Thymosin α1 synergizes with immune checkpoint inhibitors, remodeling the tumor microenvironment to enhance efficacy and safety.

While immune checkpoint inhibitors (ICIs) have transformed solid tumor therapy, their utility is limited by tumor heterogeneity, immunosuppressive tumor microenvironments, and immune-related adverse events (irAEs), leading to suboptimal response rates. Current ICI monotherapies often fall short in achieving durable responses across diverse patient populations. Thymosin α1 (Tα1), a pleiotropic immunomodulator, offers a unique mechanism by enhancing immune competence and regulating excessive immune activation, alongside direct antitumor effects. This dual action positions Tα1 as a promising candidate to overcome ICI resistance and improve tolerability.

This comprehensive review synthesized evidence from a growing body of preclinical and clinical studies investigating the combination of Thymosin α1 (Tα1) with various immune checkpoint inhibitors (ICIs). The authors systematically summarized the biological characteristics of Tα1 and analyzed existing data on its synergistic effects when combined with ICIs. The methodology involved discussing how Tα1's immunoregulatory and antitumor properties contribute to augmenting ICI efficacy and mitigating associated limitations, focusing on its role in remodeling the tumor immune microenvironment and managing irAEs.

The review highlights that combining Thymosin α1 with ICIs synergistically remodels the tumor immune microenvironment, thereby enhancing antitumor responses. Tα1 was found to not only enhance immune competence but also regulate excessive immune activation, directly addressing key limitations of ICI monotherapy. > Preliminary findings consistently suggest that this combination exhibits promising clinical efficacy with manageable safety profiles in various cancer therapies. Specifically, the combination demonstrated potential to augment ICI efficacy and mitigate immune-related adverse events (irAEs). This dual benefit of improved response rates and reduced toxicity underscores the therapeutic potential of Tα1 as an adjunct to ICIs, offering a strategy to overcome resistance and improve patient outcomes.