Tag Archives: therapeutic drug monitoring

Another Study Justifying Higher Infliximab Dosing in Pediatrics

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S Lawrence et al. JPGN 2022; 75: 601-607. Optimized Infliximab Induction Predicts Better Long-Term Clinical and Biomarker Outcomes Compared to Standard Induction Dosing

In this retrospective observational cohort study (n=140 children), patients were started on 5 mg/kg/dose during induction. 78 children had “optimized dosing” with an infliximab level drawn prior to 3rd dose. A level <15 mcg/g was considered subtherapeutic. It is noted that combination therapy was much higher in the standard (not optimized) group (95% vs 42%).

Key findings:

  • Combined corticosteroid-free clinical and biomarker remission (CRP < 5 mg/L) was higher in the optimized compared to the standard cohort [65/78 (83%) vs 25/62 (40%), P < 0.001]. Remission rates correlated with trough levels; those in clinical remission had a median level of 3.6 compared to 2.0 in those without clinical remission.
  • The median post-induction trough was higher in the optimized group 4.2 mg/L vs 1.9 mg/L.
  • The optimized group were significantly more likely to achieve a therapeutic level (5 mg/L or greater): 44% vs 18%.

My take:

  1. The “optimized” group was not very well optimized –only 44% had a therapeutic level >5, but still performed much better than the standard group (which more often had combination therapy). This indicates a need to start with higher doses and reinforces the need for therapeutic drug monitoring.
  2. This study further shows that 5 mg/kg dosing is inadequate. In the standard group, even with combination therapy, only 18% achieved therapeutic levels.
  3. This article will be another one to include to try to persuade insurance companies that kids are different and need higher doses of infliximab.
  4. Though inconvenient for families, dosing more frequently is more effective than higher doses for improving trough levels (ie 5 mg/kg q4 wks results in better trough levels than 10 mg/kg q8 wks).

Here are some additional references on this topic (from a recent appeal):

For pediatrics, studies have shown that utilizing dosing of 5 mg/kg/dose results in subtherapeutic dosing in around 80%, especially if low albumin.  This places patients at high risk for developing antibodies to infliximab and complications from Crohn’s disease.

  1. LE Bauman et al Inflamm Bowel Dis 2020 Feb 11;26(3):429-439. Improved Population Pharmacokinetic Model for Predicting Optimized Infliximab Exposure in Pediatric Inflammatory Bowel Disease. The authors identified 228 pediatric patients with IBD and developed a pharmacokinetic model using weight, albumin, sedimentation rate and antibodies to infliximab (ATI) to help predict infliximab dosing that would achieve a therapeutic trough level (>5 mcg/mL). In their study, they also simulated 1000 patients and found that only 24% of patients receiving 5 mg/kg q8weeks achieved a therapeutic level; this increased to 56% for 10 mg/kg q8weeks
  2. Frymoyer A, Piester TL, Park KT. JPGN. 2016;62(5):723-727. Infliximab dosing strategies and predicted trough exposure in children with Crohn’s disease. Only 21% of children in this modeling study achieved a trough level >3 if the albumin was 3 or lower. The goal for trough level is NOW >5.
  3. JM Shapiro et al. JPGN 2016; 62: 867-72. Durability of Infliximab Is Associated With Disease Extent in Children With Inflammatory Bowel Disease.  In this study with 98 pediatric patients, 70% with extensive disease required dose escalation.
  4. Ungar B, Levy I, Yavne Y, et al. Clin Gastroenterol Hepatol. 2016;14(4):550-557.e552. Optimizing Anti-TNF-alpha therapy: serum levels of Infliximab and Adalimumab are associated with mucosal healing in patients with inflammatory bowel diseases. Getting good levels important to achieve healing/remission.
  5. NV Castelle et al. Clin Gastroenterol Hepatol 2022; 20: 465-467. Patients With Low Drug Levels or Antibodies to a Prior Anti-Tumor Necrosis Factor Are More Likely to Develop Antibodies to a Subsequent Anti-Tumor Necrosis Factor. Good levels are associated wtih fewer antibodies to infliximab.

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On a recent trip to Florida, we picked up more than 40 sand dollars on a morning beach walk. This was during a cold snap, at low tide and after a storm.

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.

Picking Apart the SERENE-CD Study & Constipation Vibrating Capsule FDA Approved

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Several recent letters to the editor provide some insight into some of the shortcomings of the SERENE-CD study which reported that higher adalimumab induction dosing and proactive therapeutic drug monitoring (TDM) were not associated with improved outcomes.

