FDA Approves Higher Dosage of Linaclotide for IBS-C and ByHeart Formula Recall Due to Botulinism

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A Brooks. HCPLive 11/5/25: FDA Approves Linaclotide (Linzess) Capsules for Pediatric IBS-C

An excerpt:

The US Food and Drug Administration (FDA)  has approved Ironwood Pharmaceuticals’ linaclotide (Linzess) capsules for pediatric patients ≥ 7 years of age with irritable bowel syndrome with constipation (IBS-C), making it the first treatment approved for IBS-C in this patient population.1…

The approval for pediatric IBS-C was supported by extrapolation of efficacy from adequate and well-controlled studies in adults and a 12-week double-blind, randomized, parallel-group trial in pediatric patients 7-17 years of age who met modified Rome III criteria for child/adolescent IBS-C. The recommended dosage for this indication is 145 mcg orally once daily.1…

In 2023, the FDA approved linaclotide for the treatment of pediatric patients aged 6-17 years with functional constipation at a recommended dosage of 72 mcg orally once daily. 

Reference: US Food and Drug Administration. FDA approves 1st drug for children 7 years and older with irritable bowel syndrome with constipation. November 5, 2025. Accessed November 5, 2025. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-1st-drug-children-7-years-and-older-irritable-bowel-syndrome-constipation

Also, NBC news (11/08/25): ByHeart baby formula recalled amid 10-state outbreak of infant botulism The U.S. Food and Drug Administration said the outbreak includes 13 hospitalizations since August of children who consumed ByHeart Whole Nutrition Infant Formula. No deaths have been reported.

The recall includes two lots of the powdered formula with Dec. 1 “use by” dates, the FDA said in a statement Saturday. The lot numbers are 206VABP/251261P2 and 206VABP/251131P2…The FDA says ByHeart makes up less than 1% of the baby formula sold in the U.S.

Chicago Botanic Garden

Proximal Ileal Crohn’s Disease is Harder to Treat

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K Takenaka et al. Clin Gastroenterol Hepatol 2025; 23: 1991-2000. Open Access! Inadequate Efficacy of Biologics for Treating Proximal Ileal Lesions in Crohn’s Disease: A Prospective Multicenter Study

This multicenter prospective study (n=253) examined efficacy of treatment in patients with proximal ileal disease using balloon-assisted enteroscopy (BAE). The recruited patients had a mean disease duration of 4 years. 52% were naive to biologic treatment at baseline.

Key findings:

  • At baseline, 74 patients (29.2%) had proximal ileal ulcerations without terminal ileal ulcerations
  • At week 26, after treatment with anti-TNF therapy (n=103), ustekinumab (n=99) or vedolizumab (n=51), endoscopic remission was achieved in 91 patients (36.0%). Of the patients with complete ulcer healing of the terminal ileum, 28.6% (22/77) had residual ulcers in the proximal ileum
  • The rate of endoscopic remission in the proximal ileum (50.9%) was relatively lower compared with the colon (63.4%) and terminal ileum (56.7%)
  • After a median follow-up of 134 weeks, residual ulcerations in the proximal ileum were associated with a poorer prognosis (P = .0126 for hospitalization and P = .0014 for surgery). In contrast, there was no significant differences in hospitalization and surgery associated with endoscopic activity vs remission in the colon or terminal ileum.

Discussion: Residual “proximal ileal ulcerations … are associated with a poorer prognosis…Additionally, we confirmed that proximal ileal inflammation is less responsive to biologic therapies compared with colonic inflammation. Although the reasons for this disparity remain unclear”

My take: Balloon-assisted enteroscopy is not frequently used in the setting of inflammatory bowel disease, particularly in pediatrics. MRE is typically used to follow proximal small bowel disease, though it has less sensitivity for luminal mucosal disease.

