Budesonide/Formoterol for Bronchiolitis Obliterans after Hematopoietic Stem Cell Transplantation

A phase 2 multicenter trial of ruxolitinib to treat bronchiolitis obliterans syndrome after allogeneic HCT

ABSTRACT

Bronchiolitis obliterans syndrome (BOS) occurring after allogeneic hematopoietic cell transplantation (HCT) is a high-risk manifestation of chronic graft-versus-host disease. In this prospective, multicenter phase 2 trial, adult participants with BOS were treated with ruxolitinib 10 mg twice daily, continuously in 28-day cycles for up to 12 cycles. Participants enrolled into newly diagnosed (<6 months since BOS diagnosis, cohort A) or established (≥6 months since BOS diagnosis, cohort B) disease cohorts. The primary objective was to evaluate the early treatment effect of ruxolitinib, assessed by the change in forced expiratory volume in 1 second (FEV1) at 3 months compared with enrollment. The primary end point differed according to cohort (cohort A, improvement, defined as ≥10% increase in FEV1; cohort B, stabilization, defined as an absence of ≥10% decrease in FEV1). Between 2019 and 2022, 49 participants meeting the criteria for BOS were enrolled and treated (cohort A, n = 36; cohort B, n = 13). The primary end point was achieved by 27.8% of participants with new BOS and 92.3% of participants with established BOS. According to the 2014 National Institutes of Health Consensus Criteria, the best lung-specific overall response rate on ruxoltinib for the 49 participants was 34.7% (16.3% complete response and 18.4% partial response), with most responses occurring in mild or moderate disease. Noninfectious severe (grade ≥3) treatment-emergent adverse events were infrequent. Nine severe infectious events occurred and were largely respiratory in nature. These results support the use of ruxolitinib in the management of BOS after allogeneic HCT. This trial was registered at www.ClinicalTrials.gov as #NCT03674047.

Evaluation of risk for bronchiolitis obliterans syndrome after allogeneic hematopoietic cell transplantation with myeloablative conditioning regimens

Bronchiolitis obliterans syndrome (BOS), as chronic manifestation of graft-versus-host disease (GVHD), is a debilitating complication leading to lung function deterioration in patients after allogeneic hematopoietic cell transplantation (allo-HCT). In the present study, we evaluated BOS development risk in patients after receiving myeloablative conditioning (MAC) regimens. We performed a retrospective analysis of patients undergoing allo-HCT, who received MAC with busulfan/cyclophosphamid (BuCy, n = 175) busulfan/fludarabin (FluBu4, n = 29) or thiotepa/busulfan/fludarabine (TBF MAC, n = 37). The prevalence of lung disease prior allo-HCT, smoking status, GvHD prophylaxis, HCT-CI score, EBMT risk score and GvHD incidence varied across the groups. The cumulative incidence of BOS using the NIH diagnosis consensus criteria at 2 years after allo-HCT was 8% in FluBu4, 23% in BuCy and 19% in TBF MAC (p = 0.07). In the multivariate analysis, we identified associated factors for time to BOS such as FEV1 Collapse

Key Words

• translational research
• risk factors

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MESH Headings

• Humans
• Transplantation Conditioning/adverse effects
• Transplantation Conditioning/methods
• Bronchiolitis Obliterans/etiology
• Hematopoietic Stem Cell Transplantation/adverse effects
• Hematopoietic Stem Cell Transplantation/methods
• Male
• Female
• Adult
• Middle Aged
• Retrospective Studies
• Busulfan/adverse effects
• Busulfan/administration & dosage
• Risk Factors
• Graft vs Host Disease/etiology
• Vidarabine/analogs & derivatives
• Vidarabine/adverse effects
• Vidarabine/therapeutic use
• Vidarabine/administration & dosage
• Transplantation, Homologous/methods
• Transplantation, Homologous/adverse effects
• Aged
• Myeloablative Agonists/adverse effects
• Myeloablative Agonists/therapeutic use
• Young Adult
• Cyclophosphamide/adverse effects
• Cyclophosphamide/therapeutic use
• Thiotepa/administration & dosage
• Incidence
• Allografts
• Bronchiolitis Obliterans Syndrome

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Affiliation(s)

Jesús Duque-Afonso Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Paraschiva Rassner Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Kristin Walther Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Gabriele Ihorst Clinical Trials Unit, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Claudia Wehr Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Reinhard Marks Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Ralph Wäsch Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Hartmut Bertz Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Thomas Köhler Clinic of Respiratory Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Björn Christian Frye Clinic of Respiratory Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Daiana Stolz Clinic of Respiratory Medicine, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Robert Zeiser Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Jürgen Finke Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany
Kristina Maas-Bauer Department of Hematology/Oncology/Stem Cell Transplantation, Faculty of Medicine and Medical Center-University of Freiburg, Freiburg, Germany.

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Pulmonary complications of bone marrow transplantation

Bone marrow transplantation, now often known as haematopoietic stem cell transplantation (HSCT), is a complex choreographed procedure used to treat both acquired and inherited disorders of the bone marrow. It has proven invaluable as therapy for haematological and immunological disorders, and more recently in the treatment of metabolic and enzyme disorders. As the number of performed transplants grows annually, and with patients enjoying improved survival, a knowledge of both early and late complications of HSCT is essential for respiratory trainees and physicians in practice. This article highlights the spectrum of respiratory complications, both infectious and non-infectious, the timeline of their likely occurrence, and the approaches used for diagnosis and treatment, keeping in mind that more than one entity may occur simultaneously. As respiratory issues are often a leading cause of short- and long-term morbidity, consideration of a combined haematology/respiratory clinic may prove useful in this patient population.

Late-onset pulmonary complications following allogeneic hematopoietic cell transplantation in pediatric patients: a prospective multicenter study

The primary objective of our multicenter prospective study was to describe the incidence of late-onset non-infectious pulmonary complications (LONIPCs) in children undergoing hematopoietic cell transplantation (HCT) using sensitive criteria for pulmonary function test (PFT) abnormalities including the non-specific pattern of airflow obstruction. Secondary objectives were to assess the factors associated with LONIPC occurrence and the sensitivity of the 2014 NIH-Consensus Criteria of bronchiolitis obliterans syndrome (BOS). PFT and clinical assessment were performed prior to HCT and at 6, 12, 24, and 36 months post-HCT. LONIPC diagnosis was validated by an Adjudication Committee. The study comprised 292 children from 12 centers. Thirty-two individuals (11%, 95% CI: 8-15%) experienced 35 LONIPCs: 25 BOS, 4 interstitial lung diseases, 4 organizing pneumonia and 2 pulmonary veno-occlusive diseases. PFT abnormalities were obstructive defects (FEV1/FVC z-score < -1.645; n = 12), restrictive defects (TLC < 80% predicted, FEV1 and FVC z-scores < -1.645; n = 7) and non-specific pattern (FEV1 and FVC z-score< -1.645, FEV1/FVC z-score > -1.645, and TLC > 80% predicted; n = 8). HCT for malignant disease was the only factor associated with LONIPC (P = 0.04). The 2014 NIH-Consensus Criteria would only diagnose 8/25 participants (32%) as having BOS. In conclusion, 11% of children experienced a LONIPC in a prospective design. Clinical Trials.gov identifier (NCT number): NCT02032381.

A placebo-controlled, crossover trial to investigate the efficacy of tiotropium bromide or placebo added to usual care in stable symptomatic post-hematopoietic stem cell transplantation (HSCT) bronchiolitis obliterans syndrome (BOS)

BACKGROUND

Despite the fundamental progress in hematopoietic stem cell transplant, this treatment is also associated with complications. Graft-versus-host disease is a possible complication of HSCT. Bronchiolitis obliterans syndrome (BOS) is the pulmonary form of this syndrome. Due to the high morbidity and mortality rate of BOS, various studies have been conducted in the field of drug therapy for this syndrome, although no standard treatment has yet been proposed. According to the hypotheses about the similarities between BOS and chronic obstructive pulmonary disease, the idea of using tiotropium bromide as a bronchodilator has been proposed.

METHOD/DESIGN

A randomized, double-blind, placebo-controlled, and crossover clinical trial is being conducted to evaluate the efficacy of tiotropium in patients with BOS. A total of 20 patients with BOS were randomly assigned (1:1) to receive a once-daily inhaled capsule of either tiotropium bromide (KP-Tiova Rotacaps 18 mcg, Cipla, India) or placebo for 1 month. Patients will receive tiotropium bromide or placebo Revolizer added to usual standard care. Measurements will include spirometry and a 6-min walking test.

