Advanced Pulmonary Sarcoidosis

Anti-inflammatory Therapy for Sarcoidosis

Over 50% of patients with sarcoidosis will require anti-inflammatory therapy at some point in their disease course. Indications for therapy are to improve health-related quality of life, prevent or arrest organ dysfunction (or organ failure) or avoid death. Recently published treatment guidelines recommended a stepwise approach to therapy however there are some patients for whom up front combination or more intense therapy maybe reasonable. The last decade has seen an explosion of studies and trials evaluating novel therapeutic agents and treatment strategies. Currently available anti-inflammatory therapies and several novel therapies are discussed here.

Fibrotic Pulmonary Sarcoidosis

Fibrotic pulmonary sarcoidosis (fPS) affects about 20% of patients. fPS carries a significant morbidity and mortality. However, its prognosis is highly variable, depending mainly on fibrosis extent, functional impairment severity, and the development of pulmonary hypertension. Moreover, fPS outcomes are also influenced by several other complications, including acute exacerbations, and infections. fPS natural history is unknown, in particular regarding the risk of progressive self-sustaining fibrosis. The management of fPS is challenging, including anti-inflammatory treatment if granulomatous activity persists, rehabilitation, and in highly selected patients antifibrotic treatment and lung transplantation.

High-Risk Sarcoidosis: A Focus on Pulmonary, Cardiac, Hepatic and Renal Advanced Diseases, as Well as on Calcium Metabolism Abnormalities

Although sarcoidosis is generally regarded as a benign condition, approximately 20-30% of patients will develop a chronic and progressive disease. Advanced pulmonary fibrotic sarcoidosis and cardiac involvement are the main contributors to sarcoidosis morbidity and mortality, with failure of the liver and/or kidneys representing additional life-threatening situations. In this review, we discuss diagnosis and treatment of each of these complications and highlight how the integration of clinical, pathological and radiological features may help predict the development of such high-risk situations in sarcoid patients.

Clinical Manifestations and Management of Fibrotic Pulmonary Sarcoidosis

Fibrotic pulmonary sarcoidosis represents a distinct and relatively uncommon manifestation within the spectrum of sarcoidosis and has substantial morbidity and mortality. Due to the scarcity of research focused on this specific disease subtype, our current understanding of pathogenesis and optimal management remains constrained. This knowledge gap underscores the need for further investigation into areas such as targeted therapies, lung transplantation, and quality of life of patients with fibrotic pulmonary sarcoidosis. The primary aim of this review is to discuss recent developments within the realm of fibrotic pulmonary sarcoidosis to foster a more comprehensive understanding of the underlying mechanisms, prognosis, and potential treatment modalities.

Lung transplantation in pulmonary sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology and variable clinical course. Pulmonary sarcoidosis is the most common presentation and accounts for most morbidity and mortality related to sarcoidosis. While sarcoidosis generally has good outcomes, few patients experience chronic disease. A minority of patients progress to a specific phenotype of sarcoidosis referred to advanced pulmonary sarcoidosis (APS) which includes advanced fibrosis, pulmonary hypertension and respiratory failure, leading to high morbidity and mortality. In patients with advanced disease despite medical therapy, lung transplantation may be the last viable option for improvement in quality of life. Though post-transplant survival is similar to that of other end-stage lung diseases, it is imperative that patients are evaluated and referred early to transplant centers with experience in APS. A multidisciplinary approach and clinical experience are crucial in detecting the optimal timing of referral, initiating comprehensive transplantation evaluation and listing, discussing surgical approach, and managing perioperative and post-transplant care. This review article seeks to address these aspects of lung transplantation in APS.

Sarcoidosis lung transplantation waitlist mortality, a national registry database study

Background

The Lung Allocation Score (LAS) prioritises lung transplantation candidates, balancing waitlist mortality and post-transplant survival. The score groups sarcoidosis candidates based on mean pulmonary artery pressure: those with ≤30 mmHg (sarcoidosis A) are grouped with COPD and those with >30 mmHg (sarcoidosis D) with idiopathic pulmonary fibrosis (IPF). We hypothesise that sarcoidosis candidates have a higher waitlist mortality than other candidates within their LAS grouping.

Methods

This is a retrospective cohort study of consecutive lung transplantation candidates from the Scientific Registry of Transplant Recipients database from May 2005 to May 2019. We included candidates aged ≥18 years diagnosed with sarcoidosis, COPD or IPF. Univariate, multivariate and survival estimate analyses were performed.

Results

We identified 385 sarcoidosis A, 642 sarcoidosis D, 7081 COPD and 10 639 IPF lung transplantation candidates. 17.3% of sarcoidosis D, 14.8% of IPF, 14.3% of sarcoidosis A and 9.8% of COPD candidates died awaiting transplant. Sarcoidosis A was an independent risk factor for waitlist mortality. Sarcoidosis A had a lower waitlist survival probability compared to COPD. Sarcoidosis D had the highest waitlist mortality. IPF candidates had lower waitlist survival probability than sarcoidosis D in the first 60 days after listing.

