Collagen-Anchored Interleukin-2 and Interleukin-12 Safely Reprogram the Tumor Microenvironment in Canine Soft-Tissue Sarcomas

Abstract

Purpose: Cytokine therapies such as IL2 and IL12 suffer from impractically small therapeutic windows driven by their on-target, off-tumor activity, limiting their clinical potential despite potent antitumor effects. We previously engineered cytokines that bind and anchor to tumor collagen following intratumoral injection, and sought to test their safety and biomarker activity in spontaneous canine soft-tissue sarcomas (STS). Experimental Design: Collagen-binding cytokines were canine-ized to minimize immunogenicity and were used in a rapid dose-escalation study in healthy beagles to identify a maximum tolerated dose. Ten client-owned pet dogs with STS were then enrolled into trial, receiving cytokines at different intervals prior to surgical tumor excision. Tumor tissue was analyzed through IHC and NanoString RNA profiling for dynamic changes within treated tumors. Archived, untreated STS samples were analyzed in parallel as controls. Results: Intratumorally administered collagen-binding IL2 and IL12 were well tolerated by STS-bearing dogs, with only Grade 1/2 adverse events observed (mild fever, thrombocytopenia, neutropenia). IHC revealed enhanced T-cell infiltrates, corroborated by an enhancement in gene expression associated with cytotoxic immune function. We found concordant increases in expression of counter-regulatory genes that we hypothesize would contribute to a transient antitumor effect, and confirmed in mouse models that combination therapy to inhibit this counter-regulation can improve responses to cytokine therapy. Conclusions: These results support the safety and activity of intratumorally delivered, collagen-anchoring cytokines for inflammatory polarization of the canine STS tumor microenvironment. We are further evaluating the efficacy of this approach in additional canine cancers, including oral malignant melanoma.

Tumor-localized interleukin-2 and interleukin-12 combine with radiation therapy to safely potentiate regression of advanced malignant melanoma in pet dogs

“…To this end, we are interested in evaluating the combination of checkpoint inhibitors with the RT plus intratumoral cytokine treatment in future studies. Our prior work with canine soft tissue sarcomas indicated that checkpoint blockade might relieve counter-regulatory responses to intratumoral cytokine therapy, which we confirmed in the murine B16F10 tumor model 50 .…”

“…Similar to the pivotal Phase III clinical trials with T-VEC 77 , out of concern that longitudinal sampling of the primary treated tumors could confound results by introducing additional paths for intratumoral dose egress, we did not profile the immune response to therapy during treatment. However, building upon our prior characterization of the immune-mediated response to collagen-anchored cytokines in canine soft tissue sarcoma and murine tumors 35,50 , we highlight an anecdotal case of long-term anti-tumor response after the completion of treatment in oral melanoma which presumably involved immune activity.…”

“…Approaches to restrict the activity of potent cytokines to the tumor have gained momentum, one of which includes the retention of engineered cytokines to tumor extracellular matrix following intratumoral injection 25,[35][36][37] . We and others have previously reported on the safety improvements provided by this strategy of anchoring cytokines to tumor collagen in both mice and pet dogs 25,35,50 , but the efficacy in advanced canine tumors was previously unexplored.…”

Spatiotemporally programming cytokine immunotherapies through protein engineering

“…reported on the use of a collagen-binding cytokine regimen in pet dogs with spontaneously occurring soft-tissue sarcomas. 118 The intratumorally dosed cytokines were reported to be well tolerated with promising biomarker activity as shown by increased T cell infiltration and gene expression programs associated with a strong anti-tumor response.…”

“…In comparison to syngeneic mouse tumors, which often grow and vascularize much more rapidly than human tumors, canine tumors mirror human cancers more faithfully. 118,145 Thus, they may serve as an effective bridge between murine preclinical studies and first-in-human studies.…”