How HLA DQA1*05 and Combination Therapy Modulate Treatment Outcomes in Children with Crohn’s Disease

J Adler et al. Am J Gastroenterol 2025; 120: 1076-1086. HLA DQA1*05 and Risk of Antitumor Necrosis Factor Treatment Failure and Anti-Drug Antibody Development in Children’s with Crohn’s Disease.

This was a prospective, double-blind, placebo-controlled trial with 204 patients examining the clinical outcomes of anti-TNF with or without methotrexate (COMBINE).

Key findings:

  • Treatment failure in HLA DQA1*O5: A trend toward increased treatment failure among HLA DQA1*05-positive participants was not statistically-significant (hazard ratio 1.58; P = 0.08).
  • HLA DQA1*05 and Treatment Failure Rate: During the followup period, HLA DQA1*05-positive patients had a 35% failure rate compared to 26% for those who were HLA DQA1*05-negative (P=0.098). The overall failure rate was 30%
  • Methotrexate Combined with HLA DQA1*05 Effect: Patients who were HLA DQA1*05 negative and assigned to methotrexate experienced less treatment failures than HLA DQA1*05-positive patients on placebo (hazard ratio 0.31, 95% CI 0.13-0.70; P = 0.005).
  • Anti-TNF Medication Comparison: Treatment failure was similar between infliximab and adalimumab, 29% and 33% respectively
  • Antidrug antibodies (ADA): A trend toward increased ADA development among HLA DQA1*05-positive participants was not significant (odds ratio 1.96, P = 0.09). The addition of methotrexate to the treatment regimen mitigated the risk of treatment failure among individuals positive for HLA DQA1*05 and reduced the odds of developing ADA by 90%.
  • Rate of ADA: “After further stratification, HLA DQA1*05-negative participants assigned to methotrexate were less likely to develop ADA relative to HLA DQA1*05-positive patients on placebo (odds ratio 0.12; P = 0.008).”

Discussion Points:

  • “A retrospective by Fuentes-Valenzuela et al …found that if patients underwent proactive TDM, there was no increase in the rate of treatment discontinuation among those who were HLA DQ-A105 positive compared with HLA DQ-A105 negative”
  • “The totality of evidence suggests that HLA DQ-A1*05 seems to confer a risk of both immunogenicity and treatment failure, particularly among infliximab-treated patients. Furthermore, this risk may be mitigated by the use of proactive TDM and/or concomitant immunomodulators.”

My take (borrowed in part from authors):  “40% of patients were HLA DQ-A1*05 positive, which was associated with a trend toward increased risk of both treatment failure and ADA. These risks were mitigated, but not eliminated, by adding oral methotrexate.” The use of combination therapy (methotrexate with anti-TNF) was associated with the lowest failure rates.

Also, unrelated article: DA Carlson et al. Gastroenterology 2025; 168: 1114-1127. A Standardized Approach to Performing and Interpreting Functional Lumen Imaging Probe Panometry for Esophageal Motility Disorders: The Dallas Consensus. Congratulations to Dr. Garza from our group who was one of the authors

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Effects of Thiopurine Withdrawal in Randomized Trial of Vedolizumab-Treated Patients with Ulcerative Colitis

A Pudipeddi et al. Clin Gastroenterol Hepatol 2024; 22: 2299-2308. Open Access! Effects of Thiopurine Withdrawal on Vedolizumab-Treated Patients With Ulcerative Colitis: A Randomized Controlled Trial

Methods: This was a multicenter randomized controlled trial recruited UC patients (n=62) on vedolizumab 300 mg intravenously every 8 weeks and a thiopurine. Patients in steroid-free clinical remission for ≥6 months and endoscopic remission/improvement (Mayo endoscopic subscore ≤1) were randomized 2:1 to withdraw or continue thiopurine.

