#NASPGHAN17 Is it time to stop using thiopurine therapy?

This blog entry has abbreviated/summarized this presentation. Though not intentional, some important material is likely to have been omitted; in addition, transcription errors are possible as well.

Safety in Pediatric IBD Therapy: Is it time to stop using thiopurines?

Jeffrey Hyams  Connecticut Children’s Medical Center

Key points from this lecture:

  • Dr. Hyams:  “There are better options than thiopurines in 2017 due to infrequent but serious risks”
  • The DEVEVOP study showed that anti-TNF agents did NOT increase the risk of lymphoma or hemophagocytic lymphohistiocytosis (HLH).  In contrast, these risks do occur with thiopurines –this is infrequent but remains significant.
  • Therapeutic drug monitoring may obviate the need for combination/dual therapy which has been shown to improve response rates to anti-TNF agents; methotrexate may work for combination therapy and may be safer than thiopurines
  • If a thiopurine is used as part of combination therapy, short duration (~6 months) is likely to have low risks
  • In addition to Dr. Hyams, Dr. Baldassano, in his discussion of treat to target (discussed in subsequent post), echoed the sentiment that he no longer recommends thiopurine therapy

Dr. Hyams slides list some of the relative risks of thiopurine therapy.  To understand these risks, the absolute risk is probably more helpful.

My take: This lecture did not focus on the main benefit of thiopurines which is its use in combination therapy. Many experts consider combination therapy to be the standard of care for adults with Crohn’s disease.  The advantages of combination therapy are mainly due to improved durability of anti-TNF therapy and lower antidrug antibodies.  How this benefit stacks up against the risks discussed in this lecture and whether this benefit can be supplanted by the use of therapeutic drug monitoring is uncertain.

 

Related blog posts:

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

What I did not know …a few items

  1. 6-Mercaptopurine (6-MP) often can be used when patients are intolerant of azathioprineS Hubener et al. Clin Gastroenterol Hepatol 2016; 14: 445-53.  This retrospective study showed that 15 of 20 patients with autoimmune hepatitis and prior azathioprine intolerance responded to 6-MP.  This is somewhat unexpected as azathioprine is metabolized into 6-MP.  However, rather than 6-thiouracil, the “imidazol component of azathioprine, which is cleaved off…might trigger adverse reactions.”  Another artical on thiopurines (Aliment Pharmacol Ther 2016; 43: 863-883) (thanks to Ben God for this reference) provides a thorough review of the pharmacogenetics and pharmocokinetics of these medications.  While this review reinforces the recommendation to check TPMT before treatment, it notes that only a small proportion of thiopurine toxicity is related to deficient TPMT activity.
  2. There is no formal validated or consensus definitions of mild, moderate, or severe IBD. L Peyrin-Biroulet et al. Clin Gastroenterol Hepatol 2016; 14: 348-54.  While the Lemann index measures the cumulative structural bowel disease, the authors propose criteria which involves three areas of severity: impact of the disease on the patient (eg. clinical symptoms), inflammatory burden (eg. biomarkers, mucosal disease, disease extent), and disease course (eg. structural disease, intestinal resection, perianal disease, extraintestinal manifestations)
  3. Fundic gland polyps (often associated with proton pump inhibitor therapy) are not premalignant lesions. There is an “inverse correlation between the FGPs and gastric neoplasia.” S Varghese et al. Gastroenterol Hepatol; 2016; 12: 153-4.
  4. Parents of newborns do not know how to use car seats.  BD Hoffman et al (J Pediatr 2016; 171: 48-54) showed that 95% of car seats were misused (291 families).  Serious misuse was present in 91%.

 

Related blog posts: Lemann index: Short Takes on IBD Articles | gutsandgrowth

Gibbs Gardens has >20 million daffodils

Gibbs Gardens has >20 million daffodils

Not Much Data with Allopurinol

The authors of a recent case report (JPGN 2014; 59: 22-24) note that there has been “only 1 study on the pediatric use of allopurinol in inflammatory bowel disease.”  A previous post on this blog has reviewed the use of allopurinol for IBD and provided several references –mainly from use in adults (Data on Allopurinol | gutsandgrowth).

