Therapeutic Drug Monitoring for Current and Investigational Inflammatory Bowel Disease Treatments

This article reviews therapeutic drug monitoring (TDM) use for current inflammatory bowel disease (IBD) treatments. IBD comprises Crohn's disease and ulcerative colitis-chronic gastrointestinal inflammatory disorders. Treatment options for moderate to severe IBD include thiopurines; methotrexate; biologic agents targeting tumor necrosis factor, α4β7 integrin or interleukins 12 and 23; and Janus kinase inhibitors. TDM is recommended to guide treatment decisions for some of these agents. Published literature concerning TDM for IBD treatments was reviewed. S.D.L., R.S., and E.V.L. drew on their clinical experiences. Polymorphisms resulting in altered enzymatic activity inactivating thiopurine metabolites can lead to myelotoxicity and hepatotoxicity. Increased elimination of biologic agents can result from immunogenicity or higher disease activity, leading to low drug concentration and consequent nonresponse or loss of response. TDM may aid treatment and dose decisions for individual patients, based on monitoring metabolite levels for thiopurines, or serum drug trough concentration and antidrug antibody levels for biologic agents. Challenges remain around TDM implementation in IBD, including the lack of uniform assay methods and guidance for interpreting results. The Janus kinase inhibitor tofacitinib is not impacted by enzyme polymorphisms or disease activity, and is not expected to stimulate the formation of neutralizing antidrug antibodies. TDM is associated with implementation challenges, despite the recommendation of its use for guiding many IBD treatments. Newer small molecules with less susceptibility to patient variability factors may fulfill the unmet need of treatment options that do not require TDM, although further study is required to confirm this.

Efficacy and safety of tofacitinib dose de-escalation and dose escalation for patients with ulcerative colitis: results from OCTAVE Open

BACKGROUND

For patients with UC, flexible maintenance dosing therapy may confer advantages for safety, efficacy, costs and patient preference. Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of UC.

AIM

To assess the efficacy and safety of tofacitinib dose de-escalation and escalation in patients with UC.

METHODS

We evaluated data (November 2017 data cut-off) from OCTAVE Open, an ongoing, open-label, long-term extension study. The dose de-escalation group comprised 66 tofacitinib induction responders in remission following 52 weeks' tofacitinib 10 mg b.d. maintenance therapy, subsequently de-escalated to 5 mg b.d. in OCTAVE Open. The dose escalation group comprised 57 tofacitinib induction responders who experienced treatment failure while receiving 5 mg b.d. maintenance therapy, subsequently escalated to 10 mg b.d. in OCTAVE Open.

RESULTS

After tofacitinib de-escalation, 92.4% (61/66) and 84.1% (53/63) of patients maintained clinical response and 80.3% (53/66) and 74.6% (47/63) maintained remission, at months 2 and 12, respectively. After dose escalation, 57.9% (33/57) and 64.9% (37/57) of patients recaptured clinical response and 35.1% (20/57) and 49.1% (28/57) were in remission, at months 2 and 12, respectively. The incidence rate of herpes zoster with dose escalation (7.6 patients with events/100 patient-years) was numerically higher than in the overall tofacitinib UC programme.

CONCLUSIONS

Following tofacitinib de-escalation in patients already in remission on 10 mg b.d., most maintained remission, although 25.4% lost remission, at month 12. For induction responders who dose-escalated following treatment failure on 5 mg b.d. maintenance therapy, 49.1% achieved remission by month 12. (ClinicalTrials.gov number: NCT01470612).

Patient and physician preferences for ulcerative colitis treatments in the United States

Purpose: This study aimed to elicit patient and physician preferences for ulcerative colitis (UC) treatments in the United States (US).

Patients and methods: The following UC treatment attributes included in the discrete-choice experiment (DCE) were identified during qualitative interviews with both patients and physicians: time to symptom improvement, chance of long-term symptom control, risks of serious infection and malignancy, mode and frequency of administration, and need for steroids. The DCE survey instruments were developed and administered to patients and physicians. A random-parameters logit model was used to estimate preference weights and conditional relative importance for these attributes.

Results: A total of 200 patients with moderate to severe UC (status determined using self-reported medication history) and 200 gastroenterologists completed the survey. Patients’ average age was 42 years; most (59%) were female. Patients considered symptom control 2.5 times as important as time to symptom improvement and 5-year risk of malignancy almost as important as long-term symptom control (relative importance, 0.79 vs 0.96 for long-term symptom control); they preferred oral to subcutaneous or intravenous administration (relative importance, 0.47 vs 0.11 and 0.18, respectively). For physicians, symptom control was the most important attribute and was five times as important as the risk of malignancy.

