Improvement of Pulmonary Function with Imatinib Mesylate in Bronchiolitis Obliterans Following Allogeneic Hematopoietic Cell Transplantation

Treatment of steroid-refractory chronic graft-versus-host disease with imatinib: Real-life experience of the Spanish group of hematopoietic transplantation (GETH)

Treatment of steroid-refractory chronic graft-versus-host disease (cGVHD) is a challenge. Here, we describe a retrospective analysis of 66 patients with steroid-refractory cGVHD treated with imatinib (starting dose of 100 mg in 70% of patients; maximum dose of 100-200 mg in 74%). Most patients had multi-organ involvement (≥2 organs, 83%), with the most affected being skin (85%), oral mucosa (55%), eyes (42%), and lungs (33%). The overall response rate was 41% (21 partial and three complete responses). The organ with the best response rate was the skin (46%), followed by gastrointestinal tract (43%), liver (41%), the oral mucosa (36%), eyes (29%), and lungs (18%). Imatinib led to steroid tapering in 17/38 patients. Twenty-five (38%) patients experienced imatinib-related adverse events, comprising extra-hematologic toxicity (n = 24, 36%) and hematologic toxicity (n = 6, 9%). No cases of grade 4-5 toxicity were reported. The main causes of imatinib discontinuation were treatment failure (52%) and toxicity (9%). After a median follow-up of 41 months, the 3-year overall survival was 81%, with no difference between imatinib responders and non-responders. These real-life results show that imatinib is safe and has moderate efficacy in patients with heavily pre-treated cutaneous sclerotic cGVHD; however, activity against lung cGVHD is very limited.

Imatinib melylate as second-line treatment of bronchiolitis obliterans after allogenic hematopoietic stem cell transplantation in children

BACKGROUND

The onset of bronchiolitis obliterans (BO) as a pulmonary manifestation of chronic graft vs host disease dramatically changes the prognosis of children undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study aimed to evaluate the overall survival (OS) of children with BO treated with imatinib mesylate (IM).

METHODS

This study included children who underwent allo-HSCTs between January 2000 and December 2016.

RESULTS

Among 345 patients who underwent HSCTs, 293 were evaluable for BO and 26 (8.9%) developed BO. The cumulative incidence of BO was 4.8% (95% confidence interval [CI], 2.8-7.5) at 1 year and 7.7% (95% CI, 5.1-11.1) at 3 years after transplantation. In the group of HSCTs (n = 67) complicated by chronic GvHD (c-GVHD), the incidence rate of BO was 38.8%. In total, 96.1% of patients with BO had c-GvHD worse than moderate grade, which was present in 70.7% of patients without BO (P = .011). The mortality rates were 46.1% in the BO group and 27.4% in the group without BO. Half of the patients with BO (n = 13) received IM, and the overall response rate was 76.9%. Four years after HSCT, OS was 42.6% (95% CI, 18.2-65.3) in the group without IM and 83.3% (95% CI, 27.3-97.5) in the group with IM.

CONCLUSIONS

BO after HSCT in the pediatric population has a high incidence and mortality rate. In terms of overall response and tolerability, this study showed relevant improvements in the prognosis of children with BO after the introduction of IM. Further prospective studies among children are needed to confirm these results.

ABL kinase inhibition promotes lung regeneration through expansion of an SCGB1A1+ SPC+ cell population following bacterial pneumonia

Current therapeutic interventions for the treatment of respiratory infections are hampered by the evolution of multidrug resistance in pathogens as well as the lack of effective cellular targets. Despite the identification of multiple region-specific lung progenitor cells, the identity of molecules that might be therapeutically targeted in response to infections to promote activation of progenitor cell types remains elusive. Here, we report that loss of Abl1 specifically in SCGB1A1-expressing cells leads to a significant increase in the proliferation and differentiation of bronchiolar epithelial cells, resulting in dramatic expansion of an SCGB1A1+ airway cell population that coexpresses SPC, a marker for type II alveolar cells that promotes alveolar regeneration following bacterial pneumonia. Furthermore, treatment with an Abl-specific allosteric inhibitor enhanced regeneration of the alveolar epithelium and promoted accelerated recovery of mice following pneumonia. These data reveal a potential actionable target that may be exploited for efficient recovery after pathogen-induced infections.

