Abatacept
Abatacept was the predecessor of belatacept; in the latter two amino acid substitutions provided a more potent binding of its ligands CD80 and CD86. This led to the approval of belatacept for use in kidney transplantation while abatacept is used in rheumatoid arthritis. While belatacept is available for intravenous use only, abatacept can also be given by subcutaneous injections. This led a French group to test the replacement of belatacept by abatacept sc in stable transplant recipients, as a feasible alternative to belatacept to reduce their need to visit the hospital during the initial stay-at-home order in France under the COVID-19 pandemic. Data on the use of abatacept in kidney transplantation are scarce, patients in the study were switched from abatacept after three months. In this perspective the treatment was successful with only two rejection episodes (n=176) while 19 patients (11%) had abatacept discontinued for various reasons. In this study the abatacept dosage was 125mg sc every week for all patients [32].
This study raises questions whether abatacept sc could be an alternative to belatacept in stable kidney transplant recipients long term. Another alternative, if feasible, would be to have a formulation of belatacept for sc administration. If these options should be further explored, it could also provide an opportunity to investigate the potential for a more individualized dosing. So far this has not been advocated for abatacept on any of its indications [33].