Bioequivalence of Two Perampanel Oral Suspension Formulations in Healthy Subjects: A Randomized Crossover Study

Perampanel has been approved for the adjunctive treatment of partial-onset seizures and primary generalized tonic-clonic seizures. The oral suspension formulation benefits patients who have difficulty swallowing tablets. The unavailability of an affordable generic perampanel oral suspension formulation increased the need for a cheaper bioequivalent alternative to the marketed reference product. The study aimed to assess the bioequivalence of two formulations of perampanel oral suspension (0.5 mg/mL) administered under fasting conditions focusing on providing a cost-effective and accessible alternative to current formulations.

This was an open-label, two-period, two-sequence, crossover, bioequivalence study conducted under fasting conditions. Healthy subjects were randomized to receive single doses of perampanel oral suspension (12 mg), Lepsiramp and Fycompa^® separated by a 6-week washout period. The maximum concentration and area under the concentration-time curve up to 72 h were the primary pharmacokinetic parameters used to assess bioequivalence.

The geometric mean ratio of test to reference formulations and 90% confidence interval were 109.55 (99.49-120.64) for maximum concentration and 98.15 (90.68-106.23) for the area under the concentration-time curve up to 72 h_, which were within the 80-125% bioequivalence range. The adverse events were mild headache and dizziness.

The two oral suspension formulations were bioequivalent, safe, and well tolerated. This provides a beneficial affordable alternative for patients requiring non-tablet oral formulations.

The ClinicalTrials.gov registration number is NCT06969963, retrospectively registered on 13 May, 2025.