Serum infliximab concentrations and disease activity: a descriptive study of patients with psoriasis

Best Practice for Therapeutic Drug Monitoring of Infliximab: Position Statement from the International Association of Therapeutic Drug Monitoring and Clinical Toxicology

BACKGROUND

Infliximab, an anti-tumor necrosis factor monoclonal antibody, has revolutionized the pharmacological management of immune-mediated inflammatory diseases (IMIDs). This position statement critically reviews and examines existing data on therapeutic drug monitoring (TDM) of infliximab in patients with IMIDs. It provides a practical guide on implementing TDM in current clinical practices and outlines priority areas for future research.

METHODS

The endorsing TDM of Biologics and Pharmacometrics Committees of the International Association of TDM and Clinical Toxicology collaborated to create this position statement.

RESULTS

Accumulating data support the evidence for TDM of infliximab in the treatment of inflammatory bowel diseases, with limited investigation in other IMIDs. A universal approach to TDM may not fully realize the benefits of improving therapeutic outcomes. Patients at risk for increased infliximab clearance, particularly with a proactive strategy, stand to gain the most from TDM. Personalized exposure targets based on therapeutic goals, patient phenotype, and infliximab administration route are recommended. Rapid assays and home sampling strategies offer flexibility for point-of-care TDM. Ongoing studies on model-informed precision dosing in inflammatory bowel disease will help assess the additional value of precision dosing software tools. Patient education and empowerment, and electronic health record-integrated TDM solutions will facilitate routine TDM implementation. Although optimization of therapeutic effectiveness is a primary focus, the cost-reducing potential of TDM also merits consideration.

CONCLUSIONS

Successful implementation of TDM for infliximab necessitates interdisciplinary collaboration among clinicians, hospital pharmacists, and (quantitative) clinical pharmacologists to ensure an efficient research trajectory.

Association between infliximab concentrations and clinical response in psoriasis: a prospective cohort study

BACKGROUND

Infliximab (IFX) trough concentrations (C_min) have been linked to treatment efficacy in psoriatic patients. Inter-individual IFX C_min variability and factors influencing IFX pharmacokinetics could explain differences in treatment response.

OBJECTIVE

To evaluate the association between IFX C_min and clinical outcomes in psoriatic patients.

METHODS

Prospective study of 33 patients with moderate to severe psoriasis receiving IFX at Bellvitge University Hospital, between October 2013 and November 2016. IFX C_min and antibodies toward infliximab (ATI) were measured.

RESULTS

We collected 155 IFX C_min and ATI values (mean age, 46 (14) years; 11 (33.3%) women). Mean IFX C_min was 2.5 (2.4) mg/L and ATIs were detected in six patients, resulting in undetectable IFX C_min. IFX C_min was significantly associated with ATI and body mass index (BMI) (β -2.51, 95% CI -3.56 to -1.4 and β -0.05, 95% CI -0.09 to -0.01). PASI score and PASI 90/100 response were significantly associated with IFX C_min (IRR 0.80, 95% CI 0.70 to 0.92; OR 1.79, 95% CI 1.18 to 2.71 and OR 1.79, 95% CI 1.14 to 2.81).

CONCLUSION

IFX C_min significantly influences PASI 90/100 response rates. IFX C_min wa significantly associated with ATI and BMI. The observed inter-individual variability in IFX C_min supports the need for IFX drug monitoring.