Alemtuzumab dose adjusted for body weight is associated with earlier lymphocyte repletion and less infective episodes in the first year post renal transplantation - a retrospective study

Multicenter, Real-World Clinical Evaluation of Alemtuzumab and Anti-Thymocyte Globulin for Severe Acute T Cell-Mediated Kidney Transplant Rejection

BACKGROUND

Alemtuzumab can be an alternative to rabbit anti-thymocyte globulin (rATG) to treat severe or glucocorticoid-resistant acute T cell-mediated kidney transplant rejection (TCMR). Yet, there are few reports in which these two treatments are evaluated let alone, compared. This study describes the real-world clinical experience of both therapies and compares their efficacy and toxicity.

METHODS

Kidney transplant recipients of two Dutch transplant centers who received lymphocyte-depleting antibody therapy for severe or glucocorticoid-resistant TCMR were retrospectively evaluated. In the first, alemtuzumab was the standard treatment for this indication, in the second, it was rATG. Patient survival, graft survival and function, and the occurrence of infections and malignancies were reported and compared.

RESULTS

One hundred and forty-three patients treated with alemtuzumab and 57 patients with rATG were evaluated. Patient survival was not significantly different during follow-up (p = 0.55), and 5-year survival rates were 71.0% (95% confidence interval [CI]: 63.0-79.9) after alemtuzumab and 70.7% (95% CI: 58.3-85.7) after rATG. Graft survival was not significantly different during follow-up either (p = 0.24), and 5-year graft loss rates were 32.3% (95% CI: 24.2-40.5) after alemtuzumab and 29.2% (95% CI: 16.0-42.4) after rATG. The occurrence of infections and malignancies did not differ between groups.

CONCLUSION

Mostly, severe TCMRs have good long-term graft survival and function after either alemtuzumab or rATG therapy. No significant differences between the two therapies were found in this real-world clinical experience. Alemtuzumab is an effective alternative to rATG for the treatment of severe TCMR.

A Decade of Experience With Alemtuzumab Therapy for Severe or Glucocorticoid-Resistant Kidney Transplant Rejection

Alemtuzumab is used as lymphocyte-depleting therapy for severe or glucocorticoid-resistant kidney transplant rejection. However, the long-term efficacy and toxicity of alemtuzumab therapy are unclear. Therefore, all cases of alemtuzumab anti-rejection therapy between 2012 and 2022 in our institution were investigated. Graft survival, graft function, lymphocyte depletion, serious infections, malignancies, and patient survival were analyzed and compared with a reference cohort of transplanted patients who did not require alemtuzumab anti-rejection therapy. A total of 225 patients treated with alemtuzumab were identified and compared with a reference cohort of 1,668 patients. Over 60% of grafts was salvaged with alemtuzumab therapy, but graft survival was significantly poorer compared to the reference cohort. The median time of profound T- and B lymphocyte depletion was 272 and 344 days, respectively. Serious infection rate after alemtuzumab therapy was 54.1/100 person-years. The risk of death (hazard ratio 1.75, 95%-CI 1.28-2.39) and infection-related death (hazard ratio 2.36, 95%-CI 1.35-4.11) were higher in the alemtuzumab-treated cohort. In conclusion, alemtuzumab is an effective treatment for severe kidney transplant rejection, but causes long-lasting lymphocyte depletion and is associated with frequent infections and worse patient survival outcomes.

Population pharmacokinetics of subcutaneous alemtuzumab in kidney transplantation

AIM

Alemtuzumab is a monoclonal antibody used as induction immunosuppressive therapy in kidney transplantation. It targets CD52 on lymphocytes, inducing profound immune cell depletion upon administration. Owing to its off-label status in kidney transplantation, its pharmacokinetic characteristics are largely unknown in this setting, and its current fixed dosing algorithm originates from other populations. We developed a population pharmacokinetic model for alemtuzumab in kidney transplant recipients and investigated the potential of personalized alemtuzumab therapy.

METHODS

In total, 362 pharmacokinetic observations drawn 0-165 days after transplantation were available from 61 adult kidney transplant recipients who received two consecutive doses of 15 mg alemtuzumab subcutaneously. A population pharmacokinetic model was developed using nonlinear mixed-effects modelling and applied to simulate various dosing regimens.

RESULTS

The alemtuzumab concentration-time data were best described by a two-compartmental model with first-order absorption and parallel first-order and time-varying concentration-dependent elimination, with between-subject variability on the first-order elimination (39.6%) and central distribution volume (39.6%). Alemtuzumab pharmacokinetics varied with body size, rendering lighter individuals exposed to lympholytic alemtuzumab concentrations (>0.1 mg/L) for prolonged durations as compared to their heavier peers. This between-subject variability could be reduced through lean bodyweight-adjusted dosing, showing a twofold to threefold reduction in the slope of the median alemtuzumab exposure over the bodyweight range.

CONCLUSION

Alemtuzumab displays substantial pharmacokinetic variability in kidney transplant recipients, which may warrant a personalized treatment strategy. Lean bodyweight-adjusted dosing poses an option for individualized dosing, but further evaluation of its potential clinical benefit is warranted.

Investigational drugs for the treatment of kidney transplant rejection

INTRODUCTION

Kidney transplant rejection remains an important clinical problem despite the development of effective immunosuppressive drug combination therapy. Two major types of rejection are recognized, namely T-cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR), which have a different pathophysiology and are treated differently. Unfortunately, long-term outcomes of both TCMR and ABMR remain unsatisfactory despite current therapy. Hence, alternative therapeutic drugs are urgently needed.

