Everolimus in heart transplantation: does it finally have a home?

Long-term experience using CNI-free immunosuppression in selected paediatric heart transplant recipients

BACKGROUND

CNI-free immunosuppression with conversion to mTORi-based immunosuppression has been demonstrated to reduce CNI-toxicity and to exhibit anti-proliferative properties. However, the experience of CNI-free immunosuppression in paediatric heart transplantation is limited.

METHODS

A retrospective analysis was conducted of 129 paediatric heart transplants performed between 1997 and 2015. Fifteen patients with clinically indicated conversion from CNI-based to CNI-free immunosuppression were identified. Survival data, rejection episodes, renal function, post-transplantation lymphoproliferative disorder and CAV, including examination with OCT were analysed.

RESULTS

Immunosuppression conversion was successful in all patients. Fourteen of 15 patients (93%) are currently living with good graft function. Median post-transplant survival was 15 years (range, 5-23 years), and median follow-up since conversion was 6 years (range, 1-11 years). Mild (grade 1R) ACR was present in three patients after discontinuation of CNIs. The recovery of renal function with a significant increase in eGFR was observed at 1 and 3 years after conversion. No patient had angiographic signs of macroscopic CAV according to the current ISHLT classification; however, OCT showed the signs of angiographically silent CAV in all patients. CAV did not progress in any patient, implying CAV was stabilised by mTORi-based CNI-free immunosuppression.

CONCLUSIONS

CNI-free immunosuppression based on mTORis is a safe and appropriate strategy for maintenance therapy in selected paediatric patients, significantly improves renal function and stabilises CAV. OCT revealed early development of angiographically silent CAV.

Invasive haemodynamics in de novo everolimus vs. calcineurin inhibitor heart transplant recipients

Aims

Invasive haemodynamic profiles at rest and during exercise after heart transplantation (HTx) have never been described in a randomized trial where de novo everolimus (EVR)‐based therapy with early calcineurin inhibitor (CNI) withdrawal has been compared with conventional CNI treatment. We report central invasive haemodynamic parameters at rest and exercise during a 3 year follow‐up after HTx in a sub‐study of the SCandiavian Heart transplant Everolimus De novo stUdy with earLy calcineurin inhibitor avoidancE trial. We hypothesized that the nephroprotective properties, the less development of cardiac allograft vasculopathy (CAV), and the antifibrotic properties of EVR, in comparison with CNI‐based immunosuppression, would demonstrate favourable invasive haemodynamic profiles in patients at rest and during exercise.

Methods and results

Ninety of 115 HTx recipients randomized to EVR or CNI treatment performed right heart catheterization at rest and 68 performed right heart catheterization at exercise up to 3 years after HTx. Haemodynamic profiles were compared between EVR and CNI treatment groups. Resting haemodynamics improved in both groups from pre‐HTx to the first follow‐up at 7–11 weeks post‐HTx and thereafter remained unchanged up to 3 years of follow‐up. During follow‐up, cardiac reserve during exercise increased with higher levels of maximum heart rate (118 to 148 b.p.m., P < 0.001), mean arterial pressure (103 to 128 mmHg, P < 0.001), and cardiac output (10.3 to 12.2 l/min, P < 0.001). No significant differences in haemodynamic parameters were observed between the EVR and CNI groups at rest or exercise. Isolated post‐capillary pulmonary hypertension (mean pulmonary arterial pressure > 20 mmHg, pulmonary arterial wedge pressure ≥ 15 mmHg, and pulmonary vascular resistance <3) were measured in 11% of the patients at 7–11 weeks, 5% at 12 months, and 6% at 36 months after HTx. The EVR group had significantly better kidney function (76 mL/min/1 vs. 60 mL/min/1, P < 0.001) and reduced CAV (P < 0.01) but an increased rate of early biopsy‐proven treated rejections (21.2% vs 5.7%, P < 0.01) compared with the CNI group at any time point. The differences in renal function, CAV, or early biopsy‐proven treated acute rejections were not associated with altered haemodynamics.

Conclusions

De novo EVR treatment with early CNI withdrawal compared with conventional CNI therapy did not result in differences in haemodynamics at rest or during exercise up to 3 years after HTx despite significant differences in renal function, reduced CAV, and number of early biopsy‐proven treated rejections.

A Single-Center Experience of the Optimal Initial Immunosuppressive Strategy for Preventing Early Acute Cellular Rejection in Orthotopic Heart Transplantation Associated With Renal Dysfunction

BACKGROUND

Renal dysfunction is a common complication following heart transplantation that may be worsened by the early initiation of calcineurin inhibitors. Antithymocyte globulin (ATG) or basiliximab has been used to delay or avoid calcineurin inhibitors. The most effective strategy for preventing early acute cellular rejection in this context is uncertain.

METHODS

We retrospectively reviewed all heart transplant cases between January 2012 and June 2017. The standard therapy consisted of mycophenolate mofetil, prednisolone, and tacrolimus. In patients at high risk of post-transplant renal dysfunction, an early calcineurin inhibitor-free regimen with basiliximab and/or ATG was used. Patients were assigned to cohorts based on the initial immunosuppressive strategy. The primary end point was the freedom rate of acute cellular rejection within 4 weeks post-transplant.

RESULTS

Of 93 cases, 21 patients received standard therapy, 64 patients received an initial calcineurin inhibitor-free regimen with basiliximab, and 8 patients received ATG and basiliximab. Freedom from acute rejection was greater in the ATG plus basiliximab group (all rejection free), compared to 40 (63%) of 64 patients treated with basiliximab and 10 (48%) of 21 patients treated with standard therapy (P < .05, log rank test). In patients treated with basiliximab, early administration (<24 hours) was associated with a higher freedom from acute rejection compared to ≥24 hours, (72% vs 29%, P < .05).

CONCLUSIONS

The combination of ATG and basiliximab was more effective in preventing acute cellular rejection. In those patients treated with basiliximab, rejection rates were no worse than standard therapy; however, it was only effective when administered within 24 hours.

Everolimus immunosuppression for renal protection, reduction of allograft vasculopathy and prevention of allograft rejection in de-novo heart transplant recipients: could we have it all?

PURPOSE OF REVIEW

De-novo introduction of everolimus (Eve) in heart transplant recipients opens for early reduction of calcineurin inhibitors (CNI) and potential of preserving renal function, attenuate progression of coronary allograft vasculopathy (CAV) and maintain rejection efficacy.

RECENT FINDINGS

The first trials demonstrated adequate rejection prophylaxis and favorable outcomes on CAV, but observed enhanced nephrotoxicity because of insufficient CNI reduction. The SCHEDULE trial compared de-novo Eve with significantly reduced CNI exposure and conversion to CNI-free treatment week 7-11 postheart transplant, with standard CNI immunosuppression. Improved renal function and attenuation of CAV was found among Eve patients, with higher numbers of treated acute rejections observed. With sustained superior renal and CAV related data also after 36 months with the Eve protocol, cardiac function was equally well preserved in both groups. According to the International Society of Heart and Lunge Transplantation registry, mammalian target of rapamycin inhibitor treatment is uncommon during the first postoperative year, with a prevalence of 20% in patients after 5 years.

SUMMARY

Current evidence suggests a greater benefit from these immunosuppressives if introduced at an earlier timepoint. Immunosuppressive protocols based on Eve treatment in de-novo patients should be further investigated and developed, enabling CNI avoidance before accelerating side-effects lead to irreversible damage.