Impact of Lung Function on Bronchiolitis Obliterans Syndrome and Outcome after Allogeneic Hematopoietic Cell Transplantation with Reduced-Intensity Conditioning

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.

Identification of clinical factors impacting outcome in patients undergoing autologous hematopoietic cell transplantation after BEAM and TEAM conditioning

Organ dysfunction, including pulmonary function impairment, plays a key role in the choice of conditioning chemotherapy before autologous hematopoietic stem cell transplantation (auto-HSCT). Replacement of BCNU/carmustine as part of BEAM (BCNU/carmustine, etoposide, cytarabine, and melphalan) conditioning protocol by thiotepa (TEAM) reduces pulmonary toxicity while maintaining efficacy. We retrospectively analyzed the association of clinical characteristics, comorbidities, and organ function with outcomes after conditioning with BEAM or TEAM. Three hundred ninety-six patients undergoing auto-HSCT (n = 333 with BEAM; n = 63 with TEAM) at our institution between 2008 and 2021 were included in this study. In the multivariate analysis, CO-diffusion capacity corrected for hemoglobin (DLCOcSB) ≤ 60% of predicted, progressive disease (PD) before auto-HSCT, Karnofsky performance score (KPS) ≤ 80%, HCT-CI score ≥ 4, and cardiac disease before auto-HSCT were associated with decreased overall survival (OS) in patients treated with BEAM. In contrast, only PD before auto-HSCT was identified in patients treated with TEAM. Patients conditioned with BEAM and DLCOcSB ≤ 60% had higher non-relapse mortality, including pulmonary cause of death. In summary, we have identified clinical and pulmonary risk factors associated with worse outcomes in patients conditioned with BEAM compared to TEAM. Our data suggest TEAM conditioning as a valid alternative for patients with comorbidities, including pulmonary dysfunction and/or poorer performance scores, before auto-HSCT.

Comparison of fludarabine/melphalan (FluMel) with fludarabine/melphalan/BCNU or thiotepa (FBM/FTM) in patients with AML in first complete remission undergoing allogeneic hematopoietic stem cell transplantation - a registry study on behalf of the EBMT Acute Leukemia Working Party

Conditioning protocols for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) are being developed continuously to improve their anti-leukemic efficacy and reduce their toxicity. In this study, we compared the conditioning protocol of fludarabine with melphalan 140 mg/m2 (FluMel) with conditioning protocols based on this same backbone but with an additional alkylating agent i.e., either fludarabine/BCNU (also known as carmustine)/melphalan (FBM), or fludarabine/thiotepa/melphalan (FTM) 110 mg/m2. We included 1272 adult patients (FluMel, n = 1002; FBM/FTM, n = 270) with acute myeloid leukemia (AML) with intermediate/poor cytogenetic risk in first complete remission (CR) from the registry of the EBMT Acute Leukemia Working Party. Despite patients in the FBM/FTM group were older (64.1 years vs. 59.8 years, p < 0.001) and had a worse Karnofsky performance score (KPS < 90, 33% vs. 24%, p = 0.003), they showed a better overall survival (OS) (2 y OS: 68.3% vs. 58.1%, p = 0.02) and less non-relapse mortality (NRM) (2 y NRM: 15.8% vs. 22.2%, p = 0.009) compared to patients treated with FluMel. No significant differences were observed in relapse incidence (RI) (2 y RI: 24.9% vs. 23.7%, p = 0.62). In conclusion, the addition of a second alkylating agent (BCNU/carmustine or thiotepa) to FluMel as FBM/FTM conditioning, improves OS in AML patients in first CR with intermediate/poor risk cytogenetics after allo-HCT.

