SparX Biopharmaceutical Corp. announced plans to present clinical updates on its lead asset SPX-303, a first-in-class bispecific antibody targeting LILRB2 and PD-L1, at the upcoming American Association for Cancer Research (AACR) Annual Meeting. The presentation, scheduled for April 28, 2025, marks the one-year anniversary of the first patient dosing in the ongoing Phase 1 clinical trial.
The company will showcase SPX-303 during the Trial-in-Progress poster session at McCormick Place, Chicago, from 2:00 PM to 5:00 PM. The poster (CT116-11) will highlight progress in the Phase 1 trial, which is currently enrolling patients with resistant or refractory solid tumors at a dose level of 20 mg/kg.
Novel Dual-Checkpoint Mechanism
SPX-303 represents a significant advancement in immuno-oncology by simultaneously targeting two distinct immune checkpoint pathways. The bispecific antibody inhibits both LILRB2, a myeloid checkpoint, and PD-L1, a T-cell checkpoint, potentially offering a more comprehensive approach to overcoming tumor immune evasion mechanisms.
"This innovative program represents a significant advancement in macrophage checkpoint blockade and T cell co-engagement strategies," said Dr. Gui-Dong Zhu, CEO of SparX. "It holds promise as a potential next-generation immuno-oncology therapy—or 'Super IO' booster—for patients with limited treatment options."
Satellite Symposium on "Super IO" and ADC Synergies
In addition to the poster presentation, SparX will provide a more comprehensive overview of SPX-303's dual mechanism at a Satellite Symposium themed "Harnessing Super Immunotherapy and ADCs to Redefine the Standard of Care." The symposium, co-hosted by the University of Illinois at Chicago Cancer Center and Yao Yuan-Academy for Pharma Innovation, will bring together expert clinicians, academic investigators, and industry leaders.
The event will explore how next-generation immuno-oncology approaches (termed "Super IO") can be synergized with antibody-drug conjugates (ADCs). This innovative combination aims to leverage the tumor-targeting precision of ADCs with the immune-activating power of checkpoint inhibitors to deliver deeper and more durable anti-tumor responses.
The Satellite Symposium will be held at the Trump International Hotel & Tower Chicago. SparX encourages interested attendees to register early through the registration portal to secure a seat.
Advancing Nanobody-Based Therapeutics
SparX Biopharmaceutical Corp. is a development-stage biopharmaceutical company focused on advancing transformative nanobody-based therapeutics. The company integrates AI-enabled discovery with in-house cGMP manufacturing capabilities to drive innovation from target identification through clinical development.
With its SAILING™ platform and proprietary Nab2 bi-ADC technology, SparX is positioned to support clinical and commercial-scale production from its facilities in Chicago. This infrastructure enables the company's evolution toward becoming a fully integrated, independent biopharmaceutical organization.
Clinical Trial Details
The Phase 1 trial of SPX-303 (NCT06259552) represents an important milestone in the development of dual checkpoint inhibitors. By targeting both myeloid and lymphoid immune responses, SPX-303 aims to address limitations of current immunotherapies, particularly for patients who have developed resistance to existing treatments.
The current dose level of 20 mg/kg suggests the trial has progressed through initial dose-escalation phases, though complete safety and efficacy data have not yet been disclosed. The focus on resistant or refractory solid tumors indicates the company is targeting an area of significant unmet medical need.
As the field of immuno-oncology continues to evolve, approaches like SPX-303 that target multiple immune checkpoints simultaneously may represent the next frontier in cancer immunotherapy, potentially offering new options for patients who have exhausted conventional treatment approaches.
