ANNUAL FINANCIAL REPORT 2010 2010 - TiGenix

While debridement and lavage is the most frequently usedprocedure, microfracture appears to be the currently acceptedstandard of care for small-sized cartilage defects. However,it is recognised that microfracture often leads to scar-likerepair tissue, which, unlike stable hyaline-like cartilage, hasnot been associated with long-term durable outcomes.Various investigators have communicated a reducing clinicalbenefit from microfracture after 2 to 3 years 17 . Recent clinicalexperience has also identified issues in the subchondral bonerelated to a moving up of the bone front after microfracture.This could eventually compromise subsequent cartilage repairprocedures such as autologous chondrocyte implantation 18 .Autologous Chondrocyte Implantation (“ACI”) is a techniquedesigned to repair articular cartilage by implanting the patient’sown expanded cartilage cells, and was developed in order toaddress the limitations of the surgical procedures describedabove. ACI was invented in the early 1980s by researchers at theHospital for Joint Diseases in New York and was subsequentlyimproved at the University of Göteborg in Sweden 19 . Figure6.2 gives an overview of the ACI procedure. When a patient isdiagnosed with a symptomatic cartilage defect eligible for ACItreatment, a small cartilage biopsy is taken arthroscopicallyfrom a healthy, non-weight bearing area of the joint. The cellsare subsequently transported to a cell expansion laboratoryand, after approximately 4-5 weeks of cell culture, the expandedcells are sent back to the surgeon for re-implantation in thepatient. In conventional ACI, the cells are implanted underneatha periosteal flap, which has been harvested from the patient’stibia and sewn onto the cartilage defect. Newer techniques usea biodegradable membrane or a matrix in which the cells areseeded.Although over 20,000 patients have been treated using ACIsince the 1980s, only a fraction of patients suffering fromcartilage defects are currently treated in this way. The Companybelieves that the limited market share of ACI procedures isattributable to several factors, most notably the lack of proofwith regard to the reproducibility of formation of stablearticular cartilage, the lack of clinical validation and the relativelycomplex surgical procedure associated with the implantationof the cells.The ChondroCelect development programme has focusedon providing solutions for these hurdles and thus aims toexploit the potential of the ACI market. ChondroCelect is acharacterised cell-based medicinal product, used in an ACIprocedure, in which the cell culture methods have beenfocused to maintain the phenotypical stability of the cells inview of favouring the formation of stable hyaline-like articularcartilage. The product has been validated in a prospective,controlled randomised clinical trial and can be used incombination with an easy-to-use collagen membrane.17 Mithoefer et al., Am J Sports Med 2009.18 Minas et al., Am J Sports Med 2009.19 Grande et al. J Orthoped Res 1989; Brittberg et al. NEJM 1994.111 •