Antithymocyte globulin induction therapy improves survival in lung transplantation for cystic fibrosis

Rabbit Antithymocyte Globulin for Treatment of Corticosteroid Refractory Acute Cellular Rejection After Lung Transplantation

BACKGROUND

Chronic lung allograft dysfunction (CLAD) remains a major cause of death after the first year posttransplant, with acute cellular rejection (ACR) being a major risk factor for CLAD. We evaluated the use of rabbit antithymocyte globulin (rATG) for corticosteroid refractory ACR in lung transplant recipients.

METHODS

We retrospectively identified 112 adult lung transplant recipients who received rATG for refractory ACR after lung transplantation. The primary endpoint was the incidence of ACR on follow-up transbronchial biopsy. Secondary endpoints included freedom from ACR within 1 y post-rATG, CLAD progression at 1 y post-rATG, and all-cause mortality at 1 y post-rATG.

RESULTS

A complete resolution of ACR was observed in 60.2% of patients, an improvement but not complete resolution in 22.1%, and no response on follow-up biopsy in 17.8%. Mean A grade 1 y post-rATG was 0.51 in complete responders, 1.01 in partial responders, and 2.19 in nonresponders ( P  < 0.001). Complete responders had significantly less new or worsening CLAD at 1 y than partial responders (17% versus 40%; P  = 0.02). All-cause mortality rate was 14.9% in complete responders, 40% in partial responders, and 30% in nonresponders ( P  < 0.01).

CONCLUSIONS

rATG appears to be an effective treatment of refractory ACR in lung transplant recipients. Failure to respond to rATG carries an increased risk of early CLAD and death.

Conventional and Novel Approaches to Immunosuppression in Lung Transplantation

Most therapeutic advances in immunosuppression have occurred over the past few decades. Although modern strategies have been effective in reducing acute cellular rejection, excess immunosuppression comes at the price of toxicity, opportunistic infection, and malignancy. As our understanding of the immune system and allograft rejection becomes more nuanced, there is an opportunity to evolve immunosuppression protocols to optimize longer term outcomes while mitigating the deleterious effects of traditional protocols.

Current perspective of immunomodulators for lung transplant

Lung transplantation is an effective treatment option for selected patients suffering from end-stage lung disease. More intensive immunosuppression is enforced after lung transplants owing to a greater risk of rejection than after any other solid organ transplants. The commencing of lung transplantation in the modern era was in 1983 when the Toronto Lung Transplant Group executed the first successful lung transplant. A total of 43,785 lung transplants and 1365 heart-lung transplants have been performed from 1 Jan 1988 until 31 Jan 2021. The aim of this review article is to discuss the existing immunosuppressive strategies and emerging agents to prevent acute and chronic rejection in lung transplantation.

The effect of the cystic fibrosis care center on outcomes after lung transplantation for cystic fibrosis

BACKGROUND

The purpose of this study was to evaluate outcomes in people with cystic fibrosis (CF) who underwent lung transplant (LT) at a transplant center with an accredited Cystic Fibrosis Care Center (CFCC) in the United States.

METHODS

We reviewed the Scientific Registry of Transplant Recipients for all adult patients with CF who received a first-time LT from 2005 to 2018. The primary outcome was graft failure. Unadjusted Kaplan-Meier analysis and adjusted multilevel Cox proportional hazards models were used to evaluate outcomes in CF patients undergoing lung transplantation at a CFCC.

RESULTS

2,573 patients with CF underwent a first time LT during the study period. Of the 68 lung transplantation centers, 50 were CFCCs (73.5%). After adjustment for potential confounders, patients who underwent lung transplantation at a hospital with an accredited CFCC had a 33% reduction in risk of death or re-transplantation compared to those transplanted at a hospital without an accredited CFCC (HR: 0.67, 95% CI: 0.56-0.82, p < 0.001).

CONCLUSIONS

People with CF who undergo LT at a transplant center with a CFCC have improved graft survival and decreased need for re-transplantation compared to those who undergo LT at a non-CFCC, independent of volume.

Immunosuppression in Lung Transplantation

Immunosuppression in lung transplantation is an area devoid of robust clinical data. This chapter will review the history of immunosuppression in lung transplantation. Additionally, it will evaluate the three classes of induction, maintenance, and rescue immunosuppression in detail. Induction immunosuppression in lung transplantation aims to decrease incidence of lung allograft rejection, however infectious risk must be considered when determining if induction is appropriate and which agent is most favorable. Similar to other solid organ transplant patient populations, a multi-drug approach is commonly prescribed for maintenance immunosuppression to minimize single agent drug toxicities. Emphasis of this review is placed on key medication considerations including dosing, adverse effects, and drug interactions. Clinical considerations will be reviewed per drug class given available literature. Finally, acute cellular, antibody mediated, and chronic rejection are reviewed.

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

Immunosuppressive strategies in lung transplantation

Lung transplantation is a viable option for those with end-stage lung disease which is evidenced by the continued increase in the number of lung transplantations worldwide. However, patients and clinicians are constantly faced with acute and chronic rejection, infectious complications, drug toxicities, and malignancies throughout the lifetime of the lung transplant recipient. Conventional maintenance immunosuppression therapy consisting of a calcineurin inhibitor (CNI), anti-metabolite, and corticosteroids have become the standard regimen but newer agents and modalities continue to be developed. Here we will review induction agents, maintenance immunosuppressives, adjunctive therapies and other strategies to improve long-term outcomes.

