In the last few years, pharmaceutical companies have become increasingly interested in biomarkers and their incorporation into company drug development programmes and use as companion tests for targeted therapeutics. Identifying patients that will benefit from a drug and eliminating those that will not is increasingly important. A simple analysis of the number of biomarker deals recorded in PharmaVentures' PharmaDeals database shows a rise from just seven in 2001 to 130 in 2007. There are a number of drivers for this, and these include: the increasing cost of drug development and associated decline in new molecular entities (NMEs) achieving registration; patient and regulatory authorities requesting upfront evidence of therapeutic benefit; and reimbursing bodies requiring proof of likely beneficial outcomes before payment. One would imagine that the combination of these factors would result in a highly positive outlook for biomarker researchers and developers. However, the situation is not as simple as it appears because, despite the factors listed above, it is hard to capture the value created by the addition of a biomarker into the drug development or patient identification process, and thus to apportion returns from subsequent commercialization of the drug and/or biomarker.