Alemtuzumab in solid organ transplantation and in composite tissue allotransplantation

Alemtuzumab for multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an autoimmune, T-cell-dependent, inflammatory, demyelinating disease of the central nervous system, with an unpredictable course. Current MS therapies focus on treating and preventing exacerbations, and avoiding the progression of disability. At present, there is no treatment that is capable of safely and effectively reaching these objectives. Clinical trials suggest that alemtuzumab, a humanized monoclonal antibody, could be a promising option for MS.

OBJECTIVES

To evaluate the benefits and harms of alemtuzumab alone or associated with other treatments in people with any form of MS.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 21 June 2022.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in adults with any subtype of MS comparing alemtuzumab alone or associated with other medications versus placebo; another active drug; or alemtuzumab in another dose, regimen, or duration.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our co-primary outcomes were 1. relapse-free survival, 2. sustained disease progression, and 3. number of participants experiencing at least one adverse event. Our secondary outcomes were 4. participants free of clinical disability, 5. quality of life, 6. change in disability, 7. fatigue, 8. new or enlarging lesions on resonance imaging, and 9. dropouts. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We included three RCTs (1713 participants) comparing intravenous alemtuzumab versus subcutaneous interferon beta-1a for relapsing-remitting MS. Participants were treatment-naive (two studies) or had experienced at least one relapse after interferon or glatiramer (one study). Alemtuzumab was given at doses of 12 mg/day or 24 mg/day for five days at months 0 and 12, or 24 mg/day for three days at months 12 and 24. Participants in the interferon beta-1a group received 44 μg three times weekly. Alemtuzumab 12 mg: 1. may improve relapse-free survival at 36 months (hazard ratio [HR] 0.31, 95% confidence interval [CI] 0.18 to 0.53; 1 study, 221 participants; low-certainty evidence); 2. may improve sustained disease progression-free survival at 36 months (HR 0.25, 95% CI 0.11 to 0.56; 1 study, 223 participants; low-certainty evidence); 3. may make little to no difference on the proportion of participants with at least one adverse event at 36 months (risk ratio [RR] 1.00, 95% CI 0.98 to 1.02; 1 study, 224 participants; low-certainty evidence), although the proportion of participants with at least one adverse event was high with both drugs; 4. may slightly reduce disability at 36 months (mean difference [MD] -0.70, 95% CI -1.04 to -0.36; 1 study, 223 participants; low-certainty evidence). The evidence is very uncertain regarding the risk of dropouts at 36 months (RR 0.81, 95% CI 0.57 to 1.14; 1 study, 224 participants; very low-certainty evidence). Alemtuzumab 24 mg: 1. may improve relapse-free survival at 36 months (HR 0.21, 95% CI 0.11 to 0.40; 1 study, 221 participants; low-certainty evidence); 2. may improve sustained disease progression-free survival at 36 months (HR 0.33, 95% CI 0.16 to 0.69; 1 study, 221 participants; low-certainty evidence); 3. may make little to no difference on the proportion of participants with at least one adverse event at 36 months (RR 0.99, 95% CI 0.97 to 1.02; 1 study, 215 participants; low-certainty evidence), although the proportion of participants with at least one adverse event was high with both drugs; 4. may slightly reduce disability at 36 months (MD -0.83, 95% CI -1.16 to -0.50; 1 study, 221 participants; low-certainty evidence); 5. may reduce the risk of dropouts at 36 months (RR 0.08, 95% CI 0.01 to 0.57; 1 study, 215 participants; low-certainty evidence). For quality of life, fatigue, and participants free of clinical disease activity, the studies either did not consider these outcomes or they used different measuring tools to those planned in this review.

AUTHORS' CONCLUSIONS

Compared with interferon beta-1a, alemtuzumab may improve relapse-free survival and sustained disease progression-free survival, and make little to no difference on the proportion of participants with at least one adverse event for people with relapsing-remitting MS at 36 months. The certainty of the evidence for these results was very low to low.

