Latiglutenase

Latiglutenase (IMGX003) is an orally administered mixture of two gluten-specific recombinant proteases that degrades gluten proteins into small physiologically irrelevant fragments, and is to be administered as an adjunct to a gluten-free diet (GFD). As illustrated in the below figure, one protease (IMGX001) is effective at breaking glutamine-leucine bonds and the other protease (IMGX002) targets most proline bonds.

Schematic diagram illustrating the breaking of glutamine (Q) and proline (P) bond in a prototypical immunogenic gluten fragment.

In Phase 2a and 2b clinical trials Latiglutenase has been shown to mitigate gluten-induced intestinal mucosal injury as well reduce the severity and frequency of symptoms in celiac disease patients. Evidence of symptom relief was particularly pronounced for patients who continue to have positive serology to gluten-induced antibodies (seropositive) despite following a GFD as seen in the results shown below (Syage 2017, 2019). These studies also demonstrated that Latiglutenase is well tolerated by CD patients with no discernable difference in adverse event profile for active vs. placebo treated patients.

ImmunogenX completed the CeliacShieldTM trial (NCT03585478) conducted at Mayo Clinic and has been published in Gastroenterology (Murray 2022). This gluten-challenge trial measured several outcomes including histology, symptoms, serology, and gluten in urine. Histologic protection was assessed by measuring changes in villous height to crypt depth ratio (DVh:Cd) and intraepithelial lymphocytes (DIEL) before and after a 6-week, 2g per day gluten challenge period. The attenuation of DVh:Cd and DIEL for the active (1200-mg latiglutenase) group relative to placebo was 88% and 60% with p-values of 0.0570 and 0.0181 (ANCOVA), respectively. Measurements of gluten immunogenic peptides (GIP) in urine showed reduction of gluten of about 95% for latiglutenase vs. placebo with p < 0.0001. Symptom attenuation was 93% (abdominal pain), 53% (bloating), 99% (tiredness) and 70% (non-stool composite) with a 3 x 2-week trend-line significance of p = 0.0142, 0.0298, 0.0018 and 0.0002, respectively.

Percent reductions in symptom severity relative to placebo for the combined 600 mg and 900 mg treatment groups.

(Left) GIP concentration in urine before (V3), during (6 weekly readings) and after (V4) the GC treatment period with unpaired, 2-tailed, t-test p-value. (Right) Mean change from baseline (% worsening) for Non-stool composite for three 2-week sequential GC treatment periods for IMGX003 vs. placebo. P-values are by unpaired, 2-tailed, t-test.

CypCel

A majority of individuals with CD do not recover well under a GFD. Furthermore, there is still no effective means for monitoring the intestinal health of a recovering celiac other than an invasive biopsy and even that method is prone to interpretive analysis. This problem is particularly acute in the United States where recent studies have shown that more than 50% of adult celiac patients have persistent villous atrophy.

For disease management we are currently in a clinical study for a metabolic marker compound that can measure the state of recovery of a celiac patient undergoing a GFD. This study follows a very successful proof of concept trial. This is a unique capability for which there are no other effective diagnostics.

In this test (referred to as CypCel), a single oral dose of the widely used cholesterol-lowering agent, simvastatin (SV), is administered to a patient. The serum concentration of SV is then measured as an indicator of the health of the intestinal epithelium resulting from adherence to a GFD. CypCel is based on the insight that SV is principally metabolized by cytochrome P450 monooxygenase 3A4 (CYP3A4) in the small intestinal epithelium.

Because intestinal inflammation results in reduced CYP3A4 activity in the epithelium, the serum concentration of SV correlates with the recovery of a CD patient. A preliminary clinical study in CD patients demonstrated the proof of concept that CypCel was markedly more effective at detecting subclinical disease in treated CD patients than other serum markers that have been investigated in recent years, including anti-TG2 IgA, anti-DGP IgA, and intestinal fatty acid binding protein (I-FABP) (Moron 2013). CypCel has potentially huge implications for post-diagnostic management of CD for which methods do not currently exist.

