Tumor immune surveillance and cancer immunotherapies are thought to depend on the intratumoral infiltration of activated CD8(+) T cells. Intratumoral CD8(+) T cells are rare and lack activity. IL-10 is thought to contribute to the underlying immune suppressive microenvironment. Defying those expectations we demonstrate that IL-10 induces several essential mechanisms for effective antitumor immune surveillance: infiltration and activation of intratumoral tumor-specific cytotoxic CD8(+) T cells, expression of the Th1 cytokine interferon-γ (IFNγ) and granzymes in CD8(+) T cells, and intratumoral antigen presentation molecules. Consequently, tumor immune surveillance is weakened in mice deficient for IL-10 whereas transgenic overexpression of IL-10 protects mice from carcinogenesis. Treatment with pegylated IL-10 restores tumor-specific intratumoral CD8(+) T cell function and controls tumor growth.

The presence of activated intratumoral T cells correlates clinically with better prognosis in patients with cancer. Although tumor vaccines can increase the number of tumor-specific CD8 þ T cells in systemic circulation,

Graphical Abstract Highlights d Pegilodecakin induces systemic and intratumoral CD8 + T cell activation in patients d PD-1 + Lag3 + CD8 + T cells and previously undetected T cell clones are expanded d IFN-g, IL-18, GranzymeB, and FasL are elevated across tumor types d The magnitude of systemic immune activation correlates with tumor response SUMMARYTumor-reactive T cell exhaustion prevents the success of immune therapies. Pegilodecakin activates intratumoral CD8 + T cells in mice and induces objective tumor responses in patients. Here we report that pegilodecakin induces hallmarks of CD8 + T cell immunity in cancer patients, including elevation of interferon-g and GranzymeB, expansion and activation of intratumoral CD8 + T cells, and proliferation and expansion of LAG-3 + PD-1 + CD8 + T cells. On pegilodecakin, newly expanded T cell clones, undetectable at baseline, become 1%-10% of the total T cell repertoire in the blood. Elevation of interleukin-18, expansion of LAG-3 + PD-1 + T cells and novel T cell clones each correlated with objective tumor responses. Combined pegilodecakin with anti-PD-1 increased the expansion of LAG-3 + PD-1 + CD8 + T cells.

Interleukin-10 (IL-10) stimulates the expansion and cytotoxicity of tumor-infiltrating CD8+ T cells and inhibits inflammatory CD4+ T cells. Pegylation prolongs the serum concentration of IL-10 without changing the immunologic profile. This phase I study sought to determine the safety and antitumor activity of AM0010. Patients and MethodsPatients with selected advanced solid tumors were treated with AM0010 in a dose-escalation study, which was followed by a renal cell cancer (RCC) dose-expansion cohort. AM0010 was selfadministered subcutaneously at doses of 1 to 40 mg/kg once per day. Primary end points were safety and tolerability; clinical activity and immune activation were secondary end points. ResultsIn the dose-escalation and -expansion cohorts, 33 and 18 patients, respectively, were treated with daily subcutaneous injection of AM0010. AM0010 was tolerated in a heavily pretreated patient population. Treatment-related adverse events (AEs) included anemia, fatigue, thrombocytopenia, fever, and injection site reactions. Grade 3 to 4 nonhematopoietic treatment-related AEs, including rash (n = 2) and transaminitis (n = 1), were observed in five of 33 patients. Grade 3 to 4 anemia or thrombocytopenia was observed in five patients. Most treatment-related AEs were transient or reversible. AM0010 led to systemic immune activation with elevated immune-stimulatory cytokines and reduced transforming growth factor beta in the serum. Partial responses were observed in one patient with uveal melanoma and four of 15 evaluable patients with RCC treated at 20 mg/kg (overall response rate, 27%). Prolonged stable disease of at least 4 months was observed in four patients, including one with colorectal cancer with disease stabilization for 20 months. ConclusionAM0010 has an acceptable toxicity profile with early evidence of antitumor activity, particularly in RCC. These data support the further evaluation of AM0010 both alone and in combination with other immune therapies and chemotherapies.