6075 Background: The rising incidence of oropharyngeal squamous cell carcinoma (OPSCC) is largely attributable to human papillomavirus associated (HPV+) disease, which accounts for ~70% of OPSCC cases. Circulating tumor (ct)DNA has the potential to enable more accurate treatment response assessment, guide response-adaptive management, and detect minimal residual disease to indicate persistence or recurrence. Both mutation-based tumor-informed ctDNA and ctHPV-DNA testing have demonstrated utility in HPV+ disease, but prospective intrapatient evaluations remain limited. A direct comparison of these approaches is essential to determine redundancy versus complementarity and to guide optimal integration into OPSCC patient management. Methods: In an ongoing prospective study, serial plasma samples were obtained from patients with stages I-IV OPSCC undergoing curative intent treatment. Up to 50 patient specific somatic variants were selected based on tumor whole exome sequencing to develop a personalized tumor-informed next generation sequencing (NGS) ctDNA assay (Haystack MRD) for plasma analysis. In patients with HPV+ disease (determined via ISH, IHC, and/or NGS), plasma was also analyzed using an NGS-based assay interrogating 13 high-risk HPV strains (Haystack HPV). Paired intrapatient samples were analyzed using percent agreement with 95% confidence intervals and Cohen’s kappa; concordance of dynamic changes was assessed using Spearman’s correlation. Results: As of January 2026, ctDNA results were available for 111 serial timepoints from 26 patients. The median number of timepoints per patient was 4 (range 1-9). Seventeen patients (65%) had HPV+, and 9 (35%) had HPV− disease. In HPV+ patients, across 85 longitudinal samples collected during multimodal treatment and post-treatment surveillance, mutation-based ctDNA and ctHPV demonstrated high concordance (91%; 95% CI, 82.5–95.2; κ=0.80). Of 30 ctDNA+ samples, 28 were ctHPV+ (93%; 95% CI, 78.7–98.2%), while 49 of 55 ctDNA- samples were ctHPV- (89%; 95% CI, 78.2–94.9%). Discordance was infrequent (8/85, 9.4%), predominantly ctHPV+/ctDNA- (6/85, 7.1%). All ctHPV+/ctDNA- cases occurred during neoadjuvant treatment monitoring and reflected earlier clearance of ctDNA, with ctHPV clearance lagging by several weeks to months. Two low-level (<100 parts per million) ctDNA+/ctHPV- cases were observed in the adjuvant setting. When both analytes were present, dynamic changes in ctDNA and ctHPV levels were highly concordant (Spearman’s ρ=0.94), although ctHPV was consistently detected at higher absolute levels. Conclusions: In HPV-driven OPSCC, tumor-informed ctDNA and ctHPV show high longitudinal concordance and distinct clearance kinetics, with earlier ctDNA clearance. Ongoing analyses will define how these assays can be optimally integrated into response assessment, treatment adaptation, and surveillance strategies.

6091 Background: Human papillomavirus-associated (HPV+) oropharyngeal carcinoma (OPC) is linked to favorable survival outcomes, prompting efforts to de-intensify treatment strategies. Circulating tumor HPV-DNA (ctHPV-DNA) is a promising biomarker for assessing treatment response and guiding de-escalation strategies. This study evaluates how patient characteristics influence ctHPV-DNA dynamics during neoadjuvant therapy across two de-escalation clinical trials. Methods: Patients with non-metastatic HPV+ OPC enrolled across two trials of neoadjuvant carboplatin/paclitaxel (NCT04572100) or carboplatin/ nab -paclitaxel/nivolumab (OPTIMA II, NCT03107182), with ctHPV-DNA available at baseline and post-neoadjuvant, were eligible. All participants received three cycles of neoadjuvant therapy followed by response-adapted de-escalated locoregional treatment. ctHPV-DNA values (copies per ml plasma) were measured at baseline and after 2-3 cycles of neoadjuvant therapy, and percentage reductions were calculated. We defined “ctHPV-DNA clearance” as ≥ 95% reduction from baseline and compared data distribution between patients who achieved clearance and those who did not using Kruskal-Wallis, Pearson’s χ2, or Fisher’s exact tests. Overall survival (OS) and progression free survival (PFS) probabilities were compared using log-rank test. Results: The study included 84 patients . The mean age was 60.9 years. 93% of patients with neoadjuvant nivolumab/chemotherapy achieved ctHPV-DNA clearance compared to 82% with chemotherapy alone, p =0.298. Patients with T1-T2 tumors (AJCC 8 th edition) were significantly more likely to achieve ctHPV-DNA clearance compared to those with T3-T4 tumors ( p =0.0254). Age, race/ethnicity, smoking history, tumor site (e.g., tonsil), and risk group were not significantly associated with ctHPV-DNA clearance rates. ctHPV-DNA clearance by cycle 2-3 of neoadjuvant therapy predicted radiographic response per RECIST v1.1 ( p =0.001), and significantly improved OS ( p =0.025) and PFS ( p <0.001). Survival outcomes were similar across OPTIMA II and NCT04572100 as previously reported. Conclusions: Earlier T-stage tumors were associated with