Anti-Platelet-Derived Growth Factor Receptor Alpha Chain Antibodies Predict for Response to Nilotinib in Steroid-Refractory or -Dependent Chronic Graft-Versus-Host Disease

Imatinib has clinical activity in chronic graft-versus-host disease (cGVHD), a significant complication of allogeneic hematopoietic cell transplant. Nilotinib is a tyrosine kinase inhibitor that targets the same receptors as imatinib but with different affinities. We tested the hypothesis that nilotinib is safe and has clinical activity in cGVHD. Thirty-three participants were enrolled in a phase I/II dose escalation and dose extension clinical trial of nilotinib for the treatment of steroid-refractory or- dependent cGVHD (ClinicalTrials.gov, NCT01155817). We assessed safety, clinical response, and pretreatment anti-platelet-derived growth factor receptor alpha chain (anti-PDGFRA) antibody levels. The 200-mg dose was identified as the maximum tolerated dose and used for the phase II dose extension study. At 6 months the incidence of failure-free survival (FFS), cGVHD progression, and nilotinib intolerance resulting in its discontinuation was 50%, 23%, and 23%, respectively. cGVHD responses in skin, joints, and mouth were observed at 3 and 6 months based on improvement in respective National Institutes of Health organ severity scores. Pretreatment anti-PDGFRA antibody levels ≥ .150 optical density as measured by ELISA correlated with longer FFS time (P < .0005) and trended with time until cGVHD progression (P < .06) but not drug intolerance. Nilotinib may be effective for corticosteroid-resistant or -refractory cGVHD in some patients, but its use is limited by intolerable side effects. Selection of patients with high pretreatment anti-PDGFRA antibody levels might improve the risk-to-benefit ratio of nilotinib and better justify its side effects.

Update in Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is the major limitation to posttransplant survival. This review highlights the evolving definition of CLAD, risk factors, treatment, and expected outcomes after the development of CLAD.

Chronic graft-versus-host disease presenting as eosinophilic fasciitis: therapeutic challenges and an additional case

Chronic graft-versus-host disease (cGVHD) is one of the main late complications of allogeneic hematopoietic stem cell transplant and a major contributor to the mortality and morbidity in surviving recipients. Skin is the most common involved organ in cGVHD and may mimic a wide spectrum of dermatological conditions in its clinical and histopathologic manifestations. Some of the commonly simulated diseases are scleroderma, morphea, and lichen sclerosus. Chronic GVHD simulating eosinophilic fasciitis (EF) is relatively rare, frequently presenting with skin induration, a typical "peau d'orange" appearance, peripheral blood eosinophilia, myalgia, arthralgia, and arthritis leading to joint contractures in severe cases.Diagnosis is based on clinical manifestations and histopathology. Treatment is challenging because most cases are refractory to first-line therapy of glucocorticoids and calcineurin inhibitors (CNIs), and there is no standard second-line therapy.We report a comprehensive review of literature on all reported cases of CGVHD presenting as EF. We also describe an additional interesting case of cGVHD presenting as EF that was resistant to traditional therapy of high-dose glucocorticoids and cyclosporin A, but showed complete resolution of skin manifestations after addition of imatinib.Chronic GVHD presenting as EF is a rare variant of sclerodermatous cGVHD. Diagnosis is difficult, and treatment of cGVHD mimicking EF remains a therapeutic challenge because of obscure pathogenesis and poor response to traditional immunosuppressive medications. Emerging insights into the pathogenesis of cGVHD have resulted in the development of novel targeted therapies, which may improve outcomes and should be attempted in this subset of the disease. Larger studies are warranted to substantiate these preliminary findings.

