Bronchiolitis obliterans in patients undergoing allogeneic hematopoietic SCT

Pulmonary Immunocompromise in Stem Cell Transplantation and Cellular Therapy

Hematopoietic cell transplantation (HCT) and cellular therapies, such as chimeric-antigen receptor T-cell (CAR-T) treatments, are potentially curative treatments for certain hematologic malignancies and some nonmalignant disorders. However, pulmonary complications, both infectious and noninfectious, remain a significant cause of morbidity and mortality in patients who receive cellular therapies. This review article provides an overview of pulmonary complications encountered in the context of HCT and CAR-T. The authors discuss mechanisms of underlying immunocompromise that lead to a rise in infections. Additionally, they highlight key noninfectious complications of HCT that can mimic acute infections and suggest diagnostic approaches and preventive strategies to distinguish these entities promptly.

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.

Evaluation of safety and efficacy of allogeneic adipose tissue-derived mesenchymal stem cells in pediatric bronchiolitis obliterans syndrome (BoS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT)

BACKGROUND

Allo-HSCT is a definite approach for the management of a wide variety of lethal and debilitating malignant and non-malignant disorders. However, its two main complications, acute and chronic graft-versus-host disease (GVHD), exert significant morbidities and mortalities. BoS, as a manifestation of chronic lung GVHD, is a gruesome complication of allo-HSCT, and for those with steroid-refractory disease, no approved second-line therapies exist. Mesenchymal stem cells (MSCs) exert anti-inflammatory and growth-promoting effects, and their administration against a wide range of inflammatory and neurologic disorders, as well as GVHD, has been associated with promising outcomes. However, literature on the safety and effectiveness of MSC therapy for BoS and pediatric cGVHD is scarce.

METHODS

We designed a single-arm trial to administer adipose tissue (AT)-derived MSCs to pediatric patients with refractory BoS after allo-HSCT. AT-MSCs from obese, otherwise healthy donors were cultured in an ISO class 1 clean room and injected into the antecubital vein of eligible patients with a dose of 1 × 106/kg. The primary endpoints included a complete or partial response to therapy [in terms of increased forced expiratory volume in one second (FEV1) values and steroid dose reduction] and its safety profile.

RESULTS

Four eligible patients with a median age of 6.5 years were enrolled in the study. Steroid-induced osteoporosis and myopathy were present in three cases. A partial response was evident in three cases after a single injection of AT-MSCs. The treatment was safe and tolerable, and no treatment-related adverse events were noted. Two patients developed manageable COVID-19 infections one and 4 months after AT-MSC injection. After a median follow-up duration of 19 months, all cases are still alive and have had no indications for lung transplantation.

CONCLUSIONS

AT-MSCs could be safely administered to our pediatric cases with BoS post-allo-HSCT. Considering their advanced stage of disease, their sub-optimal functional capacity due to steroid-induced complications, and COVID-19 infection post-treatment, we believe that AT-MSC therapy can have possible efficacy in the management of pediatric BoS. The conduction of further studies with larger sample sizes and more frequent injections is prudent for further optimization of AT-MSC therapy against BoS. Trial registration Iranian Registry of Clinical Trials (IRCT), IRCT20201202049568N2. Registered 22 February 2021, https://en.irct.ir/trial/53143 .

Risk Factors for Bronchiolitis Obliterans Syndrome after Initial Detection of Pulmonary Impairment after Hematopoietic Cell Transplantation

