Quantitative Systems Pharmacology for Rare Disease Drug Development

Integrated Applied Clinical Pharmacology in the Advancement of Rare and Ultra-Rare Disease Therapeutics

The introduction of safe and effective rare/ultra-rare disease treatments is a focus of many biotherapeutic enterprises. Despite this increased activity, a significant unmet need remains, and the responsibility to meet this need is augmented by enhanced genomic, biologic, medical, analytical, and informatic tools. It is recognized that the development of an effective and safe rare/ultra-rare disease therapeutic faces a number of challenges with an important role noted for clinical pharmacology. Clinical pharmacology is foundationally an integrative discipline which must be embedded in and is interdependent upon understanding the pathogenic biology, clinical presentation, disease progression, and end-point assessment of the disease under study. This manuscript presents an overview and two case examples of this integrative approach, the development of C5-targeted therapeutics for the treatment of generalized myasthenia gravis and asfotase alpha for the treatment of hypophosphatasia. The two presented case examples show the usefulness of understanding the biological drivers and clinical course of a rare disease, having relevant animal models, procuring informative natural history data, importing assessment tools from relevant alternative areas, and using integrated applied clinical pharmacology to inform target engagement, dose, and the cascade of pharmacodynamic and clinical effects that follow. Learnings from these programs include the importance of assuring cross-validation of assays throughout a development program and continued commitment to understanding the relationship among the array of Pd end points and clinical outcomes. Using an integrative approach, substantive work remains to be done to meet the unmet needs of patients with rare/ultra-rare disease.

Creating a Roadmap to Quantitative Systems Pharmacology-Informed Rare Disease Drug Development: A Workshop Report

One of the goals of the Accelerating Rare Disease Cures (ARC) program in the Center for Drug Evaluation and Research (CDER) at the US Food and Drug Administration (FDA) is the development and use of regulatory and scientific tools, including drug/disease modeling, dose selection, and translational medicine tools. To facilitate achieving this goal, the FDA in collaboration with the University of Maryland Center of Excellence in Regulatory Science and Innovation (M-CERSI) hosted a virtual public workshop on May 11, 2023, entitled "Creating a Roadmap to Quantitative Systems Pharmacology-Informed Rare Disease Drug Development." This workshop engaged scientists from pharmaceutical companies, academic institutes, and the FDA to discuss the potential utility of quantitative systems pharmacology (QSP) in rare disease drug development and identify potential challenges and solutions to facilitate its use. Here, we report the main findings from this workshop, highlight the key takeaways, and propose a roadmap to facilitate the use of QSP in rare disease drug development.

Chemical Adjustment of Fibrinolysis

Fibrinolysis is the process of the fibrin-platelet clot dissolution initiated after bleeding has been stopped. It is regulated by a cascade of proteolytic enzymes with plasmin at its core. In pathological cases, the balance of normal clot formation and dissolution is replaced by a too rapid lysis, leading to bleeding, or an insufficient one, leading to an increased thrombotic risk. The only approved therapy for emergency thrombus lysis in ischemic stroke is recombinant tissue plasminogen activator, though streptokinase or urokinase-type plasminogen activators could be used for other conditions. Low molecular weight compounds are of great interest for long-term correction of fibrinolysis dysfunctions. Their areas of application might go beyond the hematology field because the regulation of fibrinolysis could be important in many conditions, such as fibrosis. They enhance or weaken fibrinolysis without significant effects on other components of hemostasis. Here we will describe and discuss the main classes of these substances and their mechanisms of action. We will also explore avenues of research for the development of new drugs, with a focus on the use of computational models in this field.