Lung transplantation for bronchiolitis obliterans after allogeneic hematopoietic stem cell transplantation

Bronchiolitis obliterans (BO) is a late onset complication of allogeneic hematopoietic stem cell transplantation (HSCT), and treatment outcome is dismal if it does not respond to immunosuppressive therapy. A 21-year-old male diagnosed with acute myeloid leukemia received an allogeneic HSCT from human leukocyte antigen- identical sibling donor. Twenty one months after transplantation, he developed progressive dyspnea and was diagnosed BO. Despite standard immunosuppressive therapy, the patient rapidly progressed to respiratory failure and Novalung® interventional lung-assist membrane ventilator was applied in the intensive care unit. Three months after the diagnosis of BO, the patient underwent bilateral lung transplantation (LT) and was eventually able to wean from the ventilator and the Novalung®. Since the LT, the patient has been under a strict rehabilitation program in order to overcome a severe lower extremity weakness and muscle atrophy. Histologic findings of the explanted lungs confirmed the diagnosis of BO. Nine months after the LT, the patient showed no signs of rejection or infectious complications, but still required rehabilitation treatment. This is the first LT performed in a patient with BO after allogeneic HSCT in Korea. LT can be an effective therapy in terms of survival for patients with respiratory failure secondary to development of BO following HSCT.

Time to explore preventive and novel therapies for bronchiolitis obliterans syndrome after allogeneic hematopoietic stem cell transplantation

Although allogeneic hematopoietic stem cell transplant (allo-HSCT) is performed to treat otherwise incurable and fatal diseases, transplantation itself can lead to life-threatening complications due to organ damage. Pulmonary complications remain a significant barrier to the success of allo-HSCT. Lung injury, a frequent complication after allo-HSCT, and noninfectious pulmonary deaths account for a significant proportion of non-relapse mortality. Bronchiolitis obliterans syndrome (BOS) is a common and potentially devastating complication. BOS is now considered a diagnostic criterion of chronic graft-versus-host-disease (cGVHD), and National Institutes of Health (NIH) consensus has been published to establish guidelines for diagnosis and monitoring of BOS. It usually occurs within the first 2 years but may develop as late as 5 years after transplantation. Recent prevalence estimates suggest that BOS is likely underdiagnosed, and when severe BOS does occur, current treatments have been largely ineffective. Prevention and effective novel approaches remain the primary tools in the clinician's arsenal in managing BOS. This article provides an overview of the currently available and novel strategies for BOS, and we also discuss specific preventive interventions to reduce severe BOS after allo-HSCT. Therapeutic trials continue to be needed for this orphan disease.

Tirosin kinase inhibitors in chronic graft versus host disease: from bench to bedside

Chronic Graft Versus Host Disease (cGVHD) is a major complication of allogeneic stem-cell transplantation (SCT). In many inflammatory fibrotic diseases, such as Systemic Scleroderma (SSc) and cGVHD with fibrotic features, an abnormal activation of transforming growth factor (TGFβ) and platelet-derived growth factor receptor (PDGF-R) pathways have been observed. Tyrosin Kinase Inhibitors (TKIs), which are currently used for treatment of patients with Chronic Myeloid Leukemia (CML), share potent antifibrotic and antiinflammatory properties, being powerful dual inhibitors of both PDGF-R and TGFβ pathways. Moreover accumulating in vitro data confirm that TKIs, interacting with the TCR and other signalling molecules, carry potent immunomodulatory effects, being involved in both T-cell and B-cell response. Translation to the clinical setting revealed that treatment with Imatinib can achieve encouraging responses in patients with autoimmune diseases and steroid-refractory cGVHD, showing a favourable toxicity profile. While the exact mechanisms leading to such efficacy are still under investigation, use of TKIs in the context of clinical trials should be promoted, aiming to evaluate the biological changes induced in vivo by TKIs and to assess the long term outcome of these patients. Second-generation TKIs, with more favourable toxicity profile are under evaluation in the same setting.

