Kristi Manjarrez

A Phase I Dose-Finding Study of the Novel Toll-like Receptor 8 Agonist VTX-2337 in Adult Subjects with Advanced Solid Tumors or Lymphoma

Purpose: This phase I, open-label, uncontrolled, ascending-dose study explored the safety, maximum tolerated dose (MTD), pharmacokinetics, and pharmacology of the TLR8 agonist VTX-2337 in subjects with advanced solid tumors or lymphoma. Experimental Design: VTX-2337 doses (0.1–3.9 mg/m2) were administered subcutaneously on days 1, 8, and 15 of each 28-day cycle. Safety/tolerability assessments included adverse events (AE); physical, ophthalmologic, and laboratory evaluations; and electrocardiograms. Dose-limiting toxicities (DLT) were evaluated during the first cycle. Pharmacokinetics were evaluated after the first dose. Plasma samples were quantitatively assessed for chemokines, cytokines, and other inflammatory mediators. Antitumor activity was assessed. Results: Thirty-three subjects were enrolled in 8 cohorts and received an average of 2 treatment cycles (range, 1–8 cycles). Most AEs were grades 1 to 2; the most common drug-related AEs were injection site reactions, chills, pyrexia, and influenza-like illness. One DLT was reported: grade 3 hypotension (3.9 mg/m2). The MTD was considered the highest dose administered. Peak drug plasma levels and total systemic exposure were generally dose proportional. At doses ≥0.4 mg/m2, increases above baseline levels were observed for plasma levels of G-CSF, monocyte chemoattractant protein-1, macrophage inflammatory protein-1β, and TNFα. Eight subjects (24.2%) had a best response of stable disease (median duration, 54.5 days). Conclusions: VTX-2337 is clinically well tolerated and biologically active with a predictable pharmacokinetic profile. Suitable doses for testing in combination studies were identified. Phase II placebo-controlled studies of VTX-2337 in combination with doxorubicin in ovarian cancer, and in combination with platinum chemotherapy, 5 FU, and cetuximab in head and neck cancer have been initiated (NCT #01666444 and NCT#01836029). Clin Cancer Res; 20(14); 3683–91. ©2014 AACR.

Late-Stage Cancer Patients Remain Highly Responsive to Immune Activation by the Selective TLR8 Agonist Motolimod (VTX-2337)

Purpose: Immunotherapy as a treatment for cancer holds the promise of complete and durable tumor remission, yet the immunosuppressive environment created by many tumors, advanced patient age, and previous treatments with cytotoxic agents may limit the approach. The activity of motolimod (VTX-2337), a potent and selective Toll-like receptor 8 (TLR8) agonist, was therefore assessed in the context of advanced, late-stage cancer patients. Experimental Design: The repertoire of mediators induced from human peripheral blood mononuclear cells in response to motolimod was characterized. Translational studies in cynomolgus monkeys elucidated the activity of motolimod on an intact immune system, identified biomarkers of TLR8 activation, and defined the relationship between the pharmacokinetic and pharmacodynamic (PK/PD) response. The PK/PD relationship for motolimod in cancer patients was assessed, compared with preclinical findings, and contrasted with activity in healthy volunteers. Results: In late-stage cancer patients, plasma levels of multiple biomarkers, including IL6, G-CSF, MCP-1, and MIP1-β, increased with increasing motolimod dose. The magnitude and breadth of the biomarker response closely aligned with the response seen in preclinical studies, demonstrating that advanced cancer patients remained responsive to TLR8 activation. In addition, the PK/PD response in cancer patients closely aligned with the activity of motolimod seen in healthy volunteers. Conclusions: Late-stage cancer patients are highly sensitive to TLR8 activation by motolimod. Tumor burden, advanced age, and prior treatment history with cytotoxic agents did not moderate or modify the response predicted by nonclinical studies and confirmed in healthy volunteers. Clin Cancer Res; 21(24); 5445–52. ©2015 AACR.