This current study reports on three cases.  In all three cases the combination of allopurinol with low-dose 6-mercaptopurine resulted in clinical remission, including one patient which was poorly responsive to infliximab.  In all three cases, frequent thiopurine metabolites were obtained to help guide dosing.  Prior to allopurinol, all 3 patients had a 6-MMP/6-TG ratio >20; with use of allopurinol there was a decrease in this ratio.

Among these patients, one developed mild leukopenia which resolved with medication adjustment.

Bottomline: Allopurinol can be effective in optimizing thiopurine treatment, but need to be administered carefully.  More studies on its use are needed.

Sticky Decisions with IBD Therapy – When an Infection or Malignancy Develops

A recent review article provides advice for management of biologics and immunomodulators when an infection or malignancy develops (Inflamm Bowel Dis 2014; 20: 926-35).  Serious infections are noted in 3-5% of adults receiving either thiopurines or anti-tumor necrosis factor agents (anti-TNFs); less than 0.1% of adults develop treatment-related lymphoma.  The recommendations are provided in 5 separate tables.

Table 1 addresses the issue of bacterial infectionsFor mild infections, the authors recommend that thiopurines (azathiopurine, 6-mercaptopurine) as well as anti-tumor necrosis factor agents (infliximab, adalimumab, certolizumab, golimumab) be continued.  Examples of these ‘mild’ infectious included E. coli UTI and strep pharyngitis.  For severe bacterial infections (eg. pneumococcal pneumonia), for both these therapies, the authors recommend: “stop, but may restart once treated.”  For bacterial opportunistic infections (eg. mycobacterium), for latent infections, “do not start until 2 to 4 wk INH” whereas for active infections, the authors recommend (for anti-TNFs) “stop, only restart after full treatment, and if IBD is severe.”

  • Table 2 addresses fungal infections.
  • Table 3 addresses viral infections (eg. CMV, EBV).  For EBV, the authors recommend stopping thiopurines and not restarting in male patients.
  • Table 4 addresses malignancy: solid tumors, hepatosplenic T-cell, EBV-associated lymphoma, and lymphoproliferative lymphoma.
  • Table 5 addresses skin cancers.

Towards the end of the review, the authors provide some context for the risks with thiopurines and anti-TNFs.  “The majority of side effects associated with thiopurines and anti-TNFs are mild, self-limited and reversible…the risk of a lymphoma developing on AZA/6-MP (4/10,000 patient-years) is comparable with the lifetime risk of dying from drowning (1/1112) or dying in a bicycle accident (1/5000).  The risk is much less than the risk of dying in an automobile accident (1/108).  Patients are willing to accept risks..if their disease is severe and the chance of a clinical response outweighs the risk.”

With regard to dual therapy, the authors note, “it has been our practice to lower the concomitant AZA/6-MP in patients on combination therapy with anti-TNF and then to stop the thiopurine in patients in deep remission for 3 years. However, this decision must be individualized, and for patients with severe, disabling disease, we generally do not alter treatment.”

Bottomline: This is a useful advice/handy reference for the sticky situation of managing IBD in the face of infections and malignancy.

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.

 

AGA Guidelines for the Use of Thiopurines and Anti-TNF Agents for Crohn’s

The link (from KT Park’s twitter feed): gastrojournal.org/article/S0016-5085(13)01521-7/fulltext …

Some of the key points/recommendations for adults with Crohn’s disease:

  • In clinical practice, CD of moderate severity is defined as disease requiring systemic corticosteroids for symptom control.