Conclusion: Both patients and physicians considered long-term symptom control the most important attribute relative to others; however, risk of malignancy was of almost-equal importance to patients but not physicians. Differences between patients’ and physicians’ preferences highlight the need for improved communication about the relevant benefits and risks of different UC treatments to improve therapeutic decision-making.

Outcomes of Pregnancies With Maternal/Paternal Exposure in the Tofacitinib Safety Databases for Ulcerative Colitis

BACKGROUND

Active inflammatory bowel disease increases the risk of adverse pregnancy outcomes. Tofacitinib is an oral, small molecule Janus kinase inhibitor for the treatment of ulcerative colitis (UC). As a small molecule, tofacitinib is likely to cross the placental barrier; however, information on the effects of tofacitinib on pregnancy outcomes is limited. We report pregnancy and newborn outcomes among patients in UC clinical studies with prenatal (maternal/paternal) exposure to tofacitinib.

METHODS

Pregnancies with maternal/paternal exposure to tofacitinib were identified and outcomes reported in 5 tofacitinib UC interventional studies (up to March 2017). Outcomes from tofacitinib rheumatoid arthritis (RA), psoriasis, and psoriatic arthritis interventional studies, and RA noninterventional postapproval safety studies, spontaneous adverse event reporting, and registry data are also reported.

RESULTS

Of 1157 patients enrolled in the UC interventional studies, 301 were women of childbearing age. Eleven cases of maternal exposure and 14 cases of paternal exposure to tofacitinib (doses of 5 mg or 10 mg twice daily) before/at the time of conception or during pregnancy were identified. Outcomes included 15 healthy newborns, no fetal deaths, no neonatal deaths, no congenital malformations, 2 spontaneous abortions, and 2 medical terminations. Outcomes across other tofacitinib studies and postmarketing cases were consistent, with a healthy newborn being the most common outcome and no fetal deaths.

CONCLUSIONS

Based on the limited data available, pregnancy and newborn outcomes among patients with prenatal (maternal/paternal) exposure to tofacitinib in UC studies appear similar to those reported for other tofacitinib clinical study populations and the general population.

Immunogenicity of biologics in inflammatory bowel disease

Crohn's disease and ulcerative colitis are chronic inflammatory disorders of the gastrointestinal tract. Treatment options include biologic therapies; however, a proportion of patients lose response to biologics, partly due to the formation of anti-drug antibodies (ADAbs). Concomitant immunosuppressive agents reduce the development of ADAbs. This review article aims to assess the immunogenicity of biologic therapies and their clinical implications. A comprehensive literature search was conducted for articles published January 2009 to August 2015 reporting immunogenicity to adalimumab (ADM), certolizumab pegol (CZP), golimumab, infliximab (IFX), ustekinumab, and vedolizumab in inflammatory bowel disease (IBD). Eligible articles were reviewed and quality assessed by independent reviewers. Overall, 122 publications reporting 114 studies were assessed. ADAbs were reported for all agents, but the percentage of patients developing ADAbs was extremely variable, with the highest (65.3%) being for IFX administration to patients with IBD. ADAb presence was frequently associated with a reduction in primary efficacy and a loss of response, and, for IFX, an increase in adverse events (AEs). Lower serum levels of ADM, CZP and IFX were seen in ADAbs-positive rather than ADAbs-negative patients; pharmacokinetic data were unavailable for other therapies. Little information was available regarding the timing of ADAb development; studies reported their detection from as early as 10-14 days up to months after treatment initiation. Biologic therapies carry an intrinsic risk of immunogenicity, although reported rates of ADAbs vary considerably. The clinical implications of immunogenicity are a concern for effective treatment; further research, particularly into the more recently approved biologics, is required.

Pregnancy Outcomes in the Tofacitinib Safety Databases for Rheumatoid Arthritis and Psoriasis

INTRODUCTION

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA), and is being investigated for the treatment of psoriasis. Both conditions can present in women of child-bearing potential, but pregnancy was an exclusion and discontinuation criterion in tofacitinib randomized controlled trials (RCTs) because of the unknown effects of tofacitinib on mother and child. Tofacitinib is a small molecule that has the potential to cross the placenta.

OBJECTIVE

The objective was to report outcomes of pregnancy cases identified through April 2014 from tofacitinib RA/psoriasis RCTs, RA post-approval non-interventional studies, and spontaneous adverse-event reporting.

METHODS

Pregnancy outcomes were categorized as follows: healthy newborn, medical termination, fetal death, congenital malformation, spontaneous abortion, or pending/lost to follow-up.