rapid ctHPV-DNA clearance by cycle 2 with a trend towards higher clearance rate with neoadjuvant nivolumab/chemotherapy. Rapid clearance predicts radiographic response, OS, and PFS, supporting ctHPV-DNA as a useful biomarker for treatment monitoring with neoadjuvant treatment in HPV+ OPC. Clinical trial information: NCT03107182 . ctHPV-DNA % reduction between baseline and follow up at cycle 2-3. ≥ 95% reductionN (%) < 95% reductionN (%) p Age, (mean ± sd) 60.4 ± 10 61.3 ± 8.5 0.656 Gender (Male) 59 (86.8) 9 (13.2) 1 Race (Caucasian) 54 (86) 9 (14) 0.583 Risk (High) 34 (92) 3 (8) 0.309 T1 stage 12 (75) 4 (25) 0.0254 T2 stage 30 (97) 1 (3) T3 stage 8 (89) 1 (11) T4 stage 3 (60) 2 (40) Tumor shrinkage (median %, range) -64.2 (-23, -100) -42 (-14, -71) 0.001

Neoadjuvant immunotherapy in human papillomavirus (HPV)–negative locoregionally advanced (LA) head and neck squamous cell carcinoma (HNSCC) appears promising, yet its role in nonsurgical treatment for head and neck cancer remains undefined. Neoadjuvant nivolumab plus chemotherapy followed by response-stratified de-escalated chemoradiation therapy (CRT) in HPV-negative LA stage IVa/b HNSCC may improve treatment efficacy while reducing treatment-related toxic effects. To determine the deep response rate and tolerability of neoadjuvant nivolumab plus chemotherapy followed by response-stratified CRT in nonvirally mediated stage IVa/b HNSCC. In this investigator-initiated phase 2 nonrandomized clinical trial conducted at a single academic center, patients with stage IVa/b (American Joint Committee on Cancer Tumor Classification, 8th edition) HPV-negative LA HNSCC were enrolled between 2019 and 2022. Data were analyzed from February 2023 to January 2024. The DEPEND trial evaluated neoadjuvant nivolumab plus carboplatin and paclitaxel, followed by response-stratified CRT. Patients with 50% or greater reduction per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 received de-escalated CRT to 66 Gy with elimination of elective nodal volumes; patients with less than 50% reduction received standard CRT to 70 to 75 Gy. Adjuvant nivolumab was administered for 9 cycles. The primary end point was deep response rate (DRR; 50% or greater shrinkage per RECIST version 1.1) following neoadjuvant nivolumab plus chemotherapy. Secondary end points included progression-free survival (PFS), overall survival (OS), locoregional control, and distant control. Exploratory end points included acute toxic effects in patients who received response-adapted de-escalated CRT. Of 36 included patients, 28 (78%) were male, and the median (range) age was 58.9 (27-77) years. All patients started treatment and were available for analysis. The median (range) follow-up was 20 (13-40) months. The primary end point was met, with a DRR following neoadjuvant nivolumab/chemotherapy of 53% (95% CI, 35-70). The objective response rate was 86% (95% CI, 71-95). A total of 19 received de-escalated CRT and 16 received standard CRT. PFS and OS at 2 years were 66% (95% CI, 34-76) and 73% (95% CI, 52-86), respectively. The most common treatment-emergent adverse events for de-escalated and standard CRT were mucositis (14 of 19 [74%] and 15 of 16 [94%], respectively), radiation dermatitis (13 of 19 [68%] and 14 of 16 [88%], respectively), and dry mouth (7 of 19 [37%] and 10 of 16 [63%], respectively). In this phase 2 nonrandomized clinical trial, neoadjuvant nivolumab/chemotherapy led to deep responses in 53% of patients with HPV-negative LA stage IVa/b HNSCC, and response-adapted de-escalated CRT led to favorable survival with lower acute toxic effects among deep responders. ClinicalTrials.gov Identifier: NCT03944915

Detecting human papillomavirus (HPV) status is crucial for treating Head and Neck Squamous Cell Carcinomas (HNSCCs). While p16 immunohistochemistry is the current standard for HPV detection, its moderate sensitivity and complex implementation limit its global utility. The ability to diagnose HPV status in HNSCC has become increasingly critical worldwide, as rising HPV-positive HNSCC rates observed in high-income countries may signal a global trend, and HPV status remains essential for treatment selection. Although hematoxylin and eosin (H&E) stained slides are clinically ubiquitous, artificial intelligence (AI) methods applied to these images have not matched molecular assays’ performance nor provided needed clinical interpretability. Recent advances in vision transformer-based foundation models for computational pathology offer a promising approach to address this unmet need. We analyzed H&E images from 981 HNSCC patients across four datasets: TCGA (n=HPV+ 33/total 401), CPTAC (n=1/109), UCH (n=159/364), and PENN (n=106/106). Fifty percent of the patients were used for validation. Using UNI, a foundation self-supervised learning (SSL) model, we extracted feature vectors from 10x effective magnification tile images across each whole slide. We identified an HPV feature axis using recursive support vector machine and principal component analysis to isolate SSL features that