ETHICS/DISSEMINATION

This study was approved by the Research Ethics Committees of Imam Khomeini Hospital Complex, Tehran University of Medical Science. Recruitment started in September 2022, with 20 patients randomized. The treatment follow-up of participants with tiotropium is currently ongoing and is due to finish in April 2024. The authors will disseminate the findings in peer-reviewed publications, conferences, and seminar presentations.

TRIAL REGISTRATION

Iranian Registry of Clinical Trial (IRCT) IRCT20200415047080N3. Registered on 2022-07-12, 1401/04/21.

Early and rapid development of bronchiolitis obliterans syndrome after allogeneic hematopoietic cell transplantation

Bronchiolitis obliterans (BO) is a form of graft-versus-host disease (GVHD) in the lung and manifests as moderate to severe airflow obstruction after hematopoietic stem cell transplantation (HCT). New-onset airflow obstruction on spirometry is considered diagnostic of bronchiolitis obliterans syndrome (BOS). BOS affects about 5% of all HCT recipients. In general, BO is thought of as a late complication of HCT, usually occurring after day 100 post-transplantation. However, the onset of airflow obstruction can be rapid and is most often irreversible even with treatment. We describe a patient who rapidly developed severe airflow obstruction less than one month after transplantation following the development of upper airway symptoms. Despite aggressive immunosuppression, the patient had no improvement in airflow obstruction. We hypothesize that early screening and treatment may help prevent BOS after HCT.

ERS/EBMT clinical practice guidelines on treatment of pulmonary chronic graft-versus-host disease in adults

Chronic graft-versus-host disease (cGvHD) is a common complication after allogeneic haematopoietic stem cell transplantation, characterised by a broad disease spectrum that can affect virtually any organ. Although pulmonary cGvHD is a less common manifestation, it is of great concern due to its severity and poor prognosis. Optimal management of patients with pulmonary cGvHD is complicated and no standardised approach is available. The purpose of this joint European Respiratory Society (ERS) and European Society for Blood and Marrow Transplantation task force was to develop evidence-based recommendations regarding the treatment of pulmonary cGvHD phenotype bronchiolitis obliterans syndrome in adults. A multidisciplinary group representing specialists in haematology, respiratory medicine and methodology, as well as patient advocates, formulated eight PICO (patient, intervention, comparison, outcome) and two narrative questions. Following the ERS standardised methodology, we conducted systematic reviews to address these questions and used the Grading of Recommendations Assessment, Development and Evaluation approach to develop recommendations. The resulting guideline addresses common therapeutic options (inhalation therapy, fluticasone-azithromycin-montelukast, imatinib, ibrutinib, ruxolitinib, belumosudil, extracorporeal photopheresis and lung transplantation), as well as other aspects of general management, such as lung functional and radiological follow-up and pulmonary rehabilitation, for adults with pulmonary cGvHD phenotype bronchiolitis obliterans syndrome. These recommendations include important advancements that could be incorporated in the management of adults with pulmonary cGvHD, primarily aimed at improving and standardising treatment and improving outcomes.

Longitudinal assessment of lung function in Swiss childhood cancer survivors-A multicenter cohort study

OBJECTIVE

Childhood cancer survivors are at risk for pulmonary morbidity due to exposure to lung-toxic treatments, including specific chemotherapeutics, radiotherapy, and surgery. Longitudinal data on lung function and its change over time are scarce. We investigated lung function trajectories in survivors over time and the association with lung-toxic treatments.

METHODS

This retrospective, multicenter cohort study included Swiss survivors diagnosed between 1990 and 2013 and exposed to lung-toxic chemotherapeutics or thoracic radiotherapy. Pulmonary function tests (PFTs), including forced expiration volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC, total lung capacity,  and diffusion capacity of the lung for carbon monoxide, were obtained from hospital charts. We calculated z-scores and percentage predicted, described lung function over time, and determined risk factors for change in FEV1 and FVC using multivariable linear regression.

RESULTS

We included 790 PFTs from 183 survivors, with a median age of 12 years at diagnosis and 5.5 years of follow-up. Most common diagnosis was lymphoma (55%). Half (49%) of survivors had at least one abnormal pulmonary function parameter, mainly restrictive (22%). Trajectories of FEV1 and FVC started at z-scores of -1.5 at diagnosis and remained low throughout follow-up. Survivors treated with thoracic surgery started particularly low, with an FEV1 of -1.08 z-scores (-2.02 to -0.15) and an FVC of -1.42 z-scores (-2.27 to -0.57) compared to those without surgery.

CONCLUSION

Reduced pulmonary function was frequent but mainly of mild to moderate severity. Nevertheless, more research and long-term surveillance of this vulnerable population is needed.

Severe cryptogenic bronchiolitis: Case report

Bronchiolitis obliterans (BO) is a progressive fibrotic process that predominantly affects the small airways and is identified as constrictive bronchiolitis by pathologists. It is commonly associated with allogeneic hematopoietic stem cell transplant (HSCT), lung transplant, exposure to inhaled toxins, post-infectious processes, autoimmune diseases, and sometimes, no known cause. In the latter case, it is referred to as cryptogenic bronchiolitis obliterans. A 52-year-old Hispanic man with a medical history of hypertension, diabetes mellitus, and coronary artery disease was referred to the pulmonary department due to experiencing dyspnea on exertion, intermittent dry cough, and progressive limitation of activities of daily living. Spirometry revealed severe obstructive changes, and chest high-resolution computed tomography showed ground-glass opacities with nodular infiltrates in the upper lobes, leading to a presumptive diagnosis of hypersensitivity pneumonitis. The patient underwent a lung surgical biopsy of the right upper and lower lobes, which revealed extensive constrictive bronchiolitis. Due to the patient's worsening general condition, bilateral lung transplantation succeeded without any further complications. Following the transplantation, the patient showed good recovery and functional improvement. Bronchiolitis obliterans, or constrictive bronchiolitis, has a variable natural history. It is associated with a higher risk of mortality in allogenic HSCT. When BO is secondary to inhalation of toxic gases, it is usually nonprogressive and limited to toxin exposure. Autoimmune diseases or cryptogenic bronchiolitis are rare and have a heterogeneous clinical course. To make a proper diagnosis, clinical history, radiologic and histologic findings must be considered.

A Nasal Inflammatory Cytokine Signature Is Associated with Early Graft-versus-Host Disease of the Lung after Allogeneic Hematopoietic Cell Transplantation: Proof of Concept

Respiratory inflammation in bronchiolitis obliterans syndrome (BOS) after hematopoietic cell transplantation (HCT) is poorly understood. Clinical criteria for early-stage BOS (stage 0p) often capture HCT recipients without BOS. Measuring respiratory tract inflammation may help identify BOS, particularly early BOS. We conducted a prospective observational study in HCT recipients with new-onset BOS (n = 14), BOS stage 0p (n = 10), and recipients without lung impairment with (n = 3) or without (n = 8) chronic graft-versus-host disease and measured nasal inflammation using nasosorption at enrollment and then every 3 mo for 1 y. We divided BOS stage 0p into impairment that did not return to baseline values (preBOS, n = 6), or transient impairment (n = 4). We tested eluted nasal mucosal lining fluid from nasosorption matrices for inflammatory chemokines and cytokines using multiplex magnetic bead immunoassays. We analyzed between-group differences using the Kruskal-Wallis method, adjusting for multiple comparisons. We found increased nasal inflammation in preBOS and therefore directly compared patients with preBOS to those with transient impairment, as this would be of greatest diagnostic relevance. After adjusting for multiple corrections, we found significant increases in growth factors (FGF2, TGF-α, GM-CSF, VEGF), macrophage activation (CCL4, TNF-α, IL-6), neutrophil activation (CXCL2, IL-8), T cell activation (CD40 ligand, IL-2, IL-12p70, IL-15), type 2 inflammation (eotaxin, IL-4, IL-13), type 17 inflammation (IL-17A), dendritic maturation (FLT3 ligand, IL-7), and counterregulatory molecules (PD-L1, IL-1 receptor antagonist, IL-10) in preBOS patients compared to transient impairment. These differences waned over time. In conclusion, a transient multifaceted nasal inflammatory response is associated with preBOS. Our findings require validation in larger longitudinal cohorts.