Epidemiology of Lower Respiratory Tract Infections and Community-Acquired Respiratory Viruses in Patients with Bronchiolitis Obliterans Syndrome after Hematopoietic Cell Transplantation: A Retrospective Cohort Study

BACKGROUND

Bronchiolitis obliterans syndrome (BOS)-chronic graft-versus-host disease (cGVHD) affecting the lungs-is an uncommon complication of allogeneic hematopoietic cell transplant (HCT). The epidemiology and complications of lower respiratory tract infections (LRTIs) and community-acquired respiratory viruses (CARVs) in these patients are poorly understood.

OBJECTIVES

We aim to characterize the epidemiology of LRTIs in patients with BOS complicating HCT. We also aim to explore the association of LRTIs and CARV detection on lung function in BOS patients.

STUDY DESIGN

Adult patients with BOS at Stanford Health Care between January 2010 and December 2019 were included in this retrospective cohort study. LRTI diagnosis was based on combined clinical, microbiologic, and radiographic criteria, using consensus criteria where available.

RESULTS

Fifty-five patients with BOS were included. BOS was diagnosed at a median of 19.2 (IQR 12.5-24.7) months after HCT, and patients were followed for a median of 29.3 (IQR 9.9-53.2) months from BOS diagnosis. Twenty-two (40%) patients died after BOS diagnosis; 17 patients died from complications of cGVHD (including respiratory failure and infection) and 5 died from relapsed disease. Thirty-four (61.8%) patients developed at least one LRTI. Viral LRTIs were most common, occurring in 29 (52.7%) patients, primarily due to rhinovirus. Bacterial LRTIs-excluding Nocardia and non-tuberculous mycobacteria (NTM)-were the second most common, occurring in 21 (38.2%) patients, mostly due to Pseudomonas aeruginosa. Fungal LRTIs, NTM, and nocardiosis occurred in 14 (25.5%), 10 (18.2%), and 4 (7.3%) patients, respectively. Median time to development of the first LRTI after BOS diagnosis was 15.3 (4.7-44.7) months. Twenty-six (76.5%) of the 34 patients who developed LRTIs had infections due to more than one type of organism-fungi, viruses, Nocardia, NTM, and other bacteria-over the observation period. Patients with at least one LRTI had significantly lower forced expiratory volume in one second percent predicted (FEV1%) (37% vs. 53%, p = 0.0096) and diffusing capacity of carbon monoxide (DLCO) (45.5% predicted vs. 69% predicted, p = 0.0001). Patients with at least one LRTI trended toward lower overall survival (OS) (p = 0.0899) and higher non-relapse mortality (NRM) (p = 0.2707). Patients with a CARV detected or LRTI diagnosed after BOS-compared to those without any CARV detected or LRTI diagnosed-were more likely to have a sustained drop in FEV1% from baseline of at least 10% (21 [61.8%] versus 7 [33.3%]) and a sustained drop in FEV1% of at least 30% (12 [36.4%] versus 2 [9.5%]).

CONCLUSIONS

LRTIs are common in BOS and associated with lower FEV1%, lower DLCO, and a trend toward decreased OS and higher NRM. Patients with LRTIs or CARVs (even absent lower respiratory tract involvement) were more likely to have substantial declines in FEV1% over time than those without. The array of organisms-including P. aeruginosa, mold, Nocardia, NTM, and CARVs-seen in BOS reflects the unique pathophysiology of this form of cGVHD, involving both systemic immunodeficiency and structural lung disease. These patterns of LRTIs and their outcomes can be used to guide clinical decisions and inform future research.

Impact of lung function impairment after allogeneic hematopoietic stem cell transplantation

Late-onset noninfectious pulmonary complications (LONIPC) are a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). However, the clinical impact of lung function deterioration itself in long-term adult survivors of HSCT remains to be fully investigated. This retrospective, longitudinal study aimed to investigate pulmonary function following HSCT in terms of its change and the clinical significance of its decline. We examined 167 patients who survived for at least 2 years without relapse. The median follow-up period was 10.3 years. A linear mixed-effects model showed that the slope of pulmonary function tests values, including percent vital capacity (%VC), percent forced expiratory volume in one second (%FEV₁), and FEV₁/forced VC ratio (FEV₁%), decreased over time. The cumulative incidence of newly obstructive and restrictive lung function impairment (LFI) at 10 years was 15.7% and 19.5%, respectively. Restrictive LFI was a significant, independent risk factor for overall survival (hazard ratio 7.11, P = 0.007) and non-relapse mortality (hazard ratio 12.19, P = 0.003). Our data demonstrated that lung function declined over time after HSCT and that the decline itself had a significant impact on survival regardless of LONIPC.