Diagnosis and treatment of pulmonary chronic GVHD: report from the consensus conference on clinical practice in chronic GVHD

This consensus statement established under the auspices of the German working group on BM and blood stem cell transplantation (DAG-KBT), the German Society of Hematology and Oncology (DGHO), the Austrian Stem Cell Transplant Working Group, the Swiss Blood Stem Cell Transplantation Group (SBST) and the German-Austrian Pediatric Working Group on SCT (Päd-Ag-KBT) summarizes current evidence for diagnosis, immunosuppressive and supportive therapy to provide practical guidelines for the care and treatment of patients with pulmonary manifestations of chronic GVHD (cGVHD). Pulmonary cGVHD can present with obstructive and/or restrictive changes. Disease severity ranges from subclinical pulmonary function test (PFT) impairment to respiratory insufficiency with bronchiolitis obliterans being the only pulmonary complication currently considered diagnostic of cGVHD. Early diagnosis may improve clinical outcome, and regular post-transplant follow-up PFTs are recommended. Diagnostic work-up includes high-resolution computed tomography, bronchoalveolar lavage and histology. Topical treatment is based on inhalative steroids plus beta-agonists. Early addition of azithromycin is suggested. Systemic first-line treatment consists of corticosteroids plus, if any, continuation of other immunosuppressive therapy. Second-line therapy and beyond includes extracorporeal photopheresis, mammalian target of rapamycin inhibitors, mycophenolate, etanercept, imatinib and TLI, but efficacy is limited. Clinical trials are urgently needed to improve understanding and treatment of this deleterious complication.

The spectrum of noninfectious pulmonary complications following hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is an established treatment for a variety of malignant and nonmalignant conditions. Pulmonary complications, infectious and noninfectious, are a major cause of morbidity and mortality in these patients. The recent advances in prophylaxis and treatment of infectious complications increased the significance of noninfectious pulmonary conditions. Acute lung injury due to diffuse alveolar hemorrhage or idiopathic pneumonia syndrome are the main acute complications, while bronchiolitis obliterans remains the most challenging pulmonary complications facing clinicians who are taking care of HSCT recipients. There are other noninfectious pulmonary complications following HSCT that are less frequent. This report provides a clinical update of the incidence, risk factors, pathogenesis, clinical characteristics and management of the main noninfectious pulmonary complications following HSCT.

Extracorporeal photopheresis in patients with refractory bronchiolitis obliterans developing after allo-SCT

Extracorporeal photopheresis (ECP) has been shown to be a promising treatment for chronic graft-versus-host disease; however, only a few case reports are available that examine the effectiveness of ECP for bronchiolitis obliterans (BO) after allo-SCT. Because of the poor response to traditional therapies, ECP has been explored as a possible therapeutic option for severe BO after allo-SCT. Nine patients received ECP between July 2008 and August 2009 after a median follow-up of 23 months (range 9-93 months) post transplant. The primary indication for ECP was the development of BO in patients who had failed prior multidrug regimens. The median number of drugs used for BO management before ECP was 5 (range 2-7); this included immunosuppressive therapy. Six of nine (67%) patients responded to ECP after a median of 25 days (range 20-958 days). No ECP-related complications occurred. ECP seemed to stabilize rapidly declining pulmonary function tests in about two-thirds of patients with severe and heavily pretreated BO that developed after allo-SCT. This finding supports the need for a larger prospective study to confirm the impact of ECP on BO, and to consider earlier intervention with ECP to improve the outcome of BO after allo-SCT.

