Low-dose Rituximab and Thymoglobulin Induction With Steroid-free Maintenance Immunosuppression and Protocol Biopsies Improves Long-term Patient and Graft Survival After Kidney Transplantation: Survival and Safety Outcomes in More Than 1100 Patients From a Single Center

Cardiovascular Risk Following Conversion to Belatacept From a Calcineurin Inhibitor in Kidney Transplant Recipients: A Randomized Clinical Trial

Rationale & Objective

In kidney transplant recipients (KTRs), a belatacept-based immunosuppressive regimen is associated with beneficial effects on cardiovascular (CV) risk factors compared with calcineurin inhibitor (CNI)-based regimens. Our objective was to compare the calculated CV risk between belatacept and CNI (predominantly tacrolimus) treatments using a validated model developed for KTRs.

Study Design

Prospective, randomized, open-label, parallel-group, investigator-initiated, international multicenter trial.

Setting & Participants

KTRs aged 18-80 years with a stable graft function (estimated glomerular filtration rate > 20 mL/min/1.73 m²), 3-60 months after transplantation, treated with tacrolimus or cyclosporine A, were eligible for inclusion.

Intervention

Continuation with a CNI-based regimen or switch to belatacept for 12 months.

Outcomes

Comparison of the change in the estimated 7-year risk of major adverse CV events and all-cause mortality, changes in traditional markers of CV health, as well as measures of arterial stiffness.

Results

Among the 105 KTRs randomized, we found no differences between the treatment groups in the predicted risk for major adverse CV events or mortality. Diastolic blood pressure, measured both centrally by using a SphygmoCor device and peripherally, was lower after the belatacept treatment than after the CNI treatment. The mean changes in traditional cardiovascular (CV) risk factors, including kidney transplant function, were otherwise similar in both the treatment groups. The belatacept group had 4 acute rejection episodes; 2 were severe rejections, of which 1 led to graft loss.

Limitations

The heterogeneous baseline estimated glomerular filtration rate and time from transplantation to trial enrollment in the participants. A limited study duration of 1 year.

Conclusions

We found no effects on the calculated CV risk by switching to the belatacept treatment. Participants in the belatacept group had not only lower central and peripheral diastolic blood pressure but also a higher rejection rate.

Funding

The trial has received a financial grant from Bristol-Myers Squibb.

Trial Registration

EudraCT no. 2013-001178-20.

Complement Components in the Diagnosis and Treatment after Kidney Transplantation-Is There a Missing Link?

Currently, kidney transplantation is widely accepted as the renal replacement therapy allowing for the best quality of life and longest survival of patients developing end-stage renal disease. However, chronic transplant rejection, recurrence of previous kidney disease or newly acquired conditions, or immunosuppressive drug toxicity often lead to a deterioration of kidney allograft function over time. Complement components play an important role in the pathogenesis of kidney allograft impairment. Most studies on the role of complement in kidney graft function focus on humoral rejection; however, complement has also been associated with cell mediated rejection, post-transplant thrombotic microangiopathy, the recurrence of several glomerulopathies in the transplanted kidney, and transplant tolerance. Better understanding of the complement involvement in the transplanted kidney damage has led to the development of novel therapies that inhibit complement components and improve graft survival. The analysis of functional complotypes, based on the genotype of both graft recipient and donor, may become a valuable tool for assessing the risk of acute transplant rejection. The review summarizes current knowledge on the pathomechanisms of complement activation following kidney transplantation and the resulting diagnostic and therapeutic possibilities.

Clinical Response and Pattern of B cell Suppression with Single Low Dose Rituximab in Nephrology

Background

There is no consensus regarding dose and frequency of rituximab in nephrology with extrapolation of doses used in treating lymphoproliferative disorders. There are no guidelines on targeting initial and subsequent doses on the basis of CD19⁺ B cells.

Methods

Initially, 100 mg rituximab was given to 42 adults with steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS), idiopathic membranous nephropathy (MN), and high-immunologic-risk kidney transplantation. Absolute and percentage levels of CD19 B cells and clinical status were assessed at baseline, days 30, 90, and 180, and at 1 year. Subsequent doses of rituximab were on the basis of CD19 B cell reconstitution and clinical response.

Results

CD19 B cell percentage decreased from 16.3 ± 7.6 to 0.3 ± 0.3 (P≤0.001), 1.9 ± 1.7 (P≤0.001), and 4.0 ± 4.5 (P=0.005) by 30, 90, and 180 days, respectively. Suppression of CD19 B cell count below 1% at days 30, 90, and 180 was seen in 40 of 42 (95.2%), 18 of 42 (42.9%), and 7 of 42 (16.7%) patients, respectively. Of 30 with SDNS and FRNS followed up for 1 year, 29 (96.7%) went into remission at day 30. Remission was sustained in 23 (76.6%) at day 180 and 21 (70%) at 1 year. There was a significant decrease (P<0.001) in the dose of steroids needed to maintain remission at 180 days after rituximab (0.27 ± 0.02 mg/kg to 0.02 ± 0.00 mg/kg). CD19 B cell percentage at 90 days correlated with relapse (P=0.001; odds ratio 1.42; 95% confidence interval, 1.25 to 2.57). Eighteen (60%) required an additional dose. Of five with MN, four achieved remission by 6 months, which was sustained in three by 1 year. Of the seven kidney transplant recipients, two had antibody-mediated rejections, although CD19 B cells were suppressed even at 1 year.

Conclusions

Low-dose rituximab induces sustained depletion of CD19 B cells for up to 90 days. Its role in preventing relapses in SDNS, FRNS, MN, and rejection needs further study.