Trends in underlying causes of death in solid organ transplant recipients between 2010 and 2020: Using the CLASS method for determining specific causes of death

Safety and Immunogenicity of the mRNA-1273 Coronavirus Disease 2019 Vaccine in Solid Organ Transplant Recipients

BACKGROUND

Solid organ transplant recipients (SOTRs) are at high risk for severe COVID-19.

METHODS

This open-label, phase 3b trial evaluated mRNA-1273 in 137 kidney and 77 liver SOTRs and 20 immunocompetent participants. In part A, SOTRs received three 100-µg doses of mRNA-1273; immunocompetent participants received 2 doses. In part B, an additional 100-µg dose was offered ≥4 months after the primary series. Here, we report interim trial results.

RESULTS

mRNA-1273 was well-tolerated in SOTRs. Four serious adverse events were considered vaccine related by the investigator in 3 SOTRs with preexisting comorbidities. No vaccine-related biopsy-proven organ rejection events or deaths were reported. mRNA-1273 elicited modest neutralizing antibody responses after dose 2 and improved responses after dose 3 in SOTRs. Post-dose 3 responses among liver SOTRs were comparable to post-dose 2 responses in immunocompetent participants. Post-additional dose responses were increased in SOTRs, regardless of primary series vaccination. In liver SOTRs, post-additional dose responses were ∼3-fold higher versus post-dose 2 but lower than immunocompetent participant responses. Most kidney SOTRs received multiple immunosuppressants and had reduced antibody responses versus liver SOTRs.

CONCLUSIONS

mRNA-1273 was well-tolerated, and dose 3 and the additional dose improved antibody responses among SOTRs.

CLINICAL TRIALS REGISTRATION

NCT04860297.

Mechanistic Understanding of EBV+Lymphoproliferative Disease Development After Transplantation

Posttransplant lymphoproliferative disorders (PTLDs) are among the most common malignant complications after transplantation, leading to a drastic reduction in patient survival rates. The majority of PTLDs are tightly linked to Epstein-Barr virus (EBV+PTLDs) and are the result of an uncontrolled proliferation of EBV-infected cells. However, although EBV infections are a common finding in transplant recipients, most patients with high EBV loads will never develop EBV+PTLD. Natural killer cells and EBV-specific CD8+ T lymphocytes are critical for controlling EBV-infected cells, and the impairment of these cytotoxic immune responses facilitates the unfettered proliferation of EBV-infected cells. Recent years have seen a considerable increase in available literature aiming to describe novel risk factors associated with the development of EBV+PTLD, which may critically relate to the strength of EBV-specific natural killer cell and EBV-CD8+ T lymphocyte responses. The accumulation of risk factors and the increased risk of developing EBV+PTLD go hand in hand. On the one hand, most of these risk factors, such as the level of immunosuppression or the EBV donor and recipient serologic mismatch, and distinct genetic risk factors are host related and affect cytotoxic EBV-specific immune responses. On the other hand, there is growing evidence that distinct EBV variants may have an increased malignant potential and are thus more likely to induce EBV+PTLD. Here, we aim to review, from a mechanistic point of view, the risk factors for EBV+PTLD in the host and the infecting EBV variants that may explain why only a minority of transplant recipients develop EBV+PTLD.

Clinical characteristics and outcomes of community-acquired pneumonia in solid organ transplant recipients

BACKGROUND

Pneumonia is a frequent complication of solid organ transplantation that adversely impacts both graft and recipient survival. There is a paucity of data on community-acquired pneumonia (CAP) in transplant recipients, particularly the long term outcomes. We conducted a study to compare the clinical characteristics and outcomes of pneumonia in solid organ transplant (SOT) recipients to those in non-transplant (NT) recipients.

MATERIAL AND METHODS

Clinical characteristics were abstracted from electronic medical records. Outcomes included time to hospital discharge, short and long-term mortality. Inverse-propensity score weights were assigned to account for between-group differences. Adjusted analysis included a weighted logistic regression. Results were reported as odds ratios with a corresponding 95 % confidence interval (CI).