The Development of New Agents for Post-Hematopoietic Stem Cell Transplantation Non-Infectious Complications in Children

Hematopoietic stem cell transplantation (HSCT) is often the only curative treatment option for patients suffering from various types of malignant diseases and some non-cancerous conditions. Nevertheless, it is associated with a high risk of complications leading to transplant-related mortality and long-term morbidity. An increasing number of therapeutic and prevention strategies have been developed over the last few years to tackle the complications arising in patients receiving an HSCT. These strategies have been mainly carried out in adults and some are now being translated into children. In this manuscript, we review the recent advancements in the development and implementation of treatment options for post-HSCT non-infectious complications in pediatric patients with leukemia and other non-malignant conditions, with a special attention on the new agents available within clinical trials. We focused on the following conditions: graft failure, prevention of relapse and early interventions after detection of minimal residual disease positivity following HSCT in acute lymphoblastic and myeloid leukemia, chronic graft versus host disease, non-infectious pulmonary complications, and complications of endothelial origin.

Interstitial lung diseases after hematopoietic stem cell transplantation: New pattern of lung chronic graft-versus-host disease?

Bronchiolitis obliterans syndrome (BOS) after allogeneic HSCT is the only formally recognized manifestation of lung chronic graft-versus-host disease (GVHD). Other lung complications were reported, including interstitial lung diseases (ILDs). Whether ILDs belong to the spectrum of lung cGVHD remains unknown. We compared characteristics and specific risk factors for both ILD and BOS. Data collected from consecutive patients diagnosed with ILD or BOS from 1981-2019 were analyzed. The strength of the association between patient characteristics and ILD occurrence was measured via odds ratios estimated from univariable logistic models. Multivariable models allowed us to handle potential confounding variables. Overall survival (OS) was estimated using the Kaplan-Meier method. 238 patients were included: 79 with ILD and 159 with BOS. At diagnosis, FEV1 was lower in patients with BOS compared to patients with ILD, while DLCO was lower in ILD. 84% of ILD patients received systemic corticosteroids, leading to improved CT scans and pulmonary function, whereas most BOS patients were treated by inhaled corticosteroids, with lung-function stabilization. In the multivariable analysis, prior thoracic irradiation and absence of prior treatment with prednisone were associated with ILD. OS was similar, even if hematological relapse was more frequent in the ILD group. Both complications occurred mainly in patients with GVHD history.

Clinical response to belumosudil in bronchiolitis obliterans syndrome: a combined analysis from 2 prospective trials

Chronic graft-versus-host disease (cGVHD) of the lung, or bronchiolitis obliterans syndrome (BOS), is a high-risk disease manifestation associated with poor outcomes. Currently available treatments have demonstrated limited clinical efficacy in this setting. Belumosudil is a novel oral selective rho-associated coiled-coil-containing protein kinase-2 inhibitor that was recently approved by the US Food and Drug Administration in the treatment of cGVHD. We identified 59 subjects with BOS who were enrolled and treated in 2 prospective clinical trials of belumosudil. Patients with BOS had a percentage predicted forced expiratory volume in 1 second (FEV1) of ≤79% at enrollment and clinician attribution of lung disease owing to cGVHD. The National Institutes of Health (NIH) cGVHD lung scores at enrollment were 1 (n = 30, 59%), 2 (n = 23, 39%), or 3 (n = 6, 10%). According to NIH response criteria, the best overall response rate (ORR) for lung cGVHD was 32% (partial response: 17%; complete response: 15%). Response rates were inversely proportional to baseline NIH GVHD lung score at enrollment (lung score 1: ORR 50%; lung score 2: ORR 17%, lung score 3: ORR 0%) (P = .006). In multivariable analysis, male sex, lower baseline NIH cGVHD lung score, and partial response to previous line of cGVHD therapy before enrollment were associated with higher rates of lung-specific response. No significant correlation was identified between pulmonary function evaluations and measures of patient symptoms (NIH lung symptom score or Lee Symptom Scale score for lung). In conclusion, belumosudil treatment was associated with lung-specific clinical responses for subjects with BOS, which were more commonly observed in less advanced disease. Optimization of treatment response evaluations remains a challenge in patients with BOS.

The safety and tolerability of pirfenidone for bronchiolitis obliterans syndrome after hematopoietic cell transplant (STOP-BOS) trial

Bronchiolitis obliterans syndrome (BOS) is the most morbid form of chronic graft-versus-host disease (cGVHD) after hematopoietic cell transplantation (HCT). Progressive airway fibrosis leads to a 5-year survival of 40%. Treatment options for BOS are limited. A single arm, 52-week, Phase I study of pirfenidone was conducted. The primary outcome was tolerability defined as maintaining the recommended dose of pirfenidone (2403 mg/day) without a dose reduction totaling more than 21 days, due to adverse events (AEs) or severe AEs (SAEs). Secondary outcomes included pulmonary function tests (PFTs) and patient reported outcomes (PROs). Among 22 participants treated for 1 year, 13 (59%) tolerated the recommended dose, with an average daily tolerated dose of 2325.6 mg/day. Twenty-two SAEs were observed, with 90.9% related to infections, none were attributed to pirfenidone. There was an increase in the average percent predicted forced expiratory volume in 1 s (FEV1%) of 7 percentage points annually and improvements in PROs related to symptoms of cGVHD. In this Phase I study, treatment with pirfenidone was safe. The stabilization in PFTs and improvements in PROs suggest the potential of pirfenidone for BOS treatment and support the value of a randomized controlled trial to evaluate the efficacy of pirfenidone in BOS after HCT. The study is registered in ClinicalTrials.gov (NCT03315741).

Bronchiolitis obliterans syndrome after lung or haematopoietic stem cell transplantation: current management and future directions

Bronchiolitis obliterans syndrome (BOS) may develop after either lung or haematopoietic stem cell transplantation (HSCT), with similarities in histopathological features and clinical manifestations. However, there are differences in the contributory factors and clinical trajectories between the two conditions. BOS after HSCT occurs due to systemic graft-versus-host-disease (GVHD), whereas BOS after lung transplantation is limited to the lung allograft. BOS diagnosis after HSCT is more challenging, as the lung function decline may occur due to extrapulmonary GVHD, causing sclerosis or inflammation in the fascia or muscles of the respiratory girdle. Treatment is generally empirical with no established effective therapies. This review provides rare insights and commonalities of both conditions, that are not well elaborated elsewhere in contemporary literature, and highlights the importance of cross disciplinary learning from experts in other transplant modalities. Treatment algorithms for each condition are presented, based on the published literature and consensus clinical opinion. Immunosuppression should be optimised, and other conditions or contributory factors treated where possible. When initial treatment fails, the ultimate therapeutic option is lung transplantation (or re-transplantation in the case of BOS after lung transplantation) in carefully selected candidates. Novel therapies under investigation include aerosolised liposomal cyclosporine, Janus kinase inhibitors, antifibrotic therapies, and (in patients with BOS after lung transplantation) B-cell–directed therapies. Effective novel treatments that have a tangible impact on survival and thereby avoid the need for lung transplantation or re-transplantation are urgently required.

The economic burden of NIPC and BOS following allogeneic HSCT in patients with commercial insurance in the United States

Noninfectious pulmonary complications (NIPC) after allogeneic hematopoietic stem cell transplantation (alloHSCT), including bronchiolitis obliterans syndrome (BOS), cause significant morbidity and mortality, but their impact on health care resource utilization (HRU) and costs is unknown. This longitudinal retrospective study quantified the economic burden of NIPC and BOS in alloHSCT patients using commercial claims data from the IQVIA PharMetrics Plus database. Study patients were aged 0 to 64 years and underwent alloHSCT between 1 January 2006 and 30 September 2018, and were observable 12 months before and up to 5 years after index alloHSCT. NIPC patients were identified using International Classification of Disease (ICD) diagnosis codes. Outcomes were mean per patient HRU (inpatient admissions, outpatient office, hospital visits, and prescription medications) and costs paid by insurers in each post-transplant year. Among 2162 alloHSCT patients, 254 developed NIPCs, and 155 were propensity score (PS)-matched to non-NIPC patients. The year following transplantation, NIPC patients had significantly higher inpatient admission rates (3.8 ± 3.2 vs non-NIPC: 2.6 ± 2.4; P < .001) and higher total costs ($567 870 vs $412 400; P = .07), reflecting higher costs for inpatient admissions ($452 475 vs $300 202; P = .06). Among those observable for more years, costs remained higher for NIPC patients, reflecting significantly higher inpatient admission rates in the first 3 years following transplant. Subanalysis of patients with diagnoses likely reflective of BOS were consistent with these findings. AlloHSCT patients who developed NIPC had higher health care resource utilization and incurred higher costs compared with alloHSCT patients who did not develop NIPC following transplant.