Testicular Cancer in a Lung Transplant Patient With Cystic Fibrosis: A Case Report

BACKGROUND

Cystic fibrosis (CF) is one of the most common genetic disorders that develops from a mutation of the cystic fibrosis transmembrane regulator gene. Patients with CF are known to be at risk for malignancies, and lung transplantation-associated immunosuppression further increases this risk.

CASE REPORT

We describe a case of a 29-year-old male patient with CF who developed testicular cancer 14 months after a lung transplantation. Immunosuppressive therapy included antithymocyte globulin induction and tacrolimus, mycophenolate, and prednisolone maintenance therapy as compared to standard alemtuzumab induction, followed by tacrolimus and prednisolone, as used in our center. He underwent semicastration and refused chemotherapy. Immunosuppressive treatment was changed to tacrolimus, everolimus, and prednisolone, which did not influence excellent graft function. This case report highlights the importance of uro-oncological observation of patients with CF following lung transplantations.

A Peptide to Reduce Pulmonary Edema in a Rat Model of Lung Transplantation

BACKGROUND

Despite significant advances in organ preservation, surgical techniques and perioperative care, primary graft dysfunction is a serious medical problem in transplantation medicine in general and a specific problem in patients undergoing lung transplantation. As a result, patients develop lung edema, causing reduced tissue oxygenation capacity, reduced lung compliance and increased requirements for mechanical ventilatory support. Yet, there is no effective strategy available to protect the grafted organ from stress reactions induced by ischemia/reperfusion and by the surgical procedure itself.

METHODS

We assessed the effect of a cingulin-derived peptide, XIB13 or a random peptide in an established rat model of allogeneic lung transplantation. Donor lungs and recipients received therapeutic peptide at the time of transplantation and outcome was analyzed 100min and 28 days post grafting.

RESULTS

XIB13 improved blood oxygenation and reduced vascular leak 100min post grafting. Even after 28 days, lung edema was significantly reduced by XIB13 and lungs had reduced fibrotic or necrotic zones. Moreover, the induction of an allogeneic T cell response was delayed indicating a reduced antigen exchange between the donor and the host.

CONCLUSIONS

In summary, we provide a new tool to strengthen endothelial barrier function thereby improving outcomes in lung transplantation.

A randomized, double-blind, placebo-controlled, multicenter study of rabbit ATG in the prophylaxis of acute rejection in lung transplantation

ATG-Fresenius S (ATG-F) is a polyclonal anti-human-T-lymphocyte immunoglobulin preparation that has been clinically developed to prevent episodes of acute cellular rejection. This study evaluated the efficacy and safety of ATG-F at doses of 5 and 9 mg/kg versus placebo in adult recipients of a primary lung allograft. The primary efficacy composite end point was defined as death, graft loss, acute rejection and/or loss to follow-up within 12 months of transplantation. The interim analysis showed the ATG-F 5 mg/kg treatment to be inefficacious, and it would be impossible to enroll enough patients to power the study to show a difference between the 9 mg/kg arm and the placebo arm. Therefore, the main focus of the study shifted to the safety end points and a descriptive analysis of the primary end point. At 12 months posttransplant, the efficacy failure rate was not significantly different between the ATG-F 9 mg/kg group and the placebo group (40.2% vs. 36.7%, respectively). This large study did not demonstrate a significant reduction in acute cellular rejection, graft loss or death with single-dose induction therapy with ATG-F within the first year after lung transplantation.

Lung transplantation in patients with cystic fibrosis: special focus to infection and comorbidities

Despite advances in medical care, patients with cystic fibrosis still face limited life expectancy. The most common cause of death remains respiratory failure. End-stage cystic fibrosis can be treated with lung transplantation and is the third most common reason for which the procedure is performed. Outcomes for cystic fibrosis are better than most other lung diseases, but remain limited (5-year survival 60%). For patients with advanced disease lung transplantation appears to improve survival. Outcomes for patients with Burkholderia cepacia remain poor, although they are better for patients with certain genomovars. Controversy exists about Mycobacterium abscessus infection and appropriateness for transplant. More information is also becoming available for comorbidities, including diabetes and pulmonary hypertension among others. Extra-corporeal membrane oxygenation is used more frequently for end-stage disease as a bridge to lung transplantation and will likely be used more in the future.

[Lung transplantation]

Lung transplantation is a therapeutic option for patients with end-stage lung diseases. Selection of candidates requires careful consideration of the disease-specific indications and contraindications for transplantation. Advances have been made in candidate selection via the ability to prognosticate outcomes of various lung diseases and through the implementation of the lung allocation score (LAS) with specific consideration of the degree of urgency and good postoperative survival rate, after neglecting the waiting time. This system has resulted in decreased mortality on the waiting list for lung transplantation. The availability of donor organs can possibly be increased by implementation of ex vivo lung perfusion as an alternative to conventional organ preservation. Risk factors for poor outcomes post-lung transplantation have been identified and understanding of the physiological, cellular and molecular mechanisms responsible for lung and airway damage has been extensively expanded. Primary graft dysfunction, infectious diseases, acute rejection, antibody-mediated rejection, lymphocytic bronchiolitis, obliterative bronchiolitis, restrictive allograft syndrome, and chronic lung allograft dysfunction are well defined complications and continue to be common causes of morbidity and mortality. This article provides a comprehensive update on these topics for the non-transplantation clinician.