“The rerandomization design of SERENE CD, which selectively enrolled patients with clinical response at week 12 to the TDM vs CA part of the study, may have resulted in the exclusion of those who would have benefited the most from early adjustment of their anti-tumor necrosis factor (TNF) dose. The rerandomization design and the late adaptation of the proactive strategy at week 12 were 2 significant aspects of the design that may have led to the negative results. On the other hand, PAILOT, which showed beneficial effects of proactive TDM, randomized patients as early as week 4 and assessed the outcome at week 72. This is distinct from the 1-year time frame used in most other studies, including SERENE CD.8 A properly designed, adequately powered clinical trial is needed before we can make a judgement on the use of proactive TDM in patients with inflammatory bowel disease. Until then, the jury remains out.”

“The study design only allowed patients in the TDM group with adalimumab concentrations of ≥5 and ≤10 μg/mL to be escalated to 40 mg every week if their CD activity index was ≥220 or their high-sensitivity C-reactive protein level was ≥10 mg/L.. The goal of proactive TDM is to attain a threshold concentration regardless of disease activity. This design probably led the 2 groups to have similar drug concentrations at week 56…

Second, a rather low targeted drug concentration of 5 μg/mL was used, although previous studies have suggested that higher concentrations are more appropriate.5, 6, 7, 8 A study from Ungar et al5 showed that adalimumab concentrations of 8–12 μg/mL are required to achieve mucosal healing in 80%–90% of patients with IBD, and the prospective PANTS (The Personalised Anti-TNF Therapy in Crohn’s Disease Study) study identified an adalimumab concentration of 12 μg/mL at week 14 associated with remission at both week 14 and week 54.8..

Third, dose escalation for the TDM group could only happen at weeks 14, 28, or 42 (and not earlier and more often). In the PAILOT RCT, proactive TDM based on adalimumab concentration evaluations started as early as week 4 followed by week 8 and every 8 weeks thereafter until the end of the follow-up at week 72.3 Fourth, there was a rather short follow-up of the patients (44 weeks).”

” Even with the assumption of a 30% benefit of proactive TDM and that 20% of patients would have low drug levels in the absence of symptoms, the sample size for 80% power would range from 1228 to 2170. Thus, although SERENE CD1 and other clinical trials3,4 have suggested a lack of benefit of proactive TDM in adults with inflammatory bowel disease, all were likely substantially underpowered to do so.”

My take: While the SERENE-CD results have suggested that a strategy of proactive TDM may not be helpful, there are a lot of reasons to disregard these findings. Achieving a therapeutic level is a fundamental principle and proactive TDM, particularly in pediatrics, is well-supported by other studies.

Related blog posts:

Also noted:

IBD Updates: Rising Burden of IBD, Calprotectin in Severe Colitis, Postoperative Therapeutic Drug Monitoring, Formula Choice for EEN

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M Agrawal et al. Gastroenterol 2022; 163: 1547-1554. Open Access! The Rising Burden of Inflammatory Bowel Disease in Denmark Over Two Decades: A Nationwide Cohort Study

Key findings:

  • Between 1995 and 2016, the incidence rate (95% confidence interval) per 100,000 person-years rose from 9.1 (8.3–10.0) to 17.8 (16.8–19.0) for CD, and from 21.0 (19.8–22.3) to 28.4 (27.0–29.8) for UC.
  • The highest increase in CD and UC incidence rates occurred in children and young adults, respectively.
  • The prevalence of IBD doubled from 1995 to 2016; the greatest increase (2.5-fold) was in UC prevalence among individuals aged >40 years. During this period, the median age of the IBD population increased by 6 to 7 years.

Y Pan et al. Inflamm Bowel Dis 2022; 28: 1865-1871. Utility of Therapeutic Drug Monitoring for Tumor Necrosis Factor Antagonists and Ustekinumab in Postoperative Crohn’s Disease

In this retrospective study (n=130), therapeutic drug levels in the postoperative period were associated with improved outcomes for anti-TNF agents (infliximab (IFX) or adalimumab (ADA) but NOT for ustekinumab (UST):

  • In patients with IFX ≥3 µg/mL, higher rates of deep remission (39% vs 0%; P = .02) existed compared with those with IFX less than 3 µg/mL. This was true for clinical remission (44% vs 9%; P = .04) and objective (83% vs 62%; P = .1) remission. 
  •  In patients with ADA ≥7.5 µg/mL, rates of deep (42% vs 0%; P = .02), clinical (42% vs 0%; P = .02), and objective (88% vs 40%; P = .007) remission were higher than patients with lower concentrations.
  • For UST, rates of deep (28% vs 17%; P = 1.0), clinical (33% vs 33%; P = 1.0), and objective (70% vs 67%; P = 1.0) remission were similar between patients regardless of drug concentration.

