Introduction

Micronutrient deficiency of amino acids display a hitherto underappreciated role in the pathophysiology of IBD. Serine is a nonessential amino acid and directly involved in the cellular redox balance. In the absence of sufficient external supply, serine can be synthesized via glycolysis through the rate-limiting enzyme phosphoglycerate dehydrogenase (PHGDH). Serine metabolism is upregulated in cancer and immune cells, maintaining survival and growth. However, its role in coordinating cellular function in the context of IBD is not known.

Aims & Methods

We hypothesized that serine metabolism provides a novel and underappreciated metabolic switch to maintain immunological homeostasis in the intestinal epithelium of IBD patients.We assessed the gene expression of the rate-limiting enzymes of de novo serine synthesis PHGDH in two cross-sectional IBD cohorts (1. N=67, 2. N=212 patients) and linked PHGDH expression with endoscopic or clinical disease activity. We used murine small intestinal epithelial cells (Mode-K cells) and murine small intestinal and colon organoids to understand the molecular regulator of de novo serine synthesis via PHGDH. To assess the potential role of PHGDH in coordinating innate immune response, Mode-K cells were treated with LPS or tunicamycin in the presence or absence of the Phgdh inhibitor BI-4916. The impact of proinflammatory cytokines Cxcl1 and Il6 was assessed through qPCR and ELISA. Upstream activation of the NFκB signaling pathway was assessed by WB. Seahorse assay was conducted to evaluate the impact of Phgdh on mitochondrial function.

Results

Compared with healthy control, serine metabolic enzyme PHGDH was significantly increased in both UC and CD patients. PHGDH expression correlated with the degree of inflammation in tissue biopsies of IBD patients correlated with ER stress marker (HSP90B1). Chemical induction of ER stress strongly increased the expression of Phgdh, Psat1, and Psph in Mode-K cells and intestinal organoids. To assess the regulatory role of serine metabolism on innate immune function, Mode-K cells were treated in serine/glycine-deprived medium. PHGDH function was inhibited using the specific inhibitor BI-4916. Treatment with tunicamycin or LPS resulted in strong induction of the proinflammatory cytokines Cxcl1 and Il6. Parallel Seahorse assay displayed significantly disrupted mitochondrial function (basal-, ATP linked- and maximum respiration). As serine feeds into the 1C-metabolism to provide mitochondrial-derived formate, we co-treated cells with glycine and formate to overcome the functional consequences of deprived de novo serine synthesis. We show that co-treatment of glycine and formate rescued mitochondrial dysfunction and inhibited Cxcl1 overactivation in intestinal epithelial cells.

Conclusion

Our data provide a novel link on how disrupted serine metabolism directly fuels epithelial-derived proinflammatory mechanisms via disruption of mitochondrial function. Our data suggest a so far underappreciated role of cellular serine metabolism on IBD pathophysiology.

Introduction

Long-term data on bowel urgency (BU) in Crohn’s disease (CD) are limited, and the associations with other efficacy outcomes are not well studied.

Aims & Methods

Our aims were to examine the long-term efficacy of mirikizumab (MIRI) on BU remission and the associations between BU remission and clinical remission, endoscopic remission, and patient-reported outcomes (PRO) improvement at week (W) 104 in patients with moderately to severely active CD who were randomized to MIRI in the Phase 3 study VIVID-1 and continued into the long-term extension study VIVID-2. In VIVID-1, the MIRI group received induction with 900 mg intravenously (IV) at W0, W4, and W8, then 300 mg subcutaneously (SC) every 4W. W52 endoscopic responders (≥50% reduction from baseline in Simple Endoscopic Score for CD [SES-CD]) continued MIRI SC dosing in VIVID-2. Endoscopic non-responders received reinduction with MIRI IV (3x Q4W) at the start of VIVID-2 followed by SC dosing (IV-SC) as described. Patients that had an Urgency Numeric Rating Scale (UNRS) ≥3 (least to worst range 0-10) at baseline were included in these analyses. BU remission was defined as an UNRS score of ≤2. Associations between BU remission with clinical remission by Crohn’s Disease Activity Index (CDAI), endoscopic remission, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue (range 0-52, higher is better), and Inflammatory Bowel Disease Questionnaire (IBDQ) remission, were assessed at W104, within the VIVID-1 W52 endoscopic response subgroups as well as the MIRI total group. Discontinuations or missing data were handled using modified non-responder imputation (mNRI) for categorical data. Missing values were imputed by multiple imputation and modified baseline observation carried forward for FACIT-Fatigue change from baseline.

