Novel approaches in the management of refractory celiac disease

Safety and efficacy of AMG 714 in patients with type 2 refractory coeliac disease: a phase 2a, randomised, double-blind, placebo-controlled, parallel-group study

BACKGROUND

Refractory coeliac disease type 2 is a rare subtype of coeliac disease with high mortality rates; interleukin 15 (IL-15) is strongly implicated in its pathophysiology. This trial aimed to investigate the effects of AMG 714, an anti-IL-15 monoclonal antibody, on the activity and symptoms of refractory coeliac disease type 2.

METHODS

This was a randomised, double-blind, placebo-controlled, phase 2a study of adults with a confirmed diagnosis of refractory coeliac disease type 2. Patients were randomly assigned at a 2:1 ratio to receive seven intravenous doses over 10 weeks of AMG 714 (8 mg/kg) or matching placebo. Biopsy samples were obtained at baseline and week 12 for cellular analysis and histology. The change in the proportion of aberrant intraepithelial lymphocytes from baseline to week 12 with respect to all intraepithelial lymphocytes was the primary endpoint and was quantified using flow cytometry. Secondary endpoints were the change in aberrant intraepithelial lymphocytes with respect to intestinal epithelial cells; intestinal histological scores (villous height-to-crypt depth ratio; VHCD); intraepithelial lymphocyte counts; Marsh score; and patient-reported symptom measures, including the Bristol stool form scale (BSFS) and gastrointestinal symptom rating scale (GSRS). Main analyses were done in the per-protocol population of patients who received their assigned treatment, provided evaluable biopsy samples, and did not have major protocol deviations; only patients with non-atypical disease were included in the analyses of aberrant intraepithelial lymphocytes, including the primary analysis. Safety was assessed in all patients who received at least one dose of study drug. This study is registered at ClinicalTrials.gov (NCT02633020) and EudraCT (2015-004063-36).

FINDINGS

From April 13, 2016, to Jan 19, 2017, 28 patients were enrolled and randomly assigned to AMG 714 (n=19) and placebo (n=9). Six patients were not included in the primary analysis because of protocol deviation (one in the AMG 714 group), insufficient biopsy samples (one in the AMG 714 group), and atypical intraepithelial lymphocytes (three in the AMG 714 group and one in the placebo group). At 12 weeks, the least square mean difference between AMG 714 and placebo in the relative change from baseline in aberrant intraepithelial lymphocyte percentage was -4·85% (90% CI -30·26 to 20·56; p=0·75). The difference between the AMG 714 and placebo groups in aberrant intraepithelial lymphocytes with respect to epithelial cells at 12 weeks was -38·22% (90% CI -95·73 to 19·29; nominal p=0·18); the difference in change in Marsh score from baseline was 0·09% (95% CI -1·60-1·90; nominal p=0·92); the difference in VHCD ratio was 10·67% (95% CI -38·97 to 60·31; nominal p=0·66); and the difference in change in total intraepithelial lymphocyte count was -12·73% (95% CI -77·57-52·12); nominal p=0·69). Regarding symptoms, the proportion of patients with diarrhoea per the BSFS score decreased from ten (53%) of 19 at baseline to seven (37%) of 19 at week 12 in the AMG 714 group and increased from two (22%) of nine at baseline to four (44%) of nine at week 12 in the placebo group (nominal p=0·0008); and the difference between the groups in change in GSRS score was -0·14 (SE 0·19; nominal p=0·48). Eight (89%) patients in the placebo group and 17 (89%) in the AMG 714 group had treatment-emergent adverse events, including one (11%) patient in the placebo group and five (26%) in the AMG 714 group who had serious adverse events. The most common adverse event in the AMG 714 group was nasopharyngitis (eight [42%] patients vs one [11%] in the placebo group).

INTERPRETATION

In patients with refractory coeliac disease type 2 who were treated with AMG 714 or placebo for 10 weeks, there was no difference between the groups in terms of the primary endpoint of aberrant intraepithelial lymphocyte reduction from baseline. Effects on symptoms and other endpoints suggest that further research of AMG 714 may be warranted in patients with refractory coeliac disease type 2.