differentiated HPV tumors, then interpreted the relevant histologic features using HistoXGAN to generate synthetic histology images. This approach enabled the isolation of histologic features specific to HPV+ tumors, whereas real histology images contain multiple sources of variation. An expert pathologist validated the biological relevance of the identified HPV-axis features. We developed a predictive model for HPV status by varying the percentages of tiles within each slide required to exceed a binary threshold on the HPV-axis. This model was robust across threshold choices. Our method identified an HPV-axis that robust HPV detection performance (sensitivity 0.83, specificity 0.88) across all datasets (balanced accuracy - TCGA 0.77, CPTAC 0.98, UCH 0.78, PENN 1.00). Using synthetic histology images and pathologist validation, we identified key, morphological features aligning with established HPV-associated histology, including nuclei size, color, and cell borders. Together with our Grundium slide scanning pipeline the time-to-prediction for a slide is less than 3 minutes. Foundation models and synthetic digital pathology enabled HPV detection from histology with accuracy comparable to current diagnostic standards, while providing pathologist-interpretable predictions. This accessible, rapid, and explainable method holds promise for expanding testing of HPV and potentially other molecular features in resource-limited settings. Hanna M. Hieromnimon, Anna Trzcinska, Frank Wen, Frederick M. Howard, James M. Dolezal, Emma Dyer, Sara Kochanny, Jefree Schulte, Cindy Wang, Heather Chen, Jeffrey Chin, Elizabeth Blair, Nishant Agrawal, Ari Rosenberg, Everett Vokes, 1 Rohan Katipally, Aditya Juloori, Evgeny Izumchenko, Mark W. Lingen, Nicole Cipriani, Jalal B. Jalaly, Devraj Basu, Samantha J. Riesenfeld, Alexander T. Pearson. Interpretable HPV detection in head and neck cancer using foundation models and synthetic digital pathology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2471.

Importance:Neoadjuvant immunotherapy in human papillomavirus (HPV)-negative locoregionally advanced (LA) head and neck squamous cell carcinoma (HNSCC) appears promising, yet its role in nonsurgical treatment for head and neck cancer remains undefined. Neoadjuvant nivolumab plus chemotherapy followed by response-stratified de-escalated chemoradiation therapy (CRT) in HPV-negative LA stage IVa/b HNSCC may improve treatment efficacy while reducing treatment-related toxic effects. Objective:To determine the deep response rate and tolerability of neoadjuvant nivolumab plus chemotherapy followed by response-stratified CRT in nonvirally mediated stage IVa/b HNSCC. Design, Setting, and Participants:In this investigator-initiated phase 2 nonrandomized clinical trial conducted at a single academic center, patients with stage IVa/b (American Joint Committee on Cancer Tumor Classification, 8th edition) HPV-negative LA HNSCC were enrolled between 2019 and 2022. Data were analyzed from February 2023 to January 2024. Interventions:The DEPEND trial evaluated neoadjuvant nivolumab plus carboplatin and paclitaxel, followed by response-stratified CRT. Patients with 50% or greater reduction per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 received de-escalated CRT to 66 Gy with elimination of elective nodal volumes; patients with less than 50% reduction received standard CRT to 70 to 75 Gy. Adjuvant nivolumab was administered for 9 cycles. Main Outcomes and Measures:The primary end point was deep response rate (DRR; 50% or greater shrinkage per RECIST version 1.1) following neoadjuvant nivolumab plus chemotherapy. Secondary end points included progression-free survival (PFS), overall survival (OS), locoregional control, and distant control. Exploratory end points included acute toxic effects in patients who received response-adapted de-escalated CRT. Results:Of 36 included patients, 28 (78%) were male, and the median (range) age was 58.9 (27-77) years. All patients started treatment and were available for analysis. The median (range) follow-up was 20 (13-40) months. The primary end point was met, with a DRR following neoadjuvant nivolumab/chemotherapy of 53% (95% CI, 35-70). The objective response rate was 86% (95% CI, 71-95). A total of 19 received de-escalated CRT and 16 received standard CRT. PFS and OS at 2 years were 66% (95% CI, 34-76) and 73% (95% CI, 52-86), respectively. The most common treatment-emergent adverse events for de-escalated and standard CRT were mucositis (14 of 19 [74%] and 15 of 16 [94%], respectively), radiation dermatitis (13 of 19 [68%] and 14 of 16 [88%], respectively), and dry mouth (7 of 19 [37%] and 10 of 16 [63%], respectively). Conclusions and Relevance:In this phase 2 nonrandomized clinical trial, neoadjuvant nivolumab/chemotherapy led to deep responses in 53% of patients with HPV-negative LA stage IVa/b HNSCC, and response-adapted de-escalated CRT led to favorable survival with lower acute toxic effects among deep responders. Trial Registration:ClinicalTrials.gov Identifier: NCT03944915.