Noninfectious complications of hematopoietic cell transplantation

Noninfectious lung diseases contribute to nonrelapse mortality. They constitute a spectrum of diseases that can affect the parenchyma, airways, or vascular pulmonary components and specifically exclude cardiac and renal causes. The differential diagnoses of these entities differ as a function of time after hematopoietic cell transplantation. Specific diagnosis, prognosis, and optimal treatment remain challenging, although progress has been made in recent decades.

The impact of pulmonary function in patients undergoing autologous stem cell transplantation

High-dose chemotherapy, followed by autologous hematopoietic stem cell transplantation (auto-HSCT), is an established therapy for patients with hematological malignancies. The age of patients undergoing auto-HSCT and, therefore, the comorbidities, has increased over the last decades. However, the assessment of organ dysfunction prior to auto-HSCT has not been well studied. Therefore, we retrospectively analyzed the association of clinical factors and lung and cardiac function with outcome and complications after conditioning with BEAM (BCNU/carmustine, etoposide, cytarabine, melphalan) or high-dose melphalan in patients undergoing auto-HSCT. This study included 629 patients treated at our institution between 2007 and 2017; 334 and 295 were conditioned with BEAM or high-dose melphalan, respectively. The median follow-up was 52 months (range, 0.2-152) and 50 months (range, 0.5-149), respectively. In the multivariate analysis, we identified that progressive disease, CO-diffusion capacity corrected for hemoglobin (DLCOcSB) ≤ 60% of predicted, Karnofsky Performance Status (KPS) ≤ 80%, Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) score ≥ 4, and age > 70 years were associated with decreased overall survival (OS) in patients treated with BEAM. Similarly, DLCOcSB ≤ 60% of predicted, HCT-CI score ≥ 4, and age > 60 years were identified in patients treated with high-dose melphalan. Abnormalities in DLCOcSB ≤ 60% of predicted were associated with chemotherapy with lung-toxic substances, mediastinal radiotherapy, KPS ≤ 80%, current/previous smoking, and treatment in the intensive care unit. More often, patients with DLCOcSB ≤ 60% of predicted experienced nonrelapse mortality, including pulmonary causes of death. In summary, we identified DLCOcSB ≤ 60% of predicted as an independent risk factor for decreased OS in patients conditioned with BEAM or high-dose melphalan prior to auto-HSCT.

The pulmonary metatranscriptome prior to pediatric HCT identifies post-HCT lung injury

Lung injury after pediatric allogeneic hematopoietic cell transplantation (HCT) is a common and disastrous complication that threatens long-term survival. To develop strategies to prevent lung injury, novel tools are needed to comprehensively assess lung health in HCT candidates. Therefore, this study analyzed biospecimens from 181 pediatric HCT candidates who underwent routine pre-HCT bronchoalveolar lavage (BAL) at the University Medical Center Utrecht between 2005 and 2016. BAL fluid underwent metatranscriptomic sequencing of microbial and human RNA, and unsupervised clustering and generalized linear models were used to associate microbiome gene expression data with the development of post-HCT lung injury. Microbe-gene correlations were validated using a geographically distinct cohort of 18 pediatric HCT candidates. The cumulative incidence of post-HCT lung injury varied significantly according to 4 pre-HCT pulmonary metatranscriptome clusters, with the highest incidence observed in children with pre-HCT viral enrichment and innate immune activation, as well as in children with profound microbial depletion and concomitant natural killer/T-cell activation (P < .001). In contrast, children with pre-HCT pulmonary metatranscriptomes containing diverse oropharyngeal taxa and lacking inflammation rarely developed post-HCT lung injury. In addition, activation of epithelial-epidermal differentiation, mucus production, and cellular adhesion were associated with fatal post-HCT lung injury. In a separate validation cohort, associations among pulmonary respiratory viral load, oropharyngeal taxa, and pulmonary gene expression were recapitulated; the association with post-HCT lung injury needs to be validated in an independent cohort. This analysis suggests that assessment of the pre-HCT BAL fluid may identify high-risk pediatric HCT candidates who may benefit from pathobiology-targeted interventions.