FUNDING

Celimmune and Amgen.

T-cell repertoires in refractory coeliac disease

OBJECTIVE

Refractory coeliac disease (RCD) is a potentially hazardous complication of coeliac disease (CD). In contrast to RCD type I, RCD type II is a precursor entity of enteropathy-associated T-cell lymphoma (EATL), which is associated with clonally expanding T-cells that are also found in the sequentially developing EATL. Using high-throughput sequencing (HTS), we aimed to establish the small-intestinal T-cell repertoire (TCR) in CD and RCD to unravel the role of distinct T-cell clonotypes in RCD pathogenesis.

DESIGN

DNA extracted from duodenal mucosa specimens of controls (n=9), active coeliacs (n=10), coeliacs on a gluten-free diet (n=9), RCD type I (n=8), RCD type II (n=8) and unclassified Marsh I cases (n=3) collected from 2002 to 2013 was examined by TCRβ-complementarity-determining regions 3 (CDR3) multiplex PCR followed by HTS of the amplicons.

RESULTS

On average, 10⁶ sequence reads per sample were generated consisting of up to 900 individual TCRβ rearrangements. In RCD type II, the most frequent clonotypes (ie, sequence reads with identical CDR3) represent in average 42.6% of all TCRβ rearrangements, which was significantly higher than in controls (6.8%; p<0.01) or RCD type I (6.7%; p<0.01). Repeat endoscopies in individual patients revealed stability of clonotypes for up to several years without clinical symptoms of EATL. Dominant clonotypes identified in individual patients with RCD type II were unique and not related between patients. CD-associated, gliadin-dependent CDR3 motifs were only detectable at low frequencies.

CONCLUSIONS

TCRβ-HTS analysis unravels the TCR in CD and allows detailed analysis of individual TCRβ rearrangements. Dominant TCRβ sequences identified in patients with RCD type II are unique and not homologous to known gliadin-specific TCR sequences, supporting the assumption that these clonal T-cells expand independent of gluten stimulation.

Creation of a model to predict survival in patients with refractory coeliac disease using a multinational registry

BACKGROUND

Refractory coeliac disease is a severe complication of coeliac disease with heterogeneous outcome.

AIM

To create a prognostic model to estimate survival of patients with refractory coeliac disease.

METHODS

We evaluated predictors of 5-year mortality using Cox proportional hazards regression on subjects from a multinational registry. Bootstrap resampling was used to internally validate the individual factors and overall model performance. The mean of the estimated regression coefficients from 400 bootstrap models was used to derive a risk score for 5-year mortality.

RESULTS

The multinational cohort was composed of 232 patients diagnosed with refractory coeliac disease across seven centres (range of 11-63 cases per centre). The median age was 53 years and 150 (64%) were women. A total of 51 subjects died during a 5-year follow-up (cumulative 5-year all-cause mortality = 30%). From a multiple variable Cox proportional hazards model, the following variables were significantly associated with 5-year mortality: age at refractory coeliac disease diagnosis (per 20 year increase, hazard ratio = 2.21; 95% confidence interval, CI: 1.38-3.55), abnormal intraepithelial lymphocytes (hazard ratio = 2.85; 95% CI: 1.22-6.62), and albumin (per 0.5 unit increase, hazard ratio = 0.72; 95% CI: 0.61-0.85). A simple weighted three-factor risk score was created to estimate 5-year survival.

CONCLUSIONS

Using data from a multinational registry and previously reported risk factors, we create a prognostic model to predict 5-year mortality among patients with refractory coeliac disease. This new model may help clinicians to guide treatment and follow-up.

Lymphoma development and survival in refractory coeliac disease type II: Histological response as prognostic factor

BACKGROUND

Refractory coeliac disease type II (RCDII) frequently transforms into an enteropathy-associated T-cell lymphoma (EATL) and therefore requires intensive treatment. Current evaluated treatment strategies for RCDII include cladribine (2-CdA) and autologous stem cell transplantation (auSCT).