6068 Background: Human papillomavirus (HPV) positive OPSCC is known to have a favorable prognosis compared to its HPV negative counterparts. It is thus important to limit treatment-related toxicity while preserving functional and survival outcomes. In this pooled study, we report functional and survival outcomes across prospective cohorts treated with chemotherapy-response-adaptive dose and volume de-escalation of radiation. Methods: Patients with non-metastatic HPV positive OPSCC were sequentially treated at an academic center on either an interventional de-escalation trial: OPTIMA 1 (NCT02258659); OPTIMA II (NCT03107182); (NCT04572100 ) or off-protocol in a prospective registry. Eligible patients had N1-3 or T3-4 (AJCC 8 th edition) disease. Very low-risk patients T0-2N0-1 (single lymph node <3cm) were excluded. Patients were stratified as low risk (LR) or high risk (HR) according to T/N stage and smoking history. Following chemotherapy (carboplatin and paclitaxel or nab -paclitaxel) with or without nivolumab, patients received de-escalated treatment with low dose arm (LDA; radiation [RT] alone to 50Gy or transoral robotic surgery), intermediate dose arm (IDA; chemoRT [CRT] to 45-50Gy) or regular dose arm (CRT to 70-75Gy). To analyze functional outcomes, we compared swallowing performance scores (SPS), trismus, percutaneous endoscopic gastrostomy (PEG) tube placement obtained from pre- and post-(C)RT. Comparisons across risk categories and treatment arms using Chi-square, Fisher, and Student t-tests. Survival outcomes were compared using log-rank statistic. Results: Eligible patients (n=242) started treatment between 2014 and 2024: 116 LR and 126 HR patients; 83% received de-escalated treatment (LDA/IDA) and 17% received standard dose (RDA). Post-treatment SPS (p=0.0002) and trismus scores (p=0.0013) was better among de-escalated versus non-de-escalated patients. Lower PEG placement rates were observed among de-escalated patients 33/196 (16.8%) vs 27/39 (69.2%) (p<.0001). With median follow-up of 48 months, no statistically significant differences in overall survival or progression free survival were observed between treatment arms. OS (95.1% (95% CI 90.8%-97.4%) vs 93.7%( 95% CI 77.72%- 98.4%), P=0.185) and PFS (92.2% (95% CI 87.1%-95.2%) vs 90.7% (95% CI 73.9% - 96.9%, p=0.202) were similar in deescalated and non-deescalated patients at 3 years. Low risk individuals also had better OS (97.1% vs 92.1%, p=0.01) and PFS (96.1% vs 88.3%, p=0.004) at three years. Conclusions: Improved functional outcomes including posttreatment swallowing function, trismus, and lower PEG placement rates were observed with chemotherapy-response-adaptive radiation de-escalation with excellent survival in the largest prospective cohort reported to date. Response-adaptive de-escalation warrants further comparative study.