Consensus Conference on Clinical Practice in Chronic GVHD: Second-Line Treatment of Chronic Graft-versus-Host Disease

Steroid refractory chronic graft-versus-host disease (cGVHD) is associated with a significant morbidity and mortality. Although first-line treatment of cGVHD is based on controlled trials, second-line treatment is almost solely based on phase II trials or retrospective analyses. The consensus conference on clinical practice in cGVHD held in Regensburg aimed to achieve a consensus on the current evidence of treatment options as well as to provide guidelines for daily clinical practice. Treatment modalities are the use of steroids and calcineurin inhibitors as well as immunomodulating modalities (photopheresis, mTOR-inhibitors, thalidomide, hydroxychloroquine, vitamin A analogs, clofazimine), and cytostatic agents (mycophenolate mofetil, methotrexate, cyclophosphamide, pentostatin). Recent reports showed some efficacy of rituximab, alemtuzumab, and etanercept in selected patients. Moreover, tyrosine kinase inihibitors such as imatinib came into the field because of their ability to interfere with the platelet-derived growth factor (PDGF-R) pathway involved in fibrosis. An other treatment option is low-dose thoracoabdominal irradiation. Although different treatment options are available, the "trial-and-error system" remains the only way to identify the drug effective in the individual patient, and valid biomarkers are eagerly needed to identify the likelihood of response to a drug in advance. Moreover, the sparse evidence for most treatment entities indicates the urgent need for systematic evaluation of second-line treatment options in cGVHD.

Bronchiolitis obliterans syndrome after allogeneic hematopoietic stem cell transplantation-an increasingly recognized manifestation of chronic graft-versus-host disease

Bronchiolitis obliterans syndrome (BOS) is a progressive, insidious, and often fatal lung alloreaction that can occur following allogeneic hematopoietic stem cell transplantation (HSCT) or allogeneic lung transplantation. Current estimates in the literature suggest that approximately 2% to 3% of all allogeneic HSCT recipients and 6% of patients who develop chronic graft-versus-host disease (cGVHD) will develop this syndrome. However, based on newer data it is likely that the true incidence of BOS is higher. Unfortunately, the survival and treatment of patients with BOS after HSCT has not improved over the last 20 years. Attempts at clinical trials have been hindered by the lack of uniform diagnostic criteria and inability to detect the syndrome at a reversible stage in its natural history. Recently, the National Institutes of Health (NIH) consensus project for criteria in cGVHD has made recommendations regarding the diagnosis of BOS and monitoring of lung disease among long-term survivors. Although a rare and poorly understood manifestation of cGVHD, BOS occurs commonly after lung transplantation and is similar in pathology, clinical presentation, radiographic presentation, and presumed immunologic pathogenesis. This review describes the current understanding of the epidemiology and pathogenesis of BOS and presents information on evaluations and therapies for patients with BOS after HSCT.

Imatinib mesylate as salvage therapy for refractory sclerotic chronic graft-versus-host disease

Imatinib is a promising candidate for the treatment of fibrotic diseases. This retrospective study evaluated the use of imatinib for the treatment of refractory sclerotic chronic graft-versus-host disease in 14 patients with different hematologic malignancies. Imatinib was started at a median of 44 months after transplantation (range, 16-119 months after transplantation) and was administered for a median of 5.9 months from time of initiation (range, 2.1-74 months from time of initiation). With a median overall follow-up of 11.6 months from time of initiation (range, 4.1-74 months from time of initiation) of imatinib, 4 patients (29%) had to stop imatinib because of drug intolerance. All other adverse reactions were of mild-to-moderate grade and could be managed symptomatically. Overall, 7 patients responded to imatinib (50%; 95% confidence interval, 24%-76%) with 4 patients improving their Rodman score more than or equal to 90%. In addition, imatinib therapy allowed for a significant reduction of corticosteroid dosage. Despite its limited size, this cohort suggests some beneficial activity of imatinib in sclerotic chronic graft-versus-host disease, warranting further prospective investigations.

Innovative approaches to treat steroid-resistant or steroid refractory GVHD

First-line treatment of GVHD is based on steroids and produces sustained responses in 50-80% of patients with acute GVHD (aGVHD) and 40-50% of patients with chronic GVHD (cGVHD) depending on the initial disease severity. Non-responding children are offered second-line therapy with combinations of various agents, but currently available agents have not improved survival in these high-risk populations. In this minireview, we will focus on new agents to treat GVHD in paediatric patients.