Phase 1b Trial of the Toll-Like Receptor 8 Agonist, Motolimod (VTX-2337), Combined with Cetuximab in Patients with Recurrent or Metastatic SCCHN

Purpose: As Toll-like receptors (TLR) are key mediators of immune responses, TLR agonists may be important for augmenting the efficacy of therapies for squamous cell carcinoma of the head and neck (SCCHN). Motolimod (VTX-2337), a selective small-molecule agonist of TLR8, stimulates natural killer (NK) cells, dendritic cells, and monocytes. A phase Ib clinical trial assessed the safety and antitumor activity of motolimod in combination with cetuximab in patients with SCCHN. Correlative biomarkers of immune activity were explored. Experimental Design: Thirteen patients with recurrent or metastatic SCCHN were enrolled in this open-label, dose–escalation study using a standard 3 + 3 design. Doses of motolimod (2.5, 3.0, or 3.5 mg/m2) were given on days 1, 8, and 15, in combination with fixed weekly doses of cetuximab in 28-day cycles. Results: There were no protocol-defined dose-limiting toxicities, drug-related deaths, or evidence of synergistic toxicities between motolimod and cetuximab. Clinical tolerability at the 3.5 mg/m2 dose level was not optimal for repeated dosing and 3.0 mg/m2 was identified as the MTD. Two patients achieved partial responses for an overall response rate of 15%. Five patients had disease stabilization equating to a disease control rate of 54%. Statistically significant increases in plasma cytokines and in the frequency and activation of circulating NK cells were observed. Conclusions: Motolimod can be safely administered in combination with cetuximab with an acceptable toxicity profile. Encouraging antitumor activity and robust pharmacodynamic responses were observed. Motolimod is being further investigated in a phase II trial in patients with SCCHN (ClinicalTrials.gov ID: NCT01836029). Clin Cancer Res; 23(10); 2442–50. ©2016 AACR.

Integrative development of a TLR8 agonist for ovarian cancer chemoimmunotherapy

Purpose: Immunotherapy is an emerging paradigm for the treatment of cancer, but the potential efficacy of many drugs cannot be sufficiently tested in the mouse. We sought to develop a rational combination of motolimod—a novel Toll-like receptor 8 (TLR8) agonist that stimulates robust innate immune responses in humans but diminished responses in mice—with pegylated liposomal doxorubicin (PLD), a chemotherapeutic that induces immunogenic cell death. Experimental Design: We followed an integrative pharmacologic approach including healthy human volunteers, non-human primates, NSG-HIS (“humanized immune system”) mice reconstituted with human CD34+ cells, and patients with cancer to test the effects of motolimod and to assess the combination of motolimod with PLD for the treatment of ovarian cancer. Results: The pharmacodynamic effects of motolimod monotherapy in NSG-HIS mice closely mimicked those in non-human primates and healthy human subjects, whereas the effects of the motolimod/PLD combination in tumor-bearing NSG-HIS mice closely mimicked those in patients with ovarian cancer treated in a phase Ib trial (NCT01294293). The NSG-HIS mouse helped elucidate the mechanism of action of the combination and revealed a positive interaction between the two drugs in vivo. The combination produced no dose-limiting toxicities in patients with ovarian cancer. Two subjects (15%) had complete responses and 7 subjects (53%) had disease stabilization. A phase II study was consequently initiated. Conclusions: These results are the first to demonstrate the value of pharmacologic approaches integrating the NSG-HIS mouse, non-human primates, and patients with cancer for the development of novel immunomodulatory anticancer agents with human specificity. Clin Cancer Res; 23(8); 1955–66. ©2016 AACR.

Effect of Adding Motolimod to Standard Combination Chemotherapy and Cetuximab Treatment of Patients With Squamous Cell Carcinoma of the Head and Neck: The Active8 Randomized Clinical Trial.

