Amgen’s Dazodalibep Meets Phase 3 OASIZ 301 Goal in Sjögren’s Disease

Phase 3 Study Shows Improvement in Systemic Disease Activity

Amgen has reported positive topline results from the Phase 3 OASIZ 301 study evaluating dazodalibep in adults with Sjögren’s disease and moderate-to-severe systemic disease activity.

The study met its primary endpoint, showing a statistically significant and clinically meaningful improvement in disease activity at Week 48 compared with placebo.

The improvement was measured using the EULAR Sjögren's Syndrome Disease Activity Index, known as ESSDAI.

Amgen also reported that improvements in ESSDAI scores were seen as early as Week 4 in patients receiving dazodalibep. These improvements continued through Week 48.

The company plans to present detailed results from the study at an upcoming medical meeting.

What Is Sjögren’s Disease?

Sjögren’s disease is a systemic autoimmune disease.

That means the immune system mistakenly attacks the body's own tissues and the disease can affect different parts of the body.

One of the most familiar symptoms is dryness. Patients can experience very dry eyes and mouth because the disease can affect glands that normally produce tears and saliva.

But Sjögren’s disease is not limited to dryness.

Some patients can also experience severe fatigue, chronic pain, nerve problems and inflammation affecting major organs.

The disease can also increase the risk of lymphoma, a type of cancer affecting the lymphatic system.

Sjögren’s Disease Can Affect the Whole Body

People with Sjögren’s disease can experience very different symptoms.

Some may mainly deal with dryness, while others can develop problems involving joints, nerves, lungs, kidneys or other organs.

The disease can therefore be difficult to manage.

Symptoms such as fatigue and pain can also affect a person's ability to work, exercise, sleep and carry out normal daily activities.

The condition is considered the second most common autoimmune rheumatic disease, but it remains widely underrecognized.

There Are Currently No FDA-Approved Medicines for Sjögren’s Disease

Despite the number of people affected by the disease and the range of symptoms it can cause, there are currently no FDA-approved medicines specifically approved for Sjögren’s disease.

Doctors may use different medicines and supportive treatments to manage individual symptoms or complications.

However, there is still a need for treatments that can directly modify the underlying disease process.

This is the area Amgen is targeting with dazodalibep.

What Is Dazodalibep?

Dazodalibep is an investigational medicine being developed by Amgen for Sjögren’s disease.

It is designed as a potential first-in-class CD40L antagonist fusion protein.

The treatment is intended to interfere with immune system interactions that contribute to autoimmune disease.

More specifically, dazodalibep targets CD40L, a protein involved in communication between different immune cells.

By blocking this interaction, the treatment is designed to reduce excessive immune activation.

How Dazodalibep Is Designed to Work

The immune system relies on communication between different types of cells.

T cells, B cells and antigen-presenting cells interact with each other to coordinate immune responses.

CD40L is one of the proteins involved in these interactions.

Dazodalibep is designed to block CD40L and disrupt these immune-cell interactions.

The goal is to reduce abnormal immune activation that may contribute to the inflammation and systemic effects seen in Sjögren’s disease.

Whether this mechanism can provide long-term benefits for patients will depend on the full clinical data and future studies.

OASIZ 301 Met Its Primary Endpoint

The OASIZ 301 study was designed to evaluate whether dazodalibep could reduce systemic disease activity in patients with moderate-to-severe Sjögren’s disease.

The study met its primary endpoint.

At Week 48, patients treated with dazodalibep showed a statistically significant and clinically meaningful improvement in ESSDAI compared with patients receiving placebo.

ESSDAI is a validated tool used by doctors and researchers to measure systemic disease activity in Sjögren’s disease.

It looks at disease activity across different organ systems rather than focusing only on symptoms such as dryness.

Improvements Were Seen as Early as Week 4

One of the notable findings reported by Amgen was the timing of the response.

Improvements in ESSDAI were observed as early as Week 4 among patients receiving dazodalibep.

The improvements were then sustained through Week 48.

This means the treatment showed evidence of an effect relatively early in the study, with the difference continuing over the following months.

The detailed numerical results have not yet been released in the company's topline announcement.

What Did the Study Measure?

The primary endpoint was the change from baseline in ESSDAI score at Week 48.

The study also included several key secondary endpoints.

These looked at areas such as dryness, tender and swollen joints, fatigue and ESSDAI response.

An ESSDAI response was defined in the study as a reduction of at least five points from the baseline score.

These measurements were designed to capture different aspects of Sjögren’s disease and how patients responded to treatment.

