Chapter 5 Drugs of the Future

by Donna M. Brinton, Christine Holten, and Jodi L. Nooyen

Background | Classroom Applications | Internet Resources | Appendices

 

Background

New understanding of human genetics will not only make it easier to diagnose diseases, it will also change how diseases are treated. Scientists and drug companies are using knowledge from the Human Genome Project to find cures for everything from cancer to obesity (see chapter 1: Mapping the Human Genome). This new medicine is called "genomic" medicine. This chapter will address the following questions:

• How is genomic medicine different from traditional medicine?
  
  
• What diseases are scientists studying?
  
  
• How will people take these new drugs?
  
  
• What are the practical and ethical issues of gene-based medicines for modern medicine and human society?

This chapter examines the procedures used to develop gene-based treatments and drugs. It also looks at several cases in which genomic medicine was successful where traditional medicine had failed. Teachers can use the lesson plans and materials to acquaint students with the basic concepts genomic medicine, to give them an opportunity to discuss the possible effects of these improvements in medical treatment, and to encourage them to think about how their own future may change as a result of genomic medicine.

Background Information

As scientists complete the sequencing of the human genome, they are using this information to create new ways of fighting disease-especially life-threatening diseases such as cancer, Alzheimer's, obesity, and heart disease. Until now, doctors really haven't been able to cure these diseases using drugs; they could only treat and control the symptoms. In the case of heart disease, physicians have been treating high blood pressure with one of six different medicines. But first they have to decide which of the six drugs to use; the first one they choose might not successfully control the disease. If the drugs are successful, the symptoms decrease; however, the high blood pressure itself is not cured.

Future drug therapy will be very different. Genomic medicine, which is still experimental, will allow doctors not only to treat the symptoms but also to cure the disease itself. Using drugs that have been developed with knowledge of the human genome, doctors will be able to identify and kill sick cells while not hurting healthy cells. They will do this by "turning on and off" proteins, the body's building blocks. In other words, they will use genomic drugs to help good proteins within the body fight the bad cells. Doctors hope to be able to treat patients with genomic drugs even before they become sick. They will also be able to customize drugs to treat a disease in an individual patient.

To create drugs for individual patients, it has been necessary for scientists to locate only a few useful genes hidden among billions of other genes, similar to finding a needle in a haystack. This has required international research teams and very advanced technology. Scientists have already begun using their new knowledge to create anticancer drugs. " Smart bombs," which contain antibodies that already exist in the human body, are one type of new anticancer drug.

Researchers believe that smart bombs are able to hunt and kill cancer cells without killing the healthy cells that surround them. But before they could create these smart bombs, they had to find the genes related to these antibodies. To do this, they took genetic fragments from gene sequences they had already identified. They then looked through the human genome database to find DNA that matched these fragments and found 7000 possibly responsible genes. Then, using a sophisticated computer, they compared these gene fragments to those in cancer cells stored in a laboratory. Only 200 genes matched those active in all cancer cells. To narrow the possibilities even further, scientists next compared these 200 genes with cells from patients who currently have cancer to see which genes were found most often. This entire process narrowed the number of genes most frequently found in cancer patients from possibly thousands to only several dozen.

Once the small number of genes has been found, the process of developing a drug begins. To do this, scientists test the antibodies they have located in laboratory animals such as mice. Later, they begin to study the effects of these antibodies on humans who suffer from cancer. Once this process has been completed, the drug is reviewed by a government agency. If approved, the drug can then be sold.

Research on smart bombs has created drugs now being tested on patients with colon, head, and neck cancer to prevent the growth and spread of cancer cells. One such experimental drug has successfully reduced or eliminated head and neck tumors in 8 out of 30 cases of patients who took it along with chemotherapy. Scientists are also working on creating drugs that carry small amounts of radioactive isotopes, or poisons, that will kill cancer cells without destroying healthy cells in other parts of the body. Such research may lead to newer and better drugs that can be used to fight and even cure different types of cancer.

Not only will the types of drugs that people take in the future be very different, but also the ways in which people receive treatment may change. Big needles may be replaced by other methods of injecting drugs into the body. Some drugs (including antibiotics) may be taken using inhalers, which are now used mostly by people with asthma. To replace many drugs that are now taken in pill or liquid form, scientists are now experimenting with skin patches and ultrasonic devices.

The ultimate objective of the scientists who are working on new genomic drugs and on new ways of administering them is to produce a "magic" cure. Such a miracle drug would be smart enough to direct itself to the source of the problem in the human body, figure out what it needed to do, and cure the problem.