SVeq (SV+SVA) maximum concentration (Cmax) in serum for different subject cohort groups showing reduction in these levels with continued treatment on a gluten-free diet.

Gluten Proteomics

We are pioneering advanced proteomic methods (i.e., the study of the full complement of proteins) to identify new physiologically relevant gluten peptide sequences in wheat, barley, and rye grain to greatly improve on the capability to screen for the full range of gluten proteins in food products.

Our research is identifying new immunogenic epitopes (peptide markers) for the gluten allergen that will permit significantly more accurate screening methods. The discovery and identification of these peptide markers is based on a novel liquid chromatography 2D mass spectrometry (LC/MS/MS). Our work is focused on peptide markers for gluten proteins found in wheat, barley, and rye providing the capability for more effective quantitation of total gluten in affected foods (Sealey-Voyksner 2010).

We have developed proprietary digest methods to isolate toxic epitopes and novel LC/MS/MS methods to sequence and quantify these epitopes in different food groups. A major advance is our newly discovered sequence “QPQQPLPQPQQPF” (named WBR13), as it is present in native and processed products for wheat, barley, rye and can provide an accurate universal screen for all gluten grain types. The currently used screening methods are based on enzyme-linked immunosorbent assay (ELISA) and have limited effectiveness for processed foods and certain food groups. They also rely on a single toxic epitope and therefore do not accurately measure total gluten content.

The end goal is to develop the LC/MS/MS proteomic method as a superior diagnostic technique to ELISA for measuring gluten content in wheat, barley and rye food products.

References

Schuppan D, Junker Y, Barisani D. Celiac disease: from pathogenesis to novel therapies. Gastroenterology 2009;137:1912–33.

Rubio-Tapia A, Murray JA. Celiac disease. Curr Opin Gastroenterol 2010;26:116–22.

Kelly CP, Bai, JC, Liu E, Leffler DA. Celiac disease: clinical spectrum and management. Gastroenterol 2015;148:1175-1186.

Green PHR, Lebwohl B, Greywoode R. Celiac disease. J Allergy Clin Immunol 2015;135:1099-1106.

Syage JA, et al. Determination of gluten consumption in celiac disease patients on a gluten-free diet. Am J Clin Nutr 2018;107:201-207.

Leffler D, Kupfer SS, Lebwohl B, Bugin K, Griebel D, et al., Development of Celiac Disease Therapeutics: Report of the Third Gastroenterology Regulatory Endpoints and Advancement of Therapeutics Workshop. Gastroenterology 2016;151:407 – 411.

Syage JA, Murray JA, Green PHR, Khosla, C. Latiglutenase Improves Symptoms in Seropositive Celiac Disease Patients While on a Gluten-Free Diet. Dig Dis & Sci 2017;62:2428-2432.

Syage JA et al., Latiglutenase Treatment for Celiac Disease: Symptom and Quality of Life Improvement for Seropositive Patients on a Gluten-Free Diet. GastroHep 2019;1:293-301.

Moron B, Verma AK, … Khosla C et al. CYP3A4-catalyzed simvastatin metabolism as a non-invasive marker of small intestinal health in celiac disease. Am J Gastroenterol 2013; 108: 1-8.

Sealey-Voyksner JA, Khosla C, Voyksner RD, Jorgenson JW. Novel aspects of quantitation of immunogenic wheat gluten peptides by liquid chromatography-mass spectrometry/mass spectrometry. J. Chromatogr A 2010;1217:4167–83.

Murray JA, Syage, JA, Wu T-T, Dickason MA, et al. Latiglutenase Protects the Mucosa and Attenuates Symptom Severity in Patients with Celiac Disease Exposed to a Gluten Challenge, Gastroenterology, in press 2022. doi.org/10.1053/j.gastro.2022.07.071