Conclusion

Based on our results, the grouping of candidates with sarcoidosis in allocation systems should be revised to mitigate waitlist mortality disparity.

Immune-mediated lung diseases: A narrative review

The role of immunity in the pathogenesis of various pulmonary diseases, particularly interstitial lung diseases (ILDs), is being increasingly appreciated as mechanistic discoveries advance our knowledge in the field. Immune-mediated lung diseases demonstrate clinical and immunological heterogeneity and can be etiologically categorized into connective tissue disease (CTD)-associated, exposure-related, idiopathic, and other miscellaneous lung diseases including sarcoidosis, and post-lung transplant ILD. The immunopathogenesis of many of these diseases remains poorly defined and possibly involves either immune dysregulation, abnormal healing, chronic inflammation, or a combination of these, often in a background of genetic susceptibility. The heterogeneity and complex immunopathogenesis of ILDs complicate management, and thus a collaborative treatment team should work toward an individualized approach to address the unique needs of each patient. Current management of immune-mediated lung diseases is challenging; the choice of therapy is etiology-driven and includes corticosteroids, immunomodulatory drugs such as methotrexate, cyclophosphamide and mycophenolate mofetil, rituximab, or other measures such as discontinuation or avoidance of the inciting agent in exposure-related ILDs. Antifibrotic therapy is approved for some of the ILDs (e.g., idiopathic pulmonary fibrosis) and is being investigated for many others and has shown promising preliminary results. A dire need for advances in the management of immune-mediated lung disease persists in the absence of standardized management guidelines.

Lung Transplantation Waitlist Mortality Among Sarcoidosis Patients by Lung Allocation Score Grouping

BACKGROUND

The Lung Allocation Score (LAS) system was designed to equalize and minimize waitlist mortality among candidiates for lung transplantation. The LAS stratifies sarcoidosis patients by mean pulmonary arterial pressure (mPAP) into group A (mPAP ≤30 mm Hg) and group D (mPAP >30 mm Hg). In this study, we aimed to analyze the effect of diagnostic grouping and patient characteristics on waitlist mortality among sarcoidosis patients.

METHODS

This was a retrospective review of sarcoidosis lung transplantation candidates since LAS implementation in May 2005 through May 2019 in the Scientific Registry of Transplant Recipients database. We compared baseline characteristics, LAS variables, and waitlist outcomes between sarcoidosis groups A and D. We performed Kaplan-Meier survival analysis and multivariable regression to determine associations with waitlist mortality.

RESULTS

We identified 1027 sarcoidosis candidates since LAS implementation. Of these, 385 had mPAP ≤30 mm Hg and 642 had mPAP >30 mm Hg. Waitlist mortality was 18% in sarcoidosis group D and 14% in sarcoidosis group A. Kaplan-Meier curve showed lower waitlist survival probability for sarcoidosis group D than group A (log-rank P = .0049). Functional status, oxygen requirement, and sarcoidosis group D were associated with increased waitlist mortality. Cardiac output ≥4 L/min was associated with decreased waitlist mortality.

CONCLUSION

Sarcoidosis group D had lower waitlist survival than group A. Decreased survival appears driven by mPAP; sarcoidosis group D, functional status, oxygen requirement, and cardiac output had significant associations with waitlist mortality. These findings suggest that the current LAS grouping does not adequately reflect the risk for waitlist mortality among sarcoidosis group D patients.

An expert overview of pulmonary fibrosis in sarcoidosis

INTRODUCTION

Advanced pulmonary sarcoidosis refers to phenotypes of pulmonary sarcoidosis that often lead to significant loss of lung function, respiratory failure, or death. Around 20% of patients with sarcoidosis may progress to this state which is mainly driven by advanced pulmonary fibrosis. Advanced fibrosis often presents with associated complications of sarcoidosis including infections, bronchiectasis, and pulmonary hypertension.

AREAS COVERED

This article will focus on the pathogenesis, natural history of disease, diagnosis, and potential treatment options of pulmonary fibrosis in sarcoidosis. In the expert opinion section, we will discuss the prognosis and management of patients with significant disease.

EXPERT OPINION

While some patients with pulmonary sarcoidosis remain stable or improve with anti-inflammatory therapies, others develop pulmonary fibrosis and further complications. Although advanced pulmonary fibrosis is the leading cause of death in sarcoidosis, there are no evidence-based guidelines for the management of fibrotic sarcoidosis. Current recommendations are based on expert consensus and often include multidisciplinary discussions with experts in sarcoidosis, pulmonary hypertension, and lung transplantation to facilitate care for such complex patients. Current works evaluating treatments include the use of antifibrotic therapies for treatment in advanced pulmonary sarcoidosis.