AREAS COVERED

This review covers novel and investigational drugs for the pharmacological treatment of kidney transplant rejection. Potential therapeutic strategies and future directions are discussed.

EXPERT OPINION

The development of alternative pharmacologic treatment of rejection has focused mostly on ABMR, since this is the leading cause of kidney allograft loss and currently lacks an effective, evidence-based therapy. At present, there is insufficient high-quality evidence for any of the covered investigational drugs to support their use in ABMR. However, with the emergence of targeted therapies, this potential arises for individualized treatment strategies. In order to generate more high-quality evidence for such strategies and overcome the obstacles of classic, randomized, controlled trials, we advocate the implementation of adaptive trial designs and surrogate clinical endpoints. We believe such adaptive trial designs could help to understand the risks and benefits of promising drugs such as tocilizumab, clazakizumab, belimumab, and imlifidase.

Implications for body weight extremes in solid organ transplantation

The pharmacokinetic profiles of medications are altered in overweight and underweight patients, but few studies have described these differences in patients with body mass index extremes. As solid organ transplant programs expand their candidate selection criteria to accommodate a growing population of patients with weight extremes, it has become imperative to understand and evaluate the impact weight extremes have on the pharmacokinetics of life-sustaining immunosuppression in this population. This review will describe pharmacokinetic and dosing considerations for weight extremes in solid organ transplant recipients, including changes following bariatric surgeries, non-pharmacologic and pharmacologic management strategies for weight loss and gain, and potential drug-drug interactions with popular weight management products.

Low-dose alemtuzumab induction in a tailored immunosuppression protocol for sensitized kidney transplant recipients

Background

Induction therapy is crucial in kidney transplantation and constitutes an important cornerstone for long-term allograft survival. Alemtuzumab is a depleting CD52-specific antibody with T- and B-cell activity, leading to prolonged lymphocyte depletion for up to 12 months, with profound immunosuppression and an associated risk of serious infections. Current concepts aim to optimize dosing strategies to reduce side effects. Here we present data from an ongoing centre protocol consisting of low-dose alemtuzumab induction and tailored immunosuppression in sensitized patients undergoing kidney transplantation.

Methods

10-year results of the protocol were analysed. Low-dose alemtuzumab induction consisted of a single dose of 20 mg intraoperatively, followed by tacrolimus and corticosteroids for initial immunosuppression, with mycophenolate mofetil suspended until a total lymphocyte count (TLC) >5% or 200/μl was reached.

Results

Between 01/2007 and 04/2017, 46 patients were treated in accordance with the protocol in 48 kidney transplantations. Median PRA_max was 43 [22-76; IQR] %; all patients had negative CDC-crossmatch prior to transplantation. Low-dose alemtuzumab was well tolerated. Median time to TLC recovery was 77 [62-127; IQR] d. Within a median follow-up of 3.3 [1.5-5.6; IQR] years, 12 (25%) patients developed BPAR, 10 of which were antibody-mediated (3 acute, 7 chronic ABMR). Death-censored 5-year allograft survival was 79.2%, with an excellent allograft function at the end of follow-up. There was no increased rate of infections, in particular viral infections.

Conclusions

Our protocol, comprising low-dose alemtuzumab induction, initial suspension of mycophenolate mofetil and triple maintenance immunosuppression, provides excellent patient and allograft outcome in sensitized renal allograft recipients.

Alirocumab efficacy and safety by body mass index: A pooled analysis from 10 Phase 3 ODYSSEY trials

AIMS

Increased body mass index (BMI) contributes to cardiovascular risk and may influence efficacy of therapeutic antibodies. We investigated the effect of baseline BMI on efficacy and safety of alirocumab, a PCSK9 monoclonal antibody.

METHODS

In a post-hoc analysis, data were pooled from 10 Phase 3 trials (n=4975) of alirocumab vs. placebo/ezetimibe controls. Alirocumab dose was 150mg every 2 weeks in two trials, and 75mg every 2 weeks with possible increase to 150mg at 12 weeks (based on Week 8 low-density lipoprotein cholesterol [LDL-C]) in eight trials. Efficacy/safety data were assessed in baseline BMI subgroups of≤25,>25 to 30,>30 to 35, and>35kg/m².

RESULTS

Baseline LDL-C levels were lower among patients in the higher BMI subgroups. Significant LDL-C reductions from baseline were observed at Weeks 12 and 24 for alirocumab vs. controls, of similar magnitude regardless of baseline BMI (interaction P-value=0.7119). LDL-C<1.81mmol/L (<70mg/dL) was achieved at Week 24 by 69.8-76.4% of alirocumab-treated patients and 9.7-18.4% of control-treated patients, with no pattern by BMI. A greater proportion of patients in higher vs. lower BMI subgroups required alirocumab dose increase (P=0.0343); proportions were 22.5%, 24.9%, 31.7%, and 27.2% of patients across BMI subgroups of≤25,>25 to 30,>30 to 35, and>35kg/m², respectively. Adverse event frequencies were similar regardless of BMI; injection-site reaction frequency was higher with alirocumab (5.1-8.2% across BMI categories) vs. controls (3.6-4.8%).

CONCLUSIONS

Alirocumab provided consistent LDL-C reductions, with similar safety findings across BMI subgroups.