Biosion's Next-Gen Immunotherapy Enters Trials, Aims for Safer Attack on Cancer

NEWARK, Del. and NANJING, China – February 03, 2026 – Biotechnology firm Biosion has dosed the first patient in a clinical trial for BSI-082, a novel antibody designed to help the immune system recognize and destroy cancer cells. The Phase 1 study, initiated and conducted by the prestigious Mays Cancer Center in San Antonio, Texas, will evaluate the drug in patients with advanced solid tumors, marking a critical step for a new generation of immunotherapies aiming to succeed where others have stumbled.

The trial represents a significant validation for BSI-082, which targets the SIRPα protein. This move signals renewed hope in a challenging area of oncology research that seeks to disable a "don't eat me" signal that tumors use to hide from the body's innate immune defenses.

Navigating a Treacherous Path: The CD47-SIRPα Challenge

For years, drug developers have been intrigued by the CD47-SIRPα axis, a natural checkpoint that prevents the immune system's macrophages—the "pac-man" cells of the body—from devouring healthy cells. Many cancers exploit this system by overexpressing CD47 on their surface, effectively cloaking themselves from destruction. The therapeutic logic is simple: block this "don't eat me" signal, and you unleash macrophages to attack the tumor.

However, translating this elegant theory into a safe and effective medicine has proven exceptionally difficult. The field is littered with high-profile setbacks, most notably Gilead Sciences' anti-CD47 antibody, magrolimab. Acquired in a $4.9 billion deal, magrolimab's development was plagued by safety issues, primarily severe anemia. Because CD47 is present on nearly all cells, including vast numbers of red blood cells, early anti-CD47 drugs caused widespread, unintended destruction of these vital cells, creating a significant "antigen sink" that limited the drug's availability to target tumors and caused dangerous side effects. After multiple clinical holds and disappointing trial results in blood cancers, Gilead ultimately discontinued the program.

Other companies have faced similar hurdles. ALX Oncology's evorpacept, which targets SIRPα, recently failed to meet its goals in head and neck cancer trials, while AbbVie backed out of a major partnership with I-Mab for its anti-CD47 drug, lemzoparlimab. These challenges have underscored the critical need for a more refined approach—one that can precisely disable the tumor's shield without causing systemic collateral damage.

A Safer, Smarter Design: How BSI-082 Aims to Be Different

Biosion's BSI-082 was engineered from the ground up to overcome the specific toxicities that derailed its predecessors. Developed using the company's proprietary H³ Antibody Discovery Platform, the drug incorporates several key design features intended to create a wider therapeutic window.

First, BSI-082 targets SIRPα, which is primarily found on immune cells like macrophages, rather than the ubiquitously expressed CD47. This strategy is designed to avoid the "antigen sink" problem and reduce off-target effects on red blood cells. Furthermore, the antibody's Fc domain—the "tail" region of the antibody—has been specifically engineered to minimize binding to red blood cells and platelets. This is a crucial modification aimed directly at preventing the anemia and thrombocytopenia (low platelet counts) that were dose-limiting toxicities for first-generation agents.

"The initiation of this trial by a premier institution like the Mays Cancer Center serves as powerful validation of BSI-082's scientific rationale and therapeutic potential," said Mingjiu Chen, Ph.D., Founder and CEO of Biosion. "BSI-082's unique profile—specifically its ability to potently block the 'don't eat me' signal without compromising patient safety—positions it as an ideal combination partner for standard-of-care therapies, particularly antibody-drug conjugates (ADCs)."

Beyond safety, the antibody is designed for broad utility. It binds with high affinity to three common SIRPα variants (V1, V2, and V8), which the company states will provide coverage for over 90% of the human population. Critically, it does not bind to SIRPγ, a related protein on T-cells, ensuring that the adaptive immune system—another key pillar of cancer immunotherapy—can remain fully active.

The Power of Combination: A New Strategy for HER2-Positive Tumors

While BSI-082's improved safety profile is a key differentiator, its ultimate promise may lie in its ability to enhance other powerful cancer therapies. The Phase 1 trial is designed in two parts to explore this potential. The first part (Phase 1a) will test BSI-082 as a standalone treatment to establish its safety and determine the optimal dose.

The second part (Phase 1b) will move into a more strategic combination, pairing BSI-082 with trastuzumab deruxtecan (T-DXd), an antibody-drug conjugate (ADC) marketed as Enhertu. T-DXd has revolutionized the treatment of HER2-positive cancers by acting as a "smart bomb," delivering a potent chemotherapy payload directly to tumor cells. While highly effective, patients can eventually develop resistance, and the treatment carries its own risk of serious side effects, including a potentially fatal lung condition called interstitial lung disease.

The scientific rationale for the combination is compelling. By using BSI-082 to block the "don't eat me" signal, researchers hope to encourage macrophages to engulf tumor cells that have been "tagged" by T-DXd, a process known as antibody-dependent cellular phagocytosis (ADCP). This one-two punch could create a more profound and durable anti-tumor response, potentially overcoming resistance mechanisms and improving outcomes for patients with advanced disease.

Validated by Partnership: The Role of the Mays Cancer Center

The decision to launch BSI-082's clinical journey through an Investigator-Initiated Trial (IIT) at the Mays Cancer Center, a National Cancer Institute (NCI)-designated institution, is a strategic move that adds significant credibility. NCI designation is reserved for centers demonstrating the highest levels of scientific excellence and robust infrastructure for conducting complex cancer research.

Leading the trial is Dr. John Sarantopoulos, a medical oncologist and respected expert in early-phase clinical trials for novel cancer drugs. His involvement underscores the medical community's interest in BSI-082's differentiated approach.

"Targeting the innate immune system via the SIRPα-CD47 axis offers a compelling therapeutic strategy for refractory tumors," stated Dr. Sarantopoulos, the trial's principal investigator. "We are excited to lead the clinical evaluation of BSI-082, whose design addresses key limitations of earlier generation agents. We look forward to exploring its potential to improve outcomes for patients, particularly in combination with ADCs."

This collaboration aligns with Biosion's "Discover-Develop-Partner" business model, which focuses on internal innovation followed by strategic partnerships to validate and advance its most promising assets. By partnering with a world-class academic center, Biosion not only accelerates clinical development but also gains invaluable external validation for its technology platform and its lead oncology candidate. As the trial gets underway, the oncology community will be watching closely to see if BSI-082 can finally unlock the full potential of the innate immune system in the fight against cancer.