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Hypercoagulation with Acute Severe Ulcerative Colitis (ASUC) Persists for Months

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BJ Griffiths et al. Clin Gastroenterol Hepatol 2025; 23: 1798-1807. Open Access (PDF)! Hypercoagulation After Hospital Discharge in Acute Severe Ulcerative Colitis: A Prospective Study

Methods: In this prospective study, twenty-seven adult patients with ASUC and 25 control patients with quiescent ulcerative colitis were recruited. Thrombin generation (endogenous thrombin potential), rotational thromboelastometry (EXTEM and FIBTEM maximum clot firmness), procoagulant factors, anticoagulant factors, and fibrinolytic markers were assessed for those with ASUC on admission (Day 1), Day 5, 4 weeks, and at 8–12 weeks. These assessments were performed on a single occasion for control patients.

Key findings:

Discussion:

  • “Patients with ASUC had a hypercoagulable profile on initial presentation to the hospital, before receipt of LMWH, which was consistently demonstrated by individual and global assays of coagulation. The most marked elevations of individual factors at presentation were seen in the levels of Clauss fibrinogen, platelets, VWF, and FVIII, alongside heightened
    levels of the inhibitors of fibrinolysis PAI-1 and TAFIa.”
  • “This hypercoagulable state persisted for many weeks after hospital discharge, with levels of FVIII, fibrinogen, VWF, and inhibitors of fibrinolysis (TAFIa) remained significantly elevated at all timepoints up to 12 weeks, compared with the control population. This is despite
    intensive treatment for ASUC in all patients.”
  • “VTE and pulmonary embolism are 1 of the leading causes of morbidity and mortality during IBD flare-ups. The findings from this study reinforce the importance of thromboprophylaxis administration to all patients with ASUC at first presentation to hospital.”

My take: This study is in adults; the risk of VTE is lower in children and guidance on VTE prophylaxis is not clear.

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Dupilumab for FPIES

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M Plassmeyer et al. Journal of Allergy and Clinical Immunology 2025; Dupilumab Opens a Therapeutic Window in Food Protein Induced Enterocolitis Syndrome by un-licensing dendritic cells

Thanks for Ben Enav for this reference.

Methods: This was a two-part study: “(i) a detailed single-patient case of wheat-triggered, endoscopy-confirmed colitic FPIES treated with dupilumab 300 mg subcutaneously every two weeks and (ii) a prospective follow-up of seven additional FPIES patients all of whom initiated dupilumab for approved comorbidities. Serial flow cytometry quantified dendritic-cell OX40L and CD8+ CRTH2+ T-cell subsets before and after treatment; open food challenges assessed clinical tolerance.”

Key Findings:

  • Index case: Within two injections of dupilumab, the wheat sensitive patient tolerated a 50 g wheat protein challenge without gastrointestinal symptoms—this was the first uneventful exposure in 20 years. Discontinuation of dupilumab led to relapse; re-initiation again restored clinical tolerance
  • Cohort: All seven additional patients (ages 2–58 yr; triggers: milk, soy, rice, wheat, shellfish) achieved unrestricted dietary tolerance within three months
  • An important finding in the index case as well as the follow up cohort is the dupilumab induced drop in dendritic cell OX40L. OX40L is a TNF-superfamily co-stimulatory molecule induced on dendritic cells and other antigen-presenting cells.

My take: Dupilumab appears to be a promising medication for FPIES and warrants further study. If confirmed to be effective, it is likely to be targeted to those with approved comorbidities and those with more severe presentations.

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Amicalola Falls State Park

Kids With Acute Pancreatitis Need Followup

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F Ahmed, M Abu-El-Haija. Gastroenterol 2025; 169: 572-584. Open Access! Acute Pancreatitis in Children: It’s Not Just a Simple Attack

This is a really good review of acute pancreatitis covering epidemiology, diagnosis, severity classification, management, microbiome/metabolite derangements, genetics, and complications. Most of these topics have been covered in numerous blog posts (see below).

