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Importance The incidence of human papillomavirus type 16 (HPV16–positive) recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) is rising. Approved therapies offer a durable response to a minority of patients. Objective To determine the efficacy and safety of a therapeutic HPV16-targeted immunotherapy, PDS0101, in combination with pembrolizumab in participants with HPV16-positive R/M HNSCC, with separate evaluation of immune checkpoint inhibitor (ICI)–naive and ICI-resistant cohorts. Design, Setting, and Participants VERSATILE-002 was a phase 2, open-label, multicenter nonrandomized clinical trial conducted at 26 oncology centers from March 29, 2021, to May 15, 2025, across the US, UK, and Ireland using the Simon 2-stage optimal design. Efficacy analyses were performed on modified intent-to-treat (mITT) population; safety analyses included all participants who received 1 or more doses. Eighty-eight participants with histologically confirmed R/M HPV16-positive HNSCC were enrolled, of whom 87 (98.9%) received treatment and composed the safety population. Seventy five (85.2%) were in the mITT population used for efficacy analyses, of whom 53 (70.7%) were ICI-naive with a programmed cell death ligand 1 combined positive score of 1 or greater and 22 (29.3%) were ICI-resistant. Exposures Pembrolizumab (200 mg, intravenously, every 3 weeks for up to 35 cycles) plus subcutaneous PDS0101 (5 scheduled doses per protocol). Main Outcomes and Measures The primary end point was objective response rate (ORR) per the Response Evaluation Criteria in Solid Tumors , version 1.1, by a masked independent central reviewer. Secondary end points included progression-free survival (PFS), median overall survival (mOS), and safety, with exploratory end points of duration of response, disease control rate, and response rates by programmed cell death ligand 1 status. Results Of the 75 patients in the mITT population, the mean (SD) age was 64.0 (8.3) years; 4 individuals (5%) were female and 71 (95%) were male; and 2 individuals (3%) were Asian, 1 (1%) was Black, 5 (7%) were Hispanic, and 71 (95%) were White. Among 53 ICI-naive participants in the mITT cohort, ORR by the central reviewer was 34.0%, median PFS was 5.3 months (95% CI, 2.10-9.00), and mOS was 39.3 months (95% CI, 23.90 to not evaluable). Among 22 ICI-resistant patients in the mITT cohort, no objective responses were observed and the primary end point (ORR by central reviewer) was not met, but mOS was 14.8 months (95% CI, 8.50-26.00). The treatment was well tolerated, with 13.8% experiencing grade 3 or higher treatment-related adverse events. Conclusions and Relevance The results of this nonrandomized clinical trial suggest that PDS0101 plus pembrolizumab showed antitumor activity in ICI-naive HPV16-positive R/M HNSCC, with favorable safety, response rates, and survival outcomes. The findings support further evaluation in a first-line setting. Trial Registration ClinicalTrials.gov Identifier: NCT04260126

Chimeric antigen receptor (CAR) T cell therapy faces many challenges against solid tumors including T cell exhaustion and poor CAR durability. Here, we show that engaging the CAR T cell endogenous T cell receptor (TCR) using an oncolytic virus enhances CAR T cell functionality, durability, and therapy. Upon combination therapy of solid tumors with CAR T cells and vesicular stomatitis virus (VSV), a subpopulation of antiviral, TCR-primed CAR T cells was generated with enhanced effector functions, altered activation states, and differential gene and protein expression when compared to non–TCR-primed CAR T cells. Single-cell RNA sequencing showed clonal expansion of anti-VSV CAR T cells and enhancement of effector-associated genes with VSV-mediated CAR T cell expansion. CD4 T cells played a pivotal role in the development of these TCR-primed CAR T cells. These results provide a strong rationale both for a novel use of systemic oncolytic virotherapy and for directly exploiting the CAR T cell TCR to fine tune the CAR T cell phenotype and function.

