Monoclonal antibodies in prophylactic immunosuppression after liver transplantation. A randomized controlled trial comparing OKT3 and anti-IL-2 receptor monoclonal antibody LO-Tact-1.

A prospective trial was conducted to assess the efficacy of induction immunosuppression with antilymphocyte monoclonal antibodies in 129 primary liver transplant patients who were randomly divided into three groups according to immunosuppression during the first 10 days post-OLT: triple drug therapy only (TDIS: cyclosporine, steroids, azathioprine) (group I: n = 42); TDIS with a 10-day course of OKT3 (group II: n = 44); and LO-Tact-1 (anti-IL-2 receptor mAb) (group III: n = 43). Biopsy-proved acute rejection (AR) was treated using the same biopsy-guided protocol in the 3 groups. One-year patient survival rates were 67%, 84%, and 93% in groups I, II, and III, respectively (I vs. II, NS; I vs. III, P = 0.001; II vs. III, P = 0.044). Incidences of AR were studied in the subgroup of 100 patients who were exposed to the risk of developing rejection, with an overall rate of 89% during the first 3 months post-OLT, similar in the 3 groups. However, incidences of steroid-resistant rejection diagnosed during the 10 first days post-OLT were 54%, 24%, and 34% in groups I, II, and III and 46%, 26%, and 11%, respectively, during the 10-90 days interval. Sixteen patients with CMV had received OKT3, whereas the 5 remaining CMV cases had not (P = 0.019). In summary: (1) mAbs did not modify crude incidence of AR; (2) in the early period (< 10 days), TDIS immunoprophylaxis combined with OKT3 was more efficient than TDIS alone; (3) when compared with groups I and II, LO-Tact-1 apparently better prevented steroid-resistant rejection during the 10-90 days post-OLT; (4) OKT3 significantly increased incidence of CMV infection. In conclusion, TDIS with LO-Tact-1 seemed to achieve the better risk-benefit ratio in induction immunosuppression after OLT.