Can Therapeutic Drug Monitoring with Monotherapy Achieve Similar Results as Combination Therapy for IBD?

A recent retrospective study (S Lega et al. Inflamm Bowel Dis 2019; 25: 134-41) suggests that proactive therapeutic drug monitoring (pTDM) with infliximab (IFX) helps achieve similar outcomes as combination therapy (with immunomodulator) in patients with inflammatory bowel disease.

Before reviewing the key findings, it is important to emphasize a few crucial limitations/methods:

  • The study enrolled 83 patients; only 16 received were in the monotherapy pTDM group.
  • This was a retrospective study
  • The authors utilized TDM at week 10.  If the IFX level was <20 mcg/mL, the dose and frequency of infliximab were both adjusted. If the level was between 20 & 25, either the frequency was adjusted or no adjustment, and if the level was >25, then no adjustment in dosing was performed.

Key findings:

  • The frequency of infliximab discontinuation with mono therapy in those with pTDM was lower than in those with ‘standard of care’ TDM (P=0.04) but did not differ from patients receiving combination therapy
  • Overall 9 of the 83 patients (11%) discontinued IFX during the 1-year study

In the discussion, the authors suggest that week 14 TDM may be suboptimal as this is the first time patients have an 8-week interval.

My take: The jury is out with regard to whether pTDM can negate the need for combination therapy  –a prospective trial is needed; however, the idea of getting TDM a bit earlier is intriguing, particularly as it has been shown that a high percentage of pediatric patients are receiving an insufficient dose of infliximab (Is Standard Infliximab Dose Tool Low in Pediatrics?)

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Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  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.

View from Artist’s Drive, Death Valley

Management of Acute Severe Colitis

A recent review (KG Whatley, MJ Rosen. Inflamm Bowel Dis 2019; 25: 56-66) succinctly summarizes the contemporary medical management of acute severe ulcerative colitis (ASUC).

Figure 1 provides a useful initial checklist which includes the following:

  • PUCAI score
  • Labs/Imaging: CBC/d, CMP, CRP/ESR, Stool studies (culture/C diff), AXR
  • Pre-salvage labs: TB screen, Hep B serology, VZV serology if needing anit-TNF, TPMT if contemplating thiopurine, lipids if contemplating calcineurin inhibitor
  • Endoscopy: Consider Flex Sig (unsedated) with tissue for CMV PCR if not responding to 3 days of IV steroids
  • Thromboembolism prophylaxis: Low molecular weight heparin (adults, & high-risk pediatric patients), pneumatic compression (low-risk pediatric)
  • Nutrition plan
  • Corticosteroids: methylprednisolone 1-15. mg/kg (to max of 40-60 mg daily)

Each of these recommendations is discussed. For the flex sig recommendation, the authors note that a “full colonoscopy is not recommended due to risk of perforation.” With regard to CMV, the authors acknowledge the low quality of evidence to support antiviral treatment of CMV in this setting.  In addition, the authors suggest PCP prophylaxis in those who receive triple immunosuppression or in those receiving calcineurin inhibitors.

Figure 2 provides a handy algorithm for infliximab salvage therapy in the setting of ASUC:

  • If salvage therapy with infliximab is indicated (day 3-5 of IV steroids), the authors recommend 10 mg/kg dosing.  If there is no response after 3-5 days, repeat dosing is recommended.  If there is no response after an additional 3-5 days, colectomy is recommended.
  • If there is a response to infliximab, the algorithm recommends outpatient management. At time of the 3rd dose (week 5-6), the authors obtain an IFX level.  In those with a level <15, then dosing at 4 week maintenance is recommended; whereas in those 15 and above, every 8 week maintenance is recommended.

The authors discuss some potential emerging treatments. Recommendations from the authors with regard to surgery:

  • Most patients are best served with a subtotal colectomy/end ileostomy in preparation for future ileal pouch anal anastomosis
  • “Surgery should not be delayed to enhance nutrition or taper steroids.”

My take: This article summarizes current approaches with emphasis on not waiting a long time for salvage therapies and using early therapeutic drug monitoring to assist in dosing frequency.

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Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  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.