Airway disease in hematologic malignancies

INTRODUCTION

Hematologic malignancies are cancers of the blood, bone marrow and lymph nodes and represent a heterogenous group of diseases that affect people of all ages. Treatment generally involves chemotherapeutic or targeted agents that aim to kill malignant cells. In some cases, hematopoietic stem cell transplantation (HCT) is required to replenish the killed blood and stem cells. Both disease and therapies are associated with pulmonary complications. As survivors live longer with the disease and are treated with novel agents that may result in secondary immunodeficiency, airway diseases and respiratory infections will increasingly be encountered. To prevent airways diseases from adding to the morbidity of survivors or leading to long-term mortality, improved understanding of the pathogenesis and treatment of viral bronchiolitis, BOS, and bronchiectasis is necessary.

AREAS COVERED

This review focuses on viral bronchitis, BOS and bronchiectasis in people with hematological malignancy. Literature was reviewed from Pubmed for the areas covered.

EXPERT OPINION

Airway disease impacts significantly on hematologic malignancies. Viral bronchiolitis, BOS and bronchiectasis are common respiratory manifestations in hematological malignancy. Strategies to identify patients early in their disease course may improve the efficacy of treatment and halt progression of lung function decline and improve quality of life.

Blood and Marrow Transplant Clinical Trials Network State of the Science Symposium 2021: Looking Forward as the Network Celebrates its 20th Year

In 2021 the BMT CTN held the 4th State of the Science Symposium where the deliberations of 11 committees concerning major topics pertinent to a particular disease, modality, or complication of transplant, as well as two committees to consider clinical trial design and inclusion, diversity, and access as cross-cutting themes were reviewed. This article summarizes the individual committee reports and their recommendations on the highest priority questions in hematopoietic stem cell transplant and cell therapy to address in multicenter trials.

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: IV. The 2020 Highly morbid forms report

Chronic graft-versus-host disease (GVHD) can be associated with significant morbidity, in part because of nonreversible fibrosis, which impacts physical functioning (eye, skin, lung manifestations) and mortality (lung, gastrointestinal manifestations). Progress in preventing severe morbidity and mortality associated with chronic GVHD is limited by a complex and incompletely understood disease biology and a lack of prognostic biomarkers. Likewise, treatment advances for highly morbid manifestations remain hindered by the absence of effective organ-specific approaches targeting "irreversible" fibrotic sequelae and difficulties in conducting clinical trials in a heterogeneous disease with small patient numbers. The purpose of this document is to identify current gaps, to outline a roadmap of research goals for highly morbid forms of chronic GVHD including advanced skin sclerosis, fasciitis, lung, ocular and gastrointestinal involvement, and to propose strategies for effective trial design. The working group made the following recommendations: (1) Phenotype chronic GVHD clinically and biologically in future cohorts, to describe the incidence, prognostic factors, mechanisms of organ damage, and clinical evolution of highly morbid conditions including long-term effects in children; (2) Conduct longitudinal multicenter studies with common definitions and research sample collections; (3) Develop new approaches for early identification and treatment of highly morbid forms of chronic GVHD, especially biologically targeted treatments, with a special focus on fibrotic changes; and (4) Establish primary endpoints for clinical trials addressing each highly morbid manifestation in relationship to the time point of intervention (early versus late). Alternative endpoints, such as lack of progression and improvement in physical functioning or quality of life, may be suitable for clinical trials in patients with highly morbid manifestations. Finally, new approaches for objective response assessment and exploration of novel trial designs for small populations are required.

Follow-up on the therapeutic effects of a budesonide, azithromycin, montelukast, and acetylcysteine (BAMA) regimen in children with post-infectious bronchiolitis obliterans

Background

Post-infectious bronchiolitis obliterans (PIBO) is a rare, severe chronic lung disease without optimal treatment. Currently, treatment in children mainly relies on systemic corticosteroids, but long-term use of these drugs may lead to adverse reactions. This study aimed to evaluate the short-term efficacy of the budesonide, azithromycin, montelukast, and acetylcysteine (BAMA) regimen in paediatric PIBO patients and whether it can reduce systemic corticosteroid use.

Methods

This was a prospective study. From June 2017 to July 2020, patients diagnosed with PIBO at Yuying Children’s Hospital of Wenzhou Medical University were treated with the BAMA regimen for 3 months. Methylprednisolone was added only when the clinical manifestations did not improve or deteriorated. All patients were followed up every 2 to 4 weeks, and changes in clinical symptoms were recorded. Pulmonary function tests and high-resolution computed tomography (HRCT) were performed, and systemic corticosteroid use was recorded after the 3-month follow-up.

Results

A total of 75 patients with PIBO were included; overall, 54 patients completed the course of treatment. After treatment, the respiratory manifestations were improved in 37 patients (68.5%), but 4 patients (7.4%) showed decreased exercise tolerance, and 2 patients (3.7%) were readmitted to the hospital. Additionally, 17 (56.7%) of the 30 patients whose pulmonary function was re-examined showed improvement, and 28 (77.8%) of the 36 patients who underwent HRCT showed marked improvement. Importantly, 20 patients (54.1%) received systemic corticosteroids for 2 weeks or less, while 31.5% of patients used no corticosteroids.

Conclusions

The BAMA regimen effectively relieved clinical symptoms and signs of PIBO in children, improved pulmonary function and HRCT manifestations, and reduced the use of systemic corticosteroids.

Pulmonary Complications of Pediatric Hematopoietic Cell Transplantation. A National Institutes of Health Workshop Summary

Approximately 2,500 pediatric hematopoietic cell transplants (HCTs), most of which are allogeneic, are performed annually in the United States for life-threatening malignant and nonmalignant conditions. Although HCT is undertaken with curative intent, post-HCT complications limit successful outcomes, with pulmonary dysfunction representing the leading cause of nonrelapse mortality. To better understand, predict, prevent, and/or treat pulmonary complications after HCT, a multidisciplinary group of 33 experts met in a 2-day National Institutes of Health Workshop to identify knowledge gaps and research strategies most likely to improve outcomes. This summary of Workshop deliberations outlines the consensus focus areas for future research.

Major pulmonary complications following Hematopoietic stem cell transplantation: What the pulmonologist needs to know

Hematopoietic stem cell transplantation (HSCT) is used for treatment of a myriad of both malignant and non-malignant disorders. However, despite many advances over the years which have resulted in improved patient mortality, this subset of patients remains at risk for a variety of post-transplant complications. Pulmonary complications of HSCT are categorized into infectious and non-infectious and occur in up to one-third of patients undergoing HSCT. Infectious etiologies include bacterial, viral and fungal infections, each of which can have significant mortality if not identified and treated early in the course of infection. Advances in the diagnosis and management of infectious complications highlight the importance of non-infectious pulmonary complications related to chemoradiation toxicities, immunosuppressive drugs toxicities, and graft-versus-host disease. This report aims to serve as a guide and clinical update of pulmonary complications following HSCT for the general pulmonologist who may be involved in the care of these patients.

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: IIb. The 2020 Preemptive Therapy Working Group Report

Chronic graft-versus-host disease (GVHD) commonly occurs after allogeneic hematopoietic cell transplantation (HCT) despite standard prophylactic immune suppression. Intensified universal prophylaxis approaches are effective but risk possible overtreatment and may interfere with the graft-versus-malignancy immune response. Here we summarize conceptual and practical considerations regarding preemptive therapy of chronic GVHD, namely interventions applied after HCT based on evidence that the risk of developing chronic GVHD is higher than previously appreciated. This risk may be anticipated by clinical factors or risk assignment biomarkers or may be indicated by early signs and symptoms of chronic GVHD that do not fully meet National Institutes of Health diagnostic criteria. However, truly preemptive, individualized, and targeted chronic GVHD therapies currently do not exist. In this report, we (1) review current knowledge regarding clinical risk factors for chronic GVHD, (2) review what is known about chronic GVHD risk assignment biomarkers, (3) examine how chronic GVHD pathogenesis intersects with available targeted therapeutic agents, and (4) summarize considerations for preemptive therapy for chronic GVHD, emphasizing trial development, including trial design and statistical considerations. We conclude that robust risk assignment models that accurately predict chronic GVHD after HCT and early-phase preemptive therapy trials represent the most urgent priorities for advancing this novel area of research.

