Three-year results of an investigator-driven multicenter, international, randomized open-label de novo trial to prevent BOS after lung transplantation

BACKGROUND: Chronic lung allograft dysfunction (CLAD), predominantly manifest as bronchiolitis obliterans syndrome (BOS), is the primary cause of morbidity and death after lung transplantation. We assessed the efficacy and safety of 2 de novo immunosuppression protocols to prevent BOS.

METHODS: This was a multicenter, prospective, international, randomized (1:1) open-label superiority study of de novo enteric-coated mycophenolate sodium (MPS) vs delayed-onset everolimus (RAD), both arms in combination with cyclosporine (CsA) monitored by 2-hour post-dose (C2) levels, and corticosteroids. Target C2 levels were lower in the RAD group because RAD is known to potentiate CsA nephrotoxicity. Cytolytic induction therapy was not used. Patients were stratified at entry for cystic fibrosis. Confirmation of anastomotic healing was required for randomization. Primary efficacy was freedom from BOS Grade 1 on intention-to-treat (ITT) analysis. Secondary efficacy parameters were patient and graft survival and severity of rejection. Treatment failure was defined by graft loss, patient death, drug cessation, or need for other therapy.

RESULTS: The 3-year freedom from BOS Grade 1 was 70% for MPS (n = 80) vs 71% for RAD (n = 84; p = 0.95 by log-rank) in ITT but was lower in the RAD arm of the per-protocol population (p = 0.03). The 3-year survival was 84% (MPS) vs 76% (RAD; p = 0.19 by log-rank). Thirteen patients switched from MPS vs 31 from RAD (p < 0.01). Days on MPS were greater than days on RAD (p < 0.01). Rejection events proven by biopsy specimen were more common on MPS (p = 0.02), as were leucopenia (p < 0.01), diarrhea (p < 0.01), and cytomegalovirus infection (p = 0.04). Venous thromboembolism was more frequent on RAD (p = 0.02). Creatinine at 3 years was 160 ± 112 μmol/1iter in MPS patients vs 152 ± 98 μmol/1iter in RAD patients (p = 0.67).

CONCLUSIONS: This 3-year ITT analysis found no significant difference between arms but was underpowered to accept the null hypothesis that RAD and MPS have equivalent efficacy in preventing BOS or death after lung transplantation.