S Sasidharan et al. Inflamm Bowel Dis 2022; 28: 1833-1837. Fecal Calprotectin Is a Predictor of Need for Rescue Therapy in Hospitalized Severe Colitis

In this retrospective study (n=147), a fecal calprotectin >800 mcg/g independently predicted the need for inpatient medical rescue therapy (odds ratio, 2.61; 95% CI, 1.12-6.12). An admission calprotectin >800 mcg/g independently predicted surgery within 3 months (odds ratio, 2.88; 95% CI, 1.01-8.17). My take: This is the least surprising study I’ve read this past month —those with more severe colitis, based on calprotectin values, were more likely to need more intensive treatments.

R Dawson et al. Inflamm Bowel Dis 2022; 28: 1859-1864. Comparing Effectiveness of a Generic Oral Nutritional Supplement With Specialized Formula in the Treatment of Active Pediatric Crohn’s Disease

In this retrospective pediatric study (n=171), the authors found that a generic oral supplement (Fortsip) was as effective as a specialized formula (Modulen IBD) for enteral nutrition. “No difference was demonstrated in remission rate (Fortisip n = 67 of 106 [63%] vs Modulen IBD n = 41 of 64 [64%], P = .89), nonadherence rate (Fortisip n = 7 of 106 [7%] vs Modulen IBD 3 of 64 [5%], P = .57) or method of administration.” The main difference in outcome was a lower expense in the group receiving the generic formula. My take: This study is in agreement with previous studies.

Related blog posts:

Precision Dosing with Vedolizumab in Pediatrics

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RJ Colman et al. AP&T 2022; https://doi.org/10.1111/apt.17277. Open access! Real world population pharmacokinetic study in children and young adults with inflammatory bowel disease discovers novel blood and stool microbial predictors of vedolizumab clearance

“The study included data from 463 observed vedolizumab concentrations (59 peaks and 404 troughs) from 74 patients with IBD (52 with Crohn’s disease and 22 with ulcerative colitis or unclassified IBD, median age 16 years)…This study was part of the multicentre REFINE study, which aimed to investigate paediatric PK factors among different biological therapies. Both induction and maintenance doses were between 6 and 10 mg/kg for patients less than 30 kg and 300 mg for patients above 30 kg.”

Key findings:

  • “Using the new model in a simulation analysis of standard vedolizumab infusions (0, 2 and 6 weeks followed by every 8 weeks), we demonstrate that the expected cTrough at week 22 (infusion-5) in the majority of patients would result in drug exposure below current cTrough targets..The dosing simulations in our current study found that receiving standard dosing would lead to <20% of patients achieving a cTrough of 20 μg/ml at infusion-5.”
  • “The severity of hypoalbuminemia resulted in higher drug CL (lower cTrough) than the inflammatory burden (elevated ESR).”
  • Infusion-3 cTrough of at least 37 μg/ml and infusion-4 cTrough of at least 20 μg/ml best predicted SFCR (steroid-free clinical remission) at infusion-4. In contrast, we showed inadequate drug exposure during induction (AUCweek 14 of <134,580 μg h/ml) was associated with clinical non-response

My take: This study shows that therapeutic drug monitoring (TDM) is likely to be beneficial in improving outcomes in pediatric patients receiving vedolizumab. Low albumin in particular is associated with increased drug clearance. From this study, it looks like most pediatric patients will need dosing every 4 to 6 weeks to achieve good levels. The authors in their discussion reinforce the utility of TDM to “guide anti-TNF dose optimisations has been shown to improve durability and reduce both immunogenicity and loss of response.”

References:

13 Dubinsky MC, Mendiolaza ML, Phan BL, Moran HR, Tse SS, Mould DR. Dashboard-driven accelerated infliximab induction dosing increases infliximab durability and reduces immunogenicity. Inflamm Bowel Dis. 2022; 28: 1375– 85.

51 Strik AS, Löwenberg M, Mould DR, Berends SE, Ponsioen CI, van den Brande JMH, et al. Efficacy of dashboard driven dosing of infliximab in inflammatory bowel disease patients: a randomized controlled trial. Scand J Gastroenterol 2021; 56: 145– 154.

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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.

The Curtain or The Box: Therapeutic Dilemmas

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X Roblin et al. Inflamm Bowel Dis 2022; 28: 720-727. Swapping Versus Dose Optimization in Patients Losing Response to Adalimumab With Adequate Drug Levels

Many times, treatment decisions are like on “Let’s Make a Deal.” That is, should I stick with what I’ve got or should I try for something better & sometimes wind up with a goat. In this referenced article, patients were under maintenance therapy with adalimumab (ADA) monotherapy (40 mg every 14 days) and had experienced a secondary loss of response (LOR) despite trough levels > 4.9 μg/mL. In this nonrandomized prospective study, patients were either swapped to vedolizumab (VDZ) or optimized on adalimumab (ADA) treatment.