RESULTS

A total of 7449 patients were admitted with CAP. Patients were divided into two groups: SOT recipients 42 (0.56 %) and NT recipients 7396 (99.2 %). SOT recipients were younger, more commonly males, with higher prevalence of comorbidities. After accounting for inverse-propensity score weighting, the odds of mortality were higher in SOT recipients in hospital, at 30 days and at 1 year. The magnitude of increase in mortality for SOT recipients was greatest at 1 year with 1.41 (95 % CI: 1.38-1.44) times higher odds.

CONCLUSION

In patients with CAP, SOT recipients are younger, more commonly male and have more co-morbidities compared with NT recipients. They also have higher 1 year mortality after adjustment. Clinicians must be vigilant toward the pronounced long-term mortality risk among these patients and ensure continued follow-up care for them.

Trends in underlying causes of death in allogeneic hematopoietic cell transplant recipients over the last decade

OBJECTIVES

Improved survival after hematopoietic cell transplantation (HCT) and an increasingly comorbid transplant population may give rise to new trends in the causes of death.

METHODS

This study includes all adult allogeneic HCT recipients transplanted at Rigshospitalet between January 1, 2010 and December 31, 2019. Underlying causes of death were determined using the Classification of Death Causes after Transplantation (CLASS) method.

RESULTS

Among 802 HCT recipients, 289 died during the study period. The main causes of death were relapse (N = 133, 46.0%), graft-versus-host disease (GvHD) (N = 64, 22.1%) and infections (N = 35, 12.1%). Multivariable analyses showed that with increasing transplant calendar year, a decreased risk of all-cause mortality (HR 0.92, 95% CI 0.87-0.97) and death from GvHD (HR 0.87, 95% CI 0.78-0.97) was identified, but not for other specific causes. Standardized mortality ratios (SMRs) for all-cause mortality decreased from 23.8 (95% CI 19.1-28.5) to 18.4 (95% CI 15.0-21.9) for patients transplanted in 2010-2014 versus 2015-2019, while SMR for patients who died from GvHD decreased from 8.19 (95% CI 5.43-10.94) to 3.65 (95% CI 2.13-5.18).

CONCLUSIONS

As risk of all-cause mortality and death from GvHD decreases, death from relapse remains the greatest obstacle in further improvement of survival after HCT.

Do Infectious Diseases After Kidney Retransplantation Differ From Those After First Kidney Transplantation?

Background

Infectious diseases (IDs) are highly relevant after solid organ transplantation in terms of morbidity and mortality, being among the most common causes of death. Patients undergoing kidney retransplantation (re-K-Tx) have been already receiving immunosuppressive therapy over a prolonged period, potentially facilitating subsequent infections. Comparing ID events after re-K-Tx and first kidney transplantation (f-K-Tx) can delineate patterns and risks of ID events associated with prolonged immunosuppression.

Methods

We included adult patients with records on f-K-Tx and re-K-Tx in the Swiss Transplant Cohort Study. We analyzed ID events after f-K-Tx and re-K-Tx within the same patients and compared infection rates, causative pathogens, and infection sites. Recurrent time-to-event analyses were performed for comparison of infection rates.

Results

A total of 59 patients with a median age of 47 years (range, 18-73) were included. Overall, 312 ID events in 52 patients occurred. In multivariable recurrent event modeling, the rate of ID events was significantly lower after re-K-Tx (hazard ratio, 0.70; P = .02). More bacterial (68.9% vs 60.4%) and fungal (4.0% vs 1.1%) infections were observed after f-K-Tx but fewer viral infections (27.0% vs 38.5%) as compared with re-K-Tx (P = .11). After f-K-Tx, urinary and gastrointestinal tract infections were more frequent; after re-K-Tx, respiratory tract and surgical site infections were more frequent (P < .001).

Conclusions

ID events were less frequent after re-K-Tx. Affected sites differed significantly after f-K-Tx vs re-K-Tx.

Mycophenolate mofetil hampers antibody responses to a broad range of vaccinations in kidney transplant recipients: Results from a randomized controlled study

OBJECTIVES

To study the effect of mycophenolate mofetil (MMF) on various vaccination responses in kidney transplant recipients.

