Amgen has announced positive topline results from the Phase 3 OASIZ 301 study evaluating dazodalibep in adults with Sjögren’s disease (SjD) and moderate-to-severe systemic disease activity. The study met its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement in systemic disease activity at Week 48, as measured by the EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI).

According to Amgen, improvements in ESSDAI were observed as early as Week 4 among patients treated with dazodalibep and were sustained through Week 48. ESSDAI is a validated clinical tool used to assess systemic disease activity across multiple organ systems in people with Sjögren’s disease.

Sjögren’s disease is a systemic autoimmune condition that can affect multiple parts of the body. In addition to persistent dryness, patients may experience fatigue, chronic pain, organ involvement and neuropathy, while the disease is also associated with an increased risk of lymphoma. There are currently no FDA-approved medicines specifically indicated for Sjögren’s disease.

Jay Bradner, M.D., executive vice president, research and development, artificial intelligence and data at Amgen, said, “The results mark an important step forward for people living with Sjögren's disease, a condition with significant unmet need and no approved systemic treatment options.” The rapid and sustained improvement in systemic disease activity supports the company’s continued development of dazodalibep across its Phase 3 programme.

The most common adverse events, defined as those occurring in at least 5 percent of participants and at a higher rate with dazodalibep than placebo, included nasopharyngitis, urinary tract infection, hypertension and infusion-related reactions. These events were generally mild to moderate in severity. Discontinuations due to adverse events occurred at a low rate and were balanced between the treatment groups. Amgen reported no imbalance in thromboembolic events or opportunistic infections across the treatment arms.

Amgen plans to present detailed data from the OASIZ 301 study at an upcoming medical meeting. The Phase 3 OASIZ 303 study, which is evaluating dazodalibep in patients with moderate-to-severe symptomatic Sjögren’s disease, is expected to complete in the fourth quarter of 2026.

Dazodalibep is a potential CD40L antagonist fusion protein designed to disrupt interactions between T cells, B cells and other antigen-presenting cells involved in immune activation. Amgen is evaluating the therapy in two Sjögren’s disease populations: patients with moderate-to-severe systemic disease and those with high symptom burden but low systemic disease activity, including symptoms such as dryness, fatigue and pain.

OASIZ 301 is a Phase 3, randomised, double-blind, placebo-controlled study evaluating the efficacy and safety of dazodalibep in patients with Sjögren’s disease and moderate-to-severe systemic disease activity, defined by an ESSDAI score of at least 5. The study enroled approximately 621 participants. Its primary endpoint is the change from baseline in ESSDAI score at Week 48.

Key secondary endpoints include measures of dryness, tender and swollen joints, fatigue and ESSDAI response, defined as a reduction of at least five points from baseline.

In addition to OASIZ 301 and OASIZ 303, Amgen is conducting OASIZ 304, an open-label, long-term extension study assessing the long-term safety and tolerability of dazodalibep in eligible participants from the two Phase 3 studies.