Pulmonary Complications in Hematopoietic Stem Cell Transplant Recipients-A Clinician Primer

Hematopoietic stem cell transplants (HSCT) are becoming more widespread as a result of optimization of conditioning regimens and prevention of short-term complications with prophylactic antibiotics and antifungals. However, pulmonary complications post-HSCT remain a leading cause of morbidity and mortality and are a challenge to clinicians in both diagnosis and treatment. This comprehensive review provides a primer for non-pulmonary healthcare providers, synthesizing the current evidence behind common infectious and non-infectious post-transplant pulmonary complications based on time (peri-engraftment, early post-transplantation, and late post-transplantation). Utilizing the combination of timing of presentation, clinical symptoms, histopathology, and radiographic findings should increase rates of early diagnosis, treatment, and prognostication of these severe illness states.

Home Spirometry Telemonitoring for Early Detection of Bronchiolitis Obliterans Syndrome in Patients with Chronic Graft-versus-Host Disease

Early detection of bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic cell transplantation (HCT) depends on recognition of subclinical spirometric changes, which is possible only with frequent interval spirometry. We evaluated the feasibility of home monitoring of weekly spirometry via a wireless handheld device and a web monitoring portal in a cohort of high-risk patients for the detection of lung function changes preceding BOS diagnosis. In this observational study, 46 patients with chronic graft-versus-host disease or a decline in forced expiratory volume in 1 second (FEV₁) of unclear etiology after allogeneic HCT were enrolled to perform weekly home spirometry with a wireless portable spirometer for a period of 1 year. Measurements were transmitted wirelessly to a Cloud-based monitoring portal. Feasibility evaluation included adherence with study procedures and an assessment of the home spirometry measurements compared with laboratory pulmonary function tests. Thirty-six patients (78%) completed 1 year of weekly monitoring. Overall adherence with weekly home spirometry measurements was 72% (interquartile range, 47% to 90%), which did not meet the predetermined threshold of 75% for high adherence. Correlation of home FEV₁ with laboratory FEV₁ was high, with a bias of 0.123 L (lower limit, -0.294 L; upper limit, 0.541 L), which is within acceptable limits for reliability. Of the 12 patients who were diagnosed with BOS or suspected BOS during the study period, 9 had an antecedent FEV₁ decline detected by home spirometry. Our data indicate that wireless handheld spirometry performed at home in a high-risk HCT cohort is feasible for close monitoring of pulmonary function and appears to facilitate early detection of BOS.

Salvage Therapy With Low-Dose Ruxolitinib Leads to a Significant Improvement in Bronchiolitis Obliterans Syndrome in Patients With cGVHD After Allogeneic Hematopoietic Stem Cell Transplantation

Bronchiolitis obliterans syndrome (BOS) is a life-threatening pulmonary manifestation of chronic graft versus host disease (cGVHD) post-allogeneic hematopoietic stem cell transplantation (HSCT), without clear standard of care. This study included 30 patients undergoing an allogeneic HSCT for a hematological malignancy and the outcomes with post-HSCT BOS treated with ruxolitinib as a salvage treatment were reviewed. After a median duration of ruxolitinib therapy of 9.25 (1.5–27) months, the best overall response (BOR) rate was 66.7%: three patients (10.0%) achieved complete remission, and 17 (56.7%) achieved partial remission. The median time from initiation of ruxolitinib to achieve the best responses was 3 months. Since initiating ruxolitinib, forced expiratory volume in 1 s of predicted (FEV1%pred) slightly increased after 3 and 6 months compared with measurements before ruxolitinib in responders. Only FEV1%pred mild decline before ruxolitinib with a ratio ≤15% was an independent predictor to achieve a response to ruxolitinib. Eleven patients (36.7%) had severe pulmonary infection of ≥3 grade. Following a median follow-up of 318 days after ruxolitinib, the 2-years incidence of nonrelapse mortality and 2-years overall survival rate after ruxolitinib among patients with BOS was 25.1 and 62.6%, respectively. Ruxolitinib is a promising treatment option to improve the prognosis of post-HSCT BOS.

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: IIa. The 2020 Clinical Implementation and Early Diagnosis Working Group Report

Recognition of the earliest signs and symptoms of chronic graft-versus-host disease (GVHD) that lead to severe manifestations remains a challenge. The standardization provided by the National Institutes of Health (NIH) 2005 and 2014 consensus projects has helped improve diagnostic accuracy and severity scoring for clinical trials, but utilization of these tools in routine clinical practice is variable. Additionally, when patients meet the NIH diagnostic criteria, many already have significant morbidity and possibly irreversible organ damage. The goals of this early diagnosis project are 2-fold. First, we provide consensus recommendations regarding implementation of the current NIH diagnostic guidelines into routine transplant care, outside of clinical trials, aiming to enhance early clinical recognition of chronic GVHD. Second, we propose directions for future research efforts to enable discovery of new, early laboratory as well as clinical indicators of chronic GVHD, both globally and for highly morbid organ-specific manifestations. Identification of early features of chronic GVHD that have high positive predictive value for progression to more severe manifestations of the disease could potentially allow for future pre-emptive clinical trials.

Overview and Challenges of Bronchiolar Disorders

Bronchiolar abnormalities are common and can occur in conditions that affect either the large airways or the more distal parenchyma. In this review, we focus on the diagnosis and management of primary bronchiolar disorders, or conditions in which bronchiolitis is the predominant pathologic process, including constrictive bronchiolitis, follicular bronchiolitis, acute bronchiolitis, respiratory bronchiolitis, and diffuse panbronchiolitis. Due to the nature of abnormalities in the small airway, clinical and physiological changes in bronchiolitis can be subtle, making diagnosis challenging. Primary bronchiolar disorders frequently present with progressive dyspnea and cough that can be out of proportion to imaging and physiologic studies. Pulmonary function tests may be normal, impaired in an obstructive, restrictive, or mixed pattern, or have an isolated decrease in diffusion capacity. High-resolution computed tomography scan is an important diagnostic tool that may demonstrate one or more of the following three patterns: 1) solid centrilobular nodules, often with linear branching opacities (i.e., "tree-in-bud" pattern); 2) ill-defined ground glass centrilobular nodules; and 3) mosaic attenuation on inspiratory images that is accentuated on expiratory images, consistent with geographic air trapping. Bronchiolitis is often missed on standard transbronchial lung biopsies, as the areas of small airway involvement can be patchy. Fortunately, many patients can be diagnosed with a combination of clinical suspicion, inspiratory and expiratory high-resolution computed tomography scans, and pulmonary function testing. Joint consultation of clinicians with both radiologists and pathologists (in cases where histopathology is pursued) is critical to appropriately assess the clinical-radiographic-pathologic context in each individual patient.

A case of bronchiolitis obliterans after living-donor renal transplantation

We herein report the case of a 20 year-old-man who developed bronchiolitis obliterans after living-donor renal transplantation. The patient presented with dyspnea on exertion and wheezing two years after renal transplantation, and spirometry showed an obstructive pattern. Surgical lung biopsy revealed subepithelial fibrosis that constricted and obstructed the intrabronchiolar space. Based on these findings, the patient was diagnosed with bronchiolitis obliterans. He was prescribed bronchodilators and azithromycin, and he achieved stable respiratory function for two years. The differential diagnosis of respiratory symptoms after renal transplantation includes opportunistic infection and drug-induced lung injury; however, bronchiolitis obliterans should also be considered.

Lung hyperinflation quantitated by chest CT in children with bronchiolitis obliterans syndrome following allogeneic hematopoietic cell transplantation

OBJECTIVES

Bronchiolitis obliterans syndrome (BOS) diagnosis in children following allogeneic hematopoietic stem cell transplantation (post-HSCT) is based on detection of airway obstruction on spirometry and air-trapping, small airway thickening or bronchiectasis on chest CT. We assessed the relationship between spirometry indices and low-attenuation lung volume at total lung capacity (TLC) on CT.

METHODS

Data of children post-HSCT with and without BOS were analyzed. An age-specific, low-attenuation threshold (LAT) was defined as average of (mean-1SD) lung parenchyma attenuation of 5 control subjects without lung disease matched to each age subgroup of post-HSCT patients. % CT lung volume at TLC with attenuation values <LAT was calculated. Association between % lung volume with low attenuation and FEV₁/FVC was assessed.

RESULTS

Twenty-nine children post-HSCT were referred to exclude BOS and 12 of them had spirometry and an analyzable chest CT. We studied: (i) 6 children post-HSCT/BOS (median age: 8.5 years [IQR 7, 15]; median FEV₁/FVC z-score: -2.60 [IQR -2.93, -2.14]); (ii) 6 children post-HSCT/no BOS (age: 13.5 years [9.8, 16.3]; FEV₁/FVC z-score: 0.44 [-0.30, 2.10]); and (iii) 40 controls without lung disease (age:11 years [8.3, 15.8]). Patients post-HSCT/BOS had significantly higher % lung volume with low attenuation than patients post-HSCT/no BOS: median % volume 16.4% (7.1%, 37.2%) vs. 0.61% (0.34%, 2.79%), respectively; P = .004. An exponential model described the association between % CT lung volume below LAT and FEV₁/FVC z-score (r² = 0.76; P < .001).