Key findings:

  •  At week 48, vedolizumab trough concentrations were not significantly different between continue and withdrawal groups (14.7 μg/mL versus 15.9 μg/mL, respectively, P = 0.36).
  • The continue group had significantly higher fecal calprotectin remission (calprotectin <150) (95.0%, 19/20 versus 71.4%, 30/42; P = .03), histologic remission (80.0%, 16/20 versus 48.6%, 18/37; P = .02), and histo-endoscopic remission (75.0%, 15/20 versus 32.4%, 12/37; P = .002) than the withdrawal group. Clinical and endoscopic remission favored the continue group though this did not reach statistical significance.
  • Histologic activity (hazard ratio [HR], 15.5; 95% confidence interval [CI], 1.6–146.5; P = .02) and prior anti-tumor necrosis factor exposure (HR, 6.5; 95% CI, 1.3–33.8; P = .03) predicted clinical relapse after thiopurine withdrawal.

Discussion: “In Australia, requirements are for UC patients to have failed at least 3 months of an immunomodulator before vedolizumab initiation. Consequently, UC patients are typically on combination therapy initially, and hence this study was designed as a withdrawal trial.” The authors note that previous studies have not shown superior outcomes with combination therapy (See blog post: No Benefit of Combination Therapy with Ustekinumab or Vedolizumab). “However, methodological flaws, heterogenous outcomes, and shorter durations of treatment limit these findings.”

My take (borrowed from authors): “Thiopurines might provide an incremental benefit to patients with UC using vedolizumab, … independent of vedolizumab pharmacokinetics.”

Related study: C Yzet et al. Clin Gastroenerol Hepatol 2021; 19: 668-679. Full TextNo Benefit of Concomitant Immunomodulator Therapy on Efficacy of Biologics That Are Not Tumor Necrosis Factor Antagonists in Patients With Inflammatory Bowel Diseases: A Meta-analysis

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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.

Proactive Therapeutic Drug Monitoring and Better Outcomes in Pediatric Crohn’s Disease (2024)

S Ali et al. Clinical Gastroenterology and Hepatology, Volume 22, Issue 10, 2075 – 2083.e1. Characterization of Biologic Discontinuation Among Pediatric Patients With Crohn’s Disease

Methods:  Prospective ImproveCareNow registry data (n=823, from 7 centers) were supplemented with medical record abstraction. 

Treatment/Monitoring:

  • 86% started biologics (78% infliximab, 21% adalimumab, <1% others)
  • Twenty-six percent used concomitant immunomodulators for ≥12 months
  • Most (85%) measured TDM including 47% induction, 69% proactive, and 24% reactive

Key findings:

  • Twenty-nine percent discontinued their first biologic after median 793 days because of inefficacy (34%), anti-drug antibodies (8%), adverse events (8%), or non-adherence (12%)
  • Proactive TDM and concomitant immunomodulators were associated with 60% and 32% reduced biologic discontinuation
  • Half of patients discontinued biologics without trial of high-dose therapy and 14% without any evaluation
  • Among patients started with infliximab therapy, 62% of patients started at a dose of <6 mg/kg, 18% stared at a dose >8 mg/kg. 67% of patients underwent dose escalation. This is agreement with other studies indicating that as many as 80% of children need doses in excess of ‘standard’ dosing (5 mg/kg every 8 weeks)
  • In patients with anti-TNF medication inefficacy with TDM availability, 36% had infliximab or adalimumab levels below 5 mcg/mL. and 20% had levels between 6-8 mcg/mL.
  • Among patients who discontinued anti-TNF medications, 60% had serum trough levels less than 10 mcg/mL.
  • The rate of biologic durability was lower for those (n=61) receiving a 2nd biologic who had rates of remaining on agent of 56% at 1 yr, 28% at 2 yrs, and 10% at 4 yrs. In contrast, the first biologic had durability of 90% at 1 year, 79% at 2 years, and 66% at 4 yrs.

My take: This study strongly supports the use of proactive therapeutic drug monitoring. In addition, the authors make a compelling argument to optimize a therapy and evaluate carefully before switching to a new medication/biologic. Finally, the use of concomitant immunomodulators can improve medication durability; it is particularly important if needing to switch from one anti-TNF agent to another due to anti-drug antibodies.