Pulmonary chronic graft-versus-host-disease (cGVHD), or bronchiolitis obliterans syndrome (BOS), is a highly morbid complication of hematopoietic cell transplantation (HCT). The clinical significance of a single instance of pulmonary decline not meeting the criteria for BOS is unclear. We conducted a retrospective analysis in a cohort of patients who had an initial post-HCT decline in the absolute value of forced expiratory volume in 1 second (FEV1) of ≥10% or mid-expiratory flow rate of ≥25% but not meeting the criteria for BOS (pre-BOS). We examined the impact of clinical variables in patients with pre-BOS on the risk for subsequent BOS. Pre-BOS developed in 1325 of 3170 patients (42%), of whom 72 (5%) later developed BOS. Eighty-four patients developed BOS without detection of pre-BOS by routine screening. Among patients with pre-BOS, after adjusting for other significant variables, airflow obstruction (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.1 to 3.7; P = .02), percent-predicted FEV1 on decline (HR, .98; 95% CI, .97 to 1.0; P = .02), active cGVHD (HR, 7.7; 95% CI, 3.1 to 19.3; P < .001), peripheral blood stem cell source (HR, 3.8; 95% CI, 1.7 to 8.6; P = .001), and myeloablative conditioning (HR, 2.0; 95% CI, 1.1 to 3.5; P = .02) were associated with subsequent BOS. The absence of airflow obstruction and cGVHD had a negative predictive value of 100% at 6 months for subsequent BOS, but the positive predictive value of both factors was low (cGVHD, 3%; any obstruction, 4%; combined, 6%). Several clinical factors at the time of pre-BOS, particularly active cGVHD and airflow obstruction, increase the risk for subsequent BOS. These factors merit consideration to be included in screening practices to improve the detection of BOS, with the caveat that the predictive utility of these factors is limited by the overall low incidence of BOS among patients with pre-BOS.

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.

Home-Based Spirometry Telemonitoring After Allogeneic Hematopoietic Cell Transplantation: Mixed Methods Evaluation of Acceptability and Usability

BACKGROUND

Home-based spirometry (HS) allows for the early detection of lung complications in recipients of an allogeneic hematopoietic cell transplant (AHCT). Although the usability and acceptability of HS are critical for adherence, patient-reported outcomes of HS use remain poorly understood in this setting.

OBJECTIVE

The aim of this study is to design a longitudinal, mixed methods study to understand the usability and acceptability of HS among recipients of AHCT.

METHODS

Study participants performed HS using a Bluetooth-capable spirometer that transmitted spirometry data to the study team in real time. In addition, participants completed usability questionnaires and in-depth interviews and reported their experiences with HS. Analysis of interview data was guided by the constructs of performance expectancy, effort expectancy, and social influence from the Unified Theory of Acceptance and Use of Technology model.

RESULTS

Recipients of AHCT found HS to be highly acceptable despite modest technological barriers. On average, participants believed that the HS was helpful in managing symptoms related to AHCT (scores ranging from 2.22 to 2.68 on a scale of 0-4) and for early detection of health-related problems (score range: 2.88-3.12). Participants viewed HS favorably and were generally supportive of continued use. No significant barriers to implementation were identified from the patient's perspective. Age and gender were not associated with the patient perception of HS.

CONCLUSIONS

Study participants found HS acceptable and easy to use. Some modifiable technical barriers to performing HS were identified; however, wider implementation of pulmonary screening is feasible from the patient's perspective.

Late-Onset, Noninfectious Pulmonary Complications following Allogeneic Hematopoietic Stem Cell Transplantation: A Nationwide Cohort Study of Long-Term Survivors

BACKGROUND

Survivors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) are at risk for pulmonary adverse events. Data on late-onset noninfectious pulmonary complications in long-term adult survivors of allo-HSCT are limited and incomplete.

OBJECTIVES

This study aimed (1) to determine occurrence and degree of pulmonary sequelae in adult survivors of allo-HSCT and (2) to identify associations between pulmonary function, high-resolution CT (HRCT), and clinical characteristics.

METHOD

In a nationwide, single-center cross-sectional study, 103 survivors (aged median [range] 35 [17-58] years, 53% females) were examined 17 (6-32) years after allo-HSCT and compared with healthy controls (n = 105). Methods included pulmonary function tests and HRCT.

RESULTS

Chronic graft-versus-host disease was diagnosed in 33% of survivors, including 12% with bronchiolitis obliterans syndrome (BOS). Mean lung volumes (TLC, FVC, and FEV1) and gas diffusing capacity were >80% of predicted for the survivors as a group, but significantly lower than in healthy controls. Pathological HRCT findings were detected in 48% of the survivors (71% airways disease, 35% interstitial lung disease, and 24% apical subpleural interstitial thickening). Air trapping (%) on HRCT correlated with % predicted FEV1, p < 0.001. In a multiple logistic regression model, both BOS and pathological findings on HRCT were associated with chemotherapy prior to allo-HSCT, p < 0.05.