CONCLUSION

In children post-HSCT with BOS, low-attenuation lung volume on chest CT is associated with airway obstruction severity as expressed by FEV₁/FVC z-score.

Childhood bronchiolitis obliterans in Hong Kong-case series over a 20-year period

BACKGROUND AND OBJECTIVE

Bronchiolitis obliterans (BO) is a rare but serious condition. The natural history and outcomes remain poorly understood. In this clinical review, we aimed to describe the clinical characteristics and outcomes of children diagnosed with BO in Hong Kong (HK).

METHODS

This was a retrospective study of pediatric patients with BO under the care of six respiratory units in HK from January 1996 to December 2015. Information was retrieved from medical records.

RESULTS

Fifty-six patients were included with a male predominance (67.9%). The median age at diagnosis was 1.98 years (interquartile range [IQR]: 0.84-4.99 years). Postinfectious BO (PIBO) was the commonest cause (64.3%) followed by posthematopoietic stem-cell transplant (21.4%). Adenovirus (63.2%) was the commonest causative pathogen among PIBO. The median follow-up duration was 9.7 years (IQR: 2.9-14.3 years). Twenty-five patients (44.6%) could achieve symptom-free recovery at the time of follow-up. Five (8.9%) and three (5.4%) were oxygen or ventilator dependent, respectively. There were two deaths, both had posttransplant BO. Patients who developed BO after transplant had significantly worse lung function than those with PIBO. There were no risk factors significantly associated with worse clinical outcomes (oxygen/ventilator dependence or death) by logistic regression. Among patients with PIBO, coinfection at presentation was significantly associated with persistent symptoms at follow-up (p = .028).

CONCLUSIONS

The most common cause of childhood BO in HK is postinfectious and coinfection at presentation was associated with persistent symptoms at follow-up. Further studies are needed to better elucidate disease progression, treatment options and long term outcomes.

Intractable diffuse pulmonary diseases: Manual for diagnosis and treatment

This manual has been compiled by a joint production committee with the Diffuse Lung Disease Assembly of the Japanese Respiratory Society (JRS) to provide a practical manual for the epidemiology, diagnosis, and treatment of intractable diffuse pulmonary diseases. The contents are based upon the results of research into these diseases by the Diffuse Pulmonary Diseases Study Group (principal researcher: Sakae Homma) supported by the FY2014-FY2016 Health and Labor Sciences Research Grant on Intractable Diseases. This manual focuses on: 1) pulmonary alveolar microlithiasis, 2) bronchiolitis obliterans, and 3) Hermansky-Pudlak Syndrome with interstitial pneumonia. As these are rare/intractable diffuse lung diseases (2 and 3 were first recognized as specified intractable diseases in 2015), there have not been sufficient epidemiological studies made, and there has been little progress in formulating diagnostic criteria and severity scales; however, the results of Japan's first surveys and research into such details are presented herein. In addition, the manual provides treatment guidance and actual cases for each disease, aiming to assist in the establishment of future modalities. The manual was produced with the goal of enabling clinicians specialized in respiratory apparatus to handle these diseases in clinical settings and of further advancing future research and treatment.

Risk of relapse in patients receiving azithromycin after allogeneic HSCT

Following publication of the ALLOZITHRO trial, the FDA released a safety announcement warning that azithromycin should not be given long-term to prevent BOS in patients with a blood or lymph cancer who have undergone allogeneic HSCT. Our site typically initiated azithromycin when patients were diagnosed with BOS post-transplant rather than empirically as prevention. The purpose of our study was to discern whether the use of azithromycin at the time of diagnosis of BOS increased risk of disease relapse in patients who received an allogeneic HSCT for malignant disease. We retrospectively reviewed 432 patients in 3 cohorts: Cohort (1) patients who received greater than or equal to 2 weeks of azithromycin therapy (n = 98); Cohort (2) patients who received azithromycin therapy for less than 2 weeks (n = 63); and Cohort (3) patients who never received azithromycin therapy (n = 271). Neither patients in Cohort 1 (HR 0.44; 95% CI, 0.12-1.53, P = 0.19) nor Cohort 2 (HR 0.66; 95% CI, 0.2-2.19, P = 0.49) were associated with an increased risk of relapse when compared to those who had never received azithromycin. Our data indicate that the prolonged use of azithromycin after allogeneic HSCT is not associated with an increased rate of hematologic relapse.

Machine Learning Algorithms to Differentiate Among Pulmonary Complications After Hematopoietic Cell Transplant

BACKGROUND

Pulmonary complications, including infections, are highly prevalent in patients after hematopoietic cell transplantation with chronic graft-vs-host disease. These comorbid diseases can make the diagnosis of early lung graft-vs-host disease (bronchiolitis obliterans syndrome) challenging. A quantitative method to differentiate among these pulmonary diseases can address diagnostic challenges and facilitate earlier and more targeted therapy.

STUDY DESIGN AND METHODS

We conducted a single-center study of 66 patients with CT chest scans analyzed with a quantitative imaging tool known as parametric response mapping. Parametric response mapping results were correlated with pulmonary function tests and clinical characteristics. Five parametric response mapping metrics were applied to K-means clustering and support vector machine models to distinguish among posttransplantation lung complications solely from quantitative output.

RESULTS

Compared with parametric response mapping, spirometry showed a moderate correlation with radiographic air trapping, and total lung capacity and residual volume showed a strong correlation with radiographic lung volumes. K-means clustering analysis distinguished four unique clusters. Clusters 2 and 3 represented obstructive physiology (encompassing 81% of patients with bronchiolitis obliterans syndrome) in increasing severity (percentage air trapping 15.6% and 43.0%, respectively). Cluster 1 was dominated by normal lung, and cluster 4 was characterized by patients with parenchymal opacities. A support vector machine algorithm differentiated bronchiolitis obliterans syndrome with a specificity of 88%, sensitivity of 83%, accuracy of 86%, and an area under the receiver operating characteristic curve of 0.85.

INTERPRETATION

Our machine learning models offer a quantitative approach for the identification of bronchiolitis obliterans syndrome vs other lung diseases, including late pulmonary complications after hematopoietic cell transplantation.

Therapeutic effect of budesonide, montelukast and azithromycin on post-infectious bronchiolitis obliterans in children

Optimal treatment options for post-infectious bronchiolitis obliterans (PIBO) have not yet been established. The present study retrospectively analyzed the effect of budesonide, montelukast and azithromycin on treating PIBO in children <5 years old.. Based on treatment regimen, the cohort was divided into group A and group B. Group A received a combination of budesonide, montelukast and azithromycin for at least 3 months and group B received unconventional treatment (budesonide for nebulization intermittently, prednisone, montelukast and antibiotics if necessary) compared with standard treatment. Tidal pulmonary function and symptoms assessment were performed at diagnosis and after 3 months of therapy. There were no significant differences in the sex, age, pulmonary function and symptoms assessment between groups A and B at diagnosis. However, following 3 months of treatment, the time to peak tidal expiratory flow as a proportion of expiratory time, and volume to peak expiratory flow as a proportion of exhaled volume in group A were significantly higher compared with those in group B. The respiratory rate in group A was significantly lower compared with group B. The symptoms assessment score in group A was significantly higher compared with that of group B. In conclusion, the present study demonstrates that combination therapy with budesonide, montelukast and azithromycin improves pulmonary function and respiratory symptoms in PIBO children <5 years old. The present study was retrospectively registered on March 22, 2020 with register no. YY202003-008-HB03.

Long-term Follow-up of Hematopoietic Stem Cell Transplant Survivors: A Focus on Screening, Monitoring, and Therapeutics

Annually, ~50,000 patients undergo hematopoietic stem cell transplantation (HCT) worldwide with almost 22,000 of these patients receiving HCT in the United States. HCT is a curative option for a wide range of hematologic malignancies, and advances in transplantation medicine have resulted in an increase in HCT survivors. It is anticipated that the number of HCT survivors will more than double from 242,000 in 2020 to ~500,000 in 2030. Survivors of HCT are at an increased risk of developing late complications due to exposure to chemotherapy and/or radiation in the pre-, peri-, and post-HCT phases and these cumulative exposures have the potential to damage normal tissue. This tissue damage leads to the early onset of chronic health conditions resulting in premature mortality in HCT survivors, who have a 15-year cumulative incidence of severe or life-threatening chronic health conditions exceeding 40%. Due to the significant burden of morbidity in HCT survivors and the delay in the development of long-term complications, this delicate patient population requires life-long monitoring due to the risk for neuropsychological, cardiac, pulmonary, renal, hepatic, ocular, skeletal, cardiac, endocrine, fertility, and sexual health complications, as well as secondary neoplasms. This review will focus on recent advances in screening, monitoring, and therapeutics for late-occurring or long-term complications in HCT survivors.