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Pitt Street Bridge (Mt Pleasant, SC)

Genetic Test to Help Determine Need for Combination Therapy with Anti-TNF

V Solitano et al. Clin Gastroenterol Hepatol 2023; 21: 3019-3029. HLA-DQA1∗05 Genotype and Immunogenicity to Tumor Necrosis Factor-α Antagonists: A Systematic Review and Meta-analysis

Key findings:

  • On meta-analysis of 13 studies (3756 patients; median follow-up, 12 months; 41% with variants), HLA-DQA1∗05 variants were associated with 75% higher risk of immunogenicity compared with non-carriers (relative risk, 1.75) with considerable heterogeneity (I2 = 62%) (low certainty evidence).
  • In addition, patients with HLA-QQA1*05 variants had clinical loss of response (LOR) in 67% compared to 30% in those without this variant (wild-type); thus, a 124% higher risk of LOR.
  • Positive and negative predictive values of HLA-DQA1∗05 variants for predicting immunogenicity were 30% and 80%, respectively
  • Proactive therapeutic drug monitoring, but not concomitant use of IMMs, IMIDs, and TNF-α antagonist-type, modified this association.

My take:

  • The ~40% of individuals with HLA-DQA1*05 variants are at higher risk of LOR and are more likely to benefit from both therapeutic drug monitoring and probably from use of combination (with immunomodulator) therapy.
  • The positive predictive value (30%) is low indicating that the majority of patients with these variants will not develop anti-drug antibodies within 12 months.
  • In those with negative testing for HLA-DQA1*05 (~60%), the higher negative predictive value indicates a patient is more likely to do well with monotherapy.
  • HLA-DQA1*05 testing is available commercially (usually part of Celiac HLA typing).

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This is the Initiation Well at Quinta da Regaleira in Sintra, Portugal.
It is pretty cool because it seems to start at ground level and then goes down many floors.
There is an exit to a number of tunnels at the lower level.

COMBO-IBD Study -Combination Immunomodulator Use and Thresholds

AJ Yarur et al. Clin Gastroenterol Hepatol 2023; 21: 2908-2917. Open Access! Combination Therapy With Immunomodulators Improves the Pharmacokinetics of Infliximab But Not Vedolizumab or Ustekinumab

In this prospective cohort with 369 patients, treatment included the following 113 infliximab, 133 vedolizumab, and 123 ustekinumab. All patients received standard dosing (eg. 5 mg/kg/dose every 8 weeks with infliximab). Per Table 1, dose of thiopurine was 100 mg (range 50-150, “using a 2:1 ratio of azathioprrine and mercaptopurine”); most patients received methotrexate at a dose of 12.5 mg. Key findings:

  • Infliximab levels were much improved in patients receiving combination therapy with either a thiopurine or methotrexate. In those patients receiving a thiopurine, a threshold of 6-TGN ≥146 was considered optimal.
  • Patients receiving combination therapy with methotrexate or a thiopurine and a 6-TGN concentration ≥146 pmol per 8 × 108 RBCs, and those with baseline infliximab level ≥12.3 μg/mL had a lower rate of secondary nonresponse when compared with those on monotherapy, thiopurine with 6-TGN <146 pmol per 8 × 108 RBCs, and baseline infliximab level <12.3 μg/mL (88.2 vs 11.8% [P = .04], 71.2 vs 45.5% [P = .04])
  • Ustekinumab and vedolizumab levels were NOT increased in patients receiving an immunomodulator

My take: This study reinforces the idea that there are pharmacokinetic benefits of combination therapy with infliximab (and extrapolated to other anti-TNF agents); there is a lack of benefit for most patients receiving ustekinumab and vedolizumab. Even with ustekinumab and vedolizumab, it is possible that patients with more severe disease may still benefit independent of pharmacokinetic effects on biologic agent.

Higher doses of infliximab monotherapy with therapeutic drug monitoring may achieve similar results as combination therapy. However, patients switching from one anti-TNF to another due to immunogenicity/antidrug antibodies are particularly likely to benefit from combination therapy. In addition, a recent ImproveCareNow study showed better outcomes for pediatric patients who received methotrexate with adalimumab (see below).

