Biopharmaceutical inventions challenge the patent system's ability to provide sufficient market exclusivity for new and emergent technologies and create a competitive advantage. Recently, the theory of 'the patent portfolio' has emerged to explain modern views of the value of exclusivity. This thesis aims to address the increasing complexity and nature of the 'private value' of patent portfolios and the related companies' patenting strategies in the biopharmaceutical industry. The inconsistent understanding of, and the underlying linkage between, the 'private value' of patent portfolios and patenting strategies often results in reduced efficiency in drug lifecycle management. In an attempt to characterize companies' patenting strategies, the logic behind the influence of patent portfolio attributes in the process of 'private value' creation has been examined. This thesis attempts to develop a novel conceptual model of 'private value' and advance the understanding of patent portfolios in therapeutic biologics. The model of 'private value' integrates a conceptual framework of the portfolio attributes of Scale, Technology Diversity, Total Citations and Age. The conceptual model was empirically investigated using data sources of patent portfolios for 116 FDA approved therapeutic biologics. Portfolio 'private value' attribute variances were employed to identify the incremental 'private value' constructs of patent portfolios using Principal Component Analysis. In addition, given the diversity of patenting strategies, an investigation of how patenting behaviours across biopharmaceutical companies influence the 'private value' of patent portfolios in the drug lifecycle management process was conducted. The findings in this thesis contribute to the understanding of the 'private value' in biopharmaceutical lifecycle management (LCM) in a number of ways. The analysis shows that the 'private value' of patent portfolios is most closely related to the technical scope constructs of 'Uncertainty' and 'Substitution'. The results also indicate that the attributes that contribute most to 'private value' are Scale, Total Citations, and Age with Scale being the most important. On the basis of my research, I suggest the consideration of alternative attributes for patent portfolio theory, i.e. the 'Technology Strength' and 'Lifetime'. Moreover, the synergy of both proposed attributes is as important as the factors themselves. iii Three patent clusters for patenting patterns were identified. The cluster taxonomy shows the impact of portfolio characteristics on the selected patenting strategies. The observed patenting strategies confirm the dominance of offensive strategies to increase the lifecycle of therapeutic biologics. Offensive blockage strategies are invariably connected with the creation of early 'Uncertainty' and later 'Substitution' constructs of 'private value'. The findings suggest that the most successful configuration of patent portfolios is characterised by targeted patenting strategies that are in alignment with the desi...