Efficacy and safety of high-dose budesonide/formoterol in patients with bronchiolitis obliterans syndrome after allogeneic hematopoietic stem cell transplant

Background

Bronchiolitis obliterans syndrome (BOS) is a rare, progressive and irreversible airway disease associated with significant mortality after allogeneic hematopoietic stem-cell transplantation (HSCT). In this study, we investigated the therapeutic effect of high-dose budesonide/formoterol (320/9 µg bid) in patients with BOS after HSCT already using low-dose budesonide/formoterol (160/4.5 µg bid).

Methods

After a retrospective chart review, patients who were initially treated with budesonide/formoterol 160/4.5 µg bid and increased their dose to 320/9 µg bid between March 2009 and February 2019 were enrolled. Pulmonary function test (PFT) and COPD assessment test (CAT) were performed before and after changing the drug dose. Efficacy was assessed within 3 months after increasing the drug dose; the primary variable was changes in forced expiratory volume in 1 second (FEV1) and CAT score. Safety was assessed as the incidence of pneumonia within 3 months after increasing the drug dose.

Results

Seventy-seven patients were treated with budesonide 160 µg plus formoterol 4.5 µg twice a day for more than 3 months and the dose was increased to budesonide 320 µg plus 9.0 µg twice a day. After treatment with high-dose ICS/LABA (budesonide 320 µg plus formoterol 9.0 µg twice a day for 12 weeks), there were no significant differences in FEV1 (before treatment 1.59 L vs. after treatment 1.65 L, P=0.182) or FVC (before treatment 2.93 L vs. after treatment 2.96 L, P=0.519) compared to before starting the high dose treatment. There were no significant differences in the total CAT score. Of all patients, 34.2% of patients had an increase in FEV1 ≥100 mL and 35.3% of patients showed a decrease ≥2 points in CAT score. In safety assessment, there were no significant differences between the two periods.

Conclusions

Our study failed to show superior effect of high-dose budesonide/formoterol (320/9 µg) compared with low-dose. However, high-dose budesonide/formoterol was safe and there was no lung function deterioration.

Long-term pulmonary function testing in pediatric bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation

RATIONALE

Bronchiolitis obliterans syndrome (BOS) is a severe, chronic inflammation of the airways leading to an obstruction of the bronchioles. So far, there are only a few studies looking at the long-term development of pulmonary impairment in children with BOS.

OBJECTIVE

The objective of this study was to investigate the incidence and long-term outcome of BOS in children who underwent allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

Medical charts of 526 children undergoing HSCT in Frankfurt/Main, Germany between 2000 and 2017 were analyzed retrospectively and as a result, 14 patients with BOS were identified. A total of 271 lung functions (spirometry and body plethysmography), 26 lung clearance indices (LCI), and 46 chest high-resolution computed tomography (HRCT) of these 14 patients with BOS were evaluated.

RESULTS

Fourteen patients suffered from BOS after HSCT (2.7%), whereby three distinctive patterns of lung function impairment were observed: three out of 14 patients showed a progressive lung function decline; two died and one received a lung transplant. In five out of 14 patients with BOS persisted with a severe obstructive and secondarily restrictive pattern in lung function (forced vital capacity [FVC] < 60%, forced expiratory volume in 1 second [FEV1] < 50%, and FEV1/FVC < 0.7) and increased LCI (11.67-20.9), six out of 14 patients recovered completely after moderate lung function impairment and signs of BOS on HRCT. Long-term FVC in absolute numbers was increased indicating that the children still have lung growth.

CONCLUSION

Our results showed that the incidence of BOS in children is low. BOS was associated with high mortality and may lead to persistent obstructive lung disease; although, lung growth continued to exist.

Noninfectious pulmonary complications of haematopoietic stem cell transplantation

Haematopoietic stem cell transplantation (HSCT) is an established treatment for a variety of malignant and nonmalignant conditions. Pulmonary complications, both infectious and noninfectious, are a major cause of morbidity and mortality in patients who undergo HSCT. Recent advances in prophylaxis and treatment of infectious complications has increased the significance of noninfectious pulmonary conditions. Acute lung injury associated with idiopathic pneumonia syndrome remains a major acute complication with high morbidity and mortality. On the other hand, bronchiolitis obliterans syndrome is the most challenging chronic pulmonary complication facing clinicians who are taking care of allogeneic HSCT recipients. Other noninfectious pulmonary complications following HSCT are less frequent. This review provides a clinical update of the incidence, risk factors, pathogenesis, clinical characteristics and management of the main noninfectious pulmonary complications following HSCT.

Bronchiolitis Obliterans after Combination Immunotherapy with Pembrolizumab and Ipilimumab

Checkpoint inhibitor therapies are members of a new, groundbreaking class of drugs that reinvigorate the immune system to directly attack tumors. A rare side effect of checkpoint inhibitor therapy is pneumonitis, which typically presents as an interstitial lung disease. In this case report, we present a patient in whom combination therapy with the PD-1 inhibitor pembrolizumab and the CTLA-4 inhibitor ipilimumab induced severe airflow obstruction. This is the first report that shows that checkpoint inhibitors may induce airflow limitation.

Postinfectious Bronchiolitis Obliterans in Children: Diagnostic Workup and Therapeutic Options: A Workshop Report

Bronchiolitis obliterans (BO) is a rare, chronic form of obstructive lung disease, often initiated with injury of the bronchiolar epithelium followed by an inflammatory response and progressive fibrosis of small airways resulting in nonuniform luminal obliteration or narrowing. The term BO comprises a group of diseases with different underlying etiologies, courses, and characteristics. Among the better recognized inciting stimuli leading to BO are airway pathogens such as adenovirus and mycoplasma, which, in a small percentage of infected children, will result in progressive fixed airflow obstruction, an entity referred to as postinfectious bronchiolitis obliterans (PIBO). The present knowledge on BO in general is reasonably well developed, in part because of the relatively high incidence in patients who have undergone lung transplantation or bone marrow transplant recipients who have had graft-versus-host disease in the posttransplant period. The cellular and molecular pathways involved in PIBO, while assumed to be similar, have not been adequately elucidated. Since 2016, an international consortium of experts with an interest in PIBO assembles on a regular basis in Geisenheim, Germany, to discuss key areas in PIBO which include diagnostic workup, treatment strategies, and research fields.

ICU Complications of Hematopoietic Stem Cell Transplant, Including Graft vs Host Disease

Hematopoietic stem cell transplant (HSCT) is an essential treatment modality for many malignant and non-malignant hematologic diseases. Advances in HSCT techniques have dramatically decreased peri-transplant morbidity and mortality, but it remains a high-risk procedure, and a significant number of patients will require critical care during the transplant process. Complications of HSCT are both infectious and non-infectious, and the intensivist must be familiar with common infections, the management of neutropenic sepsis and septic shock, the management of respiratory failure in the immunocompromised host, and a plethora of HSCT-specific complications. Survival from critical illness after HSCT is improving, but the mortality rate remains unacceptably high. Continued research and optimization of critical care provision in this population should continue to improve outcomes.

Late Noninfectious Pulmonary Complications in Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic modality for a number of malignant and nonmalignant conditions. Pulmonary complications following HSCT are associated with increased mortality and morbidity. These complications may be classified into infectious versus noninfectious, and early versus late based on the time of occurrence post-transplant. Thus, exclusion of infectious etiologies is the first step in the diagnoses of pulmonary complications. Late onset noninfectious pulmonary complications typically occur 3 months post-transplant. Bronchiolitis obliterans is the major contributor to late-onset pulmonary complications, and its clinical presentation, pathogenesis, and current therapeutic approaches are discussed. Idiopathic pneumonia syndrome is another important complication which usually occurs early, although its onset may be delayed. Organizing pneumonia is important to recognize due to its responsiveness to corticosteroids. Other late onset noninfectious pulmonary complications discussed here include pulmonary venoocclusive disease, pulmonary cytolytic thrombi, pleuroparenchymal fibroelastosis, thoracic air leak syndrome, and posttransplant lymphoproliferative disorders.

