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Novel Nondietary Therapies for Celiac Disease

2019; Elsevier BV; Volume: 8; Issue: 3 Linguagem: Inglês

10.1016/j.jcmgh.2019.04.017

2352-345X

Eaman Alhassan, Abhijeet Yadav, Ciarán P. Kelly, Rupa Mukherjee,

Helicobacter pylori-related gastroenterology studies

Celiac Disease (CeD) is defined as a chronic small intestinal immune-mediated enteropathy that is precipitated by exposure to dietary gluten in genetically predisposed individuals. CeD is one of the most common autoimmune disorders affecting around 1% of the population worldwide. Currently, the only acceptable treatment for CeD is strict, lifelong adherence to a gluten-free diet (GFD) which can often present a challenging task. A GFD alone is not sufficient to control symptoms and prevent mucosal damage that can result from unintentional gluten exposure. Moreover, long-term complications can occur in many patients. Consequently, there is an unmet need for non-dietary therapies for the management of CeD. Such therapies could serve as an adjunct to the GFD but eventually may replace it. This review will focus on and discuss non-dietary therapies currently in clinical development for the management of CeD.MethodologyWe searched clinicaltrials.gov and PubMed to extract articles about celiac disease. We used keywords including, but not limited to, "celiac disease," "non-dietary," "therapeutics," "pathophysiology," "Endopeptidases," "tight junction modulators," "vaccine," and "Nexvax2". We focused mainly on articles that conducted pathophysiologic and therapeutic research in human trials. Celiac Disease (CeD) is defined as a chronic small intestinal immune-mediated enteropathy that is precipitated by exposure to dietary gluten in genetically predisposed individuals. CeD is one of the most common autoimmune disorders affecting around 1% of the population worldwide. Currently, the only acceptable treatment for CeD is strict, lifelong adherence to a gluten-free diet (GFD) which can often present a challenging task. A GFD alone is not sufficient to control symptoms and prevent mucosal damage that can result from unintentional gluten exposure. Moreover, long-term complications can occur in many patients. Consequently, there is an unmet need for non-dietary therapies for the management of CeD. Such therapies could serve as an adjunct to the GFD but eventually may replace it. This review will focus on and discuss non-dietary therapies currently in clinical development for the management of CeD. We searched clinicaltrials.gov and PubMed to extract articles about celiac disease. We used keywords including, but not limited to, "celiac disease," "non-dietary," "therapeutics," "pathophysiology," "Endopeptidases," "tight junction modulators," "vaccine," and "Nexvax2". We focused mainly on articles that conducted pathophysiologic and therapeutic research in human trials. SummaryThe review discusses the latest non-dietary therapies currently in clinical development for the management of celiac disease. The review discusses the latest non-dietary therapies currently in clinical development for the management of celiac disease. Celiac disease (CeD) is defined as a chronic small intestinal immune-mediated enteropathy that is precipitated by exposure to dietary gluten in genetically predisposed individuals.1Ludvigsson J.F. Leffler D.A. Bai J.C. Biagi F. Fasano A. Green P.H. Hadjivassiliou M. Kaukinen K. Kelly C. Leonard J.N. Lundin K.E. Murray J.A. Sanders D.S. Walker M.M. Zingone F. Ciacci C. The Oslo definitions for coeliac disease and related terms.Gut. 2012; 62: 43-52Crossref PubMed Scopus (1110) Google Scholar CeD is one of the most common autoimmune disorders, affecting around 1% of the population worldwide.2Singh P. Arora A. Strand T.A. Leffler D.A. Catassi C. Green P.H. Kelly C.P. Ahuja V. Makharia G.K. Global prevalence of celiac disease: systematic review and meta-analysis.Clin Gastroenterol Hepatol. 