TPS6126 Background: Locoregionally advanced (LA) head and neck cancer (HNC) patients undergoing chemoradiotherapy (CRT) who are ineligible for cisplatin have comparatively poor outcomes, with only ~40% alive at 5 years. There is an urgent unmet need to improve survival in these vulnerable patients with no standard therapeutic approach. Xevinapant, an oral inhibitor of XIAP and cIAP1/2, sensitizes cancer cells to apoptosis. Randomized phase II results in patients eligible for cisplatin combining xevinapant with CRT showed improved locoregional control, manageable toxicity, and promising survival outcomes. (Sun et al. Lancet Oncol. 2020) The current trial aims to extend these benefits to patients ineligible for cisplatin using xevinapant with carboplatin-paclitaxel-based CRT, hypothesizing safety and tolerability in this high-risk group. Methods: This phase I dose escalation/expansion study investigates xevinapant combined with carboplatin and paclitaxel to treat LA HNC in patients ineligible for cisplatin. Key eligibility includes previously untreated LA HNC and specific cisplatin ineligibility criteria, including >=70yo with moderate to severe comorbidity or vulnerability (Geriatric-8 score ≤ 14 and/or CARG score ≥ 30%) or <70yo with severe comorbidity and/or vulnerability, or >=18yo with an absolute contraindication to cisplatin. The treatment regimen comprises escalating doses of oral xevinapant (50-200 mg daily) on days 1-14 of a 21-day cycle for 3 cycles concurrent with CRT and 3 cycles adjuvant, weekly carboplatin AUC 1.5 IV, and paclitaxel 30 mg/m2 IV for 7 doses, and radiotherapy to 70 Gy in standard 2Gy fractions over 7 weeks with primary endpoint of tolerability and recommended phase 2 dose. A Bayesian-modified toxicity probability interval design will identify the maximum tolerated dose (MTD), targeting a 25% dose-limiting toxicity rate, with a sample size of 24 patients in dose-finding. 18 additional patients will be enrolled in the dose-expansion cohort at the MTD, totaling 42 patients. Secondary objectives include safety, response, progression-free, overall survival, and locoregional and distant control. Exploratory aims: in-clinic geriatric evaluations (Katz ADL, Lawton iADL, MMSE), QoL surveys, symptom tracking via smartphone, and wearable-derived steps and sarcopenia assessment. Recruitment began 02/2024. Clinicaltrials.gov ID: NCT06110195. Clinical trial information: NCT06110195 .

Purpose/Objective(s) Multiple prospective trials have integrated immune checkpoint blockade (ICB) into treatment paradigms involving radiotherapy (RT) for head and neck cancer. Dosimetric predictors of hypothyroidism after RT is not well understood in this context. In this secondary analysis, we evaluate the association of radiation dose-volume metrics with hypothyroidism after definitive treatment with or without ICB for HPV-related oropharyngeal cancer (OPC). Materials/Methods This was a dosimetric secondary analysis of locally advanced HPV+ OPC treated on two prospective phase II de-escalation trials (OPTIMA / NCT02258659) and OPTIMA II / NCT03107182) and an associated expansion cohort on registry (OPTIMA-like). On OPTIMA and OPTIMA-like, patients received induction chemotherapy (platinum doublet x 3 cycles) followed by response-adapted de-escalated RT (+/- chemotherapy). On OPTIMA II, nivolumab was added to induction chemotherapy and offered adjuvantly for 6 months. After RT, hypothyroidism was defined as elevated TSH and being prescribed levothyroxine or demonstrating clinical signs/symptoms. Demographic and treatment variables were recorded, notably mean thyroid dose (Gy) and thyroid volume receiving a minimum of 30-70 Gy (V30 Gy - V70 Gy). Hypothyroidism was analyzed as a time-to-event outcome using cumulative incidence (with death and salvage reirradiation as competing risks). Optimal dosimetric cut points were defined as those with maximum Youden index. Results 134 patients met inclusion criteria (median follow-up 5.6 years, median age 61 years, 95% men). 50 patients (37%) received ICB. The mean thyroid dose was 23 Gy (median across patients; range: 0.5 – 61 Gy). Hypothyroidism occurred in 26% (n = 35) of patients (median time 0.8 years; range: 0.03 - 4.0 years). For mean thyroid dose, the optimal cut point was 35.5 Gy (31% sensitivity, 89% specificity). Across all dosimetric predictors, the optimal cut point by Youden index was V50 Gy ≥ 31.7% (43% sensitivity, 89% specificity). The cumulative incidence of hypothyroidism is displayed in Table 1. On multivariable Fine-Gray competing risks regression, V50 Gy was associated with hypothyroidism (sHR = 1.02 per % thyroid gland; 95% CI, 1.01 to 1.03; P = 0.001), while ICB (P = 0.15), age (P = 0.41), and sex (P = 0.34) were not. There was no interaction effect between thyroid dose and ICB. Conclusion The percentage of thyroid gland receiving at least 50 Gy was associated with hypothyroidism (optimal cut point V50 Gy > 31.7%). ICB was not significantly associated with hypothyroidism and did not interact with dosimetric predictors. These findings inform potential thyroid dose constraints to utilize in future trials, including those integrating ICB.

