Amgen Stock Surges on Positive Sjögren’s Disease Trial Results
Amgen stock (NASDAQ: AMGN) moved sharply higher on September 22 after the pharmaceutical giant reported positive Phase 3 results for dazodalibep, an experimental treatment for Sjögren’s disease.
Shares jumped about 4% in premarket trading after the announcement, while the stock was still trading higher later in the session. The catalyst was a successful primary endpoint in the OASIZ 301 study, which tested dazodalibep in patients with moderate-to-severe systemic Sjögren’s disease.
The result is important for Amgen because Sjögren’s disease currently has no FDA-approved medicines specifically for the condition, leaving a significant unmet medical need. For investors, the trial adds another potential growth opportunity to Amgen’s large pipeline, although the company still needs to complete the broader Phase 3 program and pursue regulatory steps before dazodalibep could become a commercial product.
What Happened in Amgen’s Sjögren’s Trial?
Amgen said the Phase 3 OASIZ 301 trial met its primary endpoint, showing a statistically significant and clinically meaningful improvement in systemic disease activity at Week 48.
The study used the EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI), a validated measure of systemic disease activity across different organ systems. Amgen said improvements were visible as early as Week 4 and were sustained through Week 48.
The randomized, double-blind, placebo-controlled study enrolled approximately 621 patients with moderate-to-severe systemic disease activity. Secondary measures included dryness, tender and swollen joints, fatigue and ESSDAI response.
Amgen plans to release detailed data from the study at an upcoming medical meeting. That means investors currently have the topline result, but not the complete dataset needed to assess the magnitude of benefit across all endpoints.
That distinction matters. A trial meeting its primary endpoint is an important development milestone, but investors generally need to see the full efficacy, safety and subgroup data before judging the commercial potential of a new medicine.
Why Dazodalibep Matters
Dazodalibep is designed as a potential first-in-class CD40L antagonist fusion protein. Its mechanism targets immune activation by disrupting interactions involving T cells, B cells and antigen-presenting cells.
Sjögren’s disease is a systemic autoimmune disorder that commonly causes dryness of the eyes and mouth but can also involve fatigue, pain, neurological complications and other organs.
The lack of an approved disease-modifying treatment gives a successful therapy a potentially differentiated commercial opportunity. However, the ultimate market size and revenue opportunity will depend on the drug's efficacy, safety, regulatory labeling, physician adoption, pricing and competition.
Amgen is therefore not simply developing another incremental product. A successful dazodalibep program could give the company an additional position in autoimmune medicine.
Amgen Has More Than One Sjögren’s Catalyst
The OASIZ 301 result is only part of the development program.
Amgen is also conducting OASIZ 303, a separate Phase 3 study in patients with moderate-to-severe symptoms but lower systemic disease activity. The company expects that study to complete in the fourth quarter of 2026. It is also conducting OASIZ 304, an open-label extension study designed to evaluate longer-term safety and tolerability in eligible participants from the Phase 3 program.
This creates another near-term catalyst for Amgen stock.
The key question will be whether dazodalibep can demonstrate useful benefits across different groups of Sjögren’s patients rather than succeeding in only one particular population.
Safety Results Were Also Closely Watched
Amgen reported that the most common adverse events occurring at a rate of at least 5% and higher than placebo included nasopharyngitis, urinary tract infections, hypertension and infusion-related reactions.
The company said these events were generally mild to moderate. Treatment discontinuations caused by adverse events were low and balanced between the treatment groups. Amgen also reported no imbalance in thromboembolic events or opportunistic infections across the treatment arms.
Full safety data will nevertheless be important when the detailed results are presented.
For a potential long-term autoimmune treatment, regulators and physicians will evaluate not only whether the medicine works but also how its safety profile compares with existing treatment approaches and the underlying risks associated with the disease.
Why Amgen Stock Reacted
The stock market response reflects the value investors place on successful late-stage clinical programs.
A Phase 3 trial is generally the final major stage of testing before a potential regulatory submission. Success at this stage can materially reduce one part of the development risk, although it does not eliminate regulatory, commercial or safety uncertainty.
In Amgen's case, the positive Sjögren’s result also comes alongside several other pipeline developments.
The company reported strong second-quarter results in August, with revenue rising 10% year over year to $10.1 billion. GAAP diluted EPS increased 65% to $4.37, while non-GAAP EPS rose 4% to $6.29. Amgen also generated $3.5 billion of free cash flow during the quarter.
Management raised its 2026 non-GAAP EPS guidance to $22.30–$23.50. The company's broader growth portfolio includes products such as Repatha, Evenity, Tezspire, Uplizna and several oncology and rare-disease medicines.
That means dazodalibep is being added to an existing commercial base rather than carrying the entire investment case for Amgen.
Amgen’s Pipeline Strategy Is Becoming More Important
For large pharmaceutical companies, the long-term challenge is replacing revenue lost when older medicines face patent expiration or increased competition.
Amgen is already dealing with pressure on some mature products. For example, Reuters reported that Prolia sales declined sharply in the second quarter following patent expiry, while newer products such as Repatha and Evenity delivered strong growth.
This makes pipeline execution particularly important.
Dazodalibep is one of several late-stage opportunities Amgen is advancing. The company has also been developing therapies across oncology, rare diseases, inflammation and cardiometabolic conditions. Its September pipeline news included positive Phase 3 data for IMDELLTRA in combination with AstraZeneca's Imfinzi in extensive-stage small-cell lung cancer.
The Sjögren’s result therefore strengthens a broader pipeline story rather than representing a standalone transformation of Amgen's business.
What Investors Should Watch Next
The next major developments for AMGN stock are likely to center on both dazodalibep and the wider pipeline.
Investors should monitor:
Detailed OASIZ 301 efficacy and safety data at the upcoming medical meeting
Completion and results of the OASIZ 303 Phase 3 study
Any regulatory discussions or filing plans for dazodalibep
Amgen's research and development spending
Growth from newer commercial products
Performance of mature products facing patent or competitive pressure
Progress of other late-stage programs, including MariTide and oncology assets
Changes to Amgen's 2026 financial outlook
The OASIZ 303 result could be particularly important because it tests dazodalibep in a different Sjögren’s population.
Risks Remain Despite the Positive Trial
The positive Phase 3 result does not mean dazodalibep is already an approved medicine.
Amgen still needs to provide detailed clinical data and determine the appropriate regulatory pathway. Regulatory agencies will assess the complete evidence, including efficacy, safety and benefit-risk considerations.
There is also commercial uncertainty. Even if approved, the drug's eventual contribution to Amgen's revenue would depend on its label, reimbursement, physician adoption and competition.
Finally, Amgen's stock is influenced by many factors beyond one clinical program. Earnings, product sales, regulatory decisions, drug pricing, patent developments and the broader pharmaceutical market can all affect valuation.
Amgen Stock Outlook
The positive Sjögren’s Phase 3 trial results give Amgen another meaningful late-stage pipeline success and explain the sharp initial reaction in AMGN shares.
Dazodalibep's OASIZ 301 study met its primary endpoint, with Amgen reporting sustained improvement in systemic disease activity through Week 48. The company now has another Phase 3 readout expected later in 2026, while detailed OASIZ 301 data should provide a clearer picture of the drug's potential.
For investors, the important issue now shifts from whether the initial trial worked to how strong the complete dataset is, whether the second Phase 3 study confirms the findings, and how Amgen can translate successful pipeline programs into long-term revenue growth.
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This article is for informational and educational purposes only and should not be considered investment advice.