2018; : 823-836Abstract Full Text Full Text PDF PubMed Scopus (610) Google Scholar There has been a notable rise in the prevalence of CeD in the last 50 years and a rise in the rate of diagnosis in the last 10 years.3Rubio-Tapia A. Hill I.D. Kelly C.P. Calderwood A.H. Murray J.A. ACG clinical guidelines: diagnosis and management of celiac disease.Am J Gastroenterol. 2013; 108: 656-676Crossref PubMed Scopus (1143) Google Scholar According to the Corazza-Villanacci classification, histopathology of duodenal biopsy tissue in CeD is divided into nonatrophic lesions (grade A) and atrophic lesions (grade B), grade B lesions are further divided into grade B1, in which the villous to crypt ratio is less than 3:1, with detectable villi, and grade B2, in which the villi are no longer detectable.4Corazza G.R. Villanacci V. Coeliac disease.J Clin Pathol. 2005; 58: 573-574Crossref PubMed Scopus (211) Google Scholar Currently, the only acceptable treatment for CeD is a strict, lifelong adherence to a gluten-free diet (GFD), which often presents a challenging task.3Rubio-Tapia A. Hill I.D. Kelly C.P. Calderwood A.H. Murray J.A. ACG clinical guidelines: diagnosis and management of celiac disease.Am J Gastroenterol. 2013; 108: 656-676Crossref PubMed Scopus (1143) Google Scholar Despite the rigid nature of the GFD, strict adherence is highly encouraged. Untreated and partially treated CeD is associated with an increased risk for poor outcomes such as infertility, osteoporosis, neuropathies, and lymphomas. Adhering to a GFD is associated with a reduction of these outcomes.5Gunn B. Murphy K.E. Greenblatt E.M. Unexplained infertility and undiagnosed celiac disease: study of a multiethnic canadian population.J Obstet Gynaecol Canada. 2018; 40: 293-298Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar However, the GFD alone is frequently not sufficient to control symptoms and prevent mucosal damage that can result from unintentional gluten exposure. Adherence to the diet can pose a challenge and lead to frustration, and many CeD patients are exposed to gluten inadvertently via contamination of food, medications, and supplements.6Sansotta N. Amirikian K. Guandalini S. Jericho H. Celiac disease symptom resolution: Effectiveness of the gluten-free diet.J Pediatr Gastroenterol Nutr. 2018; 66: 48-52Crossref PubMed Scopus (46) Google Scholar Owing to the substantial difficulties associated with adherence to the GFD, most patients with CeD are highly interested in nondietary therapies for the management of their condition, as shown by patient survey data on this topic.7Tennyson C.A. Simpson S. Lebwohl B. Lewis S. Green P.H.R. Interest in medical therapy for celiac disease.Therap Adv Gastroenterol. 2013; 6: 358-364Crossref PubMed Scopus (31) Google Scholar The pathogenesis of CeD is summarized in Figure 1. The pathways that are targeted for nondietary therapies of celiac disease discussed below are summarized with the respective therapy in Figure 2. Other therapies are discussed in this section. The pathogenesis of refractory celiac disease (RCD) is not elaborated here, as it is beyond the scope of this review.Figure 2Novel therapies for celiac disease. (1) Endopeptidases: latiglutenase (formerly ALV003), AN-PEP, and STAN-1 degrade gluten into nonimmunogenic particles, thereby alleviating mucosal injury. (2) Gluten-sequestering polymer: BL-7010 binds to intraluminal gliadin and prevents its release and breakdown into immunogenic peptides. (3) Probiotics: Bifidobacterium infantis protects epithelial