Improving therapeutic efficacy of IL-12 intratumoral gene electrotransfer through novel plasmid design and modified parameters

Abstract

The use of immunomodulatory cytokines has been shown effective in regressing a wide range of tumors. However, systemic delivery of recombinant cytokines results in serious, potentially life-threatening, adverse effects. By contrast, nucleic acid transfer via electroporation (EP) is a safe and effective method of delivering plasmid-encoded cytokines to tumors. Intratumoral delivery of IL-12 plasmid DNA by electroporation (IT-pIL12-EP) produced objective response rates in Phase 2 clinical trials in metastatic melanoma. However, only 17.9% of patients receiving IT-pIL12-EP show a complete therapeutic response. Here, we sought to improve the antitumor efficacy of our clinical IT-pIL12-EP plasmid electroporation platform. We evaluated multiple plasmid designs for IL-12 expression. IL-12 expression from a plasmid incorporating a picornavirus-derived co-translational P2A site was the most effective in expressing IL-12p70. In addition, modifying the electroporation parameters improved transfection efficiency and expression of plasmid-derived IL-12p70, as well as its downstream effector IFN-γ in vivo. Finally, using a murine melanoma model that is representative of the intended target patient population, we show that combining modified electroporation conditions with the pIL12-P2A plasmid expression enhances the systemic antitumor response. These improvements to the IT-pIL12-EP platform may improve patient clinical response rates and survival when translated to clinical trials.

Local Delivery ofOx40l,Cd80, andCd86mRNA Kindles Global Anticancer Immunity

“…Several reports have demonstrated the necessity for CD80 and CD86 expression on professional antigen presenting cells (APC) for T-cell activation and propagation (36)(37)(38)(39)(40). IL12 is a heterodimeric proinflammatory cytokine that induces the production of IFNg, which induces the differentiation of Th1 cells, and forms a link between the innate and adaptive immune responses (28)(29)(30). Recombinant IL12 has shown remarkable properties as an antitumor agent in preclinical models (41,42).…”

“…Furthermore, unlike LNP formulations, fluorophores are easily covalently attached to CART delivery vehicles (BDK-CART; McKinlay and colleagues, 2018; Benner and colleagues, 2018), which can be utilized to correlate location of transfected cells (either anatomic, or within specific cell populations) with gene expression, thus providing insight into the mechanistic basis of effective therapeutic outcomes. In this study, we utilized the BDK-CART-mRNA delivery platform to induce local expression of genes encoding the well described immunomodulatory molecules CD70 (11), OX40L (24,25), CD80 (26,27), CD86, IL12 (28)(29)(30), and IFNg (31), both individually and in combination. We used a two-tumor model to demonstrate that local administration of mRNA coding for immunomodulatory molecules can elicit a systemic response that can cure both the treated (local) and untreated (distal) tumors.…”

In situ antitumor vaccination: Targeting the tumor microenvironment

“…In recent years, gene therapy with plasmid DNA / RNA vaccines have bright prospects in the prevention and treatment of various cancers. Immunization with these vaccines allows intracellular expression of the encoded immunomodulatory cytokines and can induce a strong humoral and cellular immune response dependent on B and T cells (Burkart et al, 2018; Lopes, Vandermeulen, & Preat, 2019). Despite the infusive efficacy observed in preclinical studies, DNA / RNA vaccines are limited due to the poor immune response and toxicity in humans.…”

“…Several approaches to deliver DNA / RNA vaccines intratumorally have been proved to be safe and effective (Brown et al, 2018; Burkart et al, 2018; Guerrero‐Cazares et al, 2014; X. Liu et al, 2011). Intratumoral delivery of interleukin‐12 (IL‐12) plasmid DNA vaccine by electroporation is the driving force of strong cellular immune responses, reversing the immunosuppressive state of melanoma (Burkart et al, 2018). A recent Phase I clinical trial demonstrated that intratumoral delivery of plasmid DNA encoding IL‐12 resulted in complete regression of melanoma in two patients with minimal systemic toxicity (Daud et al, 2008).…”

“…Several approaches to deliver DNA/RNA vaccines intratumorally have been proved to be safe and effective Burkart et al, 2018;Guerrero-Cazares et al, 2014;X. Liu et al, 2011).…”