Response: Multiple administrations of the fully human monoclonal antibody Ofatumumab

We thank Tod W. Speer, MD, for his valuable comments, which basically underline what we have stated in our paper.¹  Multiple administrations of a fully human monoclonal antibody such as Ofatumumab in immunocompetent patients would not likely induce antibody formation—and thereby make the treatment ineffective—because of the lack of immunogenicity. That this might offer significant advantages above murine or chimeric antibodies, for instance, after labeling the antibody with an isotope and performing repeated radioimmunotherapy, remains to be established by the appropriate clinical studies. In that regard, Dr Speer comes forward with interesting theoretical calculations in terms of schedules inducing the most effective cell kill. Again, these hypotheses need to be proven by clinical trials.