Advances in the Treatment of CHILDHOOD DISEASES
Respiratory Distress Syndrome
Tyrosinemia
Primary IGF-1 Deficiency
Premature babies face an uphill battle as their fragile, still-developing systems fight to overcome many issues—including immature lungs struggling just to breathe. Respiratory distress syndrome (RDS) is caused by an infant's lack of surfactant, a natural lung-wetting agent, which normally develops between the 34th and 37th week of pregnancy. Without surfactant, the lungs cannot inflate.99 Its absence in premature infants causes breathing difficulties and collapsed lungs. Prompt treatment is required for high-risk and premature infants. This treatment may include medicines, supplemental oxygen, and use of a ventilator.100
Of the 250,000 infants born prematurely each year, up to 50,000 will suffer from infant RDS, and 5,000 will die from it.101 RDS usually occurs right after birth.
Three new medicines have been approved in the last decade for this one rare condition, advancing the way that neonates with immature lungs are treated. With these medicines, premature infants have a better chance of surviving this life-threatening disorder.
PHARMACEUTICAL ADVANCES
Rescuing the Tiniest Lungs
Calfactant, approved in 1997, is used to treat babies with RDS, and also to prevent premature babies from developing RDS.102 A natural bovine-derived surfactant, calfactant attaches rapidly to the surface of the air-to-liquid interface within the lung's air sacs and modifies surface tension similarly to natural lung surfactant, thereby allowing the air sacs to expand and improving newborns' breathing ability.
Nitric oxide, approved in 1999, reduces the common complications of lung hypertension in newborns by expanding blood vessels in the lungs.103 Nitric oxide reduces the need for ventilator support and helps regulate the muscle tone in the arteries of the lungs.
Poractant alfa, approved in 1999, treats RDS in premature babies by reducing the amount of air trapped in the lining of the lungs. A natural porcine-derived surfactant, poractant alfa increases lubrication within the lung's air sacs thus improving expansion and ventilation.104
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Children with the genetic, metabolic disorder tyrosinemia gradually develop liver failure and liver cancer, but a new drug, nitisinone, approved in 2002, can extend their lives. These children lack the enzyme that breaks down the amino acid tyrosine. Normally, the liver is where tyrosine is broken down; when it accumulates in the blood, it can lead to progressive liver failure and, often, cancer. Tyrosinemia may also cause damage to the kidneys, eyes, skin, and nervous system.
The most common and severe form of the disease is acute tyrosinemia, with which children are born or develop soon after birth. Infants with acute tyrosinemia exhibit rapid onset of symptoms, and they often fail to gain weight and grow. Infants with the less prevalent chronic tyrosinemia have a more gradual and less severe onset of symptoms.
Children who experience liver failure or are diagnosed with liver cancer as a result of tyrosinemia rarely make it into their twenties without a liver transplant. According to the FDA, this disorder affects 2,500 children in the United States.105
PHARMACEUTICAL ADVANCES
Patients' Pathway to Longer Life
Nitisinone opens the door to an extended lifespan for children with tyrosinemia. It decreases the level of tyrosine in the blood, thereby reducing the likelihood of liver failure and liver cancer. In combination with a diet restricted in the amino acids tyrosine and phenylalanine, this drug has been shown to increase the four-year survival rate of children who were diagnosed at less than two months of age to 88 percent. Historical data for children treated with dietary restrictions alone shows a survival rate of 29 percent for the same time period.106
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Kids labeled as having "short stature" are shorter than 97.5 percent of other children their same age and gender. Short stature can be caused by several factors, including family genetics, hormone problems, or various diseases.107
Recently, it has been found that short stature can also be the result of low insulin-like growth factor-1 (IGF-1) levels. This condition is called Primary IGF-1 Deficiency (Primary IGFD). If left untreated, Primary IGFD can lead to other complications such as lipid disorders, obesity, diabetes, or decreased bone density.108
PHARMACEUTICAL ADVANCES
First Medicine to Treat Primary IGFD
In 2005, the FDA approved mecasermin, the first treatment for approximately 6,000 children in the United States with severe Primary IGFD.109 Mecasermin is a manufactured protein that functions like the natural human protein as a growth catalyst. This protein must be present for children's bones, cartilage, and organs to grow properly. An eight-year clinical trial demonstrated that, on average, children grew one inch per year for each year of therapy using this new medicine.110
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The number of orphan drugs is expected to rise in the coming years as more new medicines are developed that target specific genetic disorders.111 |
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Endnotes:
99 American Lung Association, "Respiratory Distress Syndrome of the Newborn Fact Sheet," American Lung Association, http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=35693 (accessed 11 September 2005).
100 National Library of Medicine, MedlinePlus Medical Encyclopedia, Respiratory Distress Syndrome in Infants, http://www.nlm.nih.gov/medlineplus/ency/article/001563.htm (accessed 27 September 2005).
101 National Organization for Rare Disorders, Respiratory Distress Syndrome, Infants, full report, http://rarediseases.org/search/rdb_fullreport_pf (accessed 29 July 2005).
102 Food and Drug Administration, Infasurf, 25 July 2000, http://www.fda.gov/cder/consumerinfo/druginfo/infasurf.htm (accessed 14 September 2005).
103 S. Reents et al., Clinical Pharmacology, Gold Standard Multi-media, Inc., Nitric Oxide, http://cp.gsm.com (accessed 3 August 2005).
104 S. Reents et al., Clinical Pharmacology, Gold Standard Multi-media, Inc., Poractant Alfa, http://cp.gsm.com (accessed 3 August 2005).
105 Food and Drug Administration, "FDA Approves Drug to Treat Rare Pediatric Liver Disease," 22 January 2002, http://www.fda.gov/bbs/topics/ANSWERS/2002/ANS01131.html (accessed 3 October 2005).
106 Ibid.
107 Tercica, Understanding Short Stature, http://investor.tercica.com/releases.cfm (accessed 29 September 2005).
108 Drugs.com, "Increlex," Drugs.com, http://www.drugs.com/increlex.html (accessed 29 September 2005).
109 M. Herper, "FDA Approves Tercica's Increlex," Forbes.com, 31 August 2005, http://www.forbes.com/markets/2005/08/31/fda-increlex-tercica-0830markets01.html?partner=yahootix (accessed 29 September 2005).
110 Drugs.com, op. cit.
111 Food and Drug Administration, "Office of Orphan Products Development," Budget 2006, http://www.fda.gov/oc/oms/ofm/budget/2006/PDFs/Summary/Pages194thru199.pdf (accessed 7 September 2005).
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