Retrospective Evaluation of Rabbit Antithymocyte Globulin Induction in Heart Transplant Patients

Area of Science:

• Cardiology
• Immunology
• Transplantation Medicine

Background:

• Antithymocyte globulin (ATG) is a key induction therapy in heart transplantation.
• The optimal dosing intensity of ATG remains a subject of clinical debate.
• Evaluating different ATG dosing regimens is crucial for refining immunosuppressive protocols.

Purpose of the Study:

• To compare the efficacy and safety of a full dose (4.5 mg/kg) of rabbit antithymocyte globulin versus a partial dose (<4.5 mg/kg) as induction therapy in heart transplant recipients.
• To assess the impact of ATG dosing on acute cellular rejection, mortality, infection rates, and time to therapeutic tacrolimus levels.

Main Methods:

• Retrospective study of 201 heart transplant patients from January 2016 to December 2018.
• Patients were stratified into two groups: full ATG induction (4.5 mg/kg) and partial ATG induction (<4.5 mg/kg).
• Primary outcome: acute cellular rejection (ISHLT grade ≥2) within 2 years. Secondary outcomes: all-cause mortality, infection incidence, and time to therapeutic tacrolimus levels.

Main Results:

• No significant difference in the cumulative incidence of acute cellular rejection (grade ≥2) within 2 years (18% vs. 11.4%, P=0.209).
• Adjusted hazard ratio for rejection was 1.45 (P=0.388) for partial vs. full induction.
• No significant differences in medium-term mortality, infection incidence within 3 months, or time to therapeutic tacrolimus levels.

Conclusions:

• Neither full-dose nor partial-dose antithymocyte globulin induction therapy demonstrated a significant difference in the risk of cellular rejection.
• Landmark survival analysis indicated no difference in medium-term mortality between the two dosing groups.
• These findings suggest that both dosing strategies may be viable options for induction therapy in heart transplantation.