CONCLUSIONS

Long-term allo-HSCT survivors had significantly lower pulmonary function than age- and gender-matched healthy controls and nearly half had pathological findings on HRCT. Longitudinal data will determine if pulmonary sequelae will remain stable or progress. We recommend lifelong monitoring of pulmonary function in allo-HSCT survivors. HRCT provides additional information, but is not suited for surveillance.

Stable pulmonary function after haploidentical stem cell transplantation with post-transplant cyclophosphamide: a single center experience

Prior studies have reported pulmonary function tests (PFT) before and after related and unrelated allogeneic hematopoietic stem cell transplantation (HSCT). However, limited data exist on the evaluation of lung function after haploidentical stem cell transplantation (HAPLO) with post-transplant cyclophosphamide (PTCY). We retrospectively reported the evaluation of PFTs at screening before HAPLO in 80 patients at 100 days and 1 year of follow-up. The proportion of surviving patients with available PFTs at 100 days and 1 year were 86% and 68%, respectively. During the follow-up period, four patients met the criteria for bronchiolitis obliterans syndrome and two for interstitial lung disease. Overall survival was 73% (95% CI 62-82%) at 2 years. We observed a significant reduction in diffusing capacity of the lungs for carbon monoxide (DLCO) corrected for the most recent hemoglobin concentration (DLCOc) at 100 days after HAPLO. However, an overall substantial stable pulmonary function was observed at 1 year.

Chronic graft-versus-host disease in children and adolescents with thalassemia after hematopoietic stem cell transplantation

Data on chronic graft-versus-host disease (cGVHD) in patients with thalassemia after hematopoietic stem cell transplantation (HSCT) have not been specifically explored. The present study aimed to determine the incidence and clinical manifestations of cGVHD in children and adolescents with thalassemia who underwent HSCT and to compare healthcare utilization and medical cost between patients with and without cGVHD. We retrospectively analyzed the presentations, treatments, and outcomes of historical cGVHD (Seattle criteria), post-transplant admissions and direct medical cost for HSCT patients (n = 66). We used the 2014 NIH consensus criteria to reclassify the diagnosis of cGVHD (NIH cGVHD). Among 28 historical cGVHD patients, 13 (46.4%) fulfilled the NIH criteria. Reasons why the NIH criteria were unmet were reclassification as late acute GVHD and presence of distinctive signs without confirmatory tests. At 2 years after HSCT, the cumulative incidence of NIH cGVHD was 21.67% (95% CI, 12.31-32.74%). Lung cGVHD was associated with inferior survival with a hazard ratio of 13.6 (95% CI, 1.42-131.48). Patients with historical cGVHD had significantly increased frequency of inpatient admissions and medical cost. In conclusion, cGVHD was common in children with thalassemia receiving HSCT. Patients with cGVHD required prolonged immunosuppressive treatment and incurred high medical expenses.

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.

[Clinical analysis of bronchiolitis obliterans syndrome after haplo- hematopoietic stem cell transplantation]

Objective: To investigate the incidence, risk factors and survival of bronchiolitis obliterans syndrome (BOS) in patients who had undergone haplo-hematopoietic stem cell transplantation (haplo-HSCT) . Methods: This study retrospectively analyzed clinical data of 444 consecutive patients who underwent haplo-HSCT and survived at least 100 days after transplantation in the First Affiliated Hospital of Soochow University between January 2013 and December 2015. Results: By the end of follow-up on January 1, 2018, 25 patients (5.63%) had BOS (BOS group) . The median onset time of BOS was 448 (165-845) d post transplantation, the 1-year, 2-year and 3-year cumulative incidence of BOS was 1.6% (95%CI 1.5%-1.6%) , 4.8% (95%CI 4.7%-4.8%) and 5.8% (95%CI 5.7%-5.8%) , respectively. Among patients with chronic graft-versus-host disease (cGVHD) , the cumulative incidence at the same intervals was 2.8% (95%CI 2.7%-2.8%) , 9.5% (95%CI 9.4%-9.5%) and 11.5% (95%CI 11.4%-11.6%) , respectively. In the multivariate analysis, the risk factors for BOS were high-risk primary disease, Ⅱ-Ⅳ aGVHD and preceding cGVHD with other organs. The 3-year overall survival (OS) was lower among patients with than those without BOS, but the difference was not significant [71.8% (95%CI 53.9%-89.6%) vs 72.4% (95%CI 68.1%-76.7%) , P=0.400]. Overall 1-year, 3-year survival of patients with BOS from the time of diagnosis was 78.4% (95%CI 61.5%-95.3%) and 37.0% (95%CI 2.5%-71.5%) , respectively, significantly less than those without (93.9% and 89.3%, from day 448 after transplantation, respectively, P<0.001) . Furthermore, we found a significantly higher incidence of transplantation-related mortality (TRM) in patients with compared with patients without BOS (28.2% vs 10.9%, P<0.001) . The main risk factor for OS of BOS patients was the severity of pulmonary impairment at the time of diagnosis. Patients who developed severe BOS had a worse OS than those with moderate and mild BOS (P=0.049) . Conclusion: BOS is a severe pulmonary complication of haplo-HSCT. High-risk primary disease, Ⅱ-Ⅳ aGVHD and preceding cGVHD were independent risk factors for BOS. Patients who developed BOS had a worse OS than those without BOS. The main risk factor for OS of BOS patients was the severity of pulmonary impairment.