cells from damage caused by gliadin by downregulating the proinflammatory immune response. (4) Tight junction modulator: larazotide acetate/AT-1001 works as a tight junction modulator to prevent gliadin-induced epithelial permeability. (5) TG2 inhibitor: blocks the transformation of native gliadin peptides to the far more antigenically potent deamidated gliadin peptides. (6) DQ2/DQ8 blocking peptide analogues prevent presentation of gliadin from activating T cells. (7) Gluten tolerization: Nexvax2 and hookworm (Necator americanus) inoculation aim to downregulate the immune response to gluten. (8) CCR9 antagonist: CCX282B blocks this chemokine receptor to block lymphocyte homing. (9) Anti-IL-15 is a monoclonal antibody that may prevent immune-mediated tissue destruction. (10) Anti IFN-γ may prevent inflammation. (11) Anti-CD3 antibodies suppress gluten activated T cells; anti-CD20 antibodies suppress B cells. Modified with permission from Castillo et al.59Castillo N.E. Theethira T.G. Leffler D.A. The present and the future in the diagnosis and management of celiac disease.Gastroenterol Rep. 2015; 3: 3-11Crossref PubMed Scopus (61) Google Scholar MMP, matrix metalloproteinase.View Large Image Figure ViewerDownload Hi-res image Download (PPT) A critical step in CeD pathogenesis is the ingestion of gluten which encompasses the insoluble prolamin polypeptides found in wheat (gliadins and glutenins), rye (secalin), barley (hordein), and other closely related grains.8Rostom A. Murray J.A. Kagnoff M.F. American Gastroenterological Association (AGA) Institute technical review on the diagnosis and management of celiac disease.Gastroenterology. 2006; 131: 1981-2002Abstract Full Text Full Text PDF PubMed Scopus (604) Google Scholar Gluten is resistant to proteolytic breakdown by gastric, pancreatic, and intestinal digestive proteases due to its high proline content. These nondigested gliadin polypeptides cross into the intestinal submucosa by mechanisms that are not well understood but are considered to involve both paracellular and transcellular passage.9Ménard S. Lebreton C. Schumann M. Matysiak-Budnik T. Dugave C. Bouhnik Y. Malamut G. Cellier C. Allez M. Crenn P. Schulzke J.D. Cerf-Bensussan N. Heyman M. Paracellular versus transcellular intestinal permeability to gliadin peptides in active celiac disease.Am J Pathol. 2012; 180: 608-615Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar The gluten peptides are deamidated in the lamina propria by transglutaminase 2 (TG2) enzyme.10Sollid L.M. Coeliac disease: dissecting a complex inflammatory disorder.Nat Rev Immunol. 2002; 2: 647-655Crossref PubMed Scopus (803) Google Scholar In vitro studies have shown that Th1 and Th2 cytokines such as interferon gamma (IFN-γ), IL-4 and IL-10 are elevated in the serum of untreated celiac subjects. They decrease significantly in treated celiac subjects on a GFD.11Manavalan J.S. Hernandez L. Shah J.G. Konikkara J. Naiyer A.J. Lee A.R. Ciaccio E. Minaya M.T. Green P.H. Bhagat G. Serum cytokine elevations in celiac disease: Association with disease presentation.Hum Immunol. 2010; 71: 50-57Crossref PubMed Scopus (94) Google Scholar Similarly, activated intraepithelial lymphocytes in CeD have been shown to express tumor necrosis factor alpha (TNF-α) in the mucosa.12Di Sabatino A. Ciccocioppo R. Cupelli F. Cinque B. Millimaggi D. Clarkson M.M. Paulli M. Cifone M.G. Corazza G.R. Epithelium derived interleukin 15 regulates intraepithelial lymphocyte Th1 cytokine production, cytotoxicity, and survival in coeliac disease.Gut. 2006; 55: 469-477Crossref PubMed Scopus (219) Google Scholar A study has shown that RNA transcripts of TNF- α were significantly upregulated in patients with RCD when compared with patients with active uncomplicated CeD. Thus, anti-TNF-α agents such as infliximab do not have a therapeutic role in uncomplicated CeD.13Caruso R. Marafini I. Sedda S. Del Vecchio Blanco G. Giuffrida P. MacDonald T.T. Corazza G.R. Pallone F. Di Sabatino A. Monteleone G. Analysis of the cytokine profile in the duodenal mucosa of refractory coeliac disease patients.Clin Sci (Lond). 