The use of mathematical modelling and response-guided therapy (RGT) to reduce patient treatment duration without sacrificing efficacy is well documented in hepatitis C virus research. HCV research is relatively mature with well-established drugs for treatment and over 20 years of data and applications. It now requires larger studies for application and refinement. In contrast, HDV research is early in the research for treatments and cure (sustained virological response). The mathematical models needed to predict time to cure in HDV requires the additional consideration of viral kinetics of both HDV and HBV. Treatments may impact the suppression, elimination, and interplay of either or both viruses. Currently the only treatments for HDV are Interferon-a and Bulevirtide, an HDV entry blocker. IFN-a is seen as suboptimal, and only BLV targets HDV specifically. BLV is not an approved treatment in the U.S. but was conditionally approved in 2020 in Europe.