 

 

Glossary

AIDS: Acquired Immunodeficiency Syndrome. First reported in 1981, it has since become a major global epidemic, killing over 10 million people and infecting tens of millions more. The disease is caused by HIV, a virus that destroys the body's ability to fight infections and certain cancers. Go to the NHGRI glossary (see below) for more information.

Alzheimer's: A mental disorder that gradually destroys vital nerve cells in the brain. Symptoms include loss of memory, judgment and reasoning, and changes in mood and behavior. It is not a normal part of aging.

Antibiotics: Drugs that fight infections.

Antibodies: Protein molecules produced by the body to fight infection
or disease.

Artery: Blood vessel carrying blood away from the heart.

Arthritis: An inflammatory condition that often causes pain, swelling, and stiffness in the joints, often making even minor movements uncomfortable or painful.

Blood pressure: The pressure caused by the blood moving against the walls of the blood vessels, especially the arteries. It varies with the strength of the heartbeat, the flexibility of the arterial walls, the amount of the blood, and a person's health, age, and physical condition. Normal adult blood pressure is 120/80. If a person has high blood pressure, medication is often prescribed to lower the pressure.

Cancer: A general term for more than 100 diseases that are characterized by uncontrolled and rapid growth of abnormal cells. Cancer cells can spread locally or through the bloodstream to other parts of the body.

Chemotherapy: The treatment of cancer using specific chemical agents or drugs that harm fast-growing cells. This treatment kills fast-growing cancer cells, but often harms other fast-growing cells as well, such as the cells for hair and fingernails.

Cholesterol: A white substance found in many foods that is an important element in cell walls in the body. An unusually high level of cholesterol in the blood is often a symptom of heart disease.

Colon: A section of the large intestine, in the digestive tract. The total length is approximately 5 feet (approx. 150 centimeters) in the adult. It is responsible for forming, storing, and expelling waste.

Diagnose: To identify a person as having a certain disease or condition.

Genomic: (adj.) (medicine, treatment, drugs, researchers) Using genetic material or research.

Heart disease: A problem that prevents the heart from working normally. This problem can be with the heart's shape or how the heart works, or with the blood vessels supplying the heart.

Human Genome Project: An international research project to map each human gene and to completely sequence human DNA. (See NHGRI glossary for more information.)

Hypodermic needle: A hollow needle used to inject medicine or drugs directly into the blood.

Immune system: The body system, made up of many organs and cells, that defends the body against infection, disease and foreign substances. The immune system is often stimulated in specific ways to fight cancer cells.

Inhaler: A hand-held device used to take medicine by breathing in through the nose or mouth. Also called inhalator.

Leptin: A hormone produced by fat cells for regulation of appetite. It controls how much you want to eat, how much of the food your body stores, and how much is used for energy.

Liver: A large organ in animals that is important for digesting food and removing waste products.

Mental illness: Any of various conditions which cause problems with a person's normal thinking, feeling, or behavior, and caused by social, psychological, biochemical, genetic, or other factors, such as infection or head trauma. Also called emotional illness, mental disease, mental disorder.

Microchip: An extremely small piece of semiconducting material, which can contain a very large amount of information.

Neuron: A cell that sends electrical signals across distances. Neurons receive input from sensory cells or other neurons and send messages to muscles or other neurons.

Obesity: (n), Obese (adj.) (1) Having too much body fat.

Parkinson's: A problem with the central nervous system. A neurological disease that continues to get worse. Symptoms include uncontrolled shaking of the body and difficulties with muscular coordination.

Poison: A substance that causes injury, illness, or death

Protein: Essential components of all living cells that allow a body to function work well (including enzymes, hormones, and antibodies). Proteins are essential in the diet of animals for the growth and repair of tissue.

Radioactive isotope: Elements with an unstable nucleus that act as poisons, killing cancer cells without destroying other parts of the body.

Skin patch: A small piece of material put on the skin. It contains medicine that gradually enters the body through the skin.

Smart bomb: A genomic drug that contains natural antibodies targeted directly at cancer cells.

Swallow: (v) To cause (food or drink, for example) to pass through the mouth and throat into the stomach.

Symptom: An indication of disorder or disease that signals a change from normal function, sensation, or appearance.

Trophic compounds: The body's natural substances that help cells grow and develop.

Tumor: A mass of abnormal cells that are the result of rapid cell division. Tumors perform no useful body function. They may be either benign (non-cancerous) or malignant (cancerous).

Ultrasonic: (adj.) (1) Sounds that the human ear cannot hear. (2) Of or relating to acoustic frequencies above the range that the human ear can hear, or above approximately 20,000 hertz.

Vaccine: Weakened or dead poisonous cells injected into the blood in order to stimulate the production of antibodies.

 

 

 

 

 

 

 

 

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