Selected Key Points:

  • Diagnostic testing -Amylase/Lipase:  “The diagnostic efficacy of amylase for AP, in terms of sensitivity and specificity, is contingent on the selected threshold value. Elevating the cut-off point to 1000 IU/L results in a high specificity of approximately 95%. However, this comes at the cost of reduced sensitivity, which some studies report to be as low as 61%… the activity of serum lipase remains elevated for a longer duration, typically between 8 and 14 days,… Lipase demonstrates superior accuracy with most studies reporting specificities exceeding 95% and sensitivities ranging from 55%–100% at a threshold activity level of 600 IU/L…hese tests have excellent sensitivities, they may have a few limitations such as being poor predictors of severity”
  • Risk Factors in Children (from Figure 1):
  • Incidence and Severity in Children (from Figure 1):

[At a recent lecture, Jay Freeman (How to Upgrade Pancreas Care –Jay Freeman MD (Part 1)) noted that severe pancreatitis is often defined by degree of organ dysfunction (eg. cardiac, pulmonary, renal). A practical definition of severe pancreatitis in children is whether the patient requires admission to an ICU]

  • Diagnostic testing -Imaging: “Imaging techniques are crucial for diagnosing and managing AP in children…NASPGHAN) and the Society for Pediatric Radiology formed consensus guidelines where transabdominal ultrasonography was recommended as the primary imaging technique for pediatric cases with suspected AP…Recent studies in the pediatric population have indicated that US’s sensitivity for AP detection ranges from 47%–52%.25 …Magnetic resonance cholangiopancreatography (MRCP) is useful for anatomical assessment without radiation but may require sedation”
  • Management: “The cornerstones of therapy are early feeding and intravenous fluids… Allowing patients to eat on admission was feasible and was associated with lower length of stay. Rates of intravenous fluids are recommended at 1.5–2 times maintenance rates,49 and the preferred fluid is Lactated Ringer’s due to limited studies including a recent randomized controlled study that showed that Lactated Ringer’s was associated with a faster discharge rate when administered compared with normal saline.50“
  • Genetics:  “A recently conducted study investigated the importance of genetics in pediatric AP patients…use of an extensive panel of 8 genes… PRSS1, CFTR, SPINK1, CPA1, CTRC, CLDN2, CASR, and SBDS… genetics is a major component in all types of pancreatitis in children, with genetic variants being most prevalent in CP cases at 31%, followed by AP at 19%, and ARP at 6%. A key discovery was that variants in SPINK1, CFTR, or PRSS1 genes were associated with faster progression from first episode of AP toward CP.53“
  • Complications (from Figure 1): “After the first episode of AP, the QoL is decreased, and it may lead to other disorders such as exocrine dysfunction, endocrine dysfunction and diabetes, nutritional deficiencies, and acute recurrent pancreatitis and CP.”

My take: Even after a single episode of acute pancreatitis, there are risks for long-term complications and patients need to follow-up.

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Shared Decision-Making in Celiac Disease Diagnostic Approach

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Y Sunkoy, S Talathi. Am J Gastroenterol 2025; 2190-2193. Utility of the ESPGHAN Biopsy-Sparing Guidelines for Celiac Disease in Children

Thanks to Ben Gold for this reference.

Methods: Retrospective study of patients (n=2942 children) who had celiac serologies and duodenal biopsies

Key findings:

  • Prevalence of CD in this cohort was 9% (226 of 2942 patients)
  • In those with a high titer (>10xULN), 106 of 107 patients (99%) had celiac disease
  • In this cohort, even in those with with >7XULN, had a Sensitivity of 55.3%, a specificity of 99% and a PPV of 97%

In their discussion, the authors note that “we did not obtain an EMA in a second sample, which is recommended in the ESPGHAN guidelines.”

Associated commentary: Erica Brenner, American Journal of Gastroenterology 120(9):p 1985-1986. The No-Biopsy Approach for Pediatric Celiac Disease: Ready for Prime Time in North America?

