Biomarkers provide route to personalized medicine

Personalized medicine--the ability to target drugs to specific patients as well as to specific diseases--is a major goal for drug development, from a number of different perspectives. For patients, personalizing medicine would mean that they can get the drugs that are the most likely to treat or cure their disease, with the best possible toxicity profile, and the broadening number of biomarker-based tests could also speed up diagnosis and reduce misdiagnosis. For drug companies, personalizing medicine means that they can stratify patients for clinical trials, increasing the chance of drugs reaching the market, cutting R&D costs and reducing the current extremely high attrition rate. And for payers, providing high-cost biologic drugs to only the patients that will respond will cut their costs.

Biomarkers are providing a route to personalized medicine. There are a few biomarker-based tests already on the market, either looking at a range of markers within a disease to help physicians develop a treatment strategy or evaluate outcome, or a single biomarker to predict response to a specific targeted drug. Examples of the first type include Genomic Health's ($GHDX) Oncotype DX breast and colon cancer multigene expression tests, and Crescendo Bioscience's Vectra DA multibiomarker blood test for rheumatoid arthritis. Others are on their way through--as an example, MDxHealth ($MDXH) is developing PredictMDx tests for brain, colon, breast and ovarian cancer that aim to predict responses to drug regimes.

There are a number of marketed tests that accompany drugs, also known as companion diagnostics. These include HercepTest to select for patients expressing HER2 as being most likely to respond to Herceptin (trastuzumab), or Genzyme's BCR-ABL Mutation Analysis test, which predicts the patients who could develop resistance to Gleevec (imatinib). As companies use biomarkers more and to stratify patients in clinical trials, they are likely to develop drugs and companion diagnostics in parallel, launching both onto the market together, or even bundling as one product

As more biomarkers are discovered, the applications and opportunities for personalized medicine will increase. However, as personalized medicine becomes more of a reality and drugs become more targeted, there may be some issues--the companion diagnostics could be expensive, and may not always be reimbursed, and some payers could tie the use of new drugs to the use of the potentially costly companion diagnostics. And on a personal level, there will always be patients whose profiles don't fit the new, exquisitely targeted drugs. In this brave new world, which will be very exciting, and could bring great advantages to patients, it's vital that these patients, especially when in the minority, are not forgotten in the rush to biomarker-led success.

Want to read more? In the ebook Companion diagnostics: The future of medicine, we've looked at the development of targeted drugs and companion diagnostics, including the successful and not-so-successful projects, and what issues (and opportunities) there will be for regulators, biopharma companies and payers moving into the future. - Suzanne Elvidge (email)