the quality, safety and efficacy will be necessary before this product can be granted a marketing authorisation.