Pharmacovigilance Due Diligence in Drug Development: A Practical Playbook for Risk Identification, Compliance Assessment, and Strategic Decision Making.

In the pharmaceutical industry, due diligence (DD) is a critical, cross-functional process used to evaluate the scientific and regulatory viability of products, particularly during in-licensing or acquisition. Among the various dimensions assessed, safety evaluation plays a pivotal role in determining whether a product is likely to achieve regulatory approval, maintain a favourable benefit-risk balance, and support sustainable market access. This article focuses on the unique role of pharmacovigilance (PV) and safety experts in the DD process. It outlines the key safety-related questions that must be addressed, highlights potential red flags-such as organ-specific toxicities, labelling liabilities, or risk management burdens-and provides practical considerations for evaluating the robustness of the safety data package. Drawing on extensive industry experience and regulatory precedents, this manuscript offers structured guidance for an area where no formal framework exists. It emphasizes the importance of forecasting the likelihood of achieving a positive benefit-risk profile and identifying foreseeable safety-related barriers-ranging from boxed warnings to withdrawal risk-that could delay approval or diminish product value. By proposing a systematic approach to safety DD, including a playbook and an inclusive checklist with colour-coded categorization framework, this paper aims to support more informed, proactive, and risk-calibrated decision making in pharmaceutical transactions.