Purpose/Objective(s)Efficacy of immune checkpoint inhibitors (ICI) in curative head and neck squamous cell carcinoma (HNSCC) may be hampered by therapeutic ablation of tumor-draining lymphatics with standard chemoradiation (CRT). Recent emergence of neoadjuvant immunotherapy in HNSCC highlights the need for biomarkers to optimize anti-tumor immunity while eliminating locoregional microscopic disease. An elevated neutrophil-to-lymphocyte ratio (NLR) may reflect an unfavorable balance between pro-tumor inflammation and anti-tumor immunity and is associated with poor immunotherapy outcomes, yet its role as a biomarker of neoadjuvant HNSCC immunotherapy is unknown. We studied the association between NLR dynamics and prognosis in HNSCC patients treated with neoadjuvant immuno-chemotherapy followed by dose and volume response-stratified CRT.Materials/Methods106 (71 HPV positive and 35 HPV negative) locoregionally advanced HNSCC patients prospectively enrolled in two clinical trials (NCT03107182; NCT039449150) were treated with neoadjuvant nivolumab and chemotherapy followed by dose and volume response-stratified treatment with reduced or standard CRT (including elimination of elective nodal radiation). NLRs for each patient were calculated at baseline, after neoadjuvant therapy, and 1, 3, 6, 9, and 12 months after treatment completion. NLRs at baseline and after neoadjuvant therapy were divided into quartiles, with high NLRs being the highest quartile (>3.66 and >5.63, respectively). NLR differences between reduced and standard CRT groups were analyzed by Wilcoxon ranked sum test. Overall survival (OS) and progression free survival (PFS) were analyzed by Kaplan-Meier and Cox regression methods.ResultsAmong HPV positive patients, 37% were Stage II/III; among HPV negative patients, 97% were Stage IV (AJCC 8th ed.). 77% of all patients received reduced CRT. Median follow-up was 26.7 months. High NLRs after neoadjuvant nivolumab/chemotherapy were associated with worse OS and PFS (p=0.006 and p=0.03, respectively), while baseline high NLRs demonstrated a non-significant trend toward worse OS and PFS (p=0.16 and p=0.10, respectively). In multivariate analysis controlling for tobacco use, ECOG, stage/HPV status, treatment stratification, and PD-L1 CPS, high NLRs after neoadjuvant nivolumab/chemotherapy remained independently associated with worse OS (HR: 5.58, 95% CI: 1.51-20.56, p=0.01) and PFS (HR: 3.09, 95% CI: 1.10-8.67, p=0.03). During follow-up, NLRs were significantly lower in patients receiving reduced CRT compared to those receiving standard CRT at all time points after treatment (p<0.05).ConclusionHigh NLRs after neoadjuvant immuno-chemotherapy associated with worse survival in locoregionally advanced HNSCC patients. Reduced CRT led to more favorable NLRs which may enhance anti-tumor immunity after neoadjuvant immunotherapy. Further work characterizing dynamic changes in immune phenotype with neoadjuvant HNSCC immunotherapy is warranted.

Abstract Background: Cell-free HPV-DNA (cfHPV-DNA) in plasma represents a promising biomarker to grade treatment response and monitor for persistence/recurrence. We evaluated the dynamic changes of cfHPV-DNA during induction chemotherapy followed by response-stratified de-escalation in HPV associated (HPV+) oropharyngeal squamous cell cancer (OPSCC). Methods: A prospective biomarker clinical trial of response-stratified de-escalation therapy was conducted. Eligible patients had loco-regional HPV+ OPSCC and received induction chemotherapy with carboplatin and paclitaxel for three cycles followed by risk and response-stratified de-escalation with transoral robotic surgery (TORS), de-escalated radiation (RT) to 50Gy with or without cisplatin, or standard RT to 70Gy with cisplatin. Patients with deep response (>=50% tumor shrinkage per RECIST 1.1) qualified for de-escalated therapy. Cell-free HPV-DNA was measured using a CLIA-certified HPV-SEQ assay that utilizes NGS technology to detect and quantify HPV16 and HPV18 DNA in plasma at baseline, after each cycle of induction chemotherapy, during radiation, and post-treatment surveillance at 3, 6, 9, 12, 18, and 24 months following treatment. Results: Forty-six eligible patients were enrolled, with 464 cfHPV-DNA plasma samples analyzed (median 10 samples per patient). There were five recurrences (10.9%), all detected by HPV-SEQ. Baseline cfHPV-DNA was detected in 44/46 patients (96%). Patients with rapid early cfHPV-DNA clearance after one 3-week cycle of induction (>=95% clearance) predicted deep radiographic response following induction therapy (p=0.003). The detection of cfHPV-DNA at 3 months or later after treatment was associated with worse progression free survival (PFS), with 2-year PFS of 25% (95% CI 0.012-0.65) compared with patients without detectable cfHPV-DNA of 100% (95% CI 1.0-1.0); p<0.001). The longest lead-time from positive cfHPV-DNA to developing recurrent disease was 25 months. Conclusion: Rapid early clearance of cfHPV-DNA during induction has utility in predicting response to treatment. Detectable cfHPV-DNA following treatment is strongly associated with worse PFS. A subsequent trial using cfHPV-DNA to select patients for treatment de-escalation is ongoing. Clinicaltrials.gov ID: NCT04572100 Citation Format: Ari Rosenberg, Evgeny Izumchenko, John Cursio, Augustin Vannier, Aditya Juloori, Rohan Katipally, Rifat Hasina, Frederick Jones, Anna Starus, Elizabeth Blair, Daniel J. Haraf, Alexander T. Pearson, Everett E. Vokes, Nishant Agrawal. Cell-free HPV-DNA dynamics during induction chemotherapy and response-stratified de-escalation in viral-mediated oropharyngeal cancer [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B023.

