Belatacept
Belatacept is a soluble fusion protein combining the human IgG1 Fc
domain with the modified extracellular domain of cytotoxic T
lymphocyte–associated antigen 4 (CTLA4). As a CD28 homolog it binds to
CD80 and CD86 on the antigen-presenting cells, thus inhibiting
CD28-mediated T cell co-stimulation and thereby selectively preventing
the activation of T cells. Belatacept is approved for rejection
prophylaxis in renal transplant recipients as an alternative to
calcineurin inhibitors (CNI) and in combination with basiliximab,
mycophenolate and glucocorticoids. Further clinical trials have tested
alternative approaches like belatacept plus mTOR inhibitor, weaning of
glucocorticoids and the replacement of basiliximab with alemtuzumab in a
belatacept based regimen. A common finding in these studies is a
somewhat increased incidence of acute rejections but the decline in
renal function and other typical CNI related adverse effects has been
avoided.