Importance Immunotherapy for recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) is promising. The toll-like receptor 8 (TLR8) agonist motolimod may stimulate innate and adaptive immunity. Objective To determine whether motolimod improves outcomes for R/M SCCHN when combined with standard therapy. Design, Setting, and Participants The Active8 study was a multicenter, randomized, double-blind, placebo-controlled clinical trial enrolling adult patients (age ≥18 years) with histologically confirmed R/M SCCHN of the oral cavity, oropharynx, hypopharynx, or larynx between October 2013 and August 2015. Follow-up ended September 2016. Analysis for the present report was conducted between June 2016 and December 2017. Interventions Combination treatment with platinum (carboplatin or cisplatin), fluorouracil, cetuximab (the EXTREME regimen), and either placebo or motolimod, each administered intravenously every 3 weeks. Patients received a maximum of 6 chemotherapy cycles, after which patients received weekly cetuximab with either placebo or motolimod every 4 weeks. Main Outcomes and Measures Progression-free survival (PFS) as determined by independent central review using immune-related RECIST (Response Evaluation Criteria in Solid Tumors). Key secondary end points included overall survival (OS) and safety. Results Of 195 patients enrolled, 85% were men (n = 166); 82% were white (n = 159); median age was 58 years (range 23-81 years). Median PFS was 6.1 vs 5.9 months (hazard ratio [HR], 0.99; 1-sided 90% CI, 0.00-1.22; P = .47), and median OS was 13.5 vs 11.3 months (HR, 0.95; 1-sided 90% CI, 0.00-1.22; P = .40) for motolimod vs placebo. Increased incidence of injection site reactions, pyrexia, chills, anemia, and acneiform rash were noted with motolimod. Of 83 cases oropharyngeal cancer, 52 (63%) were human papillomavirus (HPV) positive. In a prespecified subgroup analysis of HPV-positive participants, motolimod vs placebo resulted in significantly longer PFS (7.8 vs 5.9 months; HR, 0.58; 1-sided 90% CI, 0.00-0.90; P = .046) and OS (15.2 vs 12.6 months; HR, 0.41; 1-sided 90% CI, 0.00-0.77; P = .03). In an exploratory analysis, patients with injection site reactions had longer PFS and OS (median PFS, 7.1 vs 5.9 months; HR, 0.69; 1-sided 90% CI, 0.00-0.93; P = .06; and median OS, 18.7 vs 12.6; HR, 0.56; 1-sided 90% CI, 0.00-0.81; P = .02). Conclusions and Relevance Adding motolimod to the EXTREME regimen was well tolerated but did not improve PFS or OS in the intent-to-treat population. Significant benefit was observed in HPV-positive patients and those with injection site reactions, suggesting that TLR8 stimulation may benefit subset- and biomarker-selected patients. Trial Registration ClinicalTrials.gov identifier: NCT01836029.

Abstract AS27: VTX-2337, a TLR8 agonist, plus chemotherapy in recurrent ovarian cancer: preclinical and phase 1 data by the gynecologic oncology group