For Induction of Remission:

  • We Suggest Against Using Thiopurine Monotherapy to Induce Remission in Patients With Moderately Severe CD (Weak Recommendation, Moderate-Quality Evidence)
  • We Suggest Against Using Methotrexate to Induce Remission in Patients With Moderately Severe CD (Weak Recommendation, Low-Quality Evidence)
  • We Recommend Using Anti–TNF-α Drugs to Induce Remission in Patients With Moderately Severe CD (Strong Recommendation, Moderate-Quality Evidence)
  • We Suggest Using Anti–TNF-α Drugs in Combination With Thiopurines Over Anti–TNF-α Drug Monotherapy to Induce Remission in Patients Who Have Moderately Severe CD (Weak Recommendation, Moderate-Quality Evidence)

Maintenance of Remission:

  • We Recommend Using Thiopurines Over No Immunomodulator Therapy to Maintain a Corticosteroid-Induced Remission in Patients With CD (Strong Recommendation, Moderate-Quality Evidence)
  • We Suggest Using Methotrexate Over No Immunomodulator Therapy to Maintain Corticosteroid-Induced Remission in Patients With CD (Weak Recommendation, Low-Quality Evidence)
  • We Recommend Using Anti–TNF-α Drugs Over No Anti–TNF-α Drugs to Maintain Corticosteroid- or Anti–TNF-α—Induced Remission in Patients With CD (Strong Recommendation, High-Quality Evidence)
  • We Make No Recommendation for or Against the Combination of an Anti–TNF-α Drug and a Thiopurine Versus an Anti–TNF-α Drug Alone to Maintain Remission Induced by a Combination of These Drugs in Patients With CD (No Recommendation, Low-Quality Evidence)

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Thiopurines associated with reduced risk of colon cancer

A recent study provides some good news for those using thiopurines (6-mercaptopurine and azathioprine) (Gastroenterol 2013; 145: 166-75).

Using the observational cohort enrolled in the French CESAME study (Cancers et Surrisque Associe aux Maladies Inflammatoires Intestinales En France), the authors followed 19,486 patients with IBD.  60.3% had Crohn’s disease, and 30.1% were receiving thiopurine therapy.  The study period was 2004-2007.  At the start of the study, 2841 patients (14.6%) had long-standing extensive colitis.

Among patients with long-standing extensive colitis, the hazard ratio for colrectal high grade dysplasia and cancer was 0.28 for those who received thiopurine therapy compared with those who never received thiopurine therapy.

Thus, this prospective study showed that while colorectal cancer (CRC) was increased in IBD patients with long-standing colitis, this risk was less among the subset who were treated with thiopurines.  Some previous studies have not found a reduction in CRC risk, though they may have been underpowered and biased as these studies came from referral centers.

The authors also cautioned that more than 1/3rd of CRC cases occurred in those without extensive colitis which may necessitate a lower threshold for screening colonoscopy.

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Mixed-review for Thiopurines

In this era of biologic agents for inflammatory bowel disease (IBD), the estimation of the risks and the benefits of thiopurines has been changing (Clin Gastroenterol Hepatol 2013; 11: 395-97).

The referenced article is an editorial that reviews new data on thiopurines as well as provide a background for their usage.

Main points:

  • After the SONIC trial, the usage of combination therapy in many IBD patients has regained favor with the main question: “How long to continue combination therapy?”
  • STORI trial evaluated withdrawal of infliximab (IFX) in patients on combined therapy.  More than 40% of patients who were withdrawn from IFX relapsed at 1 year.
  • After >20 years of thiopurine usage, more data is available on both short-term and long-term risks/benefits.  The risk of lymphoma in IBD patients on thiopurines is “4-fold increased…in the 6 evaluated studies.” Nonmelenoma skin cancer risk is increased by a hazard ratio of 5.9 in ongoing users and 3.9 in past thiopurine users.
  • At the same time, more recent studies have lowered the expectation of benefit for thiopurines (AZTEC trial, Cosnes study).

Related references:

  • Cosnes et al. Gastroenterol 2012; 142: s161.
  • Gastroenterol 2012; 142: 63-70.
  • Med Clin North Am 2010; 94: 93-113.

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