  • “Shiha et al (8) found that the PPV ranged from 65% for a 1% CD prevalence to a 99% for a 40% prevalence. As the 9% CD prevalence in the study by Sunkoj et al (4) exceeds the 0.81$-1.4% prevalence in the United States (9), the reported PPV may overestimate reality.” (Related post: No-Biopsy Approach to Celiac Disease Diagnosis and Positive Predictive Value (Based on Population)
  • “Children with type 1 diabetes and trisomy 21 have a higher risk of false-positive serology and therefor may not be appropriated candidates for a no-biopsy approach.”

My take: A larger recent study (Chang et al. Pediatrics. 2025;156(3):e2025070897) found that the no-biopsy approach had a significantly lower PPV in their cohort (94.9% overall, and 95.7% in those without T1DM). Thus, in cohorts with lower prevalence of CD, the no-biopsy approach could lead to 2-4% of children being placed unnecessarily on a gluten free diet. As such, it would be good practice to discuss making a diagnosis via endoscopy vs. the no-biopsy approach as part of shared decision-making.

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Stercoral Colitis

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A Bajer, E Levine. NEJM 2025;393: e23. Stercoral Colitis

This young adult presented to the ED with left-sided abdominal pain and chronic constipation. A CT scan was consistent with a diagnosis of stercoral colitis. “In stercoral colitis, chronically impacted feces distend the colon, resulting in inflammation. In some cases, the fecaloma may lead to focal-pressure necrosis or perforation.”

My take: Most often a CT is not needed in this setting. However, it is important to recognize that a severe impaction can lead to complications.

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Selective Acid Suppression for Esophageal Atresia Patients

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This year’s masterpiece!

Link from AAP HealthyChildren.org: Halloween Fun & Safety Tips for Kids of All Ages

S Zeneddin et al. J Pediatr Gastroenterol Nutr. 2025;81:960–966. Acid suppression after esophageal atresia repair: Some infants do benefit

Methods: The authors performed a retrospective study using the Pediatric Health Information System for infants undergoing EA/TEF repair between 2010 and 2022 (n=1445 infants). Acid suppression was defined as receipt of an H2 blocker or proton pump inhibitor on the day of discharge or longer than 30 inpatient days. Complex EA/TEF repair was defined as delayed repair (>7 days), G-tube placement before repair (likely a sign of a long gap or type A anomaly), prolonged hospitalization (>60 days), or multiple inpatient fluoroscopies. The authors defined stricture solely if it required intervention.

Key findings:

  • 257 (17.8%) required dilation by 1 year. Of the 688 (47.6%) infants who met criteria for complex EA/TEF, 126 (18.6%) required a dilation.
  • At 1 year, stricture rate was similar in infants with simple EA/TEF, with or without acid suppression (17.5% vs. 17.0%, p = 0.90)
  • In infants with complex EA/TEF, stricture rates were lower among those who received acid suppression compared to those who did not (15.3% vs. 26.0%, p = 0.001).

The associated editorial (D George, DK Robie. J Pediatr Gastroenterol Nutr. 2025;81:911–912) reviews some of the limitations of the study but does not provide clear recommendations on utilization of acid suppression therapy: the decision should be “should be individualized, weighing the potential benefits against the risks.”

My take: It is not surprising that more complex EA would have higher stricture rates. In my training (in the 1990s!), it was routine practice to use indefinite acid suppression. This article indicates that patients with low risk EA likely do not need acid suppression. In high risk patients, the algorithm by Yasuda et al (see post below J Am Coll Surg 2024; 238: 831-843) provides their approach to weaning acid suppression.

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Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Prior Exposure to TNF Antagonists May Increase Response to JAK Inhibitors in Patients with Ulcerative Colitis

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HH Lee et al. Clinical Gastroenterology and Hepatology 2025; 23, 2102 – 2114. Open Access! Differential Efficacy of Advanced Therapies in Inducing Remission in Ulcerative Colitis Based on Prior Exposure to TNF Antagonists

Methods: Meta-analysis of 17 randomized controlled trials in 8871 adults with moderate-severe UC. The authors calculated the ratio of odds ratio of achieving remission with active drug vs placebo, in TNF antagonist–naïve vs TNF antagonist–exposed patients.

