Pompe Disease and Treatment

Rare hereditary genetic disease called Pompe disease or infantile acid maltase deficiency, caused by a deficiency in the enzyme acid alpha-glucosidase (GAA) (Also known as lysosomal alpha-glucosidase or acid maltase. First, diagnosed in 1932 by Dutch Dr. J. C. Pompe), which is needed to break glycogen, a stored form of sugar used for energy. Increased buildup of glycogen causes increase muscle weakness throughout the body and affects various body tissues, particularly in the heart, skeletal muscles, nervous system and liver. There are forty-nine genetic disorders known as lysossomal storage disease, and Pompe disease is one of them. Also, classified as glycogen storage disease type two (GSD two). Inheriting this disease when both parents carry this abnormal gene. In the United States, estimated one in 40,000 births, will inherit Pompe disease. Worldwide 5,000 to 10,000 people are infected by Pompe disease. Three development stages of Pompe disease, attributed to age and progression of symptoms. Respiratory and cardiac complications are treated accordingly. The disease is deadly for infants and young children. Before, treatment of new drug, when mothers were diagnosed as pregnant with babies having Pompe disease, doctors would have recommend having an abortion.

Pompe disease can develop in three age groups and have progressive symptoms. Early onset or infantile period develops symptoms of severe lack of muscle tone, weakness, enlarged liver and heart. The onset of these symptoms occurs a few weeks or months after birth. Furthermore, symptoms include difficulty to swallow, tongue may protrude, and become enlarged. Within two years of age, most children die from respiratory or cardiac complications. Juvenile onset develops early or later in childhood. Symptoms progress, developing weakness of the respiratory muscles in the trunk, diaphragm, and lower limbs, and exercise becomes intolerable. Mental capacity is not impaired. These young patients become wheelchair dependent or bedridden and may require a respirator to breathe. Children that have inherited this disease do not live beyond their second or third year of life. Adult onset symptoms includes general muscle weakness, decrease function of respiratory muscles in the trunk, and lower limbs. Also diaphragm encompasses respiratory distress. Sometimes Pompe disease is misdiagnosed as multiple sclerosis, a chronic muscle disease. Furthermore symptoms include headaches at night or upon waking, decrease tendon reflexes, muscle weakness includes difficulty to climb stairs. A few adult patients continue their lives without major symptoms or limitations.

Treatment for Pompe disease includes physical and occupational therapy. Temporary relief by alterations in diet, but will not eliminate the progression of the disease. Families can receive support from counseling, and information regarding risk of future pregnancies. Family members of Pompe disease patients provide support by helping to overcome physical challenges, and emotional support, during times of fear, anger, and onset of depression.

In 2006, The Food and Drug Administration approved through the Orphan Drug Act (Provides a seven year – period of exclusive marketing to the first sponsor, who obtains marketing approval for a designated orphan drug. Research and development cost subsidized by the federal government, because there are no financial incentives for drug companies to provide it, for so few patients. Reserved for drugs that treat serious diseases affecting fewer than 200,000 people in the United States.) Myozyme (alglucosidase alfa, rhGAA) treat Pompe disease. Mozyme is manufacture by Genzyme Corporation (Public traded company) in Cambridge Massachusetts. Genzyme took eight years to develop, at a cost of more than $500 million. According to the manufacturer, the price of the drug will be similar to other Genzyme replacement therapies, which cost $200, 000 to $300,000 a year. Some analysts predict the drug could reach sales of $1 billion or more. Genzyme Corporation spent $53 million to expand its Allston Landing manufacturing facility in Belgium to handle Myozyme’s production. The Myozyme is administered by intravenous infusion of a solution into a vein every two weeks. Previous clinical trials administered the medication to 39 infantile onset patients of Pompe disease (Aged one month to 3.5 years old). The efficacy of Myozyme was later approved, after two clinical trials, which confirmed a greater survival outcome. However, long – term survival remains unknown. On April 3, 2006, Myozyme received European Medicines Agency approval, for the drug distribution in European Union. Adverse reactions reported taking Myozyme includes pneumonia, respiratory failure and distress, infections and fever. Label warning informs of possible life threatening allergic reaction. Also, label states “because of the potential for severe infusion reactions, appropriate medical support measures should be available when Myozyme is administered.” Genzyme Corporation reported that three percent of 280 patients, who had received Myozyme, experienced severe or significant hypersensitivity reaction.

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