RESULTS

Out of 9815 patients, 1821 female patients of child-bearing age were enrolled in the RA/psoriasis RCTs; 47 women became pregnant, including 33 who received tofacitinib monotherapy, 13 who received combination therapy with methotrexate (RA patients only), and one patient whose therapy was still blinded. No fetal deaths were reported. One congenital pulmonary valve stenosis (monotherapy, n = 1), seven spontaneous abortions (monotherapy, n = 4; combination therapy, n = 3), and eight medical terminations (monotherapy, n = 4; combination therapy, n = 3; blinded therapy, n = 1) were identified. Remaining cases reported healthy newborns (n = 25) or were pending/lost to follow-up (n = 6). Forty-four cases of paternal exposure to tofacitinib were reported (monotherapy, n = 43; combination therapy, n = 1), including five spontaneous abortions (monotherapy, n = 4; combination therapy, n = 1), 23 healthy newborns, and 16 pending/lost to follow-up.

CONCLUSIONS

The pregnancy outcomes reported in this small number of RA/psoriasis patients appear similar to those observed in the general population and in patients treated with biologic therapies for inflammatory diseases. However, definitive conclusions cannot be drawn, and pregnancy outcomes in patients receiving tofacitinib will continue to be monitored.

Ulcerative Colitis Treatment Patterns and Cost of Care

OBJECTIVES

To examine treatment patterns, dosing, health care resource utilization, and cost of tumor necrosis factor inhibitors (TNFi), adalimumab (ADA) and infliximab (IFX), among patients enrolled in US Humana insurance plans who have been diagnosed with ulcerative colitis (UC).

METHODS

This retrospective cohort study identified the first pharmacy or medical claim for ADA or IFX (from January 1, 2007, to December 31, 2014) in patients with continuous enrollment for 6 months or more preindex and 12 months or more postindex, with one or more UC diagnosis claim 6 months pre- or postindex. TNFi discontinuation was defined as a therapy gap of 56 days or more for ADA and 112 days or more for IFX. TNFi switch was defined as nonindex TNFi initiation. Health care resource utilization and costs were characterized quarterly according to treatment patterns.

RESULTS

The study population comprised 295 patients: mean age 50.9 years, 50.5% females, and 61.7% in southern United States. At the index date, 17% of patients received ADA and 83% received IFX. Treatment discontinuation was observed in 52% of ADA and 45% of IFX users through 12 months postindex (mean time 19 and 22 weeks, respectively). Among discontinuers, 46% of ADA and 68% of IFX users did not restart/switch TNFi. ADA and IFX showed mean times to switch of 18 and 30 weeks, respectively. TNFi discontinuers had the lowest mean quarterly total health care cost ($3,935) versus patients who initiated/switched TNFi ($15,004). Nevertheless, discontinuers had higher UC-related hospitalization versus patients receiving therapy.

CONCLUSIONS

Approximately half of ADA and IFX users discontinued, with approximately half of discontinuers not restarting/switching therapies. Further investigation of treatment patterns and outcomes after TNFi discontinuation is required.

Tofacitinib for induction and maintenance therapy of Crohn's disease: results of two phase IIb randomised placebo-controlled trials

OBJECTIVE

Tofacitinib is an oral, small-molecule Janus kinase inhibitor that is being investigated for IBD. We evaluated the efficacy and safety of tofacitinib for induction and maintenance treatment in patients with moderate-to-severe Crohn's disease (CD).

DESIGN

We conducted two randomised, double-blind, placebo-controlled, multicentre phase IIb studies. Adult patients with moderate-to-severe CD were randomised to receive induction treatment with placebo, tofacitinib 5 or 10 mg twice daily for 8 weeks. Those achieving clinical response-100 or remission were re-randomised to maintenance treatment with placebo, tofacitinib 5 or 10 mg twice daily for 26 weeks. Primary endpoints were clinical remission at the end of the induction study, and clinical response-100 or remission at the end of the maintenance study.

RESULTS

180/280 patients randomised in the induction study were enrolled in the maintenance study. At week 8 of induction, the proportion of patients with clinical remission was 43.5% and 43.0% with 5 and 10 mg twice daily, respectively, compared with 36.7% in the placebo group (p=0.325 and 0.392 for 5 and 10 mg twice daily vs placebo). At week 26 of maintenance, the proportion of patients with clinical response-100 or remission was 55.8% with tofacitinib 10 mg twice daily compared with 39.5% with tofacitinib 5 mg twice daily and 38.1% with placebo (p=0.130 for 10 mg twice daily vs placebo). Compared with placebo, the change in C-reactive protein from baseline was statistically significant (p<0.0001) with 10 mg twice daily after both induction and maintenance treatments.

CONCLUSIONS

Primary efficacy endpoints were not significantly different from placebo, although there was evidence of a minor treatment effect. No new safety signals were observed for tofacitinib.

TRIAL REGISTRATION NUMBERS

NCT01393626 and NCT01393899.