Amgen Reports Phase 3 Dazodalibep Trial Meets Primary Endpoint in Sjogren's Disease

Amgen (NASDAQ:AMGN) announced that its investigational treatment dazodalibep met the primary endpoint in the Phase 3 OASIZ-301 clinical trial, demonstrating statistically significant reductions in systemic disease activity among patients with Sjögren’s disease compared with placebo.

The 648-patient study evaluated two dosing regimens over 48 weeks, with both achieving the primary endpoint measured by the European Alliance of Associations for Rheumatology Sjögren’s Syndrome Disease Activity Index (ESSDAI).

The results build on positive preliminary findings announced in September 2026 and will be presented at the American College of Rheumatology (ACR) Convergence 2026 conference.

Both Dosing Regimens Meet Primary Endpoint

OASIZ-301 is a randomised, double-blind, placebo-controlled trial involving patients with moderate-to-severe systemic Sjögren’s disease activity.

Participants had a mean baseline ESSDAI score of 10.2, with higher scores indicating greater systemic disease activity.

At Week 48, the 1,500 mg dose administered every four weeks produced a least-squares mean reduction of 5.6 points in ESSDAI scores, compared with a 3.8-point reduction for placebo. The placebo-adjusted difference was 1.8 points (adjusted p<0.001).

The 3,000 mg dose administered every 12 weeks produced a 5.2-point reduction, representing a placebo-adjusted difference of 1.4 points (adjusted p=0.010).

Each dazodalibep treatment group included 217 patients.

Amgen reported that treatment effects were observed as early as Week 4 and maintained through Week 48.

Treatment Also Improves Patient-Reported Dryness

The 1,500 mg regimen administered every four weeks also demonstrated statistically significant improvements in patient-reported dryness at Week 48.

Compared with placebo, the treatment produced a 1.17-point greater reduction on the dryness component of the EULAR Sjögren’s Syndrome Patient Reported Index (ESSPRI) and a 0.93-point greater reduction on the Diary for Assessing Sjögren’s Patient Reported Index (DASPRI).

Both comparisons achieved adjusted p-values below 0.001.

Additional analyses showed that greater proportions of dazodalibep-treated patients achieved reductions of at least three, five or seven points in ESSDAI scores compared with placebo.

Total ESSPRI and DASPRI scores also favoured dazodalibep over 48 weeks, while both dosing regimens produced mean improvements exceeding 1.5 points in total ESSPRI scores.

The company additionally reported improvements in stimulated salivary flow and higher response rates under the composite Sjögren’s Tool for Assessing Response (STAR) criteria.

Safety Findings Reported Across Treatment Groups

The most common adverse events occurring in at least 5% of patients and at higher rates with dazodalibep than placebo included nasopharyngitis, urinary tract infections, hypertension and infusion-related reactions.

Amgen said these events were generally mild to moderate.

Serious adverse events and treatment discontinuations due to adverse events were balanced across the three study groups.

The company reported no imbalance in thromboembolic events or opportunistic infections, while malignancy rates were low and comparable between treatment groups.

Amgen Continues Phase 3 Development Programme

Dazodalibep is an investigational CD40L antagonist fusion protein designed to interfere with immune signalling involving T cells, B cells and other immune-related cells.

The treatment is being developed for Sjögren’s disease, an autoimmune condition associated with persistent dryness, fatigue, pain and, in some patients, systemic organ involvement.

There are currently no US Food and Drug Administration-approved treatments specifically for Sjögren’s disease.

“These Phase 3 results support dazodalibep’s potential as a first-in-class treatment for Sjögren’s disease and strengthen the clinical rationale for targeting CD40L-mediated immune signaling in these patients,” said Jay Bradner, Amgen’s executive vice president of Research and Development, Artificial Intelligence and Data.

“In OASIZ-301, improvements in systemic disease activity were observed as early as Week 4 and sustained through Week 48. We look forward to building on these findings as we advance a broader Phase 3 program.”

Amgen is also conducting OASIZ-303, a Phase 3 trial evaluating dazodalibep in patients with substantial symptoms but low systemic disease activity.

A separate open-label extension study, OASIZ-304, is assessing the treatment’s long-term safety and tolerability in eligible participants from both trials.

The company has not provided a regulatory submission timetable in the announcement. Dazodalibep remains investigational and has not received FDA approval for Sjögren’s disease.

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