Pre-Hematopoietic Stem Cell Transplantation Lung Computed Tomography as an Alternative to the Pulmonary Function Test during the COVID-19 Pandemic

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The pulmonary function test (PFT) is an important test for risk stratification before allogeneic hematopoietic stem cell transplantation (allo-HCT), although it might be preferable to avoid unnecessary PFT during the COVID-19 pandemic.

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Our computed tomography (CT)-based model for predicting normal PFT showed relatively high specificity (>80%).

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PFT might be omitted in patients with normal CT findings before allo-HCT.

The pulmonary function test (PFT) is an important test for risk stratification before allogeneic transplantation (allo-HCT). However, it might be preferable to avoid PFT as much as possible in the recent era of coronavirus disease 2019 (COVID-19), because PFT requires forced expirations and might produce aerosols, increasing the risk of COVID-19 transmission. Therefore, we tried to predict normal PFT results before allo-HCT based on computed tomography (CT) findings. This study included 390 allo-HCT recipients at our center for whom lung CT images and PFT results before allo-HCT were available. Abnormal CT findings were less likely to be observed in the normal PFT group (47.0% versus 67.4%, P = .015), with a high negative predictive value of 92.9%. In a multivariate analysis, normal CT was significantly associated with normal PFT (odds ratio, 2.47; 95% confidence interval, 1.22 to 4.97; P = .012). A model for predicting normal PFT was constructed based on the results of a multivariate analysis, and the area under the curve of the receiver operating characteristic analysis was 0.656, which gave a sensitivity of 45.5% and a specificity of 86.0%. The relatively high specificity of the model suggested that PFT can be omitted in patients with normal CT findings before allo-HCT.

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.

Comparison of reduced-toxicity conditioning protocols using fludarabine, melphalan combined with thiotepa or carmustine in allogeneic hematopoietic cell transplantation

The age of patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) has increased during the last decades, mainly due to improved reduced-intensity/toxicity conditioning protocols. A reduced-intensity conditioning based on fludarabin, carmustin/BCNU and melphalan (FBM) has been previously developed at our institution. Since we observed detrimental effects in individual patients with compromised lung function, efforts have been made in order to replace BCNU by thiotepa (FTM) to reduce toxicity. In this study, we retrospectively analyzed the outcome, GvHD incidence, lung function and organ toxicity of patients with a median age of 62 years (range 21–79) transplanted for malignant disease (96.7%, 62.3% in intermediate/advanced disease stage) at our institution after conditioning with FBM (n = 136) or FTM (n = 105) between 2013 and 2017. Median follow-up was 868 days (range 0–2615). In multivariate analysis for overall survival, no difference was detected between both conditioning protocols in the presence of impaired lung function, age, lower performance, and liver disease previous allo-HCT. In the subgroup analysis, FTM was not inferior to FBM in patients with pulmonary disease prior allo-HCT, lymphoid malignancies, and higher comorbidity index. In conclusion, the reduced-intensity FBM and FTM conditioning protocols show adequate antineoplastic efficacy and are suitable for patients with impaired lung function.

Conditioning protocol based on fludarabin, melphalan combined with thiotepa (FTM) showed sufficient anti-neoplastic effect and is suitable for patients with impaired lung function prior allo-HCT.

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.