OBJECTIVE

The purpose of this study was to evaluate long-term survival and define clear prognostic criteria for EATL development comparing two treatment strategies.

METHODS

A total of 45 patients were retrospectively analysed. All patients received 2-CdA, after which they were either closely monitored (monotherapy, n = 30) or a step-up approach was used including auSCT (step-up therapy, n = 15).

RESULTS

Ten patients (22%) ultimately developed EATL; nine of these had received monotherapy. Absence of histological remission after monotherapy was associated with EATL development (p = 0.010). Overall, 20 patients (44%) died with a median survival of 84 months. Overall survival (OS) within the monotherapy group was significantly worse in those without histological remission compared to those with complete histological remission(p = 0.030). The monotherapy group who achieved complete histological remission showed comparable EATL occurrence and OS as compared to the step-up therapy group (p = 0.80 and p = 0.14 respectively).

CONCLUSION

Histological response is an accurate parameter to evaluate the effect of 2-CdA therapy and this parameter should be leading in the decisions whether or not to perform a step-up treatment approach in RCDII.

Therapy in RCDII: Rationale for Combination Strategies?

Refractory coeliac disease type II (RCDII) is characterized by a continuous gluten-independent duodenal immune activation with an extremely high risk of malignant transformation. It is therefore considered as an indolent lymphoma. RCDII is characterized by the presence of villous atrophy (Marsh III A-C) in combination with an aberrant intra- epithelial lymphocyte (IEL) population consisting of >20% sCD3-CD7+iCD3+ IELs. The sCD3-CD7+iCD3+ IELs are a heterogeneous lineage-negative cell population, consisting of cells that do or do not express CD127/IL7Rα. Experiments using IEL from non-RCDII patients have indicated that while the CD127- cells are IL-15 responsive, the CD127+ cells are not. Together with the observation that some patients express an aberrant (monoclonal) TCRγδ phenotype, this confirms the heterogeneity of the aberrant IEL population in RCDII and suggests that the aberrant cells are heterogeneous with respect to their response to common γ-chain cytokines. Although cladribine with or without autologous stem cell transplantation is effective in the treatment of signs and symptoms of RCDII and improves survival as compared to symptomatic topical steroid therapy, cladribine failures still bear a high risk of malignant transformation, and the rate of enteropathy-associated T-cell lymphoma (EATL) development in this subgroup is extremely high. It might be hypothesized that the heterogenous nature of aberrant IEL and the high risk of malignant transformation require a treatment strategy which is effective despite this heterogeneity. RCDII should be seen more in the light of a low-grade/no mass lymphoma or pre-EATL. We would suggest an upfront combination therapy approach integrating inhibition of downstream Jak-STAT signalling pathways with conventional therapy (2-CDA) to hopefully effectively treat signs and symptoms of RCDII and accomplish a more effective EATL prevention.

Mesenchymal stromal cell infusions as rescue therapy for corticosteroid-refractory adult autoimmune enteropathy

Adult autoimmune enteropathy (AIE) is a rare cause of malabsorption syndrome unresponsive to dietary restriction. Its diagnostic hallmarks are small-bowel villous atrophy and antienterocyte autoantibodies. Therapy is based mainly on nutritional support and immunosuppression. We treated a 61-year-old woman with corticosteroid-refractory AIE and life-threatening malabsorption syndrome with systemic infusions of autologous, bone marrow-derived, mesenchymal stromal cells (MSCs) as rescue therapy. The MSCs were expanded ex vivo following a previously used Good Manufacturing Practice procedure, and 2 intravenous infusions of 1.8 × 10(6) MSCs/kg body weight were administered 2 weeks apart. Analysis of circulating and mucosal regulatory T-and B-cell numbers, and of serum and secretory immunoglobulin levels, was performed before and after treatment. The MSC infusions were safe and effective, leading to disappearance of disease hallmarks and recovery from the life-threatening condition. Increases in mucosal regulatory T-cell numbers and secretory immunoglobulin levels were also observed. The benefit, however, was transient, and a further MSC infusion resulted in the same short efficacy. This case encourages the use of MSCs to treat patients with life-threatening, corticosteroid-refractory AIE and suggests that MSC infusion can attenuate, albeit transiently, the autoimmune attack.