2014; 458: 451-458Crossref Scopus (26) Google Scholar The interleukin-15 (IL-15) and IL-21 cytokines appear to play an important role in CeD pathogenesis. High numbers of IL-21-producing lamina propria T cells were observed in pediatric CeD lesions including early/mild Marsh 1-2 lesions.14van Leeuwen M.A. Lindenbergh-Kortleve D.J. Raatgeep H.C. de Ruiter L.F. de Krijger R.R. Groeneweg M. Escher J.C. Samsom J.N. Increased production of interleukin-21, but not interleukin-17A, in the small intestine characterizes pediatric celiac disease.Mucosal Immunol. 2013; 6: 1202-1213Crossref PubMed Scopus (36) Google Scholar Furthermore, IL-15 upregulates IL-21 production in CeD.15Sarra M. Cupi M.L. Monteleone I. Franzè E. Ronchetti G. Di Sabatino A. Gentileschi P. Franceschilli L. Sileri P. Sica G. Del Vecchio Blanco G. Cretella M. Paoluzi O.A. Corazza G.R. Pallone F. Monteleone G. IL-15 positively regulates IL-21 production in celiac disease mucosa.Mucosal Immunol. 2013; 6: 244-255Crossref PubMed Scopus (56) Google Scholar Increased expression of IL-15 in enterocytes, lamina propria mononuclear cells, and the mucosa of untreated CeD and RCD results in overexpression of IL-15 receptor α on intraepithelial lymphocytes (IELs) causing increased cell proliferation and production of inflammatory cytokines. Thus, in turn, results in cytotoxicity and decreased apoptosis of IELs.12Di Sabatino A. Ciccocioppo R. Cupelli F. Cinque B. Millimaggi D. Clarkson M.M. Paulli M. Cifone M.G. Corazza G.R. Epithelium derived interleukin 15 regulates intraepithelial lymphocyte Th1 cytokine production, cytotoxicity, and survival in coeliac disease.Gut. 2006; 55: 469-477Crossref PubMed Scopus (219) Google Scholar, 16Mention J.-J. Ben Ahmed M. Bègue B. Barbe U. Verkarre V. Asnafi V. Colombel J.F. Cugnenc P.H. Ruemmele F.M. McIntyre E. Brousse N. Cellier C. Cerf-Bensussan N. Interleukin 15: a key to disrupted intraepithelial lymphocyte homeostasis and lymphomagenesis in celiac disease.Gastroenterology. 2003; 125: 730-745Abstract Full Text Full Text PDF PubMed Scopus (379) Google Scholar Antiapoptotic signals produced by IL-15 have been found to be due to Bcl-2 and/or Bcl-xL, IL-15Rβ, Jak3, and STAT5. Murine models have shown that treatment with this antibody induces IEL apoptosis and abolishes the massive IEL accumulation in mice overexpressing human IL-15 in their gut epithelium.17Malamut G. El Machhour R. Montcuquet N. Martin-Lannerée S. Dusanter-Fourt I. Verkarre V. Mention J.J. Rahmi G. Kiyono H. Butz E.A. Brousse N. Cellier C. Cerf-Bensussan N. Meresse B. IL-15 triggers an antiapoptotic pathway in human intraepithelial lymphocytes that is a potential new target in celiac disease-associated inflammation and lymphomagenesis.J Clin Invest. 2010; 120: 2131-2143Crossref PubMed Scopus (201) Google Scholar During antigenic stimulation of T cells via their T cell receptor, CD28 and CTLA-4 molecules (expressed by T lymphocytes) interact with their respective ligands, B7-1 (CD80) and B7-2 (CD86). As part of this interaction, CD28 provides a costimulatory signal to T cell activation, while CTLA-4 acts as a negative regulator of T cell activation. As such, these molecules may also have a role in the pathogenesis of CeD and, therefore, a potential role in CeD therapeutics.18King A.L. Moodie S.J. Fraser J.S. Curtis D. Reid E. Dearlove A.M. Ellis H.J. Ciclitira P.J. CTLA-4/CD28 gene region is associated with genetic susceptibility to coeliac disease in UK families.J Med Genet. 