Everolimus dosing recommendations for tuberous sclerosis complex-associated refractory seizures

Area of Science:

• Pharmacology
• Neurology
• Oncology

Background:

• Tuberous sclerosis complex (TSC)-associated seizures are a significant challenge.
• Everolimus is used to manage these seizures, but optimal dosing requires understanding exposure-response relationships.

Purpose of the Study:

• To examine the exposure-response relationship between everolimus predose concentration (Cmin) and seizure response in TSC patients.
• To establish target Cmin ranges for therapeutic drug monitoring (TDM) and necessary doses for effective treatment.

Main Methods:

• A model-based approach predicted daily Cmin, with time-normalized Cmin (TN-Cmin) linking exposure to efficacy and safety.
• Conditional logistic regression analyzed response probability versus exposure.
• Multiplicative linear regression assessed seizure frequency (SF) and exposure.
• Extended Cox regression evaluated exposure and time to adverse events.

Main Results:

• A strong, significant relationship was found between everolimus exposure (TN-Cmin) and seizure response (SF), irrespective of age or CYP3A4 interactions.
• Increased TN-Cmin was not significantly linked to higher risks of stomatitis or infections.

Conclusions:

• Recommended TDM targets for everolimus Cmin are 5-7 ng/mL initially, and 5-15 ng/mL for inadequate response.
• Starting doses should consider patient age and concomitant use of CYP3A4/P-glycoprotein modulators.