Abstract Most oncolytic viruses are delivered by intratumoural injection, and local administration can induce regression of both injected and distant tumours in mice and patients. However, the mechanisms by which local viral infection reprograms systemic immunity remain poorly understood. Here we show that intratumoural RP1, an oncolytic HSV-1 encoding GM-CSF and GALV-GP-R ⁻ , drives regression of injected and uninjected murine melanoma tumours and prolongs survival. RP1 elicits coordinated CD4 ⁺ and CD8 ⁺ T cell infiltration accompanied by local cytokine remodelling, reshaping the immune landscape at both tumour sites. Leveraging the Timer of Cell Kinetics and Activity (Tocky) system and Kaede photoconvertible protein technology, we resolve the temporal dynamics of CD8 ⁺ T cell responses following local virotherapy and identify two systemically induced, virus-driven CD8 ⁺ T cell populations distinguished by TCR engagement kinetics: antigen-engaged Timer-positive ‘viral-induced precursors’ (VIPs) and Timer-negative KLRG1 ⁺ ‘viral-induced terminal effectors’ (VITEs). Single-cell transcriptomic and pseudotime analyses reveal divergent differentiation trajectories; VIPs exhibit sustained antigen engagement within the tumour microenvironment (TME), a transcriptional programme associated with self-renewal, and preferential homing to draining lymph nodes. A VIP-associated gene signature correlates with clinical response to RP1 plus PD-1 blockade in the IGNYTE trial of RP1 and nivolumab in PD-1-refractory melanoma and is independently associated with response to immune checkpoint inhibitor (ICI) therapy in melanoma. These findings establish a mechanistic link between local oncolytic virotherapy, systemic CD8 ⁺ T cell reprogramming, and durable regression of distant lesions in patients.

Background Antitumor immune responses induced by oncolytic immunotherapy (OI) are often followed by upregulation of programmed death-ligand 1 (PD-L1). As such, the combination of OI with blockade of the programmed cell death protein-1 (PD-1)/PD-L1 axis has demonstrated therapeutic activity in preclinical and clinical trials. The purpose of this study is to understand further the immune-mediated mechanism of interaction between oncolytic viruses and anti-PD-1 therapy. Methods Tumor cells and immune cells (splenocytes) were cultured separately, or in co-culture with vusolimogene oderparepvec, an oncolytic herpes simplex virus expressing the fusogenic gibbon-ape leukemia virus-fusogenic membrane glycoprotein protein (GALV) and granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as RP1. Viral replication, interferon (IFN) responses and PD-L1 expression were analyzed using wild-type, IFNAR1, TNFAR1 and STING knockout splenocytes. In vivo studies evaluated immune cell infiltrates into the tumor following RP1 administration with anti-PD-1 therapy. Results RP1 replication was evident in tumor cells but not splenocytes. This was also accompanied by upregulated IFN expression in cultured splenocytes that was absent in cultured tumor cells. However, when these cell types were co-cultured, splenocytes mediated an interferon response to RP1 via STING that was transmitted to tumor cells in a non-touch-dependent manner. Tumor cells responded to these input signals via upregulation of cell surface major histocompatibility complex-I and PD-L1 through tumor intrinsic JAK-STAT signaling. In vivo, an IFN signature was observed following intratumoral injection of RP1, both in injected and non-injected tumors, which was further increased when combined with anti-PD-1 therapy. Marked upregulation of PD-L1 was observed in tumors injected with RP1 accompanied by the recruitment of CD11b+Ly6G+neutrophils into the tumor microenvironment, which stained positive for PD-L1. Conclusion Overall, the data demonstrate that RP1 remodels the tumor microenvironment through a combination of direct and indirect effects on both tumor and immune cells, resulting in an overall more inflamed phenotype.

