Quality control of clinical-grade recombinant adenovirus used in gene therapy

Objective To establish the quality control methods and reference standards for clinical-grade recombinant adenovirus products for human gene therapy. Methods The Infectivity of clinical grade recombinant adenoviral vectors is determined by a TCID 50 assay. The purity is determined by a high-performance liquid chromatography (HPLC) assay. A549 cells were used in replication competent adenovirus (RCA) assay of samples by observation of the cytopathic effect. Other quality control assays were performed in accordance with the SFDA Regulations for Biological Products. Results The recombinant adenovirus encoding human p53 gene produced at SiBiono(Lot 20010701)has the following quality attributes: viral particle concentration: 1.03(10 12 VP/ml,infectivity titer: 5.01(10 10 IU/ml,specific infectivity (IU/VP): 4.86%,higher than the 3.3% required by the Food and Drug Administration (FDA),USA; Purity by HPLC analysis: 98.62%,higher than the 95% purity specified by SFDA; and level of RCA: less than 1 RCA / 3(10 10 VP,meeting the standards established by SFDA. Conclusions A whole set of quality standards of clinical-grade recombinant adenovirus vectors has been established so as to ensure the clinical safety and efficacy of recombinant adenoviral vectors for human gene therapy.