Background: Given the absence of clear molecular drivers in high-grade serous ovarian cancer, targeting the tumor microenvironment with immunotherapy is an emerging approach. Stimulation of the innate immune system via Toll-like receptors (TLRs) may augment the antitumor activity of cytotoxic chemotherapies, including anthracyclines. VTX-2337 is a potent, small molecule agonist of TLR8 which was previously evaluated as a single agent in patients with advanced cancer. We report both pre-clinical and clinical data combining VTX-2337 with pegylated liposomal doxorubicin (PLD; Doxil®) chemotherapy in recurrent ovarian cancer. Methods: VTX-2337 was tested in an ovarian tumor model in immunocompromised mice reconstituted with a human immune system. Additionally, an open-label Phase 1 study of VTX-2337 + PLD in recurrent platinum-resistant ovarian cancer (NCT0129493, n=13) was performed. (The clinical study also evaluated the combination of VTX 2337 + weekly paclitaxel [n=7]; data is not reported herein.) PLD (40 mg/m2) was given on day 1 of a 28 day cycle. Three dose levels of VTX-2337 (2.5, 3.0, 3.5 mg/m2) were sequentially tested and given by SC injection on days 3, 10, and 17 of each treatment cycle. Responses were evaluated using RECIST 1.1. The pharmacokinetics (PK) of VTX-2337 and PLD, and plasma levels of mediators induced by TLR8 activation were assessed. Patients remained on study treatment until disease progression or unacceptable toxicity. Results: In the murine tumor model, the efficacy of the combination of VTX-2337 + PLD was increased compared to that of either agent alone. The development of an adaptive CD8+ T cell response to tumor cells was also enhanced. In humans, treatment with VTX-2337 + PLD increased levels of multiple cytokines and chemokines (G-CSF, MCP-1, MIP-1β, TNFα) consistent with TLR8 stimulation and innate immune activation. The PK of PLD was not affected by VTX-2337. The combination was well tolerated with no dose limiting toxicities and no serious, unexpected treatment-related adverse events (AEs). AEs consisted of those seen with single-agent PLD (Gr 3/4 toxicities; n=6) or VTX-2337 (Gr 1/2 injection site reaction, transient fever, flu-like symptoms; n=13). One subject with non-measurable disease achieved a complete response, 1 subject enrolled based on biochemical evidence of recurrent disease achieved a complete biochemical response, 7 subjects had stable disease, and 3 subjects had progressive disease. One subject discontinued treatment prematurely and did not undergo tumor response assessment. Overall, subjects treated with the combination of VTX 2337 + PLD experienced a response rate of 15.4% (n=2) and a disease control rate of nearly 70% (n=9; 69.2%). Conclusions: VTX-2337 enhances the therapeutic effects of PLD in a preclinical model of ovarian cancer, and the combination is well tolerated in patients. Clinical data and biomarkers consistent with immunostimulation provide rationale for the on-going randomized, placebo-controlled, Phase 2 trial comparing PLD vs PLD + VTX-2337 (GOG-3003; NCT01666444). This trial is fully enrolled. Citation Format: Bradley J. Monk, William E. Brady, Heather A. Lankes, Andrea Facciabene, Kristi L. Manjarrez, Robert M. Hershberg, Paula M. Fracasso, Katherine M. Bell-McGuinn, Joan L. Walker, Carolyn K. McCourt, Carol Aghajanian, George Coukos. VTX-2337, a TLR8 agonist, plus chemotherapy in recurrent ovarian cancer: preclinical and phase 1 data by the gynecologic oncology group [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr AS27.

Comparison of immune modulation by TLR8 agonist vtx-2337 (motolimod) in cancer patients and healthy volunteers

The potential benefits of stimulating a patients immune system to fight cancer are profound. Historically, immunotherapy has been a successful treatment approach for some cancer patients, and recent advances in immunotherapy highlight that the immune system can generate durable tumor responses and cures. However, a concern regarding immunotherapy in cancer patients is the possibility that the immune response will be compromised by the underlying cancer and/or previous anticancer therapies. A promising approach in immunotherapy is targeting pathogen-associated molecular pattern receptors, such as the Toll-like receptors (TLRs), to activate the innate immune system and enhance development of tumor-directed adaptive immune responses. To assess whether cancer patients exhibit immune insufficiency in response to the potent and selective TLR8 agonist motolimod, we compared the pharmacokinetic and pharmacodynamic (PK/PD) relationship defined in a Phase 1 study of motolimod in cancer patients to the response in healthy volunteers. Stimulation of healthy volunteer human PBMC by motolimod using the TruCulture® system (Myriad-RBM) defined the breadth and magnitude of immune mediators induced by TLR8 activation in vitro. In a Phase 1 dose-escalation study in patients with advanced solid tumors, many of these defined mediators of TLR8 activation were increased in the plasma of cancer patients treated with motolimod. Notably, multiple biomarkers of immune activation, including G-CSF, MCP-1, and MIP1-β increased in a dose-dependent manner and correlated with increasing plasma levels of motolimod. A second Phase 1 study of motolimod in healthy volunteers provided an opportunity to compare and contrast the immune response generated by treatment with motolimod in healthy volunteers to that observed in cancer patients. At comparable dose levels, the PK profile and overall exposure (AUC) to motolimod were similar for cancer patients and healthy volunteers. Motolimod induced the same repertoire of circulating cytokines and chemokines, indicative of TLR8 activation, in both populations. The magnitude of the mediator response in cancer patients was highly comparable to the response in healthy volunteers that received a similar dose. In summary, advanced cancer and prior treatment with cytotoxic agents did not appear to blunt the response to motolimod based on the PK/PD relationship using predictive biomarkers. This comparison demonstrates that the immune system of cancer patients with advanced disease remains highly responsive to TLR8 activation by motolimod.