Results

Over 50% of the MIRI total group, 56% of MIRI W52 endoscopic responders, and 43% of the MIRI W52 endoscopic non-responders achieved BU remission at W104. In the MIRI total group, a significantly higher percentage of patients achieved clinical remission, endoscopic remission and IBDQ remission at W104 in the BU remission group compared to those without BU remission. The improvement in fatigue by FACIT-Fatigue score was significantly more in the group with BU remission versus those without BU remission (p<0.0001). In both MIRI W52 endoscopic responders and non-responders, patients who achieved BU remission at W104, compared to those who did not, achieved significantly higher rates of clinical remission, greater improvements in FACIT-Fatigue, and higher rates of quality of life improvement measured by IBDQ remission (Table 1).

Table 1

Conclusion

Over 50% of patients with CD achieved BU remission at 2 years of treatment with MIRI. These results highlight that the achievement of BU remission corresponded with improvements to outcomes important to patients with CD, underscoring the importance of long-term management of BU in improving overall patient outcomes.

Disclosure

SRV: has received consulting fees, speaker’s honoraria and unrestricted research grants from Abbott, Alfasigma, Amgen, Arenapharm, BMS, Falk Pharma GmbH, Ferring Pharmaceuticals, Gilead, iQuone, Janssen, MSD, Permamed, Pfizer, Sanofi-Aventis, Schwabe Pharma, Takeda, Tillotts, UCB and Vifor
DTR: receives grants or contracts from Takeda, and discloses consultancy fees with AbbVie, Altrubio, Apex, Avalo Therapeutics, Bristol Myers Squibb, Buhlmann Diagnostics Corp, Celgene, Connect BioPharma, Intouch Group, Iterative Health, Janssen Pharmaceuticals, Lilly, Pfizer, Samsung Neurologica, and Takeda. He serves on the Board of Directors for Cornerstones Health.
JW, GY, AV, REM, and RRH: Employees and stockholders of Eli Lilly.
GD-H: Has received research grants from: Alimentiv BV, Bristol Myers Squibb, Eli Lilly and Company, Pfizer, and Takeda; and consulting fees from: AbbVie, Alimentiv, AstraZeneca, Bristol Myers Squibb, Celltrion, Eli Lilly and Company, GSK, Merck Sharp & Dohme, Pfizer, Sorriso Pharmaceuticals, Takeda, Tillotts Pharma AG, and Ventyx Biosciences
ST: has received grants from: AbbVie, BUHLMANN Diagnostics, ECCO, Eli Lilly and Company, Ferring Pharmaceuticals, International Organization for the Study of Inflammatory Bowel Disease, Janssen, Merck Sharp & Dohme, Norman Collison Foundation, Pfizer, Procter & Gamble, Schering-Plough, Takeda, UCB Pharma, Vifor Pharma, and Warner Chilcott; and reports other disclosures from: Abacus Pharma, AbbVie, Actial Farmaceutica, ai4gi, Alcimed, Allergan, Amgen, Aptel, Arena Pharmaceuticals, Asahi Kasei Pharma, Aspen Pharmacare, Astellas, AstraZeneca, Atlantic Pharmaceuticals, Barco, Biocare Medical, Biogen, BL Pharma, Boehringer Ingelheim, Bristol Myers Squibb, BUHLMANN Diagnostics, Calcico Therapeutics, Celgene, Cellerix, Cerimon Pharmaceuticals, ChemoCentryx, Chiesi, Cisbio, Comcast, Coronado Biosciences, Cosmo Pharmaceuticals, Dr. Falk Pharma, Ducentis BioTherapeutics, Dynavax Technologies, Elan Pharma, Eli Lilly and Company, Enterome, Equillium, Ferring Pharmaceuticals, Galapagos NV, Genentech/Roche, Genzyme, Gilead Sciences, GlaxoSmithKline, Glenmark Pharmaceuticals, Grünenthal, GW Pharmaceuticals, Immunocore, Indigo Biosciences, Janssen, Lexicon Pharmaceuticals, Medarex, MedTrix, Merck, Merrimack Pharmaceuticals, Mestag Therapeutics, Millennium Pharmaceuticals, Neovacs, Novartis, Novo Nordisk, NPS Pharmaceuticals/Nycomed, Ocera Therapeutics, OPTIMA Pharma, Origin Pharma, Otsuka, Palau Pharma, Pentax Medical, Pfizer, PharmaVentures, Phesi, Phillips Pharma Group, Procter & Gamble, Pronota, Proximagen, Resolute Pharma, Robarts Clinical Trials, Sandoz, Santarus, Satisfai Health, Sensyne Health, Shire, Sigmoid Pharma, Sorriso Pharmaceuticals, Souffinez, SynDermix, Synthon, Takeda, Theravance Biopharma, TiGenix, Tillotts Pharma AG, Topivert, Trino Therapeutics with Wellcome Trust, TxCell SA, UCB Pharma, Vertex Pharma, VHsquared, Vifor Pharma, Warner Chilcott, and Zeria Pharmaceutical
AW: reports consulting and/or speaking fees from Abbvie, Bristol-Myers Squibb, Ferring, Galapagos, Janssen, Pfizer, and Takeda.

