Cancer Drug Repurposed for Alzheimer's Enters Human Trials

ROCKVILLE, MD – April 09, 2026 – In a significant move that bridges the fields of oncology and neurology, biopharmaceutical company OncoC4 has announced the dosing of the first participant in a Phase 1/2 clinical trial for ONC-841, an investigational therapy for Alzheimer's disease. The trial, which received accelerated clearance in China, marks a pivotal moment for a drug originally developed to fight cancer, now repurposed with the hope of halting one of the world's most devastating neurodegenerative conditions.

The first patient was successfully dosed at the prestigious Xuanwu Hospital of Capital Medical University in China, a facility described by OncoC4 as a world-leading center for Alzheimer's research. This step initiates a crucial new chapter in the quest for a disease-modifying treatment for Alzheimer's, exploring a novel biological pathway that has garnered significant scientific interest.

From Cancer Checkpoint to Cognitive Hope

ONC-841 is the first and only clinical-stage antibody targeting SIGLEC 10, a protein that acts as an inhibitory checkpoint on immune cells. In the realm of cancer, such checkpoints can allow tumors to hide from the body's immune system. Drugs that block them, like ONC-841 in its ongoing Phase 2 oncology trials, are designed to release the brakes on the immune system, empowering it to attack cancer cells.

OncoC4's preclinical research, however, unveiled a fascinating new potential application. The same SIGLEC 10 checkpoint is present on microglia, the brain's resident immune cells. In Alzheimer's disease, microglia are believed to become dysfunctional, failing to clear the toxic protein aggregates—amyloid-beta plaques and tau tangles—that are the hallmarks of the disease. The scientific hypothesis is that by blocking SIGLEC 10 with ONC-841, the drug can rejuvenate these dormant microglia, restoring their natural ability to clear the pathogenic proteins that lead to neuronal death and cognitive decline.

This mechanism represents a distinct and potentially powerful new strategy. While recently approved treatments like lecanemab directly target and remove amyloid plaques, ONC-841 aims to empower the brain's own cleanup crew to do the job. Critically, preclinical studies cited by the company suggest that this approach may be effective against both amyloid plaques and tau tangles, offering a two-pronged attack on the disease's core pathology.

The Science of Reawakening the Brain's Immunity

For years, the narrative around Alzheimer's has been dominated by the amyloid hypothesis. Yet, the role of neuroinflammation and microglial dysfunction has steadily gained prominence. Research has shown that the genetic risk for late-onset Alzheimer's is strongly linked to genes expressed in microglia. SIGLEC 10 has emerged as a key player in this process.

Studies have correlated higher expression of SIGLEC 10 with an increased risk for Alzheimer's. The protein essentially tells microglia to stand down, inhibiting their phagocytic (cell-eating) and migratory functions. In a healthy brain, this is a normal regulatory process, but in the context of Alzheimer's, it may prevent the clearance of accumulating toxic debris. ONC-841 is designed to interrupt this inhibitory signal.

By binding to and blocking SIGLEC 10, the antibody is intended to convert dysfunctional, dystrophic microglia back into a healthy, surveillant state. This not only enhances their ability to consume harmful protein aggregates but may also temper the chronic inflammation that contributes to neurodegeneration. If successful in humans, this first-in-class approach could validate microglia modulation as a major therapeutic avenue for Alzheimer's and other neurodegenerative diseases.

A Global Collaboration and Regulatory Milestone

The decision to launch the trial in China underscores the country's growing stature as a powerhouse in global clinical research. The collaboration between Maryland-based OncoC4 and Beijing's Xuanwu Hospital, with Professors Yi Tang and Cuibai Wei serving as Principal Investigators, highlights the international effort required to tackle a global health crisis like Alzheimer's.

"Extending our clinical study from cancer to AD showcases OncoC4's research engine and Xuanwu Hospital's infrastructure as the world's eminent AD research center," said Dr. Yang Liu, CEO and Chief Scientific Officer of OncoC4. "We are extremely grateful to our colleagues at Xuanwu for the collaboration."

Professor Yi Tang, Executive Vice President at Xuanwu Hospital, echoed this enthusiasm. "We are extremely excited to collaborate with OncoC4 to explore the potential of targeting SIGLEC 10, the novel checkpoints of AD pathogenesis, to bring clinical benefit for patients with this devastating illness," he stated.

The trial's launch was expedited by a key regulatory decision. China's National Medical Product Administration (NMPA) granted accelerated clearance for the Investigational New Drug (IND) application. This was made possible by leveraging the existing safety data from ONC-841's ongoing Phase 2 trial in solid tumor patients. Such regulatory flexibility allows promising therapies to move more quickly into human testing for new indications, potentially saving years of development time and resources.

OncoC4's Pipeline and the Path Forward

For OncoC4, the Alzheimer's trial represents a significant expansion beyond its core focus in oncology. The privately held company has built a diverse pipeline that includes a bispecific antibody targeting PD-1 and VEGF (AI-081) and a strategic collaboration with BioNTech to co-develop gotistobart, an anti-CTLA-4 antibody. The advancement of ONC-841 into neurology demonstrates the company's ability to identify and pursue novel applications for its discoveries.

The Phase 1/2 trial for ONC-841 will be closely watched by the scientific community, investors, and millions of families affected by Alzheimer's. The initial phase will focus on establishing the drug's safety and determining the appropriate dosage for this new patient population. Subsequent phases will evaluate its clinical activity, looking for early signals that the therapy is having the desired biological and cognitive effects.

The journey for any new Alzheimer's drug is long and fraught with challenges. However, the initiation of this trial marks a critical and hopeful first step. By targeting a novel mechanism and leveraging a unique drug repurposing strategy, OncoC4 and its partners are opening a new front in a battle where innovation is desperately needed.