Key Development
There is still no FDA-approved therapy specifically designed to treat Sjögren’s disease. A successful Phase 3 trial therefore does more than advance another autoimmune drug — it could help establish an entirely new targeted-treatment market.
On September 22, 2026, Amgen announced that dazodalibep met the primary endpoint in the Phase 3 OASIZ 301 trial in adults with moderate-to-severe systemic Sjögren’s disease. At Week 48, treatment produced a statistically significant and clinically meaningful improvement in ESSDAI, a validated measure of systemic disease activity. Improvement was observed as early as Week 4 and sustained through Week 48. Reuters reported that most adverse events were mild to moderate and discontinuations were limited. Amgen, however, has not yet disclosed the numerical effect size, p-value or detailed secondary-endpoint results.
Dazodalibep is a CD40L antagonist fusion protein designed to disrupt immune signaling between T cells, B cells and antigen-presenting cells. OASIZ 301 enrolled approximately 621 patients. A second Phase 3 study, OASIZ 303, is testing the therapy in patients with substantial dryness, fatigue and pain but comparatively low systemic disease activity, with completion expected in Q4 2026.
Why It Matters
- The unmet need remains unusually high. No FDA-approved medicine currently targets Sjögren’s disease itself; management often relies on immunomodulation plus treatments for dryness and other symptoms.
- Amgen is developing by phenotype rather than diagnosis alone. OASIZ 301 addresses systemic disease, while OASIZ 303 addresses high symptom burden with low systemic activity — reflecting the biological and clinical heterogeneity of Sjögren’s.
- Competition is already advanced. Novartis reported in 2025 that both Phase 3 NEPTUNUS trials of ianalumab met their primary endpoints; FDA subsequently granted the asset Breakthrough Therapy designation.
- The readout also matters for the Horizon acquisition thesis. Dazodalibep entered Amgen’s pipeline through its approximately $27.8 billion acquisition of Horizon Therapeutics in 2023.
Healthcare Insight Analysis
Healthcare Insight believes the key question is not simply whether dazodalibep “won Phase 3.”
It is whether Amgen can build a treatment architecture broad enough to address the heterogeneity that has historically made Sjögren’s difficult to drug.
Two patients with the same diagnosis may have very different disease. One can have significant systemic organ involvement. Another may experience disabling dryness, pain and fatigue while showing relatively limited systemic activity on conventional measures.
That heterogeneity complicates patient selection, endpoints and placebo-adjusted efficacy. Reuters noted that analysts regard Sjögren’s as a particularly challenging development setting, in part because of high placebo responses.
Amgen’s strategy is therefore strategically interesting: it is not forcing the entire disease into one phenotype.
OASIZ 301 measures systemic activity using ESSDAI. OASIZ 303 separately addresses patients whose clinical burden is dominated by symptoms rather than systemic disease. Earlier Phase 2 results provided signals in both populations, including ESSDAI improvement in systemic disease and ESSPRI improvement among symptom-dominant patients.
If the second Phase 3 study is also positive, dazodalibep could potentially support a broader commercial proposition than a therapy limited to systemic Sjögren’s.
That does not make Amgen the clear leader.
Novartis already has positive results from two Phase 3 trials of ianalumab, which combines B-cell depletion with BAFF-R inhibition. Because Amgen has not yet released detailed OASIZ 301 numerical results, meaningful cross-trial comparisons on efficacy, durability or safety are premature.
The emerging competition is therefore likely to involve more than mechanism.
It will involve label breadth, patient segmentation, dosing, safety, physician confidence and regulatory execution.
This also matters strategically for Amgen’s $27.8 billion Horizon transaction. That acquisition was built primarily around an established rare-disease portfolio, but also brought development-stage assets including dazodalibep. A successful registration program would provide tangible evidence that Amgen acquired future pipeline value, not only current products.
Market Implications
Amgen: gains a credible opportunity to create a new autoimmune growth asset, but OASIZ 303 and the full OASIZ 301 dataset remain critical catalysts.
Novartis: retains an important development advantage with two positive pivotal trials for ianalumab. Competitive focus will now shift toward regulatory timing and differentiation.
Rheumatology: successful approvals could transform Sjögren’s from a market dominated by symptomatic management into a targeted disease-modifying biologics category.
Payers and providers: patient stratification may become commercially important because systemic disease and high symptom burden do not necessarily create identical treatment needs or cost-benefit profiles.
The two most important next signals are the full numerical OASIZ 301 dataset and the OASIZ 303 readout expected in Q4 2026.
If dazodalibep demonstrates convincing benefit across both phenotypes, the significance will extend beyond a successful Phase 3 trial: Amgen may show that the way to build the Sjögren’s market is not to find one therapy for every patient, but to match treatment strategy to the biology and burden of the patient in front of you.