Phase III study of Nucala meets primary endpoint in Hypereosinophilic Syndrome.- GSK

GlaxoSmithKline announced positive results from the pivotal study of Nucala (mepolizumab) in the treatment of patients living with Hypereosinophilic Syndrome (HES), making it the first treatment to demonstrate a reduction in flares for this rare disease. The phase III study met its primary endpoint, demonstrating a statistically significant result with 50% fewer patients experiencing a HES flare (worsening of symptoms or eosinophil threshold requiring an escalation in therapy) when treated with mepolizumab, compared to placebo, when added to standard of care treatment over the 32-week study period (56% vs 28%; p=0.002).

Secondary endpoints from the study were also statistically significant and supported the primary endpoint, showing the risk of first HES flare over the study period was 66% lower for patients treated with mepolizumab compared to placebo (hazard ratio 0.34; 95% CI 0.18, 0.67). There was a 66% reduction in the annualised rate of HES flares versus placebo (rate ratio 0.34; 95% CI 0.19, 0.63). Fatigue scores improved in mepolizumab compared to placebo (p=0.036). The safety results in the study were consistent with the known profile of mepolizumab.

Based on these data, GSK plans to progress regulatory submissions in 2020. Mepolizumab is not approved for use in HES anywhere in the world. Further results from the study will be submitted for future presentation at upcoming scientific meetings and in peer-reviewed publications.