OASIZ 301 Included About 621 Patients

OASIZ 301 was a Phase 3 randomized, double-blind, placebo-controlled clinical trial.

The study enrolled approximately 621 adults with Sjögren’s disease and moderate-to-severe systemic disease activity.

Patients had an ESSDAI score of at least 5 at the start of the study.

Randomized means participants were assigned to different treatment groups according to a study protocol.

Double-blind means neither the patients nor the study investigators knew which treatment individual participants were receiving during the blinded portion of the trial.

The placebo group provided a comparison that allowed researchers to determine whether changes were associated with dazodalibep treatment.

Dazodalibep Safety Results

Amgen also reported safety findings from OASIZ 301.

The most common adverse events reported at a rate of at least 5% and more frequently with dazodalibep than placebo were nasopharyngitis, urinary tract infection, hypertension and infusion-related reactions.

These events were generally mild to moderate.

Discontinuations caused by adverse events occurred at a low rate and were balanced between the treatment groups.

Amgen also reported no imbalance in thromboembolic events or opportunistic infections between the treatment groups.

Detailed safety data are expected to be presented at an upcoming medical meeting.

Two Different Groups of Sjögren’s Patients Are Being Studied

Amgen is studying dazodalibep in two different groups of people with Sjögren’s disease.

The first group includes patients with moderate-to-severe systemic disease activity.

OASIZ 301 is evaluating dazodalibep in this population.

The second group includes patients who have a high burden of symptoms but relatively low systemic disease activity.

These patients may experience severe dryness, fatigue and pain that can significantly interfere with daily life.

OASIZ 303 is evaluating dazodalibep in this second patient population.

OASIZ 303 Is Still Underway

The Phase 3 OASIZ 303 study is evaluating the safety and efficacy of dazodalibep in patients with high symptom burden and low systemic Sjögren’s disease activity.

According to Amgen, the study is expected to complete in the fourth quarter of 2026.

The results from OASIZ 303 will provide additional information about whether dazodalibep can help patients whose main problem is severe symptoms rather than high systemic disease activity.

OASIZ 304 Will Study Long-Term Safety

Amgen is also conducting OASIZ 304.

This is an open-label, long-term extension study.

Eligible participants who previously took part in OASIZ 301 or OASIZ 303 can continue into this study.

The purpose is to collect longer-term information about the safety and tolerability of dazodalibep.

Long-term studies are important for medicines being developed for chronic diseases because patients may need treatment for many years.

What Experts Said About the Results

Jay Bradner, M.D., executive vice president of research and development, artificial intelligence and data at Amgen, said the OASIZ 301 results represent an important development for people living with Sjögren’s disease.

He highlighted the rapid and sustained improvement in systemic disease activity seen with dazodalibep.

Ghaith Noaiseh, M.D., Associate Professor of Medicine at the University of Kansas Medical Center and lead investigator of the study, said patients with Sjögren’s disease continue to face debilitating symptoms and systemic manifestations without an approved disease-modifying therapy.

He said the topline results provide additional support for further development of dazodalibep.

Patient Advocacy Groups Continue to Highlight the Need for New Treatments

Janet E. Church, president and chief executive officer of the Sjögren’s Foundation, described Sjögren’s disease as a complex condition that affects people differently.

She noted that the disease can have a major effect on quality of life.

The Sjögren’s Foundation welcomed continued research aimed at expanding treatment options and improving care for people living with the disease.

Why New Sjögren’s Treatments Are Needed

Sjögren’s disease can be difficult to diagnose and manage because symptoms vary significantly between patients.

A person may have severe dryness, while another may experience joint problems, nerve involvement, fatigue, pain or organ complications.

The disease can also continue to affect patients even when standard treatments are being used to control individual symptoms.

This creates a need for medicines that can address broader disease activity rather than focusing only on one symptom.

What Happens Next for Dazodalibep?

Amgen plans to present detailed data from OASIZ 301 at an upcoming medical meeting.

The company is also continuing the Phase 3 OASIZ 303 study, which is expected to complete in the fourth quarter of 2026.

OASIZ 304 will provide longer-term safety and tolerability information from eligible participants who move into the extension study.

The additional clinical data will help determine the future development of dazodalibep for different groups of patients with Sjögren’s disease.

About Amgen

Amgen is a biotechnology company focused on discovering, developing, manufacturing and delivering medicines for serious diseases.

The company uses biology and technology to develop treatments across several areas of medicine.

Its research programs include medicines for autoimmune diseases and other conditions where patients continue to have significant unmet medical needs.