Good Manufacturing Practice-compliant change of raw material in the manufacturing process of a clinically used advanced therapy medicinal product-a comparability study

Abstract

The development of medicinal products often continues throughout the different phases of a clinical study and may require challenging changes in raw and starting materials at later stages. Comparability between the product properties pre- and post-change thus needs to be ensured. Here, we describe and validate the regulatory compliant change of a raw material using the example of a nasal chondrocyte tissue-engineered cartilage (N-TEC) product, initially developed for treatment of confined knee cartilage lesions. Scaling up the size of N-TEC as required for the treatment of larger osteoarthritis defects required the substitution of autologous serum with a clinical-grade human platelet lysate (hPL) to achieve greater cell numbers necessary for the manufacturing of larger size grafts. A risk-based approach was performed to fulfill regulatory requirements and demonstrate comparability of the products manufactured with the standard process (autologous serum) already applied in clinical indications and the modified process (hPL). Critical attributes with regard to quality, purity, efficacy, safety and stability of the product as well as associated test methods and acceptance criteria were defined. Results showed that hPL added during the expansion phase of nasal chondrocytes enhances proliferation rate, population doublings and cell numbers at passage 2 without promoting the overgrowth of potentially contaminant perichondrial cells. N-TEC generated with the modified versus standard process contained similar content of DNA and cartilaginous matrix proteins with even greater expression levels of chondrogenic genes. The increased risk for tumorigenicity potentially associated with the use of hPL was assessed through karyotyping of chondrocytes at passage 4, revealing no chromosomal changes. Moreover, the shelf-life of N-TEC established for the standard process could be confirmed with the modified process. In conclusion, we demonstrated the introduction of hPL in the manufacturing process of a tissue engineered product, already used in a late-stage clinical trial. Based on this study, the national competent authorities in Switzerland and Germany accepted the modified process which is now applied for ongoing clinical tests of N-TEC. The described activities can thus be taken as a paradigm for successful and regulatory compliant demonstration of comparability in advanced therapy medicinal products manufacturing.

Keywords: Good Manufacturing Practice; advanced therapy medicinal products; cartilage repair; cell-based therapies; platelet lysate; tissue engineering.