Semaglutide-Induced Symptomatic Remission in Ulcerative Colitis

Abstract

Ulcerative colitis (UC) often requires immunosuppressive therapy for remission. Glucagon-like peptide-1 receptor agonists are used for diabetes and obesity, although their role in UC is unclear. We report a 42-year-old woman with left-sided UC and poorly controlled diabetes who achieved remission after initiating semaglutide. Despite persistent symptoms on maximal mesalamine, she declined immunosuppression. After semaglutide initiation, she achieved clinical remission by 8 weeks, with improved fecal calprotectin, metabolic parameters, and mucosal healing on follow-up colonoscopy. This case suggests a potential adjunctive role for glucagon-like peptide-1 receptor agonists in UC.

INTRODUCTION

Ulcerative colitis (UC) is characterized by relapsing inflammation of the colonic mucosa and typically requires aminosalicylates, corticosteroids, or advanced immunosuppressive therapy to achieve remission.¹ Meanwhile, obesity and metabolic comorbidities are increasingly prevalent in the inflammatory bowel disease (IBD) population, contributing to disease burden and complicating management.¹ Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are a class of medications used to treat type 2 diabetes mellitus (T2DM) and obesity by enhancing insulin secretion and promoting weight loss.² Beyond their metabolic effects, GLP-1 RAs have demonstrated anti-inflammatory and immunomodulatory properties in preclinical studies and other disease contexts.² However, their role in IBD is not well established.²

To date, reports of GLP-1 RAs influencing IBD activity are scarce. Notably, 1 prior case described a patient with UC and comorbid ankylosing spondylitis who experienced symptomatic improvement on liraglutide therapy for obesity.³ Recent observational studies have reported associations between GLP-1 RA use and improved IBD-related outcomes, including reduced hospitalization and corticosteroid use.^4–6 However, most available data are retrospective and rely on administrative end points rather than detailed documentation of symptom remission, endoscopic healing, or histologic outcomes.^4–6

We present a case of moderate, endoscopically confirmed UC achieving clinical, biochemical, endoscopic, and histologic remission after initiation of semaglutide for poorly controlled T2DM, without escalation of UC-directed therapy. Notably, this case uniquely highlights early symptomatic remission preceding substantial weight loss and provides objective multidomain evidence of mucosal healing.

CASE REPORT

A 42-year-old woman with a 6-year history of left-sided UC presented with 3–5 loose stool per day, rectal bleeding, and abdominal discomfort while on maximal oral mesalamine therapy (4.8 g/d). She had remained on stable dose mesalamine for several years without achieving sustained remission. She had declined escalation to corticosteroids, immunomodulators, or biologic therapy despite ongoing symptoms.

Her medical history was notable for poorly controlled T2DM (HbA1c 8.6%) and overweight status (body mass index 29 kg/m²). She had no prior exposure to biologic or immunosuppressive therapy.

On presentation, her UC disease activity was moderate. Laboratory evaluation demonstrated mild anemia (hemoglobin 11.2 g/dL), elevated C-reactive protein (CRP) (12 mg/L), and markedly elevated fecal calprotectin (420 µg/g). Colonoscopy revealed moderately active left-sided colitis with edematous, friable mucosa and contact bleeding extending from the rectum to the distal colon, corresponding to a Mayo endoscopic subscore of 2. Baseline colonic biopsies demonstrated moderately active UC with crypt distortion and active inflammation. Stool studies were negative for infectious etiologies, and random biopsies showed no evidence of dysplasia.

Importantly, no additional UC-directed therapy was initiated at this time. Mesalamine therapy remained unchanged, and the patient again declined corticosteroids or biologic therapy.

Given her poorly controlled diabetes and obesity, semaglutide was initiated for glycemic control and weight management, with close monitoring of UC disease activity. Semaglutide was started at 0.25 mg subcutaneously once weekly as a loading dose and subsequently increased to the standard maintenance dose of 0.5 mg weekly. No further dose escalation beyond 0.5 mg was required. The patient tolerated therapy well, reporting only mild transient nausea early in treatment.

Symptomatic improvement began as early as 4 weeks after semaglutide initiation. At that time, body weight decreased by less than 2% from baseline, yet stool frequency had already declined (1–2 bowel movements per day) and rectal bleeding substantially improved. By 8 weeks, she reported near-complete resolution of symptoms. At 2 months, she described 1–2 formed bowel movements daily without blood, urgency, or abdominal pain, consistent with clinical remission.

Serial laboratory monitoring demonstrated parallel improvement in inflammatory markers. At 4 months, HbA1c improved to 6.9%, accompanied by an 8% reduction in body weight (82–75 kg). CRP declined from 12 to 3 mg/L, and fecal calprotectin decreased from 420 to 115 µg/g. Mesalamine dosing remained unchanged throughout this period, and no corticosteroids or additional UC-directed therapy were administered. Longitudinal laboratory data before and after semaglutide initiation can be found in Table 1.

Table 1.