2002; 39: 51-54Crossref PubMed Google Scholar Latiglutenase (formerly ALV003) is a combination of ALV001, an EP-B2 cysteine endopeptidase that is derived from the endosperm of germinating barley, and ALV002, a Sphingomonas capsulata prolyl endopeptidase (PEP).19Gass J. Bethune M.T. Siegel M. Spencer A. Khosla C. Combination enzyme therapy for gastric digestion of dietary gluten in patients with celiac sprue.Gastroenterology. 2007; 133: 472-480Abstract Full Text Full Text PDF PubMed Scopus (185) Google Scholar ALV001 degrades gluten proteins and reduces the immunogenic potential of gluten.20Bethune M.T. Strop P. Tang Y. Sollid L.M. Khosla C. Heterologous expression, purification, refolding, and structural-functional characterization of EP-B2, a self-activating barley cysteine endoprotease.Chem Biol. 2006; 13: 637-647Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar, 21Siegel M. Bethune M.T. Gass J. Ehren J. Xia J. Johannsen A. Stuge T.B. Gray G.M. Lee P.P. Khosla C. Rational design of combination enzyme therapy for celiac sprue.Chem Biol. 2006; 13: 649-658Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar Similarly, ALV002 catalyzes the postproline hydrolysis of proteins and peptides, similarly reducing the immunogenic potential of gluten.21Siegel M. Bethune M.T. Gass J. Ehren J. Xia J. Johannsen A. Stuge T.B. Gray G.M. Lee P.P. Khosla C. Rational design of combination enzyme therapy for celiac sprue.Chem Biol. 2006; 13: 649-658Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar, 22Marti T. Prolyl endopeptidase-mediated destruction of T cell epitopes in whole gluten: chemical and immunological characterization.J Pharmacol Exp Ther. 2004; 312: 19-26Crossref PubMed Scopus (117) Google Scholar A phase 0 study found that ALV003 pretreatment can abolish peripheral blood T cell IFN-γ ELISpot responses to an immunogenic gliadin-derived 33mer induced by gluten (16 g daily for 3 days) in patients with CeD.23Tye-Din J.A. Anderson R.P. Ffrench R.A. Brown G.J. Hodsman P. Siegel M. Botwick W. Shreeniwas R. The effects of ALV003 pre-digestion of gluten on immune response and symptoms in celiac disease in vivo.Clin Immunol. 2010; 134: 289-295Crossref PubMed Scopus (120) Google Scholar The results of 2 phase I, single, escalating-dose clinical trials showed that ALV003 appears to be stable in the fed stomach and degrades dietary gluten in this compartment.24Siegel M. Garber M.E. Spencer A.G. Botwick W. Kumar P. Williams R.N. Kozuka K. Shreeniwas R. Pratha V. Adelman D.C. Safety, tolerability, and activity of ALV003: results from two phase 1 single, escalating-dose clinical trials.Dig Dis Sci. 2012; 57: 440-450Crossref PubMed Scopus (81) Google Scholar All escalating dose levels of ALV003 (100, 300, 900, and 1800 mg) were well tolerated with no serious adverse events or allergic reactions.24Siegel M. Garber M.E. Spencer A.G. Botwick W. Kumar P. Williams R.N. Kozuka K. Shreeniwas R. Pratha V. Adelman D.C. Safety, tolerability, and activity of ALV003: results from two phase 1 single, escalating-dose clinical trials.Dig Dis Sci. 2012; 57: 440-450Crossref PubMed Scopus (81) Google Scholar In phase II clinical trial, ALV003 was shown to attenuate gluten-induced small intestinal mucosal injury in patients with CeD who underwent a 6-week gluten challenge. Histologic changes in duodenal biopsies in the placebo group showed evidence of mucosal injury after gluten challenge. However, no significant mucosal deterioration was observed in duodenal biopsies in the ALV003 group, which is a promising finding. Interestingly, there were no statistically significant differences in symptoms between CeD patients who received ALV003 and the CeD control group.25Lähdeaho M.