Key findings:

  • JAK inhibitors: Less efficacious in TNF antagonist–naïve vs exposed patients (6 trials; ratio of OR, 0.47)
  • IL-23 antagonists: No significant difference was observed in efficacy of selective interleukin-23 antagonists vs placebo in TNF antagonist–naïve vs exposed patients (6 trials; ratio of OR, 1.07)
  • Lymphocyte trafficking inhibitors: More efficacious in TNF antagonist–naïve vs exposed patients (5 trials; odds ratio [OR], 1.88)

Discussion:

  • This study “confirmed prior observations that exposure to TNF antagonists significantly reduces the efficacy of lymphocyte trafficking inhibitors in inducing remission, including both vedolizumab and S1P receptor modulators, by approximately 50%.In contrast, prior exposure to TNF antagonists was associated with a significant increase in the efficacy of JAK inhibitors in inducing remission, with 2-fold higher efficacy in TNF antagonist–exposed vs TNF antagonist–naïve patients”
  • In the SELECT-COMPARE trial in patients with rheumatoid arthritis, there was also an improved response to upadacitinib in patients with prior adalimumab.
  • “The current findings raise the intriguing possibility that exposure to TNF antagonists could result in lasting effects on the immune system that differentially alter responsiveness to therapies with distinct mechanisms of action”

My take: This study suggests that JAK inhibitors are a good choice for secondary therapy after anti-TNF agents. Other factors, besides efficacy, including safety, extraintestinal manifestations, and cost, have to be considered as well.

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Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Comprehensive ACG Clinical Guidelines for Crohn’s Disease (2025)

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GR Lichenstein et al. The American Journal of Gastroenterology 120(6):p 1225-1264, June 2025. Open Access!!  ACG Clinical Guideline: Management of Crohn’s Disease in Adults

Yesterday and Today I am highlighting two adult clinical guidelines both of which are equivalent to up-to-date textbook chapters with specific recommendations; both are open access. In addition, the articles have accompanying author podcasts. Thanks to Ben Gold for these references.

Selected Management Recommendations:

  • Table 1, #3: We suggest against requiring failure of conventional therapy before initiation of advanced therapy for the management of CD
  • Table 1, #13: We recommend combination therapy of intravenous infliximab with immunomodulators (thiopurines) as compared with treatment with either immunomodulators alone or intravenous infliximab alone in patients with CD who are naive to those agents
  • Table 1, #33: In patients with high-risk CD, we recommend anti-TNF therapy to prevent postoperative endoscopic recurrence

Key Concepts:

  • Table 2, #9: Symptoms of CD do not correlate well with the presence of active inflammation and therefore should not be the sole guide for therapy. Objective evaluation by endoscopic or cross-sectional imaging should be undertaken periodically to avoid errors of under- or over-treatment.
  • Table 2, #14: The 10-year cumulative risk of major abdominal surgery in CD is 40%–55%, although recent studies performed in the biologic era suggest that the 10-year risk may have decreased to 30%. The 10-year risk of a second resection after the first is 35%, although again more recent studies suggest that this may have dropped to closer to 30%.
  • Table 2, #15: In CD, the 5-year rate of symptomatic postoperative recurrence is ∼50%.
  • Table 2, #29: Small bowel imaging should be performed as part of the initial diagnostic workup for patients with suspected CD.
  • Table 2, #31: Because of the absence of radiation exposure, magnetic resonance enterography should be used preferentially in young patients (younger than 35 years) and in patients in whom it is likely that serial exams will need to be performed.
  • Table 2, #38: Mucosal healing as determined by endoscopy is a goal of therapy. Scoring systems are available to measure the endoscopic disease activity and may be used to monitor response to therapy.
  • Table 2, #41: Antibiotics are not an effective treatment for luminal inflammatory CD and should not be used as a primary therapy.

My take: Given the rapid changes in available therapies, it would be optimal to make these collaborative guidelines (AGA, ACG, NASPGHAN) available online with frequent updates (similar to HCVguidelines.org).

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