Key findings:

  • At 24 months, 11 out of 70 patients (16%) in the swap group discontinued treatment compared with 36 out of 61 (59%) patients in the optimization group (P < 0.001)
  • In the optimization group, treatment discontinuation was positively associated with baseline fecal calprotectin >500 μg/g (HR, 3.5)
  • In patients selected for optimization, 56% (34/61) remained on ADA at 1 year and 41% (25/61) at 2 years

In their discussion, the authors state “current guidelines recommend switching to another class of biologics in case of LOR to ADA with therapeutic drug levels.” However, the authors note that their therapeutic level cut-off of >4.9 mcg/mL is lower than the latest recommendations. In addition, in their conclusion, they note that due to limited biologic options, “ADA optimization strategy might be considered” in a subgroup.

My take: Despite better results in the patients that swapped to VDZ in this study, I think it is important to assure adequate drug levels before choosing a new drug class. For ADA, expert recommendations have suggested a level of 8-12 as therapeutic and to avoid discontinuation if ADA level is less than 10. In this study, more than 40% remained on ADA two years after LOR in those with dosing optimization.

Related blog post:

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.

Panoramic View -Sandia Mountain, NM

Here’s Why Therapeutic Drug Monitoring Should Work

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RC Ungaro et al. Inflamm Bowel Dis 2022; 28: 649-651. Impact of Thiopurine Exposure on Immunogenicity to Infliximab Is Negligible in the Setting of Elevated Infliximab Concentrations

Background: Whether proactive therapeutic drug monitoring (pTDM) is superior to reactive TDM (rTDM) is not entirely clear, though some studies have shown better outcomes with pTDM. Additionally, Colombel et al (Clin Gastroenterol Hepatol 2019; 17: 1525-32) showed that antidrug antibodies during combination therapy were detected only in those with the lowest quartile of infliximab trough levels; this suggests that optimized monotherapy should be similarly effective to combination therapy.

Methods: The authors retrospectively analyzed a commercial laboratory database (Prometheus) with 3970 patients and paired 6-thioguanine (6-TGN) levels with infliximab (IFX) and antibodies to infliximab (ATIs)

Key findings:

  • “Those with higher levels of IFX had negligible benefit from concomitant thiopurine treatment in preventing ATIs.”
  • ATIs were detected in 9.9% of all patients. IFX level of >5 mcg/mL were associated with a very low risk of ATI (OR 0.05). “Immunogenicity was negligible (<3%) in the presence of IFX concentrations greater than 5 mcg/mL.”
  • 6-TGN levels (>125) were associated with lower risk of ATI, OR 0.42; though, this effect had a significant impact, only for those with with IFX <5 mcg/mL.
  • The authors note the prospective OPTIMIZE study (NCT04835506) should help determine the effectiveness of pTDM.

My take: In patients with IFX levels >5 mcg/mL, there does not appear to be much benefit for most patients from the addition of a thiopurine; this may not be true for those who are switching to a 2nd anti-TNF agent due to antidrug antibodies. This study supports pTDM to assure adequate IFX levels.

Related blog posts:

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

White Sands National Park, New Mexico

Favorite Posts of 2021

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I am happy to say that this is the last nightcall that I will have this year!

Today, I’ve compiled some of my favorite posts from the past year. I started this blog a little more than 10 years ago. I am grateful for the encouragement/suggestions from many people to help make this blog better. Also, I want to wish everyone a Happy New Year.

GI:

IBD:

LIVER:

Nutrition:

Other Topics:

Thanks to Jennifer

Expert Consensus: New Recommendations for Therapeutic Drug Monitoring

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AS Cheifetz et al. Am J Gastroenterol 2021;116: 2014-2025. A Comprehensive Literature Review and Expert Consensus Statement on Therapeutic Drug Monitoring of Biologics in Inflammatory Bowel Disease (published online August 13, 2021)

Key recommendations:

  • The panel agreed that reactive TDM should be used for all biologics for both primary nonresponse and secondary loss of response
  • It was recommended that treatment discontinuation should not be considered for infliximab or adalimumab until a drug concentration of at least 10–15 mg/mL was achieved
  • Consensus was also achieved regarding the utility of proactive TDM for anti–tumor necrosis factor therapy. It was recommended to perform proactive TDM after induction and at least once during maintenance.
  • More data are needed with regard to proactive TDM for biologics other than anti-TNF agents
  • There are no differences in interpreting TDM between originator biologics and biosimilars
  • When considering switching within drug class in case of secondary loss of response to a first anti-TNF drug because of the development of antidrug antibodies, an immunomodulator should be added to a subsequent anti-TNF therapy
  • Low-titer antidrug antibodies can be overcome by treatment optimization (dose escalation, dose interval shortening, and/or addition of an immunomodulator)

My take: This article should help support the practice of proactive TDM and discourage stopping anti-TNF agents until an adequate therapeutic level is achieved.

