Comparison of dopamine D2 receptor occupancy profiles between risperidone ISM versus oral risperidone and monthly...

Risperidone ISM® does not require loading dose or oral supplementation. Dopamine D2 Receptor Occupancy (D2RO) profiles between Risperidone ISM® versus oral risperidone (OR) and monthly paliperidone palmitate (PP1M) were compared.

D2RO time profiles were simulated using population pharmacokinetic models in conjunction with an Emax model relating D2RO with plasma levels.

The median time <65% D2RO threshold was predicted to be 0 days for 100 mg Risperidone ISM® versus 5 and 13 days for 8 mg OR, if an intermediate or poor adherence.A D2RO of more than 65% was predicted to be reached within 1 day after the first injection of Risperidone ISM®. Less than 1% of patients treated with Risperidone ISM were predicted to remain below 65% D2RO, while ranged 7-17% on treated with 150 PP1M would be below this threshold for the 28 day-period along the 4 months studied.

Risperidone ISM® achieves threshold D2RO on the first injection day and predicts higher median time above 65% D2RO than high OR doses in real clinical practice. A much faster onset of action and better D2RO coverage during the dosing interval was predicted for Risperidone ISM® versus PP1M. Simulations suggest that Risperidone ISM® compares favorably with high doses of OR and PP1M, making it an effective therapeutic strategy for rapid and sustained symptom reduction.