VANCOUVER, BC—USL255 (Qudexy XR [topiramate]; Upsher-Smith) is an effective adjunctive treatment for refractory partial-onset seizures (POS) across patient ages and drug-resistance statuses, according to authors of an open-label extension (OLE) study presented at the 68th Annual AAN Meeting.

“These data suggest that once-daily USL255 Qudexy XR [topiramate] extended release capsules may be a useful treatment option for the long-term management of epilepsy for a broad range of patients with POS,” reported lead study author R. Edward Hogan, MD, of Washington University in St Louis, MO, and coauthors, in a poster presentation.

“Exposure to USL255 up to 400mg/day was associated with seizure reduction throughout the one-year OLE in patients with refractory POS,” the researchers wrote. “Efficacy was sustained across the one-year OLE, with seizure reduction observed as early as the first three weeks of treatment [compared to baseline]. Seizure reduction was observed across many patient subgroups, including those with highly drug-resistant seizures and in all adult age groups evaluated in this study.”

A total of 150 patients completed the 52-week OLE of the Phase 3 PREVAIL trial (NCT01142193), an 11-week study in which USL255 (250mg/day) was administered. The OLE consisted of 3-week blinded-conversion and 52-week open-label phase. Changes in USL255 dosage (50mg/week; ≤400mg/day) and concomitant AEDs were allowed after 11 weeks.

Seizure reduction during the OLE was “similar between patients within various age groups […] with efficacy observed early and maintained throughout the OLE,” the coauthors wrote. During the 52-week OLE phase, median percent-reduction in weekly POS frequency ranged between 59% (Weeks 1–12) and 72% (after Week 48), they reported.

Only 5% of patients saw a complete (100%) reduction in seizure frequency during the OLE phase.

Dr. Hogan and coauthors disclosed consultancy payments and other financial relationships with Upsher-Smith Laboratories.