Should mammalian target of rapamycin inhibitors be stopped in women with lymphangioleiomyomatosis awaiting lung transplantation?

Lung transplantation for lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease, associated with respiratory symptoms of dyspnea and spontaneous pneumothorax, along with various extra-thoracic manifestations. Often a progressive disease, albeit slowly, patients can develop chronic and severe respiratory failure and require supplemental oxygen. Lung transplantation (LTX) can offer improved duration and quality of life for patients with end-stage lung disease due to LAM. There are several unique considerations for LTX in LAM patients, and disease-specific complications of LAM prior to LTX can affect management decisions. Furthermore, there are several possible post-transplant issues specific to LAM. In this review, we discuss evaluation and management, disease-specific complications (both pre- and post-transplant), and outcomes for LAM patients undergoing lung transplantation.

Outpatient Pharmacologic Management of Lung Transplant Candidates on the Waiting List

The medical care of patients awaiting lung transplantation is complex and requires the treatment of active medical conditions, including lung disease, while at the same time maintaining candidacy for transplantation. Some medications that would otherwise be considered routine may create undesirable challenges or complications in the perioperative setting. Therefore, a comprehensive assessment of the risks and benefits of these medications must take into account both their potential utility in managing a patient's current disease state, as well as the risks of compromising postlung transplant outcomes. In this review, we summarize the available data regarding several medications that are commonly used to treat patients with a variety of lung diseases, but that may impact a patient's course on the waiting list or in the posttransplant period.

Lymphangioleiomyomatosis: pathogenesis, clinical features, diagnosis, and management

Lymphangioleiomyomatosis (LAM) is a slowly progressive, low-grade, metastasising neoplasm of women, characterised by infiltration of the lung parenchyma with abnormal smooth muscle-like cells, resulting in cystic lung destruction. The invading cell in LAM arises from an unknown source and harbours mutations in tuberous sclerosis complex (TSC) genes that result in constitutive activation of the mechanistic target of rapamycin (mTOR) pathway, dysregulated cellular proliferation, and a programme of frustrated lymphangiogenesis, culminating in disordered lung remodelling and respiratory failure. Over the past two decades, all facets of LAM basic and clinical science have seen important advances, including improved understanding of molecular mechanisms, novel diagnostic and prognostic biomarkers, effective treatment strategies, and comprehensive clinical practice guidelines. Further research is needed to better understand the natural history of LAM; develop more powerful diagnostic, prognostic, and predictive biomarkers; optimise the use of inhibitors of mTOR complex 1 in the treatment of LAM; and explore novel approaches to the development of remission-inducing therapies.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

Tuberous sclerosis complex for the pulmonologist

Tuberous sclerosis complex (TSC) is a rare multisystem genetic disorder affecting almost all organs with no sex predominance. TSC has an autosomal-dominant inheritance and is caused by a heterozygous mutation in either the TSC1 or TSC2 gene leading to hyperactivation of the mammalian target of rapamycin (mTOR). TSC is associated with several pulmonary manifestations including lymphangioleiomyomatosis (LAM), multifocal micronodular pneumocyte hyperplasia (MMPH) and chylous effusions. LAM is a multisystem disorder characterised by cystic destruction of lung parenchyma, and may occur in either the setting of TSC (TSC-LAM) or sporadically (S-LAM). LAM occurs in 30–40% of adult females with TSC at childbearing age and is considered a nonmalignant metastatic neoplasm of unknown origin. TSC-LAM is generally milder and, unlike S-LAM, may occur in males. It manifests as multiple, bilateral, diffuse and thin-walled cysts with normal intervening lung parenchyma on chest computed tomography. LAM is complicated by spontaneous pneumothoraces in up to 70% of patients, with a high recurrence rate. mTOR inhibitors are the treatment of choice for LAM with moderately impaired lung function or chylous effusion. MMPH, manifesting as multiple solid and ground-glass nodules on high-resolution computed tomography, is usually harmless with no need for treatment.

