Glossary

Haematopoeitic Stem Cell Transplantation

The time required for half the amount of a medicine to be eliminated from the body.

The endpoint of a clinical trial is a pre-defined event: for instance, the occurrence of a disease, the occurrence of a symptom, or a particular laboratory result. Once someone reaches the endpoint, they are generally excluded from further research in the trial.

A hard endpoint is an endpoint that is well defined and can be measured objectively. For example, in cancer research, the endpoint in a trial might be related to response to treatment (such as shrinkage of a tumour). Endpoints related to a response are typical in Phase II clinical trials for cancer treatments. Endpoints relating to the survival of patients are common in Phase III cancer trials. 'Progress free survival' and 'disease free survival' measure the length of time patients are alive without their disease worsening.

In contrast to hard endpoints, soft endpoints are subjective measures. Quality of life measures, for example, are soft endpoints. It is common to use quality of life measures as endpoints in Phase III trials. In this case, patients are asked specific questions about the impact of their disease and/or treatment.

The endpoints used in a trial must be defined and documented as part of the trial design.

French Health Technology Assessment body. http://www.has-sante.fr/"

A hazard ratio is a measure of how often a particular event happens in a defined period of time in one group compared to how often it happens in another group.

Heads of Medicines Agencies (HMA) http://www.hma.eu/"

A health event can be positive or negative. An example of a health event is the development of a disease, an injury, or responding to a medicine.

Irish National Competent Authority. https://www.hpra.ie/"

Health technology assessment aims to inform decision making by health care policy makers. It is a systematic process that considers health technologies (such as medicines) and can involve a review of:

• clinical evidence compared to existing models of care,
  
• cost effectiveness,
  
• social and ethical impacts on the health care system and the lives of patients.
  

The process advises whether or not a health technology should be used, and if so, how it is best used and which patients are most likely to benefit from it. Assessments vary, but most look at the health benefits and risks of using the technology. They can also look at costs and any other wider impacts that the technology may have on a population or on a society. They can also look at the relationship between costs and benefits and risks, and make determinations about value for money.

Health-Related Quality of Life considers many different aspects related to a person™s perception of quality of life affected by health status. These include physical, psychological, functional, and social aspects.

Austrian Health Technology Assessment body. https://www.sozialversicherung.at/portal27/sec/portal/esvportal/content/contentWindow?contentid=10007.683890&action=2&viewmode=content"

Herd immunity is a form of immunity that occurs when the vaccination of a significant portion of a population (or herd) provides a measure of protection for individuals who have not or cannot develop immunity.

The human Ether-a-go-go Related Gene is a gene that codes for a protein that contributes to the electrical activity of the heart that plays a role in the coordination of the heart™s beating.

Clinical diversity (or heterogeneity) is the variability between the patients or the interventions being studied, or between the outcomes that the studies measure. When comparing different studies, it is important to bear in mind that there are several types of heterogeneity.

Methodological diversity (or heterogeneity) refers to variation in study design, and in the risk of bias between studies.

Clinical and/or methodological diversity can lead to differences in the way statistics are applied to different studies (statistical heterogeneity).

Progress in medical science is improving our understanding of heterogeneity among patients with the same disease. The differences in patient responses to treatment, and the risk of adverse reactions, are being explored at the molecular level. This is leading to the development of targeted treatments for different subgroups of patients.

High Performance Liquid Chromatography

High-Throughput Screening

HIV stands for human immunodeficiency virus. It weakens the immune system by destroying important cells (T-cells or CD4 cells) that fight disease and infection. The immune system then can't protect the body from infections and disease. Ultimately, HIV can lead to AIDS, the final stage of HIV infection. In AIDS, the immune system fails.

Human Ether-a-go-go Related Gene

A hypothesis is an assumption, or set of assumptions, made on the basis of limited evidence that either:

a) asserts something as a starting point for further investigation or

b) confirms something as highly probable in light of established facts.

For a hypothesis to be a scientific hypothesis, it is required that one can test it. A working hypothesis is a provisionally accepted hypothesis proposed for further research.

For the purposes of medicines development, the interest is in the hypothesis that asserts something “ for example that a new treatment for a disease is better than the existing standard of care treatment.

Hypothesis testing is the use of statistics to determine the probability that a hypothesis is true. It comprises four steps:
1. Formulate the null hypothesis.
2. Choose the appropriate statistical tests.
3. Perform the test.
4. Accept or reject the null hypothesis.