PNU156804 prolongs the survival of heart allografts alone and acts synergistically with CsA but not RAPA.

WF (donor, RT1¹) to BUF (recipient, RT1^a) rats received alternate-day oral gavage for 14 days (6 total) of 40, 80, or 120 mg/kg PNU156804 alone or in combination with CsA at ratios of 1:1 to 1:64 or in combination with RAPA at ratios of 40:1 to 160:1. Some recipients received various amounts of CsA or RAPA, alone as indicated within the table. Graft survival was evaluated daily; the last day of a heartbeat was considered the day of rejection. CI values were calculated by the median effect analysis: CI < 1 showed synergistic interactions, CI > 1 showed antagonistic interactions, and CI = 1 showed additive interactions. See “Materials and methods” for details.