-L. Kaukinen K. Laurila K. Vuotikka P. Koivurova O.P. Kärjä-Lahdensuu T. Marcantonio A. Adelman D.C. Mäki M. Glutenase ALV003 attenuates gluten-induced mucosal injury in patients with celiac disease.Gastroenterology. 2014; 146: 1649-1658Abstract Full Text Full Text PDF PubMed Scopus (169) Google Scholar Another phase II clinical trial in CeD patients with persisting symptoms showed no improvement of histologic findings and symptom scores in patients who received latiglutenase when compared with placebo.26Murray J.A. Kelly C.P. Green P.H.R. Marcantonio A. Wu T.T. Mäki M. Adelman D.C. No difference between latiglutenase and placebo in reducing villous atrophy or improving symptoms in patients with symptomatic celiac disease.Gastroenterology. 2017; 152: 787-798.e2Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar In a post hoc subgroup analysis of seropositive CeD patients, those receiving the highest dose of latiglutenase while on a GFD had some improvement in bloating and tiredness. There was no improvement in abdominal pain and constipation, which is a major concern.27Syage J.A. Murray J.A. Green P.H.R. Khosla C. Latiglutenase improves symptoms in seropositive celiac disease patients while on a gluten-free diet.Dig Dis Sci. 2017; 62: 2428-2432Crossref PubMed Scopus (38) Google Scholar While additional studies are required to fully evaluate the therapeutic potential of endopeptidase therapy in celiac patients on a GFD, the previous studies suggest they could represent a viable therapeutic option given improvement in both mucosal inflammation and clinical symptoms, at least as seen in the post hoc subgroup analysis. See Table 1 for a summary of phase II clinical trials.Table 1Summary of Phase II Clinical TrialsTreatment ClassAgentMechanism of ActionClinicalTrials.govSummary of Clinical Trial ResultsEndopeptidasesLatiglutenase (formerly ALV003)Enzymatic degradation of glutenNCT00959114/NCT01255696Attenuated gluten challenge–induced small intestinal mucosal injury and increases in intraepithelial lymphocyte counts.NCT01917630Showed no improvement of histologic findings and symptom scores when compared with placebo. In a post hoc subgroup analysis of seropositive CeD patients, symptomatic improvement was observed in those received the highest dose of latiglutenase while on a GFD.AN-PEPPEP derived from the fungus Aspergillus nigerNCT00810654It was not effective in preventing mucosal damage induced by 7 g of gluten per day for 2 weeksGluten-sequestering polymerBL-7010Sequesters intraluminal gliadin and prevents its breakdown into immunogenic peptidesNCT01990885Not availableProbioticsBifidobacterium infantisProtect epithelial cells from damage caused by gliadinNCT01257620Significantly improved CeD symptoms. Final vs baseline IgA tTG and IgA DGP antibody concentration ratios were lower than the control group. Intestinal permeability, measured by LAMA fractional excretion ratio, was nonsignificant.Tight junction modulatorsLarazotide acetate (AT-1001)Tight junction modulator preventing gliadin-induced permeabilityNCT00362856Limited gluten-challenge induced gastrointestinal symptom severity.NCT00492960Reduced gluten-challenge induced symptoms and serum tTG increase. No significant difference in the designated primary outcome measure of intestinal permeability (LAMA ratios).NCT01396213In patients with NRCD on a GFD a dose of 0.5 mg reduced CeD symptoms better than placebo.TG2 inhibitorsZED 1227Direct and specific inhibitor of TG22017-002241-30 (Clinical Trials Register [European Union])Not availableGluten tolerization and immunomodulationHookworm infection: Necator americanusRegulate the immune system by inhibiting