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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.

Why Do Children Taking Adalimumab Benefit from Methotrexate Dual Therapy?

MD Kappelman et al. Gastroenterology. 2023: 165: 149-161. Open Access! Comparative Effectiveness of Anti-TNF in Combination With Low-Dose Methotrexate vs Anti-TNF Monotherapy in Pediatric Crohn’s Disease: A Pragmatic Randomized Trial

This study enrolled 297 children with Crohn’s disease starting anti-TNF therapy.  Patients initiating infliximab or adalimumab were randomized in 1:1 allocation to methotrexate or placebo and followed for 12–36 months. 

Methotrexate dosing: For those in the active arm, oral methotrexate was administered with a weekly dose of 15 mg for children ≥40 kg, 12.5 mg for children 30 to <40 kg, and 10 mg for children 20 to <30 kg. All participants received pretreatment with ondansetron 4 mg (or placebo) to prevent nausea and folic acid (1 mg/d).

Key findings:

  • For treatment failure: among infliximab initiators, there were no differences between combination and monotherapy (hazard ratio, 0.93; 95% CI, 0.55–1.56)
  • For treatment failure: among adalimumab initiators, combination therapy was associated with longer time to treatment failure (hazard ratio, 0.40; 95% CI, 0.19–0.81).
  • A trend toward lower anti-drug antibody development in the combination therapy arm was not significant (infliximab: odds ratio, 0.72; 95% CI, 0.49–1.07; adalimumab: odds ratio, 0.71; 95% CI, 0.24–2.07).
  • In our study, only 38% of participants underwent colonoscopy during follow-up (41% had calprotectin measurement). 

My thoughts on this study:

My take: Given the increased difficulty monitoring the kids on adalimumab, they are probably better off on dual therapy.  My suspicion, though, is that if they had optimized levels, the benefit of dual therapy is probably small and would mirror the findings with IFX.

What Can We Conclude from Five Patients Treated with a Combination of Infliximab and Tofacitinib?

Most often a letter to the editor would not grab my attention. A recent letter did: Full Text: Tofacitinib Is Safe and Effective When Used in Combination With Infliximab for the Management of Refractory Ulcerative Colitis (R Gilmore et al. Clin Gastroenterol Hepatol 2021; 1302-1303; reply 1303-1304 by JA Berinstein et al.)

This reported case series with 5 patients with severe ulcerative colitis (UC) who received a combination of tofacitinib and infliximab for at least 90 days were retrospectively reviewed. Tofacitinib dosing was de-escalated to 5 mg twice daily after 8 weeks. Thiopurine therapy was stopped with tofacitinib initiation.

Key findings:

  • Median duration of combination therapy was 9 months (range, 4–12 months). At 90 days, all patients had a reduction in Mayo score of ≥3. Four patients improved clinically and biochemically (Table 1), with 3 patients achieving steroid-free remission.
  • The only adverse event reported was one patient developing varicella zoster.

The authors letter title regarding tofacitinib being “safe and effective” is clearly overstated. The reply notes that in limited experience the group from the University of Michigan had a 50-year-old man develop severe pulmonary and CNS disease due to acquisition of legionnaires disease while on combination tofacitinib and infliximab.

My take: (borrowed from reply) “Efficacy and safety data obtained through rigorous randomized trials are needed…it is possible that long-term use of combination tofacitinib and infliximab will lead to an unacceptable risk of infection.”