Death Valley

 

ESPGHAN Position Paper: Biosimilars in Pediatric Inflammatory Bowel Disease

A recent position paper from ESPGHAN/Porto Group:

Full text: Use of Biosimilars in Pediatric Inflammatory Bowel Disease: An Updated Position Statement of the Pediatric IBD Porto Group of ESPGHAN. L de Riddler et al. JPGN 2019; 68: 144-53

Key points:

  • There are sufficient data (by extrapolation from different indications, adult data and limited pediatric data) to state that in children with IBD who are indicated for IFX treatment, CT-P13 is a safe and efficacious alternative to the originator IFX for
    induction, and maintenance, of remission. 97% agreement
  • A switch from the originator infliximab to CT-P13 may be considered in children with IBD in clinical remission, following at least 3 induction infusions. 84% agreement
  • Multiple switches (>1 switch) between biosimilars and reference drug or various biosimilars are not recommended in children with IBD, as data on interchangeability is limited and traceability of the drugs in case of loss of efficacy and/or safety signals may be compromised. 97% agreement
  • Physicians/institutions should keep records of brands and batch numbers of all biological medicines (including biosimilars) administered. 89% agreement

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Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  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.

AntiTNF Therapy Associated with Reduced Surgical Resections

Full text: Increased prevalence of anti‐TNF therapy in paediatric inflammatory bowel disease is associated with a decline in surgical resections during childhood JJ Ashton et al. Alim Pham Ther 2019; https://doi.org/10.1111/apt.15094

From absract:

Design: All patients diagnosed with PIBD within Wessex from 1997 to 2017 were assessed. The prevalence of anti‐TNF‐therapy and yearly surgery rates (resection and perianal) during childhood (<18 years) were analysed

Results: Eight‐hundred‐and‐twenty‐five children were included (498 Crohn’s disease, 272 ulcerative colitis, 55 IBD‐unclassified), mean age at diagnosis 13.6 years (1.6‐17.6), 39.6% female. The prevalence of anti‐TNF‐treated patients increased from 5.1% to 27.1% (2007‐2017), P = 0.0001. Surgical resection‐rate fell (7.1%‐1.5%, P = 0.001), driven by a decrease in Crohn’s disease resections (8.9%‐2.3%, P = 0.001)…

Patients started on anti‐TNF‐therapy less than 3 years post‐diagnosis (11.6%) vs later (28.6%) had a reduction in resections, P = 0.047. Anti‐TNF‐therapy prevalence was the only significant predictor of resection‐rate using multivariate regression (P = 0.011).

Conclusion: The prevalence of anti‐TNF‐therapy increased significantly, alongside a decrease in surgical resection‐rate. Patients diagnosed at younger ages still underwent surgery during childhood. Anti‐TNF‐therapy may reduce the need for surgical intervention in childhood, thereby influencing the natural history of PIBD.

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Big Biosimilar Study

Briefly noted: A Meyer et al. Ann Intern Med. 2018. DOI: 10.7326/M18-1512

Abstract link: Effectiveness and Safety of Reference Infliximab and Biosimilar in Crohn Disease: A French Equivalence Study

In this study with 5050 patients, based on review of an administration database, the authors found the following:

  • In multivariable analysis of the primary outcome, CT-P13 (biosimilar) was equivalent to infliximab reference product (RP) (HR, 0.92 [95% CI, 0.85 to 0.99]). 1147 patients in the RP group and 952 patients in the CT-P13 group met the composite end point (including 838 and 719 hospitalizations, respectively).
  • No differences in safety outcomes were observed between the 2 groups: serious infections (HR, 0.82 [CI, 0.61 to 1.11]), tuberculosis (HR, 1.10 [CI, 0.36 to 3.34]), and solid or hematologic cancer (HR, 0.66 [CI, 0.33 to 1.32]).

The authors conclude that “real-world data indicates that the effectiveness of CT-P13 is equivalent to that of RP for infliximab-naive patients with CD.”

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Pediatric Experience with Infliximab Biosimilar in UK

Briefly noted: N Chanchlani et al. JPGN 2018; 67: 513-9.  The authors report on the use of infliximab biosimilar (IFX-B), n=82, compared to infliximab originator (IFX-O) in 175.

  • While the authors did not find a difference with the biosimilar in terms of efficacy and adverse effects, this finding is quite limited; only 28 in IFX-O and 19 in IFX-B had a physician global assessment data which was used to determine efficacy.
  • The authors noted that less than 20% of their patients had a baseline and 3-month followup PCDAI recorded.
  • In addition, of those with available data, less than half (44%) had screening for hepatitis B and tuberculosis.
  • The authors estimate that 875,000 pounds would have been saved for a 1-year period with universal adoption of biosimilars

My take: This study, due to incomplete data, does not add much to our knowledge about biosimilars.  It does indicate that better screening prior to infusions for HBV and tuberculosis is needed along with more well-documented experience.

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Peyto Lake, Banff