A Pharmacokinetic Analysis of Molecular Cardiac Surgery With Recirculation Mediated Delivery of βARKct Gene Therapy: Developing a Quantitative Definition of the Therapeutic Window

• Published in: Journal of cardiac failure Vol. 17; no. 8; pp. 691 - 699
• Main Authors: Fargnoli, Anthony S., MS, Katz, Michael G., MD, PhD, Yarnall, Charles, CCP, Sumaroka, Marina V., PhD, Stedman, Hansell, MD, Rabinowitz, Joseph J., PhD, Koch, Walter J., PhD, Bridges, Charles R., MD, ScD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-08-2011
• Subjects: Animals; beta adrenergic signaling system; Cardiac gene therapy; cardiac surgery; Cardiac Surgical Procedures - methods; Cardiovascular; Coronary Circulation - physiology; gene pharmacokinetics; Gene Transfer Techniques; Genetic Therapy - methods; Peptides - administration & dosage; Peptides - blood; Peptides - pharmacokinetics; Recombinant Proteins - administration & dosage; Recombinant Proteins - blood; Recombinant Proteins - pharmacokinetics; Sheep; Tissue Distribution - physiology; beta adrenergic signaling system; gene pharmacokinetics; cardiac surgery; Cardiac gene therapy
• ISSN: 1071-9164; 1532-8414
• DOI: 10.1016/j.cardfail.2011.03.011

Abstract Background Two major problems for translating gene therapy for heart failure therapy are: safe and efficient delivery and the inability to establish a relationship between vector exposure and in vivo effects. We present a pharmacokinetics (PK) analysis of molecular cardiac surgery with recirculating delivery (MCARD) of scAAV6-βARKct. MCARD’s stable cardiac specific delivery profile was exploited to determine vector exposure, half-life, and systemic clearance. Methods and Results Five naive sheep underwent MCARD with 1014 genome copies of scAAV6-βARKct. Blood samples were collected over the recirculation interval time of 20 minutes and evaluated with quantitative polymerase chain reaction (qPCR). C(t) curves were generated and expressed on a log scale. The exposure, half-life, and clearance curves were generated for analysis. qPCR and Western blots were used to determine biodistribution. Finally, all in vivo transduction data was plotted against MCARD’s PK to determine if a relationship existed. Vector concentrations at each time point were (cardiac and systemic, respectively): 5 minutes: 9.16 ± 0.15 and 3.21 ± 0.38; 10 minutes: 8.81 ± 0.19 and 3.62 ± 0.37; 15 minutes: 8.75 ± 0.12 and 3.69 ± 0.31; and 20 minutes: 8.66 ± 0.22 and 3.95 ± 0.26; P < .00001. The half life of the vector was 2.66 ± 0.24 minutes. PK model data revealed that only 0.61 ± 0.43% of the original dose remained in the blood after delivery, and complete clearance from the system was achieved at 1 week. A PK transfer function revealed a positive correlation between exposure and in vivo transduction. Robust βARKct expression was found in all cardiac regions with none in the liver. Conclusion MCARD may offer a viable method to establish a relationship between vector exposure and in vivo transduction. Using this methodology, it may be possible to address a critical need for establishing an effective therapeutic window.