Renal sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology. The pathogenesis rests on an aberrant T cell response to unidentified antigens in individuals predisposed by genetic and environmental factors. Increased expression of polarized macrophages and disequilibrium between effector and regulator T cells contribute to the formation of noncaseating granulomas, that are frequently found in affected organs. The main kidney abnormalities in sarcoidosis are granulomatous interstitial nephritis (GIN) and hypercalcemia-related disorders. The clinical diagnosis is difficult. The outcome is variable, ranging from spontaneous remission to end-stage kidney disease (ESKD). Early diagnosis and prompt treatment with corticosteroids can improve the prognosis. Hypercalcemia may be responsible for acute kidney injury (AKI) caused by vasoconstriction of afferent arterioles. Complications of persistent hypercalcemia include nephrocalcinosis and renal stones. In patients with ESKD, dialysis and transplantation can offer results comparable to those observed in patients with other causes of kidney failure. Based on a review of the literature, we present an overview of the etiopathogenesis, the renal manifestations of sarcoidosis and their complications, management and prognosis.

Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches

Sarcoidosis is a systemic granulomatous inflammatory disease of unknown etiology. It affects the lungs in over 90% of patients yet extra-pulmonary and multi-organ involvement is common. Spontaneous remission of disease occurs commonly, nonetheless, over 50% of patients will require treatment and up to 30% of patients will develop a chronic progressive non-remitting disease with marked pulmonary fibrosis leading to significant morbidity and death. Guidelines outlining an immunosuppressive treatment approach to sarcoidosis were recently published, however, the strength of evidence behind many of the guideline recommended drugs is weak. None of the drugs currently used for the treatment of sarcoidosis have been rigorously studied and prescription of these drugs is often based on off-label” indications informed by experience with other diseases. Indeed, only two medications [prednisone and repository corticotropin (RCI) injection] currently used in the treatment of sarcoidosis are approved by the United States Food and Drug Administration. This situation results in significant reimbursement challenges especially for the more advanced (and often more effective) drugs that are favored for severe and refractory forms of disease causing an over-reliance on corticosteroids known to be associated with significant dose and duration dependent toxicities. This past decade has seen a renewed interest in developing new drugs and exploring novel therapeutic pathways for the treatment of sarcoidosis. Several of these trials are active randomized controlled trials (RCTs) designed to recruit relatively large numbers of patients with a goal to determine the safety, efficacy, and tolerability of these new molecules and therapeutic approaches. While it is an exciting time, it is also necessary to exercise caution. Resources including research dollars and most importantly, patient populations available for trials are limited and thus necessitate that several of the challenges facing drug trials and drug development in sarcoidosis are addressed. This will ensure that currently available resources are judiciously utilized. Our paper reviews the ongoing and anticipated drug trials in sarcoidosis and addresses the challenges facing these and future trials. We also review several recently completed trials and draw lessons that should be applied in future.

Potential therapeutic targets to prevent organ damage in chronic pulmonary sarcoidosis

INTRODUCTION

Sarcoidosis is a granulomatous inflammatory disease with high chances of reduced quality of life, irreversible organ damage, and reduced life expectancy when vital organs are involved. Any organ system can be affected, and the lungs are most often affected. There is no preventive strategy as the exact etiology is unknown, and complex immunogenetic and environmental factors determine disease susceptibility and phenotype. Present-day treatment options originated from clinical practice and are effective in many patients. However, a substantial percentage of patients suffer from unacceptable side effects or still develop refractory, threatening pulmonary or extrapulmonary disease.

AREAS COVERED

As non-caseating granulomas, the pathological hallmark of disease, are assigned to divergent activation and regulation of the immune system, targets in relation to the possible triggers of granuloma formation and their sequelae were searched and reviewed.

EXPERT OPINION

:The immunopathogenesis underlying sarcoidosis has been a dynamic field of study. Several recent new insights give way to promising new therapeutic targets, such as certain antigenic triggers (e.g. from Aspergillus nidulans), mTOR, JAK-STAT and PPARγ pathways, the NRP2 receptor and MMP-12, which await further exploration. Clinical and trigger related phenotyping, and molecular endotyping in sarcoidosis will likely hold the key for precision medicine in the future.

Management of Advanced Pulmonary Sarcoidosis

The term "advanced sarcoidosis" is used for forms of sarcoidosis with a significant risk of loss of organ function or death. Advanced sarcoidosis often involves the lung and is described as "Advanced Pulmonary Sarcoidosis" (APS) which includes advanced pulmonary fibrosis, associated complications such as bronchiectasis and infections, and pulmonary hypertension. While APS affects a small proportion of patients with sarcoidosis, it is the leading cause of poor outcomes including death. Herein we review the major patterns of APS with a focus on the current management as well as potential approaches for improved outcomes for this most serious sarcoidosis phenotype.