Drug Discovery Process

The Drug Discovery Process

The drug discovery process incorporates several distinct phases each requiring a dedication of time and resources:

Basic Science: At the basic science level, scientists discover information about individual chemicals and biological processes.

Drug Discovery: As the drug discovery process proceeds, the focus narrows as scientists develop specific chemicals and study their effects on identified disease targets. This requires sophisticated chemistry and testing on animal models of disease.

Drug Development: Finally, when a chemical is found to impact a specific target, human testing is conducted through chemical trials to show the safety and efficacy of the chemical so it may be approved by the FDA as a drug.

Drug Development: Long and Risky

Stages of Drug Development Process. This chart represents the of attrition rate of compounds as they travel through the drug development process over time. (PhRMA, 2008)

Drug discovery occurs when a new compound is developed that addresses a specific disease target. After scientists identify a potentially viable drug candidate in the early drug discovery process, that compound proceeds to laboratory testing against specific targets to determine its effect. Most compounds are eliminated as they proceed from the discovery to the human development phase.

It is estimated that for every 10,000 compounds that enter the drug discovery pipeline, only 250 will progress to pre-clinical development (2.5-5%), 5 will move forward into human testing, Phase I studies (0.1-0.5%), and only a single compound will survive to be an approved drug (0.01%). Success rates for drugs for neurodegenerative diseases such as Alzheimer’s are much lower. Indeed, for all neurodegenerative diseases there are only two FDA approved potentially disease modifying drugs (one for multiple sclerosis and one for Parkinson’s). Alzheimer’s disease obviously has an even lower success rate.

Of that single, FDA-approved drug, only 3 out of every 10 compounds that receive regulatory approval earn a profit. However, only 1 out of 10 approved medicines becomes what the pharmaceutical industry defines as a “blockbuster” - a drug that earn more than $1 billion a year - and earns enough profit to fund further industry research.

These numbers represent the average success rate across all therapeutic areas. However, success varies among diseases. Cardiovascular drug targets have a 20% success rate (with success being defined as FDA approval) while CNS drugs, the category in which Alzheimer’s drugs are included, have only an 8% success rate of achieving final FDA approval. The disparity in success rates among therapeutic categories tells us that we are searching for answers to Alzheimer’s disease in a field that still remains difficult.

What Happens in the Basic Research Lab Must Be Tested in Humans:
The Stages of Drug Discovery and Development

The Stages of Drug Discovery and Development chart shows the stages of the drug discovery process that a compound must pass through before it is considered a viable candidate for human testing as a drug. Chemistry, biology, pharmacy and medicine all converge as a drug makes its way toward human clinical trials.

Dozens of compounds are currently in clinical development for Alzheimer’s disease, mild cognitive impairment (MCI) and dementia. Many of these trials can be found at www.clinicaltrials.gov.

ADDF’s Funded Scientists Have Made Significant Progress

To determine whether ADDF-funded scientists have made progress, we performed an extensive analysis of programs funded to date. This chart demonstrates our success in accelerating drug discovery for Alzheimer’s disease.

Scientific Progress by Stage of Development. This bar chart shows the percentage of ADDF-funded programs and their progress from their initial stage (blue bar) of development to their present stage (red bar) of development. Growth in the later-stage categories of preclinical development and proof of concept from 25% to 51% of the portfolio demonstrates our funded scientists are making advances bringing us closer to clinical trials.

To request more detailed information about our progress, click here for a full report: ADDF Pipeline Report (1999-2006) Progress of Drug Discovery Programs by Stage of Discovery.