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.

Managing pulmonary complications in allogeneic hematopoietic stem cell transplantation

Introduction: Progress in allogeneic hematopoietic stem cell transplantation (HSCT) procedures has been associated with improved survival in HSCT recipients. However, they have also brought to light organ-specific complications, especially pulmonary complications. In this setting, pulmonary complications are consistently associated with poor outcomes, and improved management of these complications is required. Areas covered: We review the multiple infectious and noninfectious lung complications that occur both early and late after allogeneic HSCT. This includes the description of these complications, risk factors, diagnostic approach and outcome. A literature search was performed using PubMed-indexed journals. Expert commentary: Multiple lung complications after allogeneic HSCT can be diagnosed concomitantly and require a multidisciplinary approach. A specific clinical evaluation including a precise analysis of a lung CT scan is necessary. Management of these lung complications, especially the noninfectious ones, is impaired by the lack of prospective, randomized control trials, suggesting preventive strategies should be developed.

Pulmonary Impairment after Respiratory Viral Infections Is Associated with High Mortality in Allogeneic Hematopoietic Cell Transplant Recipients

Pulmonary impairment predicts increased mortality in many settings, and respiratory viral infection (RVI) causes considerable morbidity and mortality in allogeneic hematopoietic cell transplant recipients (allo-HCT). We hypothesized that pulmonary impairment after RVI, defined as a decline of forced expiratory volume in 1 second values by ≥10%, may identify allo-HCT recipients at high risk for mortality. We studied all allo-HCT recipients at our institution who had RVI with respiratory syncytial virus, parainfluenza virus, or influenza from 2004 to 2013 and had pre-RVI and post-RVI pulmonary function tests. We used competing risk regression models to identify risk factors for 2-year nonrelapse mortality (NRM) as the primary outcome after RVI and relapse-related mortality as a competing risk. From 223 eligible patients, pulmonary impairment after RVI was associated with over a 3-fold increase in 2-year NRM (pulmonary impairment, 25.3%; no impairment, 7.4%; univariate subhazard ratio [SHR], 3.9; 95% confidence interval [CI], 1.9 to 8.1; P < .001). After adjusting for age and systemic steroid use, pulmonary impairment after RVI was still associated with increased 2-year NRM (SHR, 3.3 [95% CI, 1.6 to 6.9]; P = .002). After adjustment for race and graft-versus-host disease (GVHD) prophylaxis, chronic GVHD at the time of RVI (odds ratio [OR], 2.8 [95% CI, 1.4 to 5.4]; p = .003) and lymphopenia (OR, 2.2 [95% CI, 1.1 to 4.2]; P = .02) were associated with increased odds of pulmonary impairment, whereas use of nonmyeloablative conditioning was associated with reduced odds of pulmonary impairment (OR, .4 [95% CI, .2 to .8]; P = .006). In allo-HCT recipients with RVIs, pulmonary impairment after RVI is associated with high NRM at 2years.