Another study of tofacitinib: GR Lichtenstein et al. Inflamm Bowel Dis 2021; 27: 816-825. Tofacitinib, an Oral Janus Kinase Inhibitor: Analysis of Malignancy (Excluding Nonmelanoma Skin Cancer) Events Across the Ulcerative Colitis Clinical Program Key finding: With an exposure of 2576.4 patient years & 124 overall cohort tofacitinib-treated patients, 20 developed a malignancy

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Key West, FL

No Benefit of Combination Therapy with Ustekinumab or Vedolizumab

C Yzet et al. Clin Gastroenerol Hepatol 2021; 19: 668-679. Full Text: No Benefit of Concomitant Immunomodulator Therapy on Efficacy of Biologics That Are Not Tumor Necrosis Factor Antagonists in Patients With Inflammatory Bowel Diseases: A Meta-analysis

In a systematic review, key findings:

  • Combination therapy was not associated with better clinical outcomes in patients receiving vedolizumab (16 studies: OR, 0.84; 95% CI, 0.68–1.05; I2=13.9%; Q test P = .17); n= 933 and n=2378 with combination therapy and monotherapy, respectively
  • Combination therapy was not associated with better clinical outcomes in patients receiving ustekinumab (15 studies: OR, 1.1; 95% CI, 0.87–1.38; I2 = 11%; Q test P = .28); n=856 and n=1926 patients with combination therapy and monotherapy, respectively

Why don’t immunomodulators seem to help? “Unlike anti-TNF, prospective studies as well as post hoc analysis of randomized controlled trial consistently reported a low immunogenicity [with ustekinumab and vedolizumab]…all the prospective studies available to date have shown no impact of immunomodulator on the trough serum level of vedolizumab or ustekinumab.”

Limitation: patients treated with combination therapy in the included studies could be more severe

My take: “This meta-analysis found that overall the use of combination therapy in patients treated with vedolizumab or ustekinumab was not associated with a clinical benefit in comparison with the use of monotherapy.”

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Combating Anti-Drug Antibodies with Immunomodulators in Pediatric IBD

RJ Colman et al. Inflamm Bowel Dis 2021; 27: 507-515. Favorable Outcomes and Anti-TNF Durability After Addition of an Immunomodulator for Anti-Drug Antibodies in Pediatric IBD Patients

In this retrospective review with 89 patients who developed antidrug antibodies (ADAs), the authors identified 30 who started an immunomodulator (IM) within 3 months of developing an ADA and compared with 59 who did not start an IM. The main IM used was methotrexate (n= 28, 93%)

Key findings:

  • 61 of the 89 patients (69%) had quiescent disease based on physician global assessment at their previous clinic visit
  • The initial anti-TNF was stopped shortly after ADA detection in 36% of the No-IM patients vs none of the IM patients. Thus, anti-TNF agents durability was prolonged in the IM group.
  • Dose intensification was also undertaken at the time of ADA detection: 25 (83%) of IM group and 28 (48%) of non-IM group.
  • At 12 months, steroid-free clinical and biochemical remission on the same anti-TNF occurred in 53.9% of the IM group vs 26.8% in the No-IM group (P = 0.025).
  • Drug levels rose higher (P = 0.003) and ADA levels fell farther (P = 0.037) in the IM group than in the No-IM group
  • Lower ADAs often improved without IM: An ADA level <329 ng/mL had a 76.2% sensitivity and an 83.3% specificity for ADA reversal without IM.

My take: If a patient develops a significantly elevated anti-drug antibody, addition of methotrexate/immunomodulator along with dose intensification increases the likelihood that the anti-TNF agent will continue to be effective.

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Converting to Monotherapy for Children with Inflammatory Bowel Disease

W El-Matary et al. JPGN 2020; 71: 740-743. Discontinuation of Immunosuppressive Medications in Children With Inflammatory Bowel Disease on Combination Therapy

This study looked at 105 patients receiving combination therapy; the a median duration of combination therapy was 2.1 years, with infliximab and either methotrexate  (53) or azathioprine (52). 89 patients had Crohn’s disease.

Key findings:

  • 11 (10.5%) patients experienced a clinical relapse over a median duration of follow-up of 12.0 months after stopping the immunomodulator.
  • In the patients who did not relapse, the median IFX trough level at IM discontinuation was 6.2; the IFX trough level was 3.8 μg/mL in those who relapsed.

In their discussion, the authors urge caution in discontinuation of immunomodulators in those with clinically-severe Crohn’s disease and those with low infliximab levels.

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Tons of shells on Picnic Island, Tampa Bay

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