6037 Background: The incidence of HPV-associated head and neck squamous cell carcinoma (HNSCC) continues to rise with over 90% of cases being driven by HPV16. Median overall survival (OS) with pembrolizumab in first-line recurrent/metastatic (R/M) HNSCC is 12.3 months in subjects with CPS ≥1, 10.8 months for CPS ≥1-19, and 14.9 months for CPS ≥20. There is an urgent need to improve survival rates in the growing population of HPV16-positive R/M HNSCC. PDS0101 (Versamune HPV) is an investigational T cell stimulating immunotherapy that unleashes a potent, durable attack against HPV16-positive cancers and is being studied in combination with pembrolizumab. Preliminary results were presented at ASCO 2023. (Price KAR, et al. ASCO 2023. Abstract 6012). Methods: VERSATILE-002 is a single-arm phase 2 study evaluating PDS0101 and pembrolizumab for first-line HPV16-positive R/M HNSCC with CPS ≥1. Subjects received pembrolizumab 200 mg IV Q3W with PDS0101 1 mL SC administered concurrently during Cycles 1, 2, 3, 4, and 12 and pembrolizumab alone for all other Cycles up to Cycle 35 (approx. 2 years). The primary study endpoint is confirmed objective response rate (ORR) per RECIST 1.1. Secondary endpoints include progression-free survival (PFS), OS, and safety. Results: The median follow-up is 18.4 months (range 0.2-42.7 months). The efficacy population consists of 53 subjects: 32 (60%) with CPS ≥1-19 and 21 (40%) with CPS ≥20. The median OS for subjects with CPS ≥1 is 30 months (95% CI 23.9, NE). For the CPS ≥1-19 subgroup, the median OS is 29.5 months (95% CI 15.3, NE). For the CPS ≥20 subgroup, the median OS is 39.3 months (95% CI 18.4, NE). Confirmed response rates by investigator assessment are shown in the Table. Twenty-three subjects are still on study: 3 on treatment and 20 in long-term follow-up. No new safety signals have emerged. The most common TRAEs are injection site reactions, fatigue, headache, and pruritus. Only 19% of subjects experienced Grade ≥3 TRAEs. No subject had a Grade 5 TRAE. Conclusions: These data represent one of the most extended follow-up periods to date of subjects receiving an HPV16-targeted therapy for HPV16-positive R/M HNSCC. The PDS0101 and pembrolizumab combination is well tolerated and has demonstrated deep and durable clinical responses. Median OS is promising in light of historic expectations, both overall and relative to PD-L1 subgroup, and remains durable with continued follow up. The results support further evaluation in a randomized phase 3 study with OS as the primary endpoint. Clinical trial information: NCT04260126 . Summary of results. CPS ≥1-19 (N=32) CPS ≥20 (N=21) CPS ≥1 (N=53) ORR, % 28.1 47.6 35.8 DCR, % 75.0 81.0 77.4 Median DOR, months (95 % CI) 21.8 (4.2, NE) NE (5.6, NE) 21.8 (11.5, NE) Median PFS, months (95% CI) 5.1 (2.4, 8.1) 14.1 (2.1, NE) 6.3 (3.5, 9.0) Median OS, months (95% CI) 29.5 (15.3, NE) 39.3 (18.4, NE) 30.0 (23.9, NE)

TPS6111 Background: Human papillomavirus (HPV)-related head and neck squamous cell carcinoma (HNSCC) has surpassed cervical cancer as the most common HPV-related cancer in the US, with the majority being caused by HPV16. Persistent expression of HPV16 oncoproteins E6 and E7 by host genome may promote HNSCC. HPV16-positive HNSCC may be associated with poor clinical outcomes in the recurrent/metastatic (R/M) setting. PDS0101 (Versamune HPV) is an HPV16-immunotherapy that generates a potent, targeted T cell attack against HPV16 E6 & E7. In a Phase 2 study, PDS0101 plus pembrolizumab has shown encouraging safety and survival benefit in patients with HPV16-positive R/M HNSCC. (Weiss J et al. ESMO 2024. Poster 879P. NCT04260126). Methods: VERSATILE-003 is a global Phase 3, randomized, controlled, open-label study evaluating PDS0101 plus pembrolizumab vs. pembrolizumab in patients with HPV16-positive R/M HNSCC with PD-L1 positive disease (CPS ≥1). Key eligibility criteria include age ≥18-years-old, histologically- or cytologically-confirmed diagnosis of R/M HNSCC with primary tumor location of oropharynx, oral cavity, hypopharynx, or larynx and no prior systemic anticancer treatment in the R/M setting, HPV16 tumor positivity (centrally tested), PD-L1 positivity defined as CPS ≥ 1 using FDA-approved PD-L1 IHC 22C3 pharmDx kit, and measurable disease based on RECIST 1.1 confirmed by blinded independent central review (BICR). Patients will be randomized 2:1 to receive pembrolizumab 200 mg IV Q3W with PDS0101 1 mL SC administered concurrently during Cycles 1, 2, 3, 4, and 12 (investigational arm), or pembrolizumab 200 mg IV Q3W alone (control arm). The primary objective is to compare overall survival (OS) between the investigational and control arms. Secondary objectives include objective response rate (ORR), disease control rate (DCR), duration of response (DOR), and progression-free survival (PFS) using RECIST 1.1 and assessed by BICR. Exploratory objectives include tumor response assessed by investigator and by irRECIST, PFS2, quality of life as assessed by EQ-5D, QLQ-C30, and QLQ H&N35, and assessment of ctHPVDNA. Updated enrollment data will be provided. Clinical trial information: NCT06790966 .