Tuberous sclerosis complex is associated with diverse pulmonary manifestations including LAM, multiple micronodular pneumocyte hyperplasia and chylous effusions. LAM occurs in 30–40% of adult females with tuberous sclerosis complex.https://bit.ly/3iLqZ08

A Retrospective Study of Lung Transplantation in Patients With Lymphangioleiomyomatosis: Challenges and Outcomes

Background: Lymphangioleiomyomatosis (LAM) is a rare systemic disease that generally leads to a progressive decline in pulmonary function. Experience, especially from the Asian population, including combined drug therapy before and after lung transplantation (LT) in LAM, is still limited. This study aimed to summarize the clinical data from patients with pulmonary LAM who underwent LT at centers in China. Methods: A retrospective review of all patients with LAM undergoing LT at the two largest centers in China between 2010 and 2018 was conducted. Pre- and posttransplant data were assessed and analyzed. Results: Overall, 25 patients with LAM underwent bilateral LT. The mean age was 35.0 ± 8.6 years at diagnosis and 36.8 ± 9.3 years at the time of transplant. Before LT, only six patients could complete pulmonary function test; the reachable mean forced expiratory volume in one second (FEV₁) before LT was 15.9 ± 6.9%. Twenty-one patients (84%) had a recurrent pneumothorax, four (16.0%) of which required pleurodesis. Eight patients (32%) were treated with sirolimus pretransplant for 3.9 years (1-9 years). The average intra-surgery bleeding volume was 1,280 ± 730 ml in need of a transfusion of 1,316 ± 874 ml due to moderate-to-severe adhesion and pretransplant pleurodesis. The causes of death of four patients (16%) included primary graft dysfunction, bronchial dehiscence with long-term use of sirolimus, and uncontrollable infections. The median follow-up time from LT was 41.1 ± 25.0 months. Conclusions: LT for LAM patients from the Asian population has been reinforced from the data that we presented. Peri-transplantation use of sirolimus and LAM-related complications should be further defined and under constant surveillance.

Long-Term Results of Bilateral Lung Transplantation in Patients With End-Stage Pulmonary Lymphangioleiomyomatosis

INTRODUCTION

Lymphangioleiomyomatosis (LAM) is a rare disease in women, leading to progressive deterioration of lung function and respiratory failure. We describe the outcome of patients with end-stage LAM who underwent lung transplantation at our center.

MATERIALS AND METHODS

The records of patients with LAM transplanted at our institution between February 1997 and May 2015 were reviewed retrospectively. Morbidity and mortality were analyzed, and actuarial survival was calculated using Kaplan-Meier methods. The cumulative survival of transplant patients with LAM at our center was compared with survival after transplantation due to different diseases at our center and the results of the International Society for Heart and Lung Transplantation. Quality of life was assessed by a patient self-report at the end of the first postoperative year.

RESULTS

During the study period, 25 patients underwent lung transplantation for LAM. All patients were women with a mean age of 50 (9) years. Thirteen patients (52%) had undergone previous thoracotomy. All patients (100%) received bilateral lung transplantation. One (4%) case of in-hospital mortality occurred and 9 (36%) late deaths. Two (8%) cases of late death were due to chronic lung allograft dysfunction. The 1-, 3-, and 5-year survival rates were 92%, 84%, and 76%, respectively. Quality-of-life ratings were above the normal in all eight 36-Item Short Form Health Survey subscales 1 year after transplantation.

CONCLUSIONS

Lung transplantation offers a valuable therapy for patients with end-stage pulmonary LAM.

Favorable survival even with high disease-specific complication rates in lymphangioleiomyomatosis after lung transplantation-long-term follow-up of a Japanese center

BACKGROUND

Lung transplantation (LT) is a reliable therapeutic option for end-stage pulmonary lymphangioleiomyomatosis (LAM). Long-term outcome of LAM recipients after LT remains unknown. The aim of this study was to describe the outcomes of LT for LAM with a long-term follow-up, comparing those for other diseases in the same period.

METHODS

We retrospectively reviewed consecutive 145 LT recipients between 1998 and 2015 at Okayama University Hospital with minimum 3-year follow-up.

RESULTS

Twelve LAM recipients including nine sporadic-LAM and three tuberous sclerosis complex -LAM were identified. Nine of 12 underwent bilateral LT including four living-donor lobar LT. There was no significant difference in overall survival between the two groups. (P = 0.15). Chronic lung allograft dysfunction free survival rate in LAM compared with other diseases tended to be better (P = 0.058). However, the rate of requiring hemodialysis was significantly higher in LAM recipients than in the recipients of other diseases (P = 0.047). Notably, 8 of 12 (67%) LAM patients encountered LAM-related complication including chylothorax and pneumothorax, seven (58%) had proliferative diseases consisting of renal angiomyolipoma and recurrent LAM. Nine patients required mTOR inhibitors for LAM-related problems, contributing to improved control of LAM-related problems. While all nine recipients of bilateral LT have still survived, two patients died of diseases in their native lungs and one required re-LT among three recipients of single LT.