Related blog posts:

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.

For the Next Insurance Appeal: Therapeutic Drug Monitoring in Adalimumab Treatment (Pediatrics) & Satire on Prior Authorizations

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There is a lot of data supporting the use of therapeutic drug monitoring (TDM) for anti-TNF agents. A recent study (MJ Kim et al. JPGN 2021; 72: 870-876. Therapeutic Drug Monitoring of Adalimumab During Long-term Follow-up in Paediatric Patients With Crohn Disease) adds to this data and supports increased adalimumab (ADL) dosing if below target values.

In this prospective study of 31 pediatric patients with Crohn’s disease, the authors found correlations between ADL values and the endpoints of clinical remission (CR) and mucosal healing (MH). The authors checked TLs at 4 months, 1, 2, and 3 years. Key findings:

  • The median trough levels (TLs) of ADL were higher in patients in CR (7.6 ± 3.5 μg/mL) than in patients with active disease (5.1 ± 2.2 μg/mL).
  • ADL TLs were significantly higher in patients who achieved MH than in those who did not (14.2 ± 7.6 vs 7.8 ± 5.2 μg/mL). 
  • The optimal cut-point for predicting MH at 1 year of ADL treatment was 8.18 μg/mL
  • MH was noted in 42% at 4 months and 55% at 1 yr; CR was noted in 90% at 4 months and 84% at 1 yr. ADL treatment was associated with positive effects on growth indicators as well.

The authors discuss TDM for anti-TNF therapy, noting that for infliximab, the AGA recommends values >5 mcg/mL and the ACG >7.5 mcg/mL. There are fewer studies of ADL TDM -prior studies have indicated goals of >5.8, >7.1, >8, and >8.1; thus, this study is in agreement with these prior studies.

My take: This study further supports the value of TDM; better drug levels correlate with better outcomes.

Related blog posts:

Fort Jefferson, Dry Tortugas. The fort has reportedly 16 million bricks (I didn’t confirm this figure).

More satire —On Prior Authorizations:

Real-World Experience with Proactive Therapeutic Drug Monitoring in Inflammatory Bowel Disease

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A recent large retrospective pediatric study provides further evidence that therapeutic drug monitoring (TDM) in inflammatory bowel disease (IBD) results in better clinical outcomes. One of my partners, Chelly Dykes, is a coauthor and leads our ImproveCareNow team.

JL Lyles et al. Inflamm Bowel Dis 2021; 27: 482-492. Effect of a Practice-wide Anti-TNF Proactive Therapeutic Drug Monitoring Program on Outcomes in Pediatric Patients with Inflammatory Bowel Disease

This single center implemented a practice wide TDM approach in 2014. This study compared a historical pre-TDM group (n=108) to the TDM group (n=206). The primary outcome was sustained clinical remission (SCR22-52), defined as physician global assessment (PGA) of inactive from 22 to 52 weeks and off corticosteroids at 52 weeks. Key findings:

  • The SCR22-52 was achieved in 42% of pre-TDM and 59% of TDM patients (risk difference, 17.6%; 95% CI, 5.4–29%; P = 0.004)
  • The TDM group had an increased adjusted odds of achieving SCR22-52 (odds ratio, 2.03; 95% CI, 1.27–3.26; P = 0.003)
  • The adjusted risk of developing high titer antidrug antibodies (ADAs) was lower in the post-TDM group (hazard ratio, 0.18; 95% CI, 0.09–0.35; P < 0.001)
  • The SCBR22-52 (which was defined by normal CRP along with SCR22-52) was 24.7% in pre-TDM and 42.7% in the TDM group
  • The authors did not identify a significantly higher rate of anti-TNF cessation in either group
  • Only 12% of patients in their practice were receiving combination therapy

In the discussion, the authors review three pivotal studies which also support proactive TDM: TAXIT, TAILORIX, and PAILOT.

My take: While this was an observational study with historical controls, the findings are convincing that proactive TDM is helpful, particularly in patients who are not receiving combination therapy.

Related blog posts:

March 31, 2021