Establishing dose response relationships in targeted patients is foundational in the development of therapeutic drugs including gene therapy products. Enlightened by interspecies normalization of plasma drug concentration-time curves using Dedrick plot, the author of this manuscript first demonstrated the feasibility of normalizing dose-response relationship of adeno-associated virus (AAV)-mediated hemophilia gene therapy products in multiple species to a species-invariant scale. Preclinical dose-response relationships of eight AAV vectors were normalized using an exponent of 0.25 and applied to first-in-human (FIH) dose prediction. The performance of this dose-response normalization approach for FIH dose prediction was compared to that of direct body weight-based dose conversion and allometric scaling approaches. The study results suggested that in addition to hemophilia dogs and non-human primates, inclusion of larger animal models (e.g., swine and cattle) in preclinical dose-finding studies of AAV vectors might improve the performance of interspecies dose-response normalization approach. Furthermore, it was found that AAV capsid-specific T cell responses in hemophilia patients might cause underprediction of FIH dose while novel bioengineered capsids with a high transduction efficiency specifically in human hepatocytes might cause overprediction of FIH dose. These factors should be considered when dose-response is extrapolated from preclinical species to patients.