Ludwig Cancer Research scientists have developed a groundbreaking immunotherapy that targets a previously unexploited metabolic vulnerability in cancer, offering new hope for patients with tumors resistant to conventional checkpoint inhibitors. The novel antibody, PLT012, blocks fat uptake by immune cells within tumors, reversing the metabolic manipulation that cancers use to suppress immune responses.
Published in Cancer Discovery, the study led by Ping-Chih Ho and Yi-Ru Yu of Ludwig Lausanne, in collaboration with researchers from Taipei Medical University, identifies CD36 as a critical metabolic checkpoint that tumors exploit to evade immune attack. The research demonstrates how fat-rich tumor microenvironments hijack immune cell metabolism to create an immunosuppressive landscape.
Targeting the CD36 Metabolic Checkpoint
CD36, a lipid transporter expressed on immune cells within fat-rich tumor microenvironments, enables these cells to absorb fatty acids that tumors weaponize to suppress anti-cancer immune responses. PLT012, a humanized antibody developed by the research team, specifically blocks CD36 activity to restore immune function.
"Though checkpoint blockade immunotherapies have transformed cancer care, they have had limited success against several major types of tumors, especially those that cultivate highly immunosuppressive microenvironments," said Dr. Ho, who presented the findings at the 2025 Annual Meeting of the American Association for Cancer Research. "Our study demonstrates that PLT012 induces potent anti-tumor responses even in immunotherapy-resistant liver cancer models."
Preclinical Efficacy and Mechanism of Action
In preclinical mouse models of hepatocellular carcinoma (HCC) and colon cancer liver metastases, PLT012 successfully reactivated immune responses that had been silenced by tumors' metabolic manipulation. The antibody demonstrated effectiveness both as a standalone therapy and in synergistic combination with traditional immune checkpoint inhibitors and other standard-of-care treatments.
Within the acidic, lipid-rich tumor microenvironment, immune cells including regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) upregulate CD36 expression, enhancing fat uptake that fuels their tumor-supporting behavior. Simultaneously, macrophages are reprogrammed into a pro-tumor state, while cytotoxic CD8+ T cells suffer from lipid-induced dysfunction and undergo ferroptosis, a form of programmed cell death.
PLT012 intervenes at this metabolic chokepoint by preventing lipid accumulation in Tregs and MDSCs while preserving and restoring the anti-tumor function of effector T cells. This results in a comprehensive reprogramming of the immune response toward tumor destruction rather than support.
Human Validation and Safety Profile
The researchers analyzed tumors isolated from HCC patients, revealing that PLT012 could rewire the immune landscape of human tumors in a manner consistent with preclinical findings. Safety studies in animal models demonstrated a favorable profile for PLT012, supporting its potential for clinical application.
"This study identifies CD36 as a targetable metabolic immune checkpoint and introduces PLT012 as a first-in-class immunotherapy," said Dr. Yu. "Unlike conventional checkpoint inhibitors that often fail in metabolically hostile tumor microenvironments, PLT012 acts upstream by remodeling lipid metabolism and dismantling the tumor's immunosuppressive infrastructure."
Regulatory Recognition and Clinical Development
The U.S. Food and Drug Administration has granted PLT012 orphan drug status, signaling regulatory support for further development. A biotech spin-off has been established to advance the antibody into clinical trials, marking a significant step toward bringing this novel therapeutic approach to patients.
The orphan drug designation provides several advantages for clinical development, including market exclusivity, tax credits for clinical trial costs, and FDA guidance throughout the development process. This regulatory milestone reflects the significant unmet medical need in treating immunotherapy-resistant cancers.
Broader Therapeutic Implications
The implications of this research extend far beyond liver cancer, as CD36 is expressed in many tumor types with lipid-rich microenvironments. This metabolic immunotherapy approach could establish a new class of treatments for cancers that have resisted existing therapies.
"Because CD36 is expressed in many tumor types with lipid-rich microenvironments, this approach could pave the way for a new class of metabolic immunotherapies, offering hope against cancers that have resisted existing treatments," said Dr. Ho.
The discovery represents a paradigm shift in cancer immunotherapy, moving beyond traditional checkpoint inhibition to target the fundamental metabolic processes that tumors exploit for immune evasion. By addressing the upstream metabolic manipulation that creates immunosuppressive environments, PLT012 offers a complementary strategy to existing immunotherapies and potentially broader applicability across cancer types.
