Impact of biomarkers on clinical trial risk in breast cancer

We determined the success rate of new drug approval by the US FDA in two breast cancer indications, one of which used a biomarker. This allowed us to assess if biomarkers improved clinical trial risk in breast cancer. We performed a retrospective screening of industry-sponsored drug development programs registered on clinicaltrials.gov from 1998 to 2012 for HER2-positive patients compared to patients that had either failed or had been exposed to anthracycline or taxane, whose first phase I in this indication occurred no earlier than 1998. Compounds not registered on clinicaltrials.gov and studied exclusively outside the US were excluded. Twenty-nine drugs for HER2-positive patients and 28 drugs for anthracycline/taxane-exposed patients met our screening criteria. The overall success rate of new drug development in anthracycline/taxane patients was only 15 %, while in HER2-positive patients it was 23 %. However, HER2-targeted therapies underperformed compared to broad acting agents. The cost for clinical trial testing alone, when adjusted for the risk of failure, for HER2-positive breast cancer patients was $199 million, significantly lower than the cost of $274 million for anthracycline/taxane-experienced patients. The use of a validated biomarker, such as HER2, reduced clinical trial risk by as much as 50 % resulting in cost savings of 27 % in advanced and metastatic breast cancer. However, these data have to be evaluated in a context in which studies combining a novel drug with a novel biomarker not yet recognized by the FDA may actually increase clinical trial risk.