• Researchers have developed a new drug called αPD-L1 × αCD3 BIPE that helps the immune system better target and kill non-small cell lung cancer cells by connecting cancer-fighting T cells directly to cancer cells expressing high levels of PD-L1, a protein that usually helps tumors evade immunity. Laboratory tests showed that this drug significantly improved T cell–mediated cancer cell destruction, especially when combined with the chemotherapy drug gemcitabine, which boosts the cancer cells’ visibility to the immune system. This combined approach shows promise as a more effective treatment for lung cancer by enhancing the body’s natural immune response.

• The overexpression of programmed cell death ligand 1 (PD-L1), a critical immune checkpoint protein, is associated with poor prognosis and reduced survival in lung cancer patients. Monoclonal antibodies targeting the PD-1/PD-L1 axis have been approved to disrupt this interaction and prevent immune cell exhaustion. Herein, to enhance the efficacy of PD-1/PD-L1 blockade, we investigated a bispecific αPD-L1 ×αCD3 protein engager (αPD-L1 ×αCD3 BIPE). The αPD-L1 ×αCD3 BIPE consists of an anti-CD3 single-chain variable fragment (scFv) linked to an anti-PD-L1 scFv, allowing it to bind to CD3-positive T cells simultaneously and PD-L1-overexpressing cancer cells. In co-culture assays with T cells and non-small cell lung cancer (NSCLC) cell lines-A549, NCI-H460, and NCI-H1975-treatment with the BIPE significantly enhanced T-cell-mediated cytotoxicity. The killing efficiency correlated with PD-L1 expression levels, with the highest cytotoxic activity observed in NCI-H1975 (high PD-L1 expression), followed by NCI-H460 (moderate PD-L1 expression) and A549 (low PD-L1 expression). Furthermore, combining the BIPE with the standard chemotherapeutic agent gemcitabine further improved anti-tumor activity. This effect was likely due to gemcitabine-induced upregulation of PD-L1 and MHC class I expression on cancer cells, enhancing T-cell recognition and cytotoxicity. These findings suggest that combining αPD-L1 ×αCD3 BIPE with gemcitabine is promising for enhancing immune checkpoint blockade and augmenting anti-tumor immunity in NSCLC.