Longitudinal laboratory data before and after semaglutide initiation

Parameter	Baseline (presemaglutide)	4 wk	8 wk	4 months	Reference range
Hemoglobin (g/dL)	11.2	11.4	11.8	12.3	12.0–16.0
White blood cell count (×103/µL)	9.5	8.8	8.2	7.9	4.0–11.0
Platelets (×103/µL)	410	395	380	360	150–400
C-reactive protein (mg/L)	12	8	4	3	<5
Erythrocyte sedimentation rate (mm/hr)	28	24	18	15	<20
Fecal calprotectin (µg/g)	420	210	140	115	<50
Albumin (g/dL)	3.6	3.8	4.0	4.2	3.5–5.0
Hemoglobin A1c (%)	8.6	7.9	7.2	6.9	<5.7
Body weight (kg)	82	80	78	75	—
Body mass index (kg/m2)	29	28.3	27.6	26.5	18.5–24.9

After 6 months of continuous weekly semaglutide therapy, a follow-up colonoscopy was performed to assess mucosal healing. This demonstrated normal to near-normal colonic mucosa in previously inflamed segments, with only minimal residual erythema in the rectosigmoid region and no ulceration or friability, corresponding to a Mayo endoscopic subscore of 0–1. Histologic examination showed quiescent chronic colitis without active cryptitis. The patient thus achieved endoscopic and histologic remission. She continues treatment with semaglutide and mesalamine and remains symptom-free at 9 months of follow-up.

DISCUSSION

This case demonstrates the induction of UC remission in a patient treated with a GLP-1 receptor agonist, suggesting a possible therapeutic benefit of GLP-1 RA therapy in IBD. Importantly, the improvement in our patient was documented across multiple objective measures including symptoms, biomarkers, and endoscopic findings, strengthening the case that disease activity truly diminished in parallel with semaglutide initiation. Although anecdotal, this finding aligns with emerging evidence that metabolic modulation can influence intestinal inflammation.

Mechanistic plausibility

GLP-1 is an incretin hormone with pleiotropic effects beyond glucose homeostasis, and accumulating evidence suggests that GLP-1RAs possess anti-inflammatory and immunomodulatory properties.² GLP-1 receptors are expressed on multiple immune and inflammatory cell populations, including lymphocytes and innate immune cells, indicating that GLP-1 signaling may directly interact with immune pathways relevant to intestinal inflammation.^2,7 Inflammatory states may also stimulate endogenous GLP-1 activity; experimental studies have demonstrated that inflammatory cytokines such as interleukin-6 can enhance GLP-1 secretion from enteroendocrine L cells, suggesting bidirectional crosstalk between immune activation and GLP-1 signaling.⁸ Preclinical studies provide direct support for an anti-inflammatory role of GLP-1 signaling in colitis.⁹ In murine models of dextran sulfate sodium–induced colitis, administration of GLP-1 or GLP-1 analogs significantly reduced colonic inflammation, lowered proinflammatory cytokine expression (including IL-1β, IL-6, and tumor necrosis factor-α), and improved histologic markers of mucosal injury.⁹ These protective effects were mechanistically linked to inhibition of key inflammatory signaling pathways, including protein kinase B/nuclear factor-kappaB and mitogen-activated protein kinase activation within colonic tissue.⁹ More broadly, GLP-1RA treatment has been shown to attenuate systemic inflammatory responses in experimental models through suppression of NF-κB–dependent cytokine production.² GLP-1 signaling has also been implicated in preservation of intestinal barrier function and modulation of host-microbiome interactions, with experimental data suggesting mitigation of colitis-associated dysbiosis in GLP-1–treated models.^9,10 In addition to direct intestinal effects, GLP-1RAs induce weight loss and improve insulin resistance, which may indirectly reduce adipose tissue–derived inflammatory mediators and systemic inflammatory burden.² Notably, semaglutide has demonstrated greater average weight loss compared with earlier GLP-1 receptor agonists in randomized obesity trials, a factor that may further enhance downstream immunometabolic effects in susceptible patients.¹¹ These mechanistic insights provide a biologic rationale for the observed improvement in our patient's UC.

Clinical evidence

Our observation is supported by a growing body of clinical data suggesting GLP-1 RAs may confer benefit in IBD management. A prior case report in 2019 described a patient with refractory UC (and coexistent ankylosing spondylitis) who experienced symptomatic UC remission after starting liraglutide for obesity.¹ Since then, several larger observational studies have evaluated IBD outcomes in patients receiving GLP-1RAs.⁴ In a retrospective cohort study including more than 1,000 patients with IBD and T2DM, treatment with GLP-1RAs was associated with significantly lower risks of adverse IBD-related outcomes, including a reduced risk of colectomy, compared with other glucose-lowering therapies.⁴ Similarly, a Danish nationwide cohort study demonstrated that patients with IBD treated with GLP-1–based therapies had a lower likelihood of requiring systemic corticosteroids or hospitalization for IBD flares compared with those receiving alternative antidiabetic medications.⁵ In addition, a cohort analysis from the epi-International IBD Research Network registry reported that GLP-1 analog use was associated with an improved IBD disease course, with the most pronounced benefit observed among patients with obesity.⁶ Collectively, these real-world data suggest that GLP-1RAs may favorably influence IBD disease trajectory in select patient populations, potentially through combined metabolic and anti-inflammatory mechanisms.^4–6 These real-world observations suggest that GLP-1 RAs may positively modify the disease trajectory in subsets of patients with IBD, possibly via the weight loss and anti-inflammatory mechanisms discussed above.