Graft-implanted, enzyme responsive, tacrolimus-eluting hydrogel enables long-term survival of orthotopic porcine limb vascularized composite allografts: A proof of concept study

Background

Currently, patients receiving vascularized composite allotransplantation (VCA) grafts must take long-term systemic immunosuppressive therapy to prevent immunologic rejection. The morbidity and mortality associated with these medications is the single greatest barrier to more patients being able to receive these life-enhancing transplants. In contrast to solid organs, VCA, exemplified by hand or face transplants, allow visual diagnosis of clinical acute rejection (AR), directed biopsy and targeted graft therapies. Local immunosuppression in VCA could reduce systemic drug exposure and limit adverse effects. This proof of concept study evaluated, in a large animal forelimb VCA model, the efficacy and tolerability of a novel graft-implanted enzyme-responsive, tacrolimus (TAC)—eluting hydrogel platform, in achieving long-term graft survival.

Methods

Orthotopic forelimb VCA were performed in single haplotype mismatched mini-swine. Controls (n = 2) received no treatment. Two groups received TAC hydrogel: high dose (n = 4, 91 mg TAC) and low dose (n = 4, 49 mg TAC). The goal was to find a dose that was tolerable and resulted in long-term graft survival. Limbs were evaluated for clinical and histopathological signs of AR. TAC levels were measured in serial blood and skin tissue samples. Tolerability of the dose was evaluated by monitoring animal feeding behavior and weight.

Results

Control limbs underwent Banff Grade IV AR by post-operative day six. Low dose TAC hydrogel treatment resulted in long-term graft survival time to onset of Grade IV AR ranging from 56 days to 93 days. High dose TAC hydrogel also resulted in long-term graft survival (24 to 42 days), but was not well tolerated.

Conclusion

Graft-implanted TAC-loaded hydrogel delays the onset of Grade IV AR of mismatched porcine forelimb VCA grafts, resulting in long term graft survival and demonstrates dose-dependent tolerability.

Anesthesia and Perioperative Care in Reconstructive Transplantation

Reconstructive transplantation of vascularized composite allografts (VCAs), such as upper extremity, craniofacial, abdominal, lower extremity, or genitourinary transplants, has emerged as a cutting-edge specialty, with more than 50 programs in the United States and 30 programs across the world performing these procedures. Most VCAs involve complicated technical planning and preparation, protracted surgery, and complex immunosuppressive or immunomodulatory protocols, each associated with unique anesthesiology challenges. This article outlines key procedural, patient, and protocol-related aspects of VCA relevant to anesthesiology management with the goal of ensuring patient safety and optimizing surgical, immunologic, and functional outcomes.

Alemtuzumab for multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an autoimmune, T-cell-dependent, inflammatory, demyelinating disease of the central nervous system, with an unpredictable course. Current MS therapies focus on treating exacerbations, preventing new exacerbations and avoiding the progression of disability. However, at present there is no effective treatment that is capable of safely and effectively reaching these objectives. This has led to the development and investigation of new drugs. Recent clinical trials suggest that alemtuzumab, a humanised monoclonal antibody against cell surface CD52, could be a promising option for MS.

OBJECTIVES

To assess the safety and effectiveness of alemtuzumab used alone or associated with other treatments to decrease disease activity in patients with any form of MS.

SEARCH METHODS

We searched the Trials Register of the Cochrane Multiple Sclerosis and Rare Diseases of the CNS Group (30 April 2015), which contains trials from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, LILACS and the trial registry databases ClinicalTrials.gov and WHO International Clinical Trials Registry Platform. There was no restriction on the source, publication date or language.

SELECTION CRITERIA

All randomised clinical trials (RCTs) involving adults diagnosed with any form of MS according to the McDonald criteria, comparing alemtuzumab alone or associated with other medications, at any dose and for any duration, versus placebo or any other active drug therapy or alemtuzumab in other dose, regimen or duration. The co-primary outcomes were relapse-free survival, sustained disease progression and number of participants with at least one of any adverse events, including serious adverse events.