Th1 immune responseNCT01661933Hookworm infection group: experienced less lethargy than control, showed unchanged intraepithelial lymphocyte counts and Marsh scores following gluten challenge. Intestinal T cells expressing IFN-γ were reduced following hookworm infection with an increase in CD4(+) Foxp3(+) regulatory T cells.NCT00671138Hookworm infection imposed no obvious benefit on CeD pathology.Immune cell-targeted therapiesAMG 714Anti-IL-15 monoclonal antibodyNCT02637141/NCT02633020/NCT03439475Not availableCCR9 antagonist (CCX282-B)Block the chemokine receptor CCR9 to prevent intestinal T-cell homingNCT00540657Not availableAN-PEP, Aspergillus niger endopeptidase; CeD, celiac disease; DGP, deamidated gliadin peptide; GFD, gluten-free diet; IFN-γ, interferon gamma; IL, interleukin; LAMA, lactulose-to-mannitol; NRCD, nonresponsive celiac disease; PEP, prolyl endopeptidase; TG2, transglutaminase 2; TNF-α, tumor necrosis factor alpha; tTG, tissue transglutaminase. Open table in a new tab AN-PEP, Aspergillus niger endopeptidase; CeD, celiac disease; DGP, deamidated gliadin peptide; GFD, gluten-free diet; IFN-γ, interferon gamma; IL, interleukin; LAMA, lactulose-to-mannitol; NRCD, nonresponsive celiac disease; PEP, prolyl endopeptidase; TG2, transglutaminase 2; TNF-α, tumor necrosis factor alpha; tTG, tissue transglutaminase. An additional endopeptidase that has been explored is STAN-1, a cocktail of microbial enzymes designed to degrade gluten before absorption in the gastrointestinal tract. It was hypothesized that treatment with STAN-1 would lead to a clinical decrease in tTG-IgA levels in CeD patients. In a randomized, double-blinded, placebo-controlled trial, 35 patients with CeD on a GFD for at least 1 year with persistently elevated tTG-IgA were randomized to STAN-1 or placebo for 12 weeks in conjunction with a daily load of 1 g of gluten. The primary endpoint of the study was the tTG-IgA titer. The authors found no significant difference between the 2 groups, suggesting that a therapeutic role for this agent remains unclear.28Ehren J. Moron B. Martin E. Bethune M.T. Gray G.M. Chaitan A food-grade enzyme preparation with modest gluten detoxification properties.PLoS One. 2009; 4: e0006313Crossref PubMed Scopus (78) Google Scholar Aspergillus niger endopeptidase (AN-PEP) is a second PEP derived from the fungus Aspergillus niger. In a randomized, double-blinded, placebo-controlled study of 16 adult patients with CeD on a GFD, AN-PEP was well tolerated. The CeD quality of subjects consuming gluten with placebo or gluten with AN-PEP did not deteriorate significantly and no difference was observed between the 2 groups. This can be attributed to small sample size and the short duration of the gluten challenge; as no significant deterioration was observed regarding immunohistological and flow cytometric evaluation between the groups. It remains to be seen whether AN-PEP can be effective in preventing mucosal damage induced by gluten. BL-7010 is a synthetic, nonabsorbable copolymer of styrene sulfate with hydroxyethyl methacrylate. This polymer is reported to have high affinity to α-gliadin peptides. Its proposed mechanism of action is to sequester intraluminal gliadin and prevent its breakdown into immunogenic peptides.29Mccarville J.L. Nisemblat Y. Galipeau H.J. Jury J. Tabakman R. Cohen A. Naftali E. Neiman B. Halbfinger E. Murray J.A. Anbazhagan A.N. Dudeja P.K. Varvak A. Leroux J.C. Verdu E.F. BL-7010 demonstrates specific binding to gliadin and reduces gluten-associated pathology in a chronic mouse model of gliadin sensitivity.PLoS One. 2014; 9: 0109972Crossref PubMed Scopus (33) Google Scholar A preclinical study in a NOD-DQ8 mouse model showed that BL-7010 was effective at preventing