Regenerative therapeutics for chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is one of the most common lung diseases worldwide, characterized by an accelerated loss of lung function. A key problem underlying COPD is increased tissue destruction in combination with defective lung tissue repair. As current therapies do not modify the progression of the disease, new therapies aimed at restoring lung tissue repair in COPD need to be developed. In an attempt to address this major unmet need, there has been a surge in both preclinical and clinical studies, aiming to identify key mechanisms underpinning defective lung repair and the ability to inhibit or even reverse this defect. This includes small molecules such as retinoids, as well as advanced therapy medicinal products such as cell therapies or therapies with cell-derived products such as extracellular vesicles, or secreted proteins. The results of these endeavors have been variable with failures as well as successful proof-of-concepts. In this review, we provide an overview of the current state of the field, including modes of action of the therapeutics that are or have been considered for lung regeneration, including a discussion on the reasons for failure where relevant. In addition, we discuss hurdles in the clinical development of regenerative therapeutics for COPD including clinical outcomes, route of administration and formulation as these are pivotal considerations moving forward. SIGNIFICANCE STATEMENT: Chronic obstructive pulmonary disease is characterized by progressive alveolar destruction and defective epithelial regeneration. Targetable mechanisms, including cellular senescence, altered mesenchymal-epithelial signaling, and chronic inflammation, impair progenitor function and niche integrity. Therapeutic strategies that restore epithelial repair, including small molecules, biologics, and cell-based approaches, represent a promising path toward disease modification and long-term lung function restoration.