DATA COLLECTION AND ANALYSIS

Two independent review authors performed study selection, data extraction and 'Risk of bias' assessment. A third review author checked the process for accuracy. We used the Cochrane 'Risk of bias' tool to assess the risk of bias of the studies included in the review. We used the GRADE system to assess the quality of the body of evidence. To measure the treatment effect on dichotomous outcomes we used the risk ratio (RR); for the treatment effect on continuous outcomes, we used the mean difference (MD) and for time-to-event outcomes we used hazard ratio (HR). We calculated 95% confidence intervals (CI) for these measures. When there was no heterogeneity, we used a fixed-effect model to pool data.

MAIN RESULTS

Three RCTs (1713 participants) fulfilled the selection criteria and we included them in the review. All three trials compared alemtuzumab versus subcutaneous interferon beta-1a for patients with relapsing-remitting MS. Patients were treatment-naive in the CARE-MS and CAMMS223 studies. The CARE-MS II study included patients with at least one relapse while being treated with interferon beta or glatiramer acetate. Alemtuzumab was given for 12 or 24 months; for some outcomes, the follow-up period reached 36 months. The regimens were (a) 12 mg or 24 mg per day administered intravenously, once a day for five consecutive days at month 0 and 12 or (b) 24 mg per day, intravenously, once a day for three consecutive days at month 12 and 24. The patients in the other arm of the trials received interferon beta-1a 44 μg subcutaneously three times weekly after dose titration.At 24 months, alemtuzumab 12 mg was associated with: (a) higher relapse-free survival (hazard ratio (HR) 0.50, 95% CI 0.41 to 0.60; 1248 participants, two studies, moderate quality evidence); (b) higher sustained disease progression-free survival (HR 0.62, 95% CI 0.44 to 0.87; 1191 participants; two studies; moderate quality evidence); (c) a slightly higher number of participants with at least one adverse event (RR 1.04, 95% CI 1.01 to 1.06; 1248 participants; two studies; moderate quality evidence); (d) a lower number of participants with new or enlarging T2-hyperintense lesions on magnetic resonance imaging (MRI) (RR 0.74, 95% CI 0.59 to 0.91; 1238 participants; two studies; I(2) = 80%); and (e) a lower number of dropouts (RR 0.31, 95% CI 0.23 to 0.41; 1248 participants; two studies, I(2) = 29%; low quality evidence).At 36 months, alemtuzumab 24 mg was associated with: (a) higher relapse-free survival (45 versus 17; HR 0.21, 95% CI 0.11 to 0.40; one study; 221 participants); (b) a higher sustained disease progression-free survival (HR 0.33, 95% CI 0.16 to 0.69; one study; 221 participants); and (c) no statistical difference in the rate of participants with at least one adverse event. We did not find any study that reported any of the following outcomes: rate of participants free of clinical disease activity, quality of life, fatigue or change in the numbers of MRI T2- and T1-weighted lesions after treatment. It was not possible to perform subgroup analyses according to disease type and disability at baseline due to lack of data.

AUTHORS' CONCLUSIONS

In patients with relapsing-remitting MS, alemtuzumab 12 mg was better than subcutaneous interferon beta-1a for the following outcomes assessed at 24 months: relapse-free survival, sustained disease progression-free survival, number of participants with at least one adverse event and number of participants with new or enlarging T2-hyperintense lesions on MRI. The quality of the evidence for these results was low to moderate. Alemtuzumab 24 mg seemed to be better than subcutaneous interferon beta-1a for relapse-free survival and sustained disease progression-free survival, at 36 months.More randomised clinical trials are needed to evaluate the effects of alemtuzumab on other forms of MS and compared with other therapeutic options. These new studies should assess additional relevant outcomes such as the rate of participants free of clinical disease activity, quality of life, fatigue and adverse events (individual rates, serious adverse events and long-term adverse events). Moreover, these new studies should evaluate other doses and durations of alemtuzumab course.

