The achievements of cell-based therapeutics over the last decades have bolstered efforts in recent years to bring more of these products to market and across an ever more diverse range of applications. These advanced therapeutics offer promising potential to treat conditions that, to date, have defied traditional treatment modalities. Interest and investment in this sector are at an all-time high and whilst many are hopeful of a boom in the number of approved therapies in the coming years, the industry still faces significant challenges, particularly with regard to the manufacture and regulation of these cell-based products. In this article, we will provide an overview of some of the key applications of cell therapies as well as look more closely at the challenges facing the evolution of this field.
To date, the applications of cell therapies have largely fallen into two broad categories; tissue regeneration and immunomodulation. With regard to the former, cell therapy has been viewed as one of the most promising techniques for the repair of damaged tissue, with applications in cardiovascular disease, neurodegenerative disease (for example, Parkinson’s and Alzheimer’s), musculoskeletal injury or degeneration and endocrine dysfunction (for example, type I diabetes).
Cell therapies have proven particularly effective in the repair of articular cartilage, for which the intrinsic capacity for repair is low. The most established of these therapies have employed the patient’s own cells, i.e. autologous cells. In brief, harvested chondrocytes are expanded ex vivo, seeded into a collagen matrix and then re-implanted into cartilage defects in joints. Such products have been available for around a decade now (ChondroCelect, developed by TiGenix was first approved in the EU in 2009) and have shown considerable efficacy, although the use of these advanced options is still low when compared to traditional treatment modalities (for example, joint replacement and analgesics). Whilst cartilage repair applications have tended to employ the terminally differentiated chondrocyte, bone repair applications have made use of the regenerative capacity of stem and progenitor cells. Bone marrow-derived mesenchymal stem cells (MSCs) have been proven in a range of orthopaedic applications over recent decades, including in the treatment of infants with osteogenesis imperfecta and in the repair of non-union fractures. Unfortunately, obtaining sufficient yields of pure MSC populations from bone marrow has proven difficult and there has been a switch in recent years to utilise MSCs derived from other sources, such as adipose tissue.