Hemophilia and hereditary angioedema (HAE) are rare monogenic disorders characterized by the dysregulation of serine protease-based biological pathways, that is, blood coagulation and the kallikrein-kinin system. Although clinical manifestations differ profoundly (bleeding vs angioedema), both diseases have recently undergone parallel therapeutic revolutions, shaped by advances in molecular biology and biotechnology. Early management in the 1970s relied for both diseases on the episodic administration of plasma-derived products, subsequently replaced by recombinant products that improved safety and feasibility of prophylaxis regimens. In the last 20 years, the development of nonreplacement products, such as emicizumab and rebalancing agents in hemophilia and kallikrein/bradykinin pathway inhibitors in HAE, shifted clinical practice from the episodic management of clinical events to their prevention. More recently, gene and RNA-based therapies are further transforming both diseases toward curative attempts: in hemophilia, adeno-associated virus vector-mediated gene therapy and lentiviral stem-cell approaches; in HAE, antisense oligonucleotide-mediated kallikrein suppression. Emerging genome-editing approaches and biomarker- and genotype-driven strategies are poised to further improve and personalize treatment. The therapeutic trajectories of rare diseases such as hemophilia and HAE illustrate how mechanistic insights enable the transition from the episodic management of acute events to long-term disease control, offering prospects for curative interventions.