Defective tight junctions in refractory celiac disease

In celiac disease, the gut-associated immune system is activated in response to the ingestion of gluten, causing an atrophy of the small intestinal mucosa. Although this condition is, in most cases, responsive to a gluten-free diet, celiac disease refractory to treatment occurs in a small percentage of celiacs. An epithelial barrier defect is known to be an integral part of celiac pathophysiology. However, the mucosa in refractory celiac disease underlies a constant inflammatory process. The epithelial barrier has not been addressed in this condition so far. Herein, the tight junction-associated barrier in refractory celiac disease is investigated functionally and structurally. Although normally expressed in celiac disease, claudin-4 is shown to be downregulated in refractory cases, presumably by two mechanisms, reduced protein expression and increased claudin endocytosis. Furthermore, the tightening claudin-5 is downregulated and the pore-forming claudin-2 is upregulated.

Evaluation of Cladribine treatment in refractory celiac disease type II

AIM: To evaluate cladribine [2-chlorodeoxyadenosine (2-CdA)] therapy in refractory celiac disease (RCD) II.

METHODS: An open-label cohort-study of RCD II patients treated with 2-CdA was performed between 2000 and 2010. Survival rate, enteropathy associated T-cell lymphoma (EATL) occurrence, clinical course, and histological and immunological response rates were evaluated.

RESULTS: Overall, 32 patients were included with a median follow-up of 31 mo. Eighteen patients responded well to 2-CdA. Patients responsive to 2-CdA had a statistically significant increased survival compared to those who were unresponsive. The overall 3- and 5-year survival was 83% in the responder and 63% and 22% in the non-responder group, respectively. The overall 2-year clinical, histological and immunological response rates were 81%, 47% and 41%, respectively. Progression into EATL was reported in 16%, all of these patients died.

CONCLUSION: Treatment of RCD II with 2-CdA holds promise, showing excellent clinical and histological response rates, and probably less frequent transition into EATL.

Cavitating mesenteric lymph node syndrome in association with coeliac disease and enteropathy associated T-cell lymphoma: a case report and review of the literature

Cavitating mesenteric lymph node syndrome (CMLNS) is a rare and poorly understood complication of coeliac disease (CD), with only 37 cases reported in the literature. CD is an immune-mediated enteropathy, with alterations seen in the small bowel architecture on exposure to ingested gluten. Those who fail to respond to a strict gluten-free diet are termed to have refractory coeliac disease (RCD). This is associated with serious complications such as enteropathy-associated T-cell lymphoma (EATL). We present the case of a 71-year-old female investigated for weight loss and a palpable intraabdominal mass. Abdominal computed tomographic (CT) scan showed multiple necrotic mesenteric lymph nodes. At operation, multiple cavitating mesenteric lymph nodes, containing milky fluid, were found. An incidental EATL was found at the terminal ileum, which was resected. The patient subsequently tested positive for CD. This is the second case report to document an association between CMLNS and EATL. This paper highlights the varied presentation of CD. In this case, the diagnosis of CD was made retrospectively after the complications were dealt with. This paper is followed by a review of relevant literature.

The spectrum of celiac disease: epidemiology, clinical aspects and treatment

Celiac disease is a gluten-sensitive enteropathy that affects people of all ages worldwide. This disease has emerged as a major health-care problem, as advances in diagnostic and screening methods have revealed its global prevalence. Environmental factors such as gluten introduction at childhood, infectious agents and socioeconomic features, as well as the presence of HLA-DQ2 and/or HLA-DQ8 haplotypes or genetic variations in several non-HLA genes contribute to the development of celiac disease. Growing insight into the variable clinical and histopathological presentation features of this disease has opened new perspectives for future research. A strict life-long gluten-free diet is the only safe and efficient available treatment, yet it results in a social burden. Alternative treatment modalities focus on modification of dietary components, enzymatic degradation of gluten, inhibition of intestinal permeability and modulation of the immune response. A small group of patients with celiac disease (2-5%), however, fail to improve clinically and histologically upon elimination of dietary gluten. This complication is referred to as refractory celiac disease, and imposes a serious risk of developing a virtually lethal enteropathy-associated T-cell lymphoma.

