# An innovative engineered IL-10 monomer strengthens T cell-mediated anti-tumor responses through anti-PD-1 cis-delivery

## TL;DR

A new fusion protein combining an anti-PD-1 antibody and a modified IL-10 monomer shows strong anti-tumor effects and reduced toxicity in preclinical models.

## Contribution

A novel fusion protein, anti-PD-1×IL-10M, is engineered to reduce IL-10 toxicity while enhancing anti-tumor T cell activation.

## Key findings

- Anti-PD-1×IL-10M reverses terminally exhausted CD8+ T cells and shows potent anti-tumor efficacy in mouse models.
- The fusion protein exhibits favorable safety in cynomolgus monkeys and works in models resistant to anti-PD-1 therapy.
- Engineered IL-10M significantly reduces activity and toxicity while maintaining therapeutic benefits.

## Abstract

Immune checkpoint blockade (ICB) therapy exerts anti-tumor efficacy mainly by activating intratumoral CD8+ T cells but fails to re-activate terminally exhausted CD8+ T cells. Interleukin-10 (IL-10) has been shown to directly expand and activate these cells and to exert a synergistic effect when combined with ICB. Nevertheless, the clinical application of IL-10 for cancer immunotherapy is restricted by severe hematological toxicity. Here, we design FP008 (anti-PD-1×IL-10M), a clinical-stage fusion protein composed of an anti-PD-1 antibody and an attenuated IL-10 monomer (IL-10M). Mechanistically, the activity and toxicity of IL-10M are significantly reduced, while its therapeutic benefits are enhanced through anti-PD-1-targeted enrichment and cis-activation. Anti-PD-1×IL-10M therapy displays robust anti-tumor activity in various mouse models, including those resistant to anti-PD-1 therapy, and exhibits promising safety in GLP toxicology studies in cynomolgus monkeys. Altogether, reinvigorating exhausted CD8+ T cells in the tumor microenvironment through anti-PD-1×IL-10M represents a promising therapeutic strategy for overcoming anti-PD-1/L1-refractory solid tumors.

•Engineered IL-10M exhibits a significant reduction in activity and toxicity•Anti-PD-1×IL-10M acquires enhanced bioactivity through anti-PD-1-mediated cis-binding•Anti-PD-1×IL-10M reverses terminally exhausted CD8+ T cells and shows potent antitumor efficacy•Anti-PD-1×IL-10M has the potential to overcome the clinical safety limitations of IL-10

Engineered IL-10M exhibits a significant reduction in activity and toxicity

Anti-PD-1×IL-10M acquires enhanced bioactivity through anti-PD-1-mediated cis-binding

Anti-PD-1×IL-10M reverses terminally exhausted CD8+ T cells and shows potent antitumor efficacy

Anti-PD-1×IL-10M has the potential to overcome the clinical safety limitations of IL-10

The clinical application of IL-10 in cancer is constrained by severe hematological toxicity. Gu et al. design the fusion protein anti-PD-1×IL-10M, composed of anti-PD-1 and an attenuated IL-10 monomer (IL-10M), which exhibits favorable safety in cynomolgus monkeys and potent anti-tumor efficacy in various preclinical models.