gluten-induced reduction in villous-to-crypt ratios, intraepithelial lymphocytosis, and alterations in paracellular permeability.29Mccarville J.L. Nisemblat Y. Galipeau H.J. Jury J. Tabakman R. Cohen A. Naftali E. Neiman B. Halbfinger E. Murray J.A. Anbazhagan A.N. Dudeja P.K. Varvak A. Leroux J.C. Verdu E.F. BL-7010 demonstrates specific binding to gliadin and reduces gluten-associated pathology in a chronic mouse model of gliadin sensitivity.PLoS One. 2014; 9: 0109972Crossref PubMed Scopus (33) Google Scholar The study also showed that BL-7010 interacted with high affinity with gliadin and had no interaction with tested vitamins and digestive enzymes.29Mccarville J.L. Nisemblat Y. Galipeau H.J. Jury J. Tabakman R. Cohen A. Naftali E. Neiman B. Halbfinger E. Murray J.A. Anbazhagan A.N. Dudeja P.K. Varvak A. Leroux J.C. Verdu E.F. BL-7010 demonstrates specific binding to gliadin and reduces gluten-associated pathology in a chronic mouse model of gliadin sensitivity.PLoS One. 2014; 9: 0109972Crossref PubMed Scopus (33) Google Scholar A phase I/II, randomized, double-blind, placebo-controlled study was conducted to evaluate the safety and systemic exposure of single escalating administrations and repeated administration of BL-7010 in well-controlled CeD. This clinical trial has been completed, and the results are yet to be published (NCT01990885). While the concept of sequestering gluten before it reaches the small intestine is an attractive one, more data are needed regarding the safety profile of such an agent given the potential that it could bind nonspecifically to other important medications. The intestinal microbiota plays a significant role in maintaining a healthy status. As we learn more about the microbiome and its relationship to health and disease, it appears that imbalance in the microbiome might be implicated in various disease states. In particular, dysbiosis has been associated with chronic inflammatory disorders, including CeD. A condition called small intestinal bacterial overgrowth has been well described in the literature, and associated with diseases such as celiac and irritable bowel syndrome. Probiotics work by downregulating the proinflammatory immune response in CeD patients.30Lindfors K. Blomqvist T. Juuti-Uusitalo K. Stenman S. Venäläinen J. Mäki M. Kaukinen K. Live probiotic Bifidobacterium lactis bacteria inhibit the toxic effects induced by wheat gliadin in epithelial cell culture.Clin Exp Immunol. 2008; 152: 552-558Crossref PubMed Scopus (155) Google Scholar, 31De Palma G. Cinova J. Stepankova R. Tuckova L. Sanz Y. Pivotal Advance: Bifidobacteria and Gram-negative bacteria differentially influence immune responses in the proinflammatory milieu of celiac disease.J Leukoc Biol. 2010; 87: 765-778Crossref PubMed Scopus (73) Google Scholar A recently published study compared fecal bifidobacterial concentrations among celiac patients and healthy individuals before and after the daily intake of 100 g of yogurt containing probiotic for 30 days.32Martinello F. Roman C.F. Souza PA De Effects of probiotic intake on intestinal bifidobacteria of celiac patients.Arg Gastroenterol. 2017; : 85-90Crossref PubMed Google Scholar Fecal bifidobacterial concentration was markedly increased in celiac patients after the probiotic supplementation, but it did not reach the concentration found in healthy individuals prior to probiotic consumption.32Martinello F. Roman C.F. Souza PA De Effects of probiotic intake on intestinal bifidobacteria of celiac patients.Arg Gastroenterol. 2017; : 85-90Crossref PubMed Google Scholar Another recently published study confirmed that probiotic Lactobacillus strains have enzymatic abilities for hydrolyzing gluten peptides.33Francavilla R. De Angelis