CONCLUSION

Although the rates of LAM-related complications were unexpectedly high in the long term, LT is a feasible therapeutic option for patients with advanced pulmonary LAM.

Clinical outcomes and survival following lung transplantation in patients with lymphangioleiomyomatosis

BACKGROUND

The primary aim of our study was to derive disease-specific outcomes following lung transplantation (LT) in patients with lymphangioleiomyomatosis (LAM).

METHODS

We queried the Organ Procurement and Transplant Network database to identify LAM patients that have undergone LT in the United States. The overall survival was analyzed with Kaplan-Meier curves. Survival estimates between subgroups of interest were compared using the log-rank method. Cox proportional hazard models were employed to determine the pre-transplant variables that impact post-LT survival.

RESULTS

One hundred and thirty-eight women with LAM underwent LT at 31 centers between January 2003 and June 2017. The median age at listing and transplant was 44 (IQR: 36-51) and 45 (IQR: 38-52) years, respectively. The median time spent on the LT waitlist was 257 (IQR: 85-616) days. The majority of the patients (109/134, 81%) received bilateral sequential LT. The median ischemic time was 4.9 (IQR: 4.1-6.1) hours. The actuarial Kaplan-Meier survival following LT for LAM patients at 1-, 5-, and 10 years was 94%, 73% and 56%, respectively. The post-LT survival was significantly better in LAM than in other lung diseases (10-year survival 56% vs. 32%, p < 0.01), and this advantage persisted after age- and gender-matched analysis (10-year survival 54% vs. 37%, p < 0.01). Pre-transplant parameters, such as the presence of pulmonary hypertension, six-minute walk distance, age at transplant, ischemic time during transplant, or type of transplant (single vs bilateral sequential LT), did not affect post-transplant survival.

CONCLUSIONS

The median survival after LT in LAM is 12 years and is substantially better than in other lung diseases.

Recent advances in the management of lymphangioleiomyomatosis

Lymphangioleiomyomatosis is a rare disorder that predominantly affects women and is characterized by progressive cystic changes in the lung, leading to gradually worsening shortness of breath and lung function impairment. Pleural complications such as pneumothorax and chylothorax commonly occur in these patients. Lymphangioleiomyomatosis can occur as a form of lung involvement in tuberous sclerosis complex or as a sporadic form (without tuberous sclerosis complex). Etiology in both forms of this disease centers on mutations in the tuberous sclerosis genes. Advances in our understanding of the regulatory role of tuberous sclerosis gene products (hamartin/tuberin) in the mechanistic target of rapamycin (mTOR) signaling pathway have led to the identification of effective therapy (mTOR inhibitors) for a rare disorder, once considered uniformly fatal. Here, we summarize the evolution of current concepts regarding lymphangioleiomyomatosis with an emphasis on recent advances and unresolved issues.

The next breakthrough in LAM clinical trials may be their design: challenges in design and execution of future LAM clinical trials

The past decade has resulted in stunning progress in the pathogenesis and therapy of lymphangioleiomyomatosis (LAM), culminating in the pivotal 'MILES' trial, the first-ever randomized, placebo-controlled trial in LAM, demonstrating the efficacy of sirolimus in 2011. Here, we review clinical progress since 2011, focusing on new therapeutic and observational trials. These trials include the second randomized, placebo-controlled trial, a 2-year study of doxycycline effectiveness in LAM. Other clinical studies have addressed lower-dose sirolimus and treatment of pulmonary hypertension. An improved understanding of LAM pathogenesis is essential to future therapeutic breakthroughs. Critical questions that remain to be addressed include the role of estrogen and lymphangiogenesis in LAM pathogenesis and therapy, mechanisms of cystic lung destruction, the role of autophagy and pro-survival pathways in LAM cell survival. Ultimately, achieving future 'breakthroughs' in LAM will require continued rigorous basic and preclinical investigation, innovative clinical trial design and robust biomarkers.