The purpose of this chapter is to explore how the role of EU competition law has evolved as an external corrective to the balance struck by the IP laws between initial inventor and follow-on innovation and to offer a re-assessment of the economic thinking in the rule based interpretation of Article 102. Part I offers a summary of the balance struck within the IP laws between initial and follow on innovation. Part II explains how competition law has evolved into its role as a regulator of the conduct of IP owners and, in the process, occasionally correcting the limitations of the existing IP laws. Part III analyses the extent to which economic thinking plays a role in the rule-based case law of Article 102 and IPRs. The chapter concludes with some thoughts about the limitations of the role of competition law in restoring a more appropriate balance to the overall legal framework balancing the rights of first inventors with follow-on and cumulative innovation.