Adenoid cystic carcinoma arising in the external auditory canal is rare, and even rarer are cases with sebaceous differentiation mimicking sebaceous carcinoma. This case with clinical, radiologic, gross, and histologic images exemplifies an unusual occurrence of adenoid cystic carcinoma in the external auditory canal with sebaceous differentiation, confirmed by MYB::NFIB fusion.

6017 Background: The role of immunotherapy in curative viral-mediated oropharyngeal cancer (OPC) remains undefined. Human papillomavirus (HPV) 16 positive (+) OPC constitutively expresses viral epitopes that drive antigen-specific anti-tumor immunity, supporting rationale for evaluating neoadjuvant HPV16 directed therapeutics in non-metastatic OPC. HB-200 is an arenavirus-based vector therapy derived from LCMV (HB-201) and Pichinde virus (HB-202) each expressing a non-oncogenic HPV16 E7E6 fusion protein to induce HPV16 specific CD8+ T-cell responses. Building on our OPTIMA II results demonstrating that neoadjuvant chemotherapy/nivolumab led to deep responses in 71% of patients who went on to receive reduced radiation (RT), we hypothesized that adding HB-200 to chemotherapy to drive HPV16-specific anti-tumor immunity would be safe and effective to further deepen responses and facilitate more de-escalation. Methods: In this Phase 1 dose escalation investigator-initiated study, patients with non-metastatic HPV16+ OPC were treated with escalating doses of HB-201 single vector (Arm A) or HB-202/201 alternating vector (Arm B) x3 with neoadjuvant carboplatin AUC5 on day 1 and paclitaxel 100mg/m2 on days 1/8/15 of a 21-day cycle for 3 cycles. Deep responders (≥50% tumor shrinkage) received transoral robotic surgery (TORS) alone or RT to 50Gy +/- cisplatin, while non-responders (<50% shrinkage) received 50 or 70Gy of RT with cisplatin. Primary objective was safety/tolerability and recommended phase 2 dose of HB-200 with chemotherapy. Additional objectives included deep response rate, circulating tumor (ct) HPV-DNA dynamics, and HPV16-specific T-cell response. Results: Twenty-one patients with HPV16+ OPC were enrolled and treated (Arm A, n=9, 43%; Arm B, n=12, 57%). Median age 57, 91% male, 75% base of tongue, 52% non-smokers, and 33% stage II/III (AJCC 8th edition). ≥Grade 3 treatment-emergent adverse events (AEs) occurred in 13 (62%) of patients overall and 3 (14%) non-hematologic during neoadjuvant. There were no Grade 4 AEs reported. All patients completed neoadjuvant HB-200/chemotherapy and response-stratified locoregional treatment. Deep responses following HB-200/chemotherapy were observed in 17/21 (81%) of patients, and in 14/15 (93%) treated on higher dose levels 1 or 2 ( p=0.05). All three patients who underwent TORS had no viable tumor at time of surgery. Two patients (9%) had persistent disease following CRT and underwent salvage surgery with no evidence of disease at last follow-up. ctHPV-DNA and HPV16-specific T-cell response data will be presented at the meeting. Conclusions: Neoadjuvant HB-200/chemotherapy is safe and feasible with early efficacy signal in this setting warranting further study. Enrollment to the subsequent randomized phase II part is ongoing (NCT05108870). Clinical trial information: NCT05108870 .