METHODS

In a randomized controlled trial (EudraCT nr.: 2014-001372-66), low immunologically risk kidney transplant recipients were randomized to TAC/MMF or TAC-monotherapy (TACmono), six months post-transplantation. One year after transplantation, in a pre-specified sub-study, recipients were vaccinated against pneumococcus, tetanus and influenza. Blood was sampled before and 21 days after vaccination. Adequate vaccination responses were defined by international criteria. A post-hoc analysis was conducted on SARS-CoV-2 vaccination responses within the same cohort.

RESULTS

Seventy-one recipients received pneumococcal and tetanus vaccines (TAC/MMF: n = 37, TACmono: n = 34), with 29 also vaccinated against influenza. When vaccinated, recipients were 60 (54-66) years old, with median eGFR of 54 (44-67) ml/min, tacrolimus trough levels 6.1 (5.4-7.0) ug/L in both groups and TAC/MMF daily MMF dose of 1000 (500-2000) mg. Adequate vaccination responses were: pneumococcal (TAC/MMF 43%, TACmono 74%, p = 0.016), tetanus (TAC/MMF 35%, TACmono 82%, p < 0.0001) and influenza (TAC/MMF 20%, TACmono 71%, p = 0.0092). Only 7% of TAC/MMF responded adequately to all three compared to 36% of TACmono (p = 0.080). Additionally, 40% of TAC/MMF responded inadequately to all three, whereas all TACmono patients responded adequately to at least one vaccination (p = 0.041). Lower SARS-CoV-2 vaccination antibody responses correlated with lower pneumococcal antibody vaccination responses (correlation coefficient: 0.41, p = 0.040).

CONCLUSIONS

MMF on top of tacrolimus severely hampers antibody responses to a broad range of vaccinations.

Survival Outcomes After Double-Lung Transplantation for Refractory Lung-Limited Cancers and Incidence of Post-Transplant Lung Cancer

BACKGROUND To evaluate the role of double-lung transplantation (DLT) for lung cancer, the survival outcomes of patients who underwent DLT for lung cancer and the incidence of de novo lung cancer after DLT were assessed. MATERIAL AND METHODS Data from all cases reported in the literature were pooled for analysis and additional data were collected from the Organ Procurement Transplantation Network (OPTN) registry. Recurrence-free survival (RFS), overall survival (OS), and cancer-specific survival (CSS) of patients who underwent DLT for lung cancer were determined. Moreover, the incidence of de novo lung cancer and associated OS in lung transplant recipients were examined. RESULTS Of the 20 cases series and 15 cases from the OPTN registry, the 5-year RFS was 55.0% and 66.7% and the 5-year OS was 55.0% and 26.7%, respectively, and the median CSS was 48.0 (range, 2.0-144.0) and 27.7 (range, 0.2-66.6) months, respectively. In the OPTN data, the incidence of post-transplant lung cancer in patients who underwent DLT for the non-cancerous disease was 0.8% and the 5-year OS was 47.3%. CONCLUSIONS In conclusion, our integrated analysis of the case series and the OPTN registry demonstrated promising survival outcomes for patients with refractory bilateral lung cancer who underwent DLT. Although there are limitations to consider, the results of this study underscore the potential benefits of DLT in managing refractory lung-limited lung cancer.

Susceptibility to SARS-CoV-2 Infection and Immune Responses to COVID-19 Vaccination Among Recipients of Solid Organ Transplants

Solid organ transplant recipients (SOTRs) are at high risk for infections including SARS-CoV-2, primarily due to use of immunosuppressive therapies that prevent organ rejection. Furthermore, these immunosuppressants are typically associated with suboptimal responses to vaccination. While COVID-19 vaccines have reduced the risk of COVID-19-related morbidity and mortality in SOTRs, breakthrough infection rates and death remain higher in this population compared with immunocompetent individuals. Approaches to enhancing response in SOTRs, such as through administration of additional doses and heterologous vaccination, have resulted in increased seroresponse and antibody levels. In this article, safety and immunogenicity of mRNA COVID-19 vaccines in SOTRs are explored by dose. Key considerations for clinical practice and the current vaccine recommendations for SOTRs are discussed within the context of the dynamic COVID-19 vaccination guideline landscape. A thorough understanding of these topics is essential for determining public health and vaccination strategies to help protect immunocompromised populations, including SOTRs.