Enteropathy associated T-cell lymphoma and its precursor lesions

Enteropathy Associated T-cell Lymphoma (EATL) is an intestinal tumour of intra-epithelial lymphocytes. Based on morphology, immunohistochemistry and genetic profile EATL can be divided into two groups. EATL type I is a large cell lymphoma which is highly associated with Coeliac Disease (CD) and mostly presents with malabsorption, weight loss and CD-related symptoms. EATL type II consists of small to medium-sized cells and presents often with obstruction or perforation of the small bowel. This type of EATL has no known association with CD. When EATL has been diagnosed a thorough diagnostic work-up is needed. This work-up preferably includes video capsule enteroscopy (VCE), double-balloon enteroscopy (DBE), computed tomography (CT) combined with 18F-fluorodeoxyglucose positron emission tomography scan (18F-FDG-PET scan) if possible and magnetic resonance enteroclysis (MRE). Nowadays, most EATL patients are treated with chemotherapy mostly preceded by resection of the tumour and followed by stem cell transplantation. Despite these therapies outcome of EATL remains very poor with a 5-year survival of 8-20%. In order to improve survival prospective multicentre trials, studying new therapies are needed. The combination of chemotherapy, monoclonal antibodies and/or apoptosis inducing small molecules might be a potential treatment for EATL in the (nearby) future.

Diagnosis and staging in gastrointestinal lymphoma

The diagnosis gastrointestinal lymphoma can be made on endoscopic biopsies in the vast majority of cases. Definitive subtyping of the lymphoma according to the WHO classification with the use of additional immunological and molecular markers is the cornerstone for further decision making. Several lymphomas may occur multifocally or show both small cell and large cell components. Therefore, a second endoscopy with an extensive biopsy protocol (mapping) may be mandatory. Staging procedures are required for therapeutic decision making and should include CT-scan, laboratory studies and bone marrow examination as required in other lymphomas. Additional studies must be performed depending subtype and localisation of the lymphoma. In gastric lymphoma endosonography reveals prognostic information. In marginal zone lymphoma of MALT-type attention to other MALT-sites and autoimmune diseases is necessary. In enteropathy-associated T-cell lymphoma screening for coeliac disease and enteroscopy are required. In several lymphomas (diffuse large B-cell lymphoma and mantle cell lymphoma) a PET-scan is considered as standard of care. The value of staging procedures after treatment is less well defined. At least in gastric lymphomas, histology is the gold standard after treatment and during follow-up.

Enteroscopy in the diagnosis and management of celiac disease

Esophagogastroduodenoscopy (EGD) with 3 to 6 biopsies in the descending duodenum is the gold standard for the diagnosis of celiac disease. At the time of the first diagnosis of celiac disease, an extensive evaluation of the small bowel is not recommended. However, video capsule endoscopy, because of its good sensitivity and specificity in recognizing the Endoscopic features of celiac disease, can be considered a valid alternative to EGD in patients unable or unwilling to undergo EGD with biopsies. Capsule endoscopy is also a possible option in selected cases with strong suspicion of celiac disease but negative first-line tests. In evaluating patients with refractory or complicated celiac disease, in whom a complete evaluation of the small bowel is mandatory (at least in refractory celiac disease type II patients) because of the possible presence of complications beyond the reach of conventional endoscopes, both capsule endoscopy and balloon-assisted enteroscopy have been found to be helpful. In these patients, capsule endoscopy offers several advantages: it is well tolerated, it allows inspection of the entire small bowel, and it is able to recognize subtle mucosal changes. However, in this setting, capsule endoscopy should ideally be coupled with imaging techniques that provide important information about the thickness of the wall of the intestine and about extraluminal abnormalities. Although deep enteroscopy (such as balloon enteroscopy) is expensive, time-consuming, and potentially risky in these frail patients, they may have a key role, because they make it possible to take tissue samples from deep in the small intestine.