Emerging data suggest that GLP-1RAs can be used safely in patients with IBD without precipitating disease flares.¹² In a multicenter cohort study, GLP-1RA therapy in patients with IBD was not associated with an increased risk of disease exacerbation or need for escalation of IBD-directed therapy over 1 year when compared with matched controls, while modest improvements in inflammatory markers were observed.¹² Additional studies have reported improvements in systemic inflammatory markers among GLP-1RA treated patients with IBD; specifically, GLP-1RA use has been associated with significant reductions in CRP levels, particularly in obese patients.¹³ In the present case, semaglutide therapy was well tolerated and coincided with marked reductions in both fecal calprotectin and CRP, objective markers of intestinal and systemic inflammation, respectively.

Implications

This case adds to the growing evidence intersecting metabolic disease management and IBD outcomes. It highlights the need for prospective studies to formally evaluate GLP-1 RAs as therapy for IBD. Two clinical trials are currently ongoing to explore this paradigm—one assessing the safety and efficacy of GLP-1 RAs in overweight patients with IBD with T2DM, and another evaluating a GLP-1 RA in Crohn's disease. Future research should clarify the mechanisms by which GLP-1 signaling influences intestinal inflammation, identify which patient populations may benefit most (eg, obese patients with IBD or those with concomitant metabolic syndrome), and determine the long-term impact on disease course. If efficacy and safety are confirmed, GLP-1 RAs could represent a novel adjunctive treatment approach in IBD, offering combined metabolic and anti-inflammatory benefits.

Clinical context and uniqueness

Emerging observational studies suggest that GLP-1 RA use in IBD is associated with reduced hospitalization and corticosteroid exposure.^4–6 However, most studies rely on administrative end points. Detailed evaluation of symptomatic remission, endoscopic healing, and histologic response is rarely reported.

Our manuscript is unique in that it specifically documents early symptomatic remission followed by objective biochemical, endoscopic, and histologic healing without escalation of UC therapy. The early improvement preceding significant weight loss strengthens the hypothesis of a direct immunomodulatory component rather than a purely weight-mediated effect.

Limitations

Obesity and diabetes independently worsen IBD outcomes, and metabolic improvement may reduce systemic inflammatory burden.^1,2 However, symptomatic improvement in this patient occurred within 4 weeks of semaglutide initiation, when body weight had decreased by less than 2%. More substantial weight loss (8%) occurred later at 4 months. This temporal separation suggests that early symptom remission may not have been solely attributable to weight reduction. Direct immunomodulatory effects of GLP-1 receptor signaling may, therefore, have contributed to disease improvement.

As a single case report, causality cannot be established, and spontaneous remission or the ongoing effect of stable mesalamine therapy cannot be excluded. However, the temporal association between semaglutide initiation and multidomain disease improvement, coupled with the patient's prior failure to achieve remission on unchanged therapy, supports a potential contributory role for GLP-1RA treatment. It is also possible that improved glycemic control independently reduced inflammatory burden; however, this effect was achieved through semaglutide itself and, therefore, remains mechanistically linked to GLP-1 signaling. Importantly, not all observational studies have demonstrated consistent improvement in IBD disease activity with GLP-1RA use. In 1 analysis of 224 patients with IBD treated with GLP-1RAs, no significant difference was observed in 1-year flare rates or corticosteroid-free remission compared with nonusers, although reductions in CRP were noted.¹⁴ Variability in study design, patient populations, follow-up duration, and treatment indications (obesity vs diabetes) likely contributes to these heterogeneous findings and underscores the need for prospective, controlled studies.

We describe a case of moderate UC achieving symptomatic, biochemical, endoscopic, and histologic remission after initiation of semaglutide for T2DM, without escalation of UC-directed therapy. Early symptom remission preceded meaningful weight loss, suggesting mechanisms beyond weight reduction alone. Although causality cannot be established, this case supports further investigation into GLP-1 receptor agonism as a potential adjunctive strategy in UC, particularly in patients with metabolic risk factors. Rigorous clinical trials are needed to determine the efficacy, safety, and appropriate context for using GLP-1–based therapy in IBD.

DISCLOSURES

Author contributions: B. Alqinai: writing the introduction, case report, and discussion sections. O. Adeniran, A. Adekolu, and S. Gayam: revision of the manuscript. B. Alqinai is the article guarantor.

Financial disclosure: None to report.

Informed consent was obtained for this case report.

ABBREVIATIONS:

CRP

C-reactive protein

GLP-1 RA

Glucagon-like peptide-1 receptor agonist

HbA1c

Hemoglobin A1c

IBD

Inflammatory Bowel Disease

IL

Interleukin

T2DM

Type 2 Diabetes Mellitus

UC

Ulcerative Colitis