Early Post-Transplantation Spirometry Is Associated with the Development of Bronchiolitis Obliterans Syndrome after Allogeneic Hematopoietic Cell Transplantation

Bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic cell transplantation (allo-HCT) is often diagnosed at a late stage when lung dysfunction is severe and irreversible. Identifying patients early after transplantation may offer improved strategies for early detection that could avert the morbidity and mortality of BOS. This study aimed to determine whether a decline in lung function before and early after (days +80 to +100) allo-HCT are associated with a risk of BOS beyond 6 months post-transplantation. In a single-center cohort of 2941 allo-HCT recipients, 186 (6%) met National Institutes of Health criteria for BOS. Pretransplantation and post-transplantation day +80 spirometric parameters were analyzed as continuous variables and included in a multivariable model with other factors, including donor source, graft source, conditioning regimen, use of total body irradiation, and immunoglobulin levels. Pre-transplantation forced expiratory flow between 25% and 75% of maximum (FEF_25-75), day +80 forced expiratory volume in 1 second (FEV₁), and day +80 FEF_25-75 had the strongest associations with increased risk of BOS. Assessment of the multivariable model showed that a decline in day +80 FEF_25-75 added additional risk to the day +80 FEV₁ model (P = .03), whereas FEV₁ decline at day +80 added no additional risk to the day +80 FEF_25-75 model (P = .645). Moreover, day +80 FEF_25-75 conferred additional risk when considered with pretransplantation FEF_25-75. These results suggest that day +80 FEF_25-75 may be more important than FEV₁ in predicting the development of BOS. This study highlights the importance of obtaining early post-transplantation pulmonary function tests for the potential risk stratification of patients at risk for BOS.

Lung evaluation in 10 year survivors of pediatric allogeneic hematopoietic stem cell transplantation

There is little data on the long-term respiratory development of children after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We describe the respiratory assessment 10 years after allo-HSCT of 35 children transplanted between 2000 and 2004. During this period, 90 children were transplanted at our center. Twenty-five children died, thirty were lost to follow-up, and thirty-five came to have a pulmonary investigation. The thirty-five participants answered a questionnaire asking if they had pulmonary symptoms, and pulmonary function tests (PFTs) were performed. The median age of these children 10 years after the transplant was 16 years old. Just over a third of them had pulmonary symptoms. Among them, 5/13 (38%) had bronchiolitis obliterans syndrome (BOS). The majority of children (62.8%) did not have respiratory symptoms. PFTs were abnormal in one-third of asymptomatic children, revealing restrictive lung disease that was always mild to moderate (p = 0.02).Conclusion: In the long term, research at the time of the medical examination for the presence of chronic cough, shortness of breath on exertion, or wheezing helps to guide the clinician as to the need for further lung exploration. Similarly, informing patients and their families about these symptoms, which can be underestimated, should allow for more specific management.What is Known:• Pulmonary complications are a major cause of hematopoietic stem cell transplantation (HSCT) morbidity and mortality.• A long time after allogeneic HSCT, pulmonary function tests abnormalities may occur in children, but it is not always related to symptoms.What is New:• The occurrence of respiratory symptoms: cough, dyspnea on exertion, chronic bronchitis, and wheezing should be systematically investigated in the follow-up of allografted patients, even at a distance.• The presence of respiratory symptoms should lead to a respiratory functional investigation to detect the presence of an obstructive syndrome.

First-Onset Herpesviral Infection and Lung Injury in Allogeneic Hematopoietic Cell Transplantation

Rationale: "Noninfectious" pulmonary complications are significant causes of morbidity and mortality after allogeneic hematopoietic cell transplant. Early-onset viral reactivations or infections are common after transplant. Whether the first-onset viral infection causes noninfectious pulmonary complications is unknown. Objectives: To determine whether the first-onset viral infection within 100 days after transplant predisposes to development of noninfectious pulmonary complications. Methods: We performed a retrospective review of 738 allogeneic hematopoietic cell transplant patients enrolled from 2005 to 2011. We also established a novel bone marrow transplantation mouse model to test whether herpesviral reactivation after transplant causes organ injury. Measurements and Main Results: First-onset viral infections with human herpesvirus 6 or Epstein-Barr virus within 100 days after transplant increase the risk of developing idiopathic pneumonia syndrome (adjusted hazard ratio [aHR], 5.52; 95% confidence interval [CI], 1.61-18.96; P = 0.007; and aHR, 9.21; 95% CI, 2.63-32.18; P = 0.001, respectively). First infection with human cytomegalovirus increases risk of bronchiolitis obliterans syndrome (aHR, 2.88; 95% CI, 1.50-5.55; P = 0.002) and grade II-IV acute graft-versus-host disease (aHR, 1.59; 95% CI, 1.06-2.39; P = 0.02). Murine roseolovirus, a homolog of human herpesvirus 6, can also be reactivated in the lung and other organs after bone marrow transplantation. Reactivation of murine roseolovirus induced an idiopathic pneumonia syndrome-like phenotype and aggravated acute graft-versus-host disease. Conclusions: First-onset herpesviral infection within 100 days after allogeneic hematopoietic cell transplant increases risk of pulmonary complications. Experimentally reactivating murine roseolovirus causes organ injury similar to phenotypes seen in human transplant recipients.

Association between chronic bacterial airway infection and prognosis of bronchiolitis obliterans syndrome after hematopoietic cell transplantation

Bronchiolitis obliterans syndrome (BOS) is a rare pulmonary complication of hematopoietic stem cell transplantation (HSCT) with high mortality. Chronic bacterial airway infection (CAI) causes exacerbation and progression of several airway diseases, and bacterial airway colonization was shown to be associated with BOS after lung transplantation.We assessed the association between CAI and clinical course in patients with BOS after HSCT. This retrospective study included 910 patients undergoing allogeneic HSCT between 2005 and 2013 at our institution. BOS diagnosis was reevaluated according to the 2014 US National Institutes of Health criteria. Sputum and bronchial lavage culture results, pulmonary function, and survival were compared between patients with and without CAI.Median follow-up was 974.5 (261.5-2748.5) days. BOS was diagnosed in 27 (3.0%) patients, including 18 males. Median age at BOS diagnosis was 45 (40.5-58) years. Nine patients had ≥2 positive sputum cultures for bacteria or one positive bronchial lavage culture for nontuberculous mycobacteria (CAI+), whereas 9 patients had negative sputum/bronchial lavage culture or only one positive sputum culture (CAI-). Median change in forced expiratory volume in 1 s within 6 months after BOS diagnosis and overall survival were significantly worse in CAI+ patients than in CAI- patients (-250 vs +260 mL, P = .002, and 1340 days vs not reached, P = .04, respectively). No other factors including patient demographics or transplant protocol affected prognosis. There were no differences in clinical characteristics of patients with and without CAI, except for the time from transplantation to BOS diagnosis (214 vs 768 days for CAI+ and CAI-, respectively; P = .02).CAI was associated with worse outcomes in patients with BOS after HSCT. Further prospective studies should assess the association between the airway microbiome and changes in pulmonary function after HSCT to improve prognosis.

[Post-transplant pulmonary complications: Guidelines from the francophone Society of bone marrow transplantation and cellular therapy (SFGM-TC)]

Pulmonary complications after allogeneic hematopoietic stem cell transplantation occur frequently (30-75%), vary in severity, and sometimes prove lethal. They may occur at an early stage post-transplant before D100 but may also surface later. Etiological support for these complications has shown a beneficial impact on survival. When faced with early complications, non-invasive tests, scans, and microbiological tests must be rapidly implemented. In the majority of cases, these tests facilitate diagnosis. In cases where microbiological non-invasive tests are negative, and the patient shows a steady respiratory condition, bronchoalveolar lavage can be effective if it is implemented in the first four days following the onset of pulmonary symptoms. This diagnostic approach should in no way occlude the introduction of broad-spectrum antibiotics in these profoundly immunocompromised patients. Later pulmonary complications are the most often not infectious. They include different anatomo-clinical conditions: cryptogenic organizing pneumonia; interstitial lung disease; idiopathic pleuroparenchymal fibroelastosis. Vascular disorders may include hypertension, thrombotic microangiopathy, venous thromboembolism, and pleural effusions. These conditions must be monitored using RFE (respiratory functional exploration) which allows early detection and therapeutic intervention. A combination of RFE and thoracic radiology scans will provide diagnostic assessment. Bronchoalveolar lavage is indicated when an infection is suspected or before systemic corticosteroid therapy. A lung biopsy should be discussed on a case-by-case basis, such as in cases of interstitial pulmonary disorders.