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- Presentation
Therapeutic Drug Monitoring in Hidradenitis Suppurativa: Adalimumab and Infliximab
Description
The transcript reviews therapeutic drug monitoring (TDM) for TNF-alpha inhibitors in hidradenitis suppurativa (HS), focusing on adalimumab and infliximab. Because HS biologics often have primary non-response and later loss of response, and because there are no validated biomarkers to guide dosing, TDM may help by measuring serum drug levels and anti-drug antibodies. In adalimumab, early trial data and retrospective studies suggested higher drug levels in responders than non-responders, but validated targets are still lacking. A recent prospective pilot study found that higher adalimumab levels correlated with better clinical response, longer treatment duration, improved quality of life, and fewer antibodies; a level around 10.7 was useful for distinguishing low responders from partial/high responders, though high responders often had much higher levels. The speaker recommends reactive, rather than proactive, monitoring in HS for patients with poor or fading response, especially when factors like high BMI, elevated CRP, low albumin, missed doses, or prior antibodies suggest low levels. If antibodies are present, low titers may sometimes be overcome by dose escalation or adding immunosuppressants, but very high titers usually require switching therapy. For infliximab, HS patients often need higher and more frequent dosing than in other diseases, and preliminary data suggest responders have substantially higher trough levels than non-responders, reinforcing the need for HS-specific research; a prospective infliximab monitoring study is underway.
View moreConclusions
- Therapeutic drug monitoring appears useful in hidradenitis suppurativa because biologic drug survival declines over time and fixed dosing may not fit all patients.
- For adalimumab, higher serum drug levels are associated with better clinical response, better quality of life, and longer treatment continuation.
- An adalimumab trough level around 10.7 µg/mL may help distinguish low responders from partial or high responders, but even higher levels may be needed for the strongest responses.
- Anti-drug antibodies are associated with lower adalimumab levels, higher drug clearance, and poorer treatment outcomes.
- Reactive therapeutic drug monitoring is the most supported approach in HS for patients with inadequate or lost response, whereas proactive monitoring remains insufficiently validated.
- If adalimumab levels are low and antibodies are low, dose escalation or adding an immunosuppressant may help, but very high antibody titers likely require switching therapy.
- Patients with high CRP, high BMI, low albumin, missed doses, or prior antibody history are more likely to have subtherapeutic drug levels and may benefit from monitoring.
- Infliximab likely also requires higher and more frequent dosing in HS than in other diseases, and HS-specific target drug levels are probably higher than inflammatory bowel disease targets.
- Overall, the data support individualized biologic dosing in HS, but larger prospective studies are still needed to define validated target levels, especially for infliximab.
- Prens et al. 2021. PMID 33544917.
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