Active8: a randomized, double-blind, placebo-controlled study of chemotherapy plus cetuximab in combination with TLR8 agonist VTX-2337 in patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN)

Meeting abstracts Recurrent or metastatic SCCHN has few effective therapeutic options. In these patients, the EXTREME regimen added Cetuximab--an EGFR-specific monoclonal antibody--to a regimen of Platinum/5-FU and improved median overall survival (OS) by 2.7 months and progression-free survival (

Abstract 2540: Immune modulation by the TLR8 agonist VTX-2337; a comparison of the pharmacodynamic response in cancer patients and healthy volunteers

Immunotherapy has proven to be a successful treatment approach for some cancer patients. One promising paradigm in immunotherapy is targeting pathogen-associated molecule pattern receptors (PAMPS) such as the toll-like receptors (TLRs) to activate the innate immune system and enhance the development of tumor-directed adaptive immune responses. However, an ongoing concern in the application of immunotherapeutics is the potential for the immune response in cancer patients to be less robust than in healthy individuals, due to the underlying advanced neoplastic disease or due to previous regimens of cytotoxic drugs. To address this concern in relation to the response to TLR8 stimulation, we compared the pharmacokinetic and pharmacodynamic (PK/PD) relationship defined in a phase 1 clinical trial of the selective small molecule TLR8 agonist VTX-2337 in oncology patients to the response in healthy volunteers. A phase 1 dose-escalation clinical trial (A101) in subjects with advanced solid tumors (n=33) demonstrated that plasma levels of multiple biomarkers of immune activation, including G-CSF, MCP-1, MIP1-β and TNFα, increased in a dose-dependent manner and correlated with increasing plasma levels of VTX-2337. The PK/PD relationship defined in the initial clinical trial was closely aligned with predictions from both in vitro assays and preclinical studies conducted in cynomolgus monkeys. A subsequent phase 1 trial (A105) was conducted as a single-center, open-label, two-period, randomized, crossover, phase 1 study in normal volunteers (n=10). The objective of this study was to compare the PK/PD profiles and local tolerance of two formulations of VTX-2337. In this study, the two preparations of VTX-2337 demonstrated comparable PK profiles and PD responses. At comparable dose levels, the PK profile and overall exposure (AUC) to VTX-2337 was similar for oncology patients and healthy volunteers. VTX-2337 induced the same repertoire of circulating cytokines and chemokines, indicative of TLR8 activation, in both populations. The magnitude of the mediator response in oncology patients was also highly comparable to the response in healthy volunteers that received a similar dose. This comparison demonstrates that the immune system of cancer patients with advanced disease remains highly responsive to TLR8 activation by VTX-2337. In summary, advanced neoplastic disease or a prior treatment history with cytotoxic agents that can negatively impact immune cell function did not appear to moderate the response to VTX-2337 based on the PK/PD relationship using predictive biomarkers. Citation Format: Greg Dietsch, Donald Northfelt, Ramesh Ramanathan, Peter Cohen, Kristi Manjarrez, Mona Newkirk, James Kyle Bryan, Robert Hershberg. Immune modulation by the TLR8 agonist VTX-2337; a comparison of the pharmacodynamic response in cancer patients and healthy volunteers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2540. doi:10.1158/1538-7445.AM2014-2540