Background MEDI5395 is a recombinant attenuated Newcastle disease virus engineered to express a human granulocyte-macrophage colony-stimulating factor transgene. Preclinically, MEDI5395 demonstrated broad oncolytic activity, augmented by concomitant programmed cell death-1/programmed cell death ligand-1 (PD-L1) axis blockade. Durvalumab is an anti-PD-L1 immune checkpoint inhibitor approved for the treatment of various solid tumors. We describe the results of the first-in-human study combining intravenous MEDI5395 with durvalumab in patients with advanced solid tumors. Methods This phase I, open-label, multicenter, dose-escalation, dose-expansion study recruited adult patients with advanced solid tumors, who had relapsed or were refractory or intolerant to ≥1 prior line of standard treatment. MEDI5395 was administered intravenously as six doses over 15–18 days. The dose-escalation phase assessed four-dose levels (108, 109, 1010, 1011 focus forming units (FFU)) of MEDI5395, with sequential or delayed durvalumab. Durvalumab 1500 mg was administered intravenously every 4 weeks up to 2 years. The dose-expansion phase was not initiated. The primary objectives were to evaluate safety and tolerability, dose-limiting toxicities (DLTs) and the dose and schedule of MEDI5395 plus durvalumab administration. Secondary objectives included the assessment of the efficacy, pharmacokinetics, pharmacodynamics, and immunogenicity of MEDI5395. Results 39 patients were treated with MEDI5395; 36 patients also received durvalumab. All 39 patients experienced ≥1 treatment-emergent adverse event (TEAE), most commonly fatigue (61.5%), nausea (53.8%) and chills (51.3%). Grade 3–4 TEAEs occurred in 27 (69.2%) patients; these were deemed MEDI5395-related in 12 (30.8%) patients. Two patients experienced a DLT, and the maximum tolerated dose of MEDI5395 with sequential and delayed durvalumab at study termination was 1011 and 1010 FFU, respectively. Four patients (10.3%) achieved a partial response (PR). Patients with PR or stable disease tended to have higher baseline PD-L1 and CD8+ levels in their tumor tissue. A tendency to dose-dependent pharmacokinetics of the viral genome was observed in whole blood and a tendency to dose-dependent viral shedding was observed in saliva and urine. Neutralizing antibodies were observed in all patients but did not appear to impact efficacy negatively. Conclusion This study demonstrates the feasibility, safety and preliminary efficacy of MEDI5395 with durvalumab in patients with advanced solid tumors. Trial registration number NCT03889275

2062 Background: While cancer therapeutics have made tremendous progress within the past several decades, this benefit has not been seen in many primary cancers of the brain. Particularly confounding have been high-grade gliomas (HGG), which retain a dismal prognosis. Currently, novel therapies are being explored to rise to this unmet, critical need. One such therapy are CAR T cells, immune cells which have been engineered to target malignancy-specific antigens. Unfortunately, the efficacy of CAR T cell therapies against solid tumors is significantly limited, in large part due to impaired expansion/persistence in the immune suppressive tumor microenvironment (TME). Here we show that in vivo reactivation of CAR T cells through their native T Cell Receptor (TCR) by an oncolytic virus (OV) has therapeutic benefit in HGG. Methods: An EGFRvIII third-generation MSGV1 retroviral CAR construct containing the CD28, 4-1BB, and CD3z moieties, in tandem with the scFv derived from the human monoclonal antibody 139 and the marker Thy1.1 (38) was used to generate our CAR T cells. C57Bl/6 mice were used for in vivo experiments and both B16- and CT2A-EGFRvIII murine glioma cell lines were injected in the brain to model HGG. OVs and CAR T cells were given systemically by tail vein. OVs used include reovirus, vesicular stomatitis virus, and adenovirus. Results: By using OV in combination with EGFRvIII CAR T cells, we were able to generate a CD8 CAR population with TCR specificity for both the EGFRvIII and OV epitopes. These dual-specific (DS) CAR T expressed a memory phenotype and persisted for much longer than conventional CAR T cells. Further, we showed that these DS CAR T cells are more cytotoxic and can respond more rapidly than their conventional counterparts. We created a novel delivery mechanism for this combination OV + CAR T therapy using virus-loaded CAR T cells to bypass initial antiviral clearance from the immune system. Treatment with these OV-loaded CAR T cells lead to significant benefit in mice with HGG tumors which could be further enhanced by a systemic boost with OV, which rapidly re-activated DS CAR T cells against tumor and resulted in long-term cures of greater than 80% of treated animals. Conclusions: These promising results show that DS CAR T cells can overcome the critical therapeutic challenge of CAR T as a treatment for solid tumors. Given these promising results, we will go on to develop a clinical trial in which CAR T cells will be pre-loaded with OV and administered intravenously to patients with HGG, followed by systemic boosting with virus to re-activate DS CAR T cells against their tumor.

