Horizon Therapeutics plc announced that the primary endpoint was met for the second population in its Phase 2 clinical trial evaluating dazodalibep for the treatment of Sjögren's syndrome. The Phase 2 trial evaluated two patient populations and positive results in the first patient population were announced in September 2022. Dazodalibep is the only medicine in development to achieve the primary endpoint in both patient populations in a Phase 2 trial.

The Company announced that the second population achieved the primary endpoint. This patient population includes those with moderate-to-severe symptomatology including dryness, pain and fatigue despite lacking additional organ involvement and is defined as patients with a European Alliance of Associations for Rheumatology (EULAR) Sjögren's Syndrome Patient Reported Index (ESSPRI) score of = 5, indicative of significant symptomatic burden, and a score of <5 on the EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI), which measures organ involvement. At Day 169, dazodalibep-treated patients achieved a 1.8-point reduction in their ESSPRI scores compared to placebo-treated patients who achieved a 0.53-point reduction, resulting in a least squares mean difference of 1.27 (p=0.0002).

The ESSPRI is a composite endpoint that measures dryness, pain and fatigue severity. The previously announced positive results were in patients with moderate-to-severe systemic disease: systemic clinical manifestations in one or more organ systems in addition to the traditional Sjogren's manifestations, and an ESSDAI of = 5. In addition to the primary endpoint, statistical significance was achieved in certain secondary quality of life measures, including fatigue as measured by Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F). Dazodalibep was well tolerated with the most common adverse events through Day 169 being COVID-19 infection, nasopharyngitis and anemia.

These data follow positive Phase 2 trial results announced in September in a separate study population. That portion of the study met its primary endpoint in patients with moderate-to-high systemic disease activity as defined by an ESSDAI score of = 5. At Day 169, patients treated with dazodalibep achieved a 6.3-point reduction in their ESSDAI score and patients treated with placebo achieved a 4.1-point reduction, resulting in a statistically significant least squares mean difference of 2.2 points (p=0.017).