Vascularized composite allotransplantation: current standards and novel approaches to prevent acute rejection and chronic allograft deterioration

The advent of more potent immunosuppressants led to the first successful human upper extremity transplantation in 1998. At this time, >100 upper extremity transplants, 30 face transplants, and a variety of other vascularized composite allotransplantation (VCA) procedures have been performed around the world. VCA recipients present unique challenges for transplantation. The incidence of acute rejection exceeds 80% in hand and face transplantation and is well documented, whereas reports about antibody-mediated rejection and chronic rejection remain scarce. Immunosuppression protocols commonly used at US centers are derived from solid organ transplantation protocols. Novel approaches to minimize rejections in VCA may include improved HLA matching and considerations toward cytomegalovirus infection status. New graft preservation techniques may decrease immunogenicity prior to transplant. Novel monitoring methods such as valid biomarkers, ultrasound biomicroscopy, and sentinel flaps may enable earlier diagnosis of rejection. Cell-based therapies are being explored to achieve immunosuppressive regimen minimization or even tolerance induction. The efficacy of local immunosuppression in clinical VCA remains controversial. In conclusion, although immunosuppressive strategies adapted from SOT have demonstrated good midterm results, focusing on the unique features of VCA grafts may enable additional, more specific treatment strategies in the future and improved long-term graft outcomes.

Alemtuzumab in multiple sclerosis: latest evidence and clinical prospects

Alemtuzumab was first used in multiple sclerosis in 1991. It is a monoclonal antibody which is directed against CD52, a protein of unknown function on lymphocytes. Alemtuzumab causes a lymphopenia, following which homeostatic reconstitution leads to prolonged alteration of the immune repertoire. This reduces the risk of relapse and disability accumulation in multiple sclerosis; it is the only drug to show superiority over interferon β-1a in disability outcomes in a monotherapy phase III trial. It should be used with a parallel risk management programme to identify the principal adverse effects of alemtuzumab, especially secondary autoimmunity months or years later, mainly against the thyroid but also immune thrombocytopenia. This review charts the development of alemtuzumab as a drug for multiple sclerosis and summarizes the latest clinical trial data.

Emerging uses for pediatric hematopoietic stem cells

Many new therapies are emerging that use hematopoietic stem and progenitor cells. In this review, we focus on five promising emerging trends that are altering stem cell usage in pediatrics: (i) The use of hematopoietic stem cell (HSC) transplantation, autologous or allogeneic, in the treatment of autoimmune disorders is one. (ii) The use of cord blood transplantation in patients with inherited metabolic disorders such as Hurler syndrome shows great benefit, even more so than replacement enzyme therapy. (iii) Experience with the delivery of gene therapy through stem cells is increasing, redefining the potential and limitations of this therapy. (iv) It has recently been shown that human immunodeficiency virus (HIV) infection can be cured by the use of selected stem cells. (v) Finally, it has long been postulated that HSC-transplantation can be used to induce tolerance in solid-organ transplant recipients. A new approach to tolerance induction using myeloid progenitor cells will be described.

Current status of immunosuppressive agents for solid organ transplantation in children

Immunosuppression after organ transplantation is complex and ever evolving. Over the past two decades, newer immunosuppressive agents have been introduced with an aim to provide better patient and graft survival. Improved therapeutic strategies have been developed offering the option to use combinations of drugs with non-overlapping toxicities. There are, however, only a few clinical studies with robust data to rationalize the use of these agents in children. This review will discuss the newer immunosuppressive agents used for solid organ transplant, their current status in post-transplant management and prevention of allograft rejection.

[Alemtuzumab: a further option for treatment of multiple sclerosis]

Alemtuzumab is a humanized monoclonal therapeutic antibody that targets the CD52 antigen which s expressed on most cells of the lymphoid lineage, exclusive of precursors. Alemtuzumab rapidly depletes CD52(+) cells from the peripheral blood. This depletion is long-lasting, and cells repopulate in a specific pattern with B cells and regulatory T cells peaking first. Alemtuzumab was examined for clinical utility in two open-labelled intervention trials in multiple sclerosis (MS). Because of very promising results its clinical efficacy was further explored in a clinical phase-II trial using s.c. interferon beta-1a as the active comparator. Severe or opportunistic infections were surprisingly rare given the long-term lymphopenia. However, up to 30% of patients developed some antibody-mediated autoimmunity. The thyroid gland was the most frequently affected organ. Immune-mediated thrombocytopenic purpura and Goodpasture's syndrome were additionally observed. This review summarizes the pre-clinical and clinical development of alemtuzumab and discusses potential modes of action as well as the pathogenetic link to the treatment emergent autoimmune phenomena.