Effect of Azithromycin on Airflow Decline-Free Survival After Allogeneic Hematopoietic Stem Cell Transplant: The ALLOZITHRO Randomized Clinical Trial

IMPORTANCE

Bronchiolitis obliterans syndrome has been associated with increased morbidity and mortality after allogeneic hematopoietic stem cell transplant (HSCT). Previous studies have suggested that azithromycin may reduce the incidence of post-lung transplant bronchiolitis obliterans syndrome.

OBJECTIVE

To evaluate if the early administration of azithromycin can improve airflow decline-free survival after allogeneic HSCT.

DESIGN, SETTING, AND PARTICIPANTS

The ALLOZITHRO parallel-group trial conducted in 19 French academic transplant centers and involving participants who were at least 16 years old, had undergone allogeneic HSCT for a hematological malignancy, and had available pretransplant pulmonary function test results. Enrollment was from February 2014 to August 2015 with follow-up through April 26, 2017.

INTERVENTIONS

Patients were randomly assigned to receive 3 times a week either 250 mg of azithromycin (n = 243) or placebo (n = 237) for 2 years, starting at the time of the conditioning regimen.

MAIN OUTCOMES AND MEASURES

The primary efficacy end point was airflow decline-free survival at 2 years after randomization. Main secondary end points were overall survival and bronchiolitis obliterans syndrome at 2 years.

RESULTS

Thirteen months after enrollment, the independent data and safety monitoring board detected an unanticipated imbalance across blinded groups in the number of hematological relapses, and the treatment was stopped December 26, 2016. Among 480 randomized participants, 465 (97%) were included in the modified intention-to-treat analysis (mean age, 52 [SD, 14] years; 75 women [35%]). At the time of data cutoff, 104 patients (22%; 54 azithromycin vs 50 placebo) had experienced an airflow decline; 138 patients (30%) died (78 azithromycin vs 60 placebo). Two-year airflow decline-free survival was 32.8% (95% CI, 25.9%-41.7%) with azithromycin and 41.3% (95% CI, 34.1%-50.1%) with placebo (unadjusted hazard ratio [HR], 1.3; 95% CI, 1.02-1.70; P = .03). Of the 22 patients (5%) who experienced bronchiolitis obliterans syndrome, 15 (6%) were in the azithromycin group and 7 (3%) in the placebo group (P = .08). The azithromycin group had increased mortality, with a 2-year survival of 56.6% (95% CI, 50.2%-63.7%) vs 70.1% (95% CI, 64.2%-76.5%) in the placebo group (unadjusted HR, 1.5; 95% CI, 1.1-2.0; P = .02). In a post hoc analysis, the 2-year cumulative incidence of hematological relapse was 33.5% (95% CI, 27.3%-39.7%) with azithromycin vs 22.3% (95% CI, 16.4%-28.2%) with placebo (unadjusted cause-specific HR, 1.7; 95% CI, 1.2-2.4; P = .002).

CONCLUSIONS AND RELEVANCE

Among patients undergoing allogeneic HSCT for hematological malignancy, early administration of azithromycin resulted in worse airflow decline-free survival than did placebo; these findings are limited by early trial termination. The potential for harm related to relapse requires further investigation.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01959100.

A call to arms: a critical need for interventions to limit pulmonary toxicity in the stem cell transplantation patient population

Noninfectious pulmonary toxicity after allogeneic hematopoietic stem cell transplantation (allo-HSCT) causes significant morbidity and mortality. Main presentations are idiopathic pneumonia syndrome (IPS) in the acute setting and bronchiolitis obliterans syndrome (BOS) and cryptogenic organizing pneumonia (COP) at later time point. While COP responds well to corticosteroids, IPS and BOS often are treatment refractory. IPS, in most cases, is rapidly fatal, whereas BOS progresses over time, resulting in chronic respiratory failure, impaired quality of life, and eventually, death. Standard second-line treatments are currently lacking, and current approaches, such as augmented T cell-directed immunosuppression, B cell depletion, TNF blockade, extracorporeal photopheresis, and tyroskine kinase inhibitor therapy, are unsatisfactory with responses in only a subset of patients. Better understanding of underlying pathophysiology hopefully results in the identification of future targets for preventive and therapeutic strategies along with an emphasis on currently underutilized rehabilitative and supportive measures.