With almost $50 billion spent on worldwide pharmaceutical R&D in 1999 and continued huge increases in R&D spending, one would think the rate of drugs making it to market is increasing. Yet while new-chemical-entity development time has decreased from 13.5 to 11 years, it’s still too long. Further, despite the novel information generated by the genomics craze, results have lagged.
Different factors may increase the drug discovery engine and drive the development of better drugs. This is the pharmacogenomics opportunity:
• Understanding the correlation between an individual patient’s genetic makeup and her response to drug treatment using markers of biological variation;
• Biological markers will identify disease predisposition via diagnostics;
• By discovering and applying knowledge of genetic variability to create individualized drug therapy and companion molecular diagnostic products, individuals will receive medicines tailored to their biological markers found using genetic diagnostics;
• Genetically stratified clinical trials or patient-specific drugs will save millions of dollars and time;
• Market opportunity will be expanded by reviving products, differentiating present products, and rescuing drugs that failed during preclinic or clinical trials. Also, new uses for existing drugs and better dosing guidance will become available.
The greatest opportunity for pharmacogenomics appears to be in the oncology disease area, and cancer is one of the first therapeutic areas in which the power of Affymetrix’s GeneChip arrays will be felt. In two recent peer-reviewed journal articles, Blood (Vol. 99; March 2002) and the Journal of Clinical Oncology (Vol. 20; April 2002), the usefulness of Affymetrix GeneChip arrays in the staging, diagnosis, and potential treatment of various types of cancer has been demonstrated. Investigators explored novel GeneChip applications, including cancer subgroup identification and potential response to chemotherapeutics.
Scientists at University of Arkansas using Affymetrix GeneChips performed “classification” studies of multiple myeloma. The investigators addressed the genetic complexity and variability of multiple myeloma cells, and the basis of their resistance to current chemotherapies. The study discussed the ability of microarrays to analyze expression patterns in thousands of genes simultaneously. Investigators identified four distinct “subgroups” of multiple myeloma types that correlate with prognosis using gene expression patterns. This class distinction provides the potential for more accurate and targeted therapies for multiple myeloma.
In the JCO article, the Whitehead Institute/MIT and Dana-Farber Cancer Institute investigated multiple applications of GeneChips in cancer classification and therapy. The study discusses the challenges posed by clinical in histologically similar tumors, including problems in therapy selection and lack of activity. One study identified the ability to predict, through gene expression, three breast cancer types, two of which had been unknown. Another finding addressed the ability to cluster patients into subtypes of acute myelogenous leukemia and acute lymphocytic leukemia solely on the basis of gene expression. In fact, this finding led to the identification of tyrosine kinase FLT3, targeted by Millennium Pharmaceuticals compound, MLN518, now in late-stage preclinical development.
These studies, along with Affymetrix’s presence at the American Association of Cancer Research meeting last month, demonstrate the growing position of the GeneChip as a standard lab tool for cancer research. The applications of GeneChip not only have the ability to identify new drug targets and select targeted therapies for patient types, but also analyze the correlation of molecular pathways with therapeutic outcome. We believe Affymetrix, and less so any of the “pharmacogenomics” companies, will be one of the true winners to capitalize on pharmacogenomics market opportunity.
Michael G. King, Jr., is a managing director and senior biotechnology analyst for Robertson Stephens.
Robertson Stephens research analyst Edward Tenthoff and research associate Ellen Lubman also contribute to Genomoney.
Robertson Stephens, which has not independently verified the information contained in this article, maintains a market in the shares of Affymetrix.