Technical Insights: Drugs in the Pipeline - An R&D Analysis
Palo Alto, Calif. May 10, 2004 Functional genomics and proteomics have been quite successful in identifying functions of potential therapeutic targets such as encoded proteins. In fact, the possibilities of identifying more than 10,000 novel target antigens in the human genome may accelerate the discovery of new drugs and therapeutic molecules.
"As opposed to conventional sequence homology, functional genomics adds structure-based predictions to locate gene sequences with assigned and confirmed functions," explains Frost & Sullivan Industry Analyst Rajaram Sankaran. "It simultaneously sifts through well established targets to detect critical therapeutic targets."
Such structural information results in enriched annotations that improve the identification process and also provide a clear understanding of interactions between specific molecules and target proteins.
Additionally, functional genomics opens up the possibilities of genetically demarcating patients and predicting individual responses to drugs. This permits customized medications and dosages that improve treatment safety and efficacy in areas such as neuropsychiatry, cardiovascular medicine, endocrinology, and oncology.
The success of functional genomics is magnified when used in conjunction with combinatorial chemistry (combichem) where a molecular compound is introduced into a compound library to chemically interconvert. It follows a target driven approach wherein, molecular building blocks are designed to react together selectively and covalently.
With an increasing number of new molecular entities (NMEs) entering clinical trials by 2008, a 65 percent increase in NMEs entering the market is expected innovative techniques for 'fast track' drug development and early screening of compounds are being devised.
One such technique gaining popularity is high-throughput screening (HTS) that detects and provides optimization guidelines for lead compounds and validates drug targets. HTS development provides numerous advantages such as lower attrition rates, reduced time-to-market, and accelerated drug screening process.
However, almost 30 percent of NMEs fail to clear Phase I clinical testing, despite speedy and extensive pre-clinical screening. This may be attributed to pre-clinical animal and 'ex vivo' models, which provide inaccurate human pharmacokinetic (PK) and absorption, distribution, metabolism, and excretion (ADME) data.
Human targets, on the other hand, offer a holistic view of expected drug performance and improve efficacy and safety of the final drug. Following this trend, accelerator mass spectrometry uses microdosing to provide faster human bioavailability data during pre-clinical screening.
In microdosing, human drug dosages, which are 100 times below the required level, are sufficient to screen numerous compounds and yield early PK and ADME data. This ensures that optimal drug candidates qualify for Phase I clinical development.
Human drug absorption is another approach to obtain accurate PK and ADME data. In this, engineered capsules are used for non-invasive, targeted drug delivery during early clinical development to provide direction for the development of selected NMEs.
"Pharmacokinetic data generated during these studies could provide a detailed understanding of the complex absorption process at distinct intestinal sites," says Sankaran. "This may be critical for quicker decision-making process and appropriate selection of drug development strategies."
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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