Abstract Background Transoral robotic surgery (TORS) is an emerging minimally invasive surgical treatment for residual, recurrent, and new primary head and neck cancers in previously irradiated fields, with limited evidence for its oncological effectiveness. Methods A retrospective observational cohort study of consecutive cases performed in 16 high-volume international centers before August 2018 was conducted (registered at clinicaltrials.gov [NCT04673929] as the RECUT study). Overall survival (OS), disease-free survival, disease-specific survivals (DSS), and local control (LC) were calculated using Kaplan-Meier estimates, with subgroups compared using log-rank tests and Cox proportional hazards modeling for multivariable analysis. Maximally selected rank statistics determined the cut point for closest surgical resection margin based on LC. Results Data for 278 eligible patients were analyzed, with median follow-up of 38.5 months. Two-year and 5-year outcomes were 69.0% and 62.2% for LC, 71.8% and 49.8% for OS, 47.2% and 35.7% for disease-free survival, and 78.7% and 59.1% for disease-specific survivals. The most discriminating margin cut point was 1.0 mm; the 2-year LC was 80.9% above and 54.2% below or equal to 1.0 mm. Increasing age, current smoking, primary tumor classification, and narrow surgical margins (≤1.0 mm) were statistically significantly associated with lower OS. Hemorrhage with return to theater was seen in 8.1% (n = 22 of 272), and 30-day mortality was 1.8% (n = 5 of 272). At 1 year, 10.8% (n = 21 of 195) used tracheostomies, 33.8% (n = 66 of 195) used gastrostomies, and 66.3% (n = 53 of 80) had maintained or improved normalcy of diet scores. Conclusions Data from international centers show TORS to treat head and neck cancers in previously irradiated fields yields favorable outcomes for LC and survival. Where feasible, TORS should be considered the preferred surgical treatment in the salvage setting.

Abstract Improving the chances of curing patients with cancer who have had surgery to remove metastatic sites of disease is a priority area for cancer research. Pexa-Vec (Pexastimogene Devacirepvec; JX-594, TG6006) is a principally immunotherapeutic oncolytic virus that has reached late-phase clinical trials. We report the results of a single-center, nonrandomized biological end point study (trial registration: EudraCT number 2012-000704-15), which builds on the success of the presurgical intravenous delivery of oncolytic viruses to tumors. Nine patients with either colorectal cancer liver metastases or metastatic melanoma were treated with a single intravenous infusion of Pexa-Vec ahead of planned surgical resection of the metastases. Grade 3 and 4 Pexa-Vec–associated side effects were lymphopaenia and neutropaenia. Pexa-Vec was peripherally carried in plasma and was not associated with peripheral blood mononuclear cells. Upon surgical resection, Pexa-Vec was found in the majority of analyzed tumors. Pexa-Vec therapy associated with IFNα secretion, chemokine induction, and resulted in transient innate and long-lived adaptive anticancer immunity. In the 2 patients with significant and complete tumor necrosis, a reduction in the peripheral T-cell receptor diversity was observed at the time of surgery. These results support the development of presurgical oncolytic vaccinia virus-based therapies to stimulate anticancer immunity and increase the chances to cure patients with cancer.