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- Accelerated approval (subpart H approval):
- A highly specialized mechanism intended to speed approval of drugs promising significant benefit over existing therapy for serious or life-threatening illnesses. It incorporates elements aimed at making sure that rapid review and approval is balanced by safeguards to protect both the public health and the integrity of the regulatory process. This mechanism may be used when approval can be reliably based on evidence of a drug’s effect on a “surrogate endpoint,” or when the FDA determines an effective drug can be used safely only under restricted distribution or use. Usually, such a surrogate can be assessed much sooner than such an endpoint as survival. The approval that is granted may be considered a provisional approval, with a written commitment to complete clinical studies that formally demonstrate patient benefit. Accelerated Approval designation does not necessarily lead to a priority review. (See also FDA.)
- Acquired immunodeficiency syndrome (AIDS):
- Caused by infection with the human immunodeficiency virus (HIV). AIDS refers to the most advanced stage of HIV.
Diagnosis
HIV infection is characterized by a gradual deterioration of immune function, where immune cells called CD4+ T cells are disabled and killed during the course of infection. These cells play a significant role in the immune response, signaling other cells in the immune system to perform their functions. In 1993, the Centers for Disease Control (CDC) revised its definition of AIDS to include all HIV-infected people who have fewer than 200 CD4+ T cells. (Healthy adults usually have average CD4+ T cell counts of about 1,000.) In addition, the AIDS definition includes 26 clinical conditions that affect people with advanced HIV disease. Most AIDS-defining conditions are opportunistic infections, which rarely cause harm in healthy individuals. In people with AIDS, however, these infections are often severe and sometimes fatal because the immune system is so ravaged by HIV that the body cannot fight off certain bacteria, viruses and other microbes.
Prognosis
A healthy person usually has 800 to 1,200 CD4+ T cells per cubic millimeter (mm3) of blood. During HIV infection, the number of these cells in a person’s blood progressively declines, and when a person’s CD4+ T cell count falls below 200/mm3, he or she becomes vulnerable to the opportunistic infections and cancers that typify AIDS. People with AIDS often suffer from serious infections, as well as debilitating weight loss, diarrhea, neurologic conditions and cancers such as Kaposi’s sarcoma and lymphomas.
- Action letter:
- An official communication from the FDA to an NDA sponsor that informs of a decision by the agency. An “approval” letter allows commercial marketing of the product and lists minor issues to be resolved before approval can be given. A “not approvable” letter describes important deficiencies that preclude approval unless corrected.
- Active site:
- A region of an enzyme surface that binds a substrate molecule forming into a new product capable of action. This site is usually located in a cleft or depression, and is very specific. Pharmaceutical research seeks to identify highly specific agents to target specific active sites to achieve desired biological activities with precision and avoid undesirable side effects.
Source: http://academic.brooklyn.cuny.edu/.../page/noncomb.htm - Adjuvant:
- Substance that either helps and enhances the pharmacological effect of a drug or increases the ability of an antigen to stimulate the immune system. Adjuvant therapy for cancer is surgery followed by chemotherapy or radiation to help decrease the risk of the cancer recurring. In addition, adjuvants are often used to enhance the immune response of a vaccine.
- Adverse drug experience/reaction (ADE/ADR):
- A harmful or unexpected event associated with the use of a drug in humans.
- Type A: An adverse reaction from a drug resulting from an extension of the drug effect. These reactions are identified before the drug enters the market and are dose related. For example, if a patient experiences too much lowering of his blood pressure from an antihypertensive medication, it is a type A reaction.
- Type B: An adverse reaction from a drug that is unrelated to the pharmacologic action of the drug. These types of reactions are uncommon and cannot be anticipated. They are referred to as idiosyncratic reactions.
- Advisory committee:
- A panel of outside experts in a specific medical specialty who convene periodically to advise the FDA on safety and efficacy issues about drugs and other FDA-regulated products. They review safety and efficacy data contained within applications and issue recommendations regarding approval. The FDA isn't bound to take committee recommendations, but usually does.
- Agonist:
- A compound, often a hormone or its analogue, that binds to a receptor and elicits a response. (See also antagonist.)
- AIDS:
- See acquired immunodeficiency syndrome.
- Allele:
- One member of a pair of genes in a diploid cell. An individual with identical alleles at a genetic locus is called a homozygote; one with nonidentical alleles is a eterozygote. In a case in which one allele leads to an observable phenotype, the allele is said to be dominant. If, on the other hand, the allele does not lead to an observable phenotype, the allele is said to be recessive.
Source: www.albany.edu/~achm110/allele.html (reproduced with permission from Dr. Ramaswamy Sarma). - Amendment to an NDA:
- A submission to change or add information to an NDA or supplement not yet approved.
- Amino acid:
- One of the 20 building blocks of protein. The sequence of amino acids in a protein and, hence, the function of that protein, is determined by the genetic code.
Source: http://ntri.tamuk.edu/cell/chapter3/amino-acids.html - Angiogenesis:
- The process involved in the formation of new blood vessels. Drugs that stimulate angiogenesis may be helpful in the management of coronary artery disease. Drugs that block angiogenesis may be useful in the management of cancer.
- Angiogenic growth factors:
- Stimulate the formation of new blood vessels. An example would be vascular endothelial growth factor (VEGF).
- Antagonist:
- A compound, often an analogue of a hormone, that binds to a receptor but elicits no response. (See also agonist.)
- Antibody:
- Specialized proteins produced by white blood cells that circulate in the blood seeking, and attaching to, foreign proteins, microorganisms or toxins to neutralize them. Antibodies help the body defend against infections. (See also monoclonal antibodies.)
- Antigen:
- Antigens are macromolecules that elicit an immune response in the body. The most common antigens are proteins and polysaccharides.
- Antigenicity:
- The degree to which the immune system is activated in response to a foreign substance. The more antigenic a substance is, the better the substance is in inducing an immune response, which can be very helpful in fighting infections and cancer but can also be harmful in allergic responses.
- Antiretroviral:
- An agent that suppresses or stops the activity of a retrovirus. Common antiretroviral agents include HIV drugs such as Efavirenz and Stavudine, among others. (See also retrovirus.)
- Antisense technology:
- A novel form of therapeutics and drug discovery method. Antisense drugs work at the genetic level to interrupt the process by which diseasecausing proteins are produced. This technique is useful in gene characterization and functionalization.
- Antisense:
- Complementary strand of a coding sequence of DNA or RNA. Also defined as a collection of nucleotide sequences that are not templates for synthesis but yet interact with complementary sequences in other molecules, thereby causing function of those molecules to be affected. Antisense technology can be applied to attack cancer and infectious disease on the genetic level. Example: Vitravene®, a treatment for cytomegalovirus retinitis, an infection that commonly afflicts AIDS patients.
- Atrophy:
- The wasting away of tissues or organs, resulting in decreased capabilities. (See also hypertrophy.)
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