Drug Target Encyclopedia Series (32) —CD47

Release Time：

2026-03-10 15:16

CD47 is a widely expressed cell-surface protein and a key innate immune checkpoint.

By binding to SIRPα on macrophages and dendritic cells, CD47 delivers a “don’t eat me” signal that suppresses phagocytosis and helps tumor cells evade immune clearance. In oncology, CD47 has become one of the most closely watched myeloid checkpoint targets for reactivating macrophage-driven antitumor immunity.

CD47 is highly relevant in:

Hematologic malignancies, including:

• Acute myeloid leukemia (AML)

• Myelodysplastic syndromes (MDS)

• Diffuse large B-cell lymphoma (DLBCL)

• Multiple myeloma (MM)

Solid tumors, including:

• Colorectal cancer

• Head and neck squamous cell carcinoma (HNSCC)

• Breast cancer

• Ovarian cancer

High CD47 expression is frequently associated with immune escape and unfavorable clinical outcomes, making the CD47–SIRPα axis an important translational and therapeutic pathway across both liquid and solid tumors.

Targeting CD47 in cancer immunotherapy

🧪 Monoclonal antibodies (mAbs)

Anti-CD47 antibodies are designed to block the inhibitory CD47–SIRPα interaction, restoring macrophage-mediated phagocytosis of tumor cells. This approach is especially attractive in malignancies where innate immune evasion is a dominant resistance mechanism.

🧪 Combination strategies

CD47 blockade is increasingly being explored in combination with:

• Tumor-targeting antibodies

• Chemotherapy or hypomethylating agents

• PD-1 / PD-L1 inhibitors

• Radiotherapy

The rationale is strong: CD47 inhibition works best when paired with treatments that increase pro-phagocytic signals or enhance adaptive immune priming.

🧪 SIRPα-Fc fusion proteins & next-generation formats

Beyond classic anti-CD47 antibodies, the field is shifting toward SIRPα-based fusion proteins, bispecifics, and affinity-tuned molecules designed to improve tumor selectivity and reduce on-target toxicity in normal cells.

🧪 Bispecific and tumor-selective engineering

Emerging CD47 programs increasingly use bispecific designs to co-target tumor antigens or other checkpoints, aiming to improve efficacy in solid tumors while minimizing red blood cell binding and hematologic adverse effects.

Key challenges

Broad expression of CD47 on normal cells—especially red blood cells—has made safety a central issue in this target class.

Key development challenges include:

• Avoiding anemia and hematologic toxicity

• Achieving sufficient tumor selectivity

• Improving activity in solid tumors

• Identifying the right combination partners and biomarkers for patient selection

🔬 Current research directions

• Next-generation CD47 antibodies with improved safety profiles

• SIRPα-based fusion proteins and myeloid-engaging biologics

• Bispecific antibodies for tumor-restricted checkpoint blockade

• Combination regimens with PD-1/PD-L1 inhibitors, cetuximab, or chemotherapy