Sumitomo Dainippon Seeks Japanese Approval for Trerief to Treat Parkinsonism in Dementia Patients

Sumitomo Dainippon Pharma has asked Japanese authorities to approve its Trerief (zonisamide) as a new therapy for parkinsonism in dementia patients with Lewy bodies, the company announced in a press release.

Trerief went on sale in Japan in March 2009 as a treatment for Parkinson’s patients who saw insufficient results with levodopa and other Parkinson’s-specific drugs. After a 2013 expansion of its original approval, Trerief is now accepted as a treatment option in Japan, where a 2014 Patient Survey reported some  144,000 patients suffering from “vascular dementia and unspecified dementia,” including dementia with Lewe’s bodies (DLB).

Parkinsonism is a general term used to describe a group of neurological disorders that cause movement problems similar to those observed in Parkinson’s disease, like tremors, slow movement and stiffness.

The DLB form of dementia causes progressive cognitive impairment. Parkinsonism is one of the four core features of DLB, alongside fluctuating cognition, recurrent visual hallucinations and rapid eye movement (REM) sleep behavior disorder.

DLB is classified as part of the Lewy body disease spectrum, which also includes Parkinson’s disease. Since symptoms of parkinsonism virtually mimic those of Parkinson’s disease, Sumitomo Dainippon is now seeking approval for Trerief as another therapeutic option for treating parkinsonism in DLB, under the assumption that its action will be equally effective.

If approved, Trerief will be the world’s first drug to treat parkinsonism in DLB. Sumitomo Dainippon based its application on data from a Phase 3, multicenter, placebo-controlled, randomized, double-blind, 12-week study of Trerief in patients with parkinsonism accompanying DLB. Topline results were disclosed in early April.

The study evaluated the efficacy and safety of Trerief in 351 patients randomized to receive the active compound at 25 mg/daily, 50 mg/daily, or placebo.

Using the Unified Parkinson’s Disease Rating Scale — a rating scale that measures disability and impairment in Parkinson’s and also the primary outcome measure in most clinical trials of Parkinson’s therapeutics – the primary endpoint of the study at 12 weeks was significantly higher in the groups receiving Trerief, compared to placebo.

According to the April report of topline results, the incidence of treatment emergent adverse effects was no different than those previously reported. Incidence at 25 mg/daily was 48.7 percent, rising to 54.5 percent at 50 mg/daily, while in the placebo group, it was 47.1 percent.