Family matters: an empirical analysis of how divisionals and secondary patents extend legal uncertainty in life sciences

When a patent application is pending, it is uncertain whether a patent will be granted and, if so, what protection it will confer. If the validity of the patent is then challenged, uncertainty continues until a final decision in opposition is obtained. This uncertainty extends when multiple applications surround a single innovation, a phenomenon that is common in life sciences and can therefore have a great impact on healthcare systems and patients. This article examines whether examination duration, and therefore the period of uncertainty, at the European Patent Office (EPO) varies systematically with parent and divisional applications, secondary patenting, and the economic value of the associated drug. Using bulk EPO Register data and IQVIA Ark5/MIDAS®6 data, 15,737 patent applications filed at the EPO between 1978 and 2026 Q1 are linked to a drug. Cox proportional hazards models show that parent applications and secondary patents are associated with significantly longer pendency than single applications, particularly for high-value drugs. Additional indicators trace where and how these delays arise. The findings suggest that delays are connected to the combined use of several procedural rights, both across a patent family and within individual applications, and are not limited to multi-generation families.