Increased lymphocyte infiltration in patients with head and neck cancer treated with the IRX-2 immunotherapy regimen.

Twenty-seven subjects with squamous cell cancer of the head and neck received the neoadjuvant IRX-2 immunotherapy regimen prior to surgery in a Phase 2 trial. Pretreatment tumor biopsies were compared with the primary tumor surgical specimens for lymphocyte infiltration, necrosis and fibrosis, using hematoxylin and eosin stain and immunohistochemistry in 25 subjects. Sections were examined by three pathologists. Relative to pretreatment biopsies, increases in lymphocyte infiltration (LI) were seen using H and E or immunohistochemistry. CD3+ CD4+ T cells and CD20+ B cells were primarily found in the peritumoral stroma and CD3+ CD8+ T cells and CD68+ macrophages were mainly intratumoral. LI in the surgical specimens were associated with reductions in the primary tumor size. Improved survival at 5 years was correlated with high overall LI in the tumor specimens. Neoadjuvant IRX-2 immunotherapy regimen may restore immune responsiveness presumably by mobilizing tumor infiltrating effector lymphocytes and macrophages into the tumor.

Novel neoadjuvant immunotherapy regimen safety and survival in head and neck squamous cell cancer.

BACKGROUND: Cellular immune suppression is observed in head and neck squamous cell cancer (HNSCC) and contributes to poor prognosis. Restoration of immune homeostasis may require primary cell-derived cytokines at physiologic doses. An immunotherapy regimen containing a biologic, with multiple-active cytokine components, and administered with cytoxan, zinc, and indomethacin was developed to modulate cellular immunity. METHODS: Study methods were designed to determine the safety and efficacy of a 21-day neoadjuvant immunotherapy regimen in a phase 2 trial that enrolled 27 therapy-naïve patients with stage II to IVa HNSCC. Methods included safety, clinical and radiologic tumor response, disease-free survival (DFS), overall survival (OS), and tumor lymphocytic infiltrate (LI) data collection. RESULTS: Acute toxicity was minimal. Patients completed neoadjuvant treatment without surgical delay. By independent radiographic review, 83% had stable disease during treatment. OS was 92%, 73%, and 69% at 12, 24, and 36 months, respectively. Histologic analysis suggested correlation between survival and tumor LI. CONCLUSION: Immunotherapy regimen was tolerated. Survival results are encouraging.

A phase 1 safety study of an IRX-2 regimen in patients with squamous cell carcinoma of the head and neck.

OBJECTIVES: Head and neck squamous cell carcinoma (HNSCC) is associated with profound defects in cellular immunity. IRX-2, a primary cell-derived biologic containing multiple cytokines, has enhanced immune responses and induced tumor rejection in preclinical studies. This phase 1 open label study aimed to determine the clinical and laboratory safety of an IRX-2 regimen in patients with HNSCC. METHODS: Patients with HNSCC who had failed surgery and/or radiation therapy were enrolled. IRX-2 was injected subcutaneously at 115 units per dose, 2 doses/d over 10 days, starting on day 4. Patients received low-dose cyclophosphamide infusion on day 1 and took oral indomethacin and zinc daily from day 1 through day 21. Safety and laboratory assessments were undertaken throughout the treatment and 4 weeks after completion of the regimen. RESULTS: A total of 13 patients with advanced disease were enrolled in the safety/intent-to-treat population; all experienced treatment-emergent adverse events (AEs). The most frequent AEs were blood and lymphatic disorders, followed by gastrointestinal disorders. Most AEs were mild to moderate in severity. Three patients discontinued the study due to an AE, including 2 deaths. Two patients died after the study period due to tumor progression. No death or discontinuation was considered related to the study drugs. Antitumor responses were noted by radiographic assessment. In the 8 patients who had antitumor data at day 21, 1 patient had complete response, 5 had stable disease, and 2 had progressive disease. CONCLUSIONS: The IRX-2 regimen was tolerated in patients with advanced HNSCC who failed surgery and/or radiation therapy. The safety and antitumor activity observed warrants further studies.

IRX-2 increases the T cell-specific immune response to protein/peptide vaccines.

Therapeutic cancer vaccines are attractive due to the prospect of specificity and their lack of toxicity; however, their clinical development has been hampered by several biologic and clinical challenges. One of the most important biologic challenges is the relative lack of effective cellular immune adjuvants. Effective physiologic immune responses are characterized by the local generation of a complex cytokine environment that activates and regulates multiple immune cell types. IRX-2 is a primary cell-derived biologic with physiological levels of multiple active cytokine components, produced under pharmaceutical standards. The hypothesis that IRX-2 amplifies the T cell response to defined antigens was assessed in mice by measuring the T cell-specific peptide response to a dominant mouse peptide (NFT) derived from human prostate-specific membrane antigen (PSMA). IRX-2 enhances the T cell response to NFT when antigens were delivered either via irradiated cells expressing human PSMA, NFT peptide in Incomplete Freund's adjuvant (IFA) or NFT peptide conjugated to KLH. The T cell-specific activity was measured in spleen or lymph nodes cells by IFN-γ ELISpot and/or IFN-γ secretion over 6 days or in vivo by peptide-specific delayed-type hypersensitivity reaction (DTH). Further more, a single administration of IRX-2 with the antigen was not active as compared to 4 or 9 additional administrations which were sufficient to enhance the T cell response to antigens. The influence of IRX-2 on the B cell response to ovalbumin when it was used as a carrier protein was measured by ELISA. IRX-2 was compared to a commercially available combination adjuvant (MPL+TDM in squalene/Tween 80) which based on the literature is a potent adjuvant in murine systems. In the T cell assay IRX-2 was superior to the commercially available combination adjuvant and while IRX-2 also increased antibody titer, it was not as potent as the combination adjuvant. Mice immunized with IRX-2 and antigen also exhibited delayed tumor progression following challenge with PSMA-expressing tumor cells. These studies demonstrate that IRX-2 is an immunomodulator with adjuvant activity which preferentially enhances the T cell-specific responses to tumor associated antigens. Based on these studies, IRX-2 is a candidate for evaluation as a T cell adjuvant in a variety of preclinical vaccine delivery systems as well as in human clinical trials with cancer vaccine candidates.

IRX-2, a novel in vivo immunotherapeutic, induces maturation and activation of human dendritic cells in vitro.

IRX-2 is a uniform, well-defined set of natural cytokines currently in Phase II clinical trials for squamous cell carcinoma of the head and neck (HNSCC). In preliminary clinical studies of HNSCC patients, IRX-2 therapy has shown promising results, increasing overall survival of patients from 32% to 61% at 48 months. Although it is known that specific cytokines in IRX-2 enhance T cell activity [e.g., interleukin-2 (IL-2), interferon-gamma, IL-1beta], we chose to investigate the influence of IRX-2 on monocyte-derived dendritic cells (Mo-DCs) isolated from human peripheral blood in an effort to further understand the clinical findings. We show here that IRX-2 treatment of human monocyte-derived DC resulted in morphologic, phenotypic, and functional changes consistent with the development of mature activated DC. Specifically, IRX-2-treated DC increased expression of CD83 and CCR7, markers for DC maturation and migration, respectively, and increased the expression of HLA-DR, CD54, and the costimulatory molecules CD86 and CD40, which are critical mediators of T cell activation. Functional changes in DC induced by IRX-2 included a reduced endocytic capacity, increased ability to stimulate T cells and increased IL-12 cytokine production. These results provide a plausible mechanistic explanation for the in vivo clinical activity of IRX-2 and an additional rationale for the use of IRX-2-based immunotherapy in patients.