Introduction

Mirikizumab, a p19-directed interleukin-23 monoclonal antibody, is efficacious in inducing clinical response at Week(W) 12 and maintaining clinical remission through W52 in patients with moderately-to-severely active Crohn’s disease (CD) as shown in the phase 3 treat-through trial VIVID-1 (NCT03926130).¹ Here, we present analysis of maintenance outcomes through W52 for Patient-Reported Outcome (PRO) clinical responders and nonresponders at W12.

Aims & Methods

The analysis set includes patients randomized to mirikizumab at baseline, who did or did not achieve PRO clinical response at W12 after intravenous (IV) induction treatment (900 mg mirikizumab IV every 4 weeks [Q4W]) before entering subcutaneous (SC) maintenance treatment (300 mg mirikizumab SC Q4W). Descriptive statistics are used to summarize the data, applying nonresponder imputation for missing binary endpoints. As a treat-through study, no rerandomization was applied.

Results

From a total of 551 patients who entered SC maintenance treatment, baseline characteristics of age, duration of CD, and baseline Crohn’s Disease Activity Index (CDAI) were similar between W12 PRO responders (n=402, 73.0%) and W12 PRO nonresponders (n=149, 27.0%). PRO responders at W12 had a higher objective inflammatory burden at baseline (faecal calprotectin, c-reactive protein, and Simple Endoscopic Score-CD), whereas concomitant or prior medication usage was similar between the groups. For W12 PRO responders, SC mirikizumab treatment from W12 to W52 resulted in an increase in CDAI clinical remission from 52.2% to 65.4%, PRO clinical remission from 53.2% to 65.4%, and endoscopic response from 35.1% to 54.7%, respectively (Table 1). Among W12 PRO nonresponders, PRO response was achieved by 39.6% at W16, 45.6% at W20, 44.3% at W24, and 56.4% at W52 with continued mirikizumab SC treatment, while CDAI clinical remission and PRO clinical remission were achieved by 33.6% and 31.5% at W52, respectively. Endoscopic response increased from 30.2% at W12 to 40.3% at W52 among W12 PRO nonresponders (Table 1).

Conclusion

Subcutaneous mirikizumab maintenance treatment over 40 weeks leads to incremental and sustained improvements in rates of clinical and endoscopic response regardless of PRO clinical response status after induction. A substantial proportion of clinical nonresponders at W12 improved early during maintenance treatment suggesting continued treatment with mirikizumab can be beneficial and lead to long-term response.

References

1. Ferrante, Marc et al. Efficacy and safety of mirikizumab in patients with moderately-to-severely active Crohn's disease: a phase 3, multicentre, randomised, double-blind, placebo-controlled and active-controlled, treat-through study. Lancet. 2024;404(10470):2423-2436. doi:10.1016/S0140-6736(24)01762-8