Cetuximab induces responses in about 13% of head and neck squamous cell carcinomas (HNSCC). We describe the molecular mechanism of acquired resistance to cetuximab, which could be overcome by switching to a different anti-EGFR antibody. Biopsies were collected at three different time points: before the start of cetuximab (PRE-cetux), at acquired resistance to cetuximab (AR-cetux), and at acquired resistance to duligotuzumab (AR-duligo). Biopsies were analyzed using tumor and normal whole-exome sequencing, RNASeq, and targeted panel sequencing with ultra-deep coverage to generate differential mutation and expression profiles. WES and targeted sequencing analysis identified an EGFR p.G465R extracellular domain mutation in AR-cetux biopsy. Furthermore, RNASeq confirmed the expression of this mutation in the tumor tissue. This mutation prevented the binding of cetuximab to EGFR and was not present in PRE-cetux and AR-duligo biopsies, suggesting a potential mechanism of acquired resistance to cetuximab. Molecular dynamic simulations confirmed that duligotuzumab effectively binds EGFR with a p.G465R mutation. Interestingly, the p.G465R mutation improved the stability of the duligotuzumab-EGFR complex as compared to the wild-type EGFR. This is the first report of an EGFR ECD mutation associated with acquired resistance to cetuximab, posing a need for further validation. We suggest appropriate serial mutational profiling to identify ECD mutations should be considered for select patients with initial cetuximab benefit.

Importance Immune checkpoint inhibitors improve survival in recurrent and/or metastatic head and neck cancer, yet their role in curative human papillomavirus-positive oropharyngeal cancer (HPV+ OPC) remains undefined. Neoadjuvant nivolumab and chemotherapy followed by response-adaptive treatment in HPV+ OPC may increase efficacy while reducing toxicity. Objective To determine the deep response rate and tolerability of the addition of neoadjuvant nivolumab to chemotherapy followed by response-adapted locoregional therapy (LRT) in patients with HPV+ OPC. Design, Setting, and Participants This phase 2 nonrandomized clinical trial conducted at a single academic center enrolled 77 patients with locoregionally advanced HPV+ OPC from 2017 to 2020. Data analyses were performed from February 10, 2021, to January 9, 2023. Interventions Addition of nivolumab to neoadjuvant nab-paclitaxel and carboplatin (studied in the first OPTIMA trial) followed by response-adapted LRT in patients with HPV+ OPC stages III to IV. Main Outcomes and Measures Primary outcome was deep response rate to neoadjuvant nivolumab plus chemotherapy, defined as the proportion of tumors with 50% or greater shrinkage per the Response Evaluation Criteria in Solid Tumors 1.1. Secondary outcomes were progression-free survival (PFS) and overall survival (OS). Swallowing function, quality of life, and tissue- and blood-based biomarkers, including programmed death-ligand 1 (PD-L1) expression and circulating tumor HPV-DNA (ctHPV-DNA), were also evaluated. Results The 73 eligible patients (median [range] age, 61 [37-82] years; 6 [8.2%] female; 67 [91.8%] male) started neoadjuvant nivolumab and chemotherapy. Deep responses were observed in 51 patients (70.8%; 95% CI, 0.59-0.81). Subsequent risk- and response-adaptive therapy was assigned as follows: group A, single-modality radiotherapy alone or transoral robotic surgery (28 patients); group B, intermediate-dose chemoradiotherapy of 45 to 50 Gray (34 patients); and group C, regular-dose chemoradiotherapy of 70 to 75 Gray (10 patients). Two-year PFS and OS were 90.0% (95% CI, 0.80-0.95) and 91.4% (95% CI, 0.82-0.96), respectively. By response-adapted group, 2-year PFS and OS for group A were 96.4% and 96.4%, and group B, 88.0% and 91.0%, respectively. Lower enteral feeding rates and changes in weight, as well as improved swallowing, were observed among patients who received response-adapted LRT. Pathologic complete response rate among patients who underwent transoral robotic surgery was 67.0%. PD-L1 expression was nonsignificantly higher for deeper responses and improved PFS, and ctHPV-DNA clearance was significantly associated with improved PFS. Conclusions and Relevance This phase 2 nonrandomized clinical trial found that neoadjuvant nivolumab and chemotherapy followed by response-adapted LRT is feasible and has favorable tolerability, excellent OS, and improved functional outcomes in HPV+ OPC, including among patients with high-risk disease. Moreover, addition of nivolumab may benefit high PD-L1 expressors, and sensitive dynamic biomarkers (eg, ctHPV-DNA) are useful for patient selection.

With a median follow-up of 5 years, this analysis demonstrates excellent long-term local control, survival, and swallowing function among patients with low-risk HPV+ oropharynx cancer treated with induction systemic therapy followed by radiotherapy to 50 Gy without concurrent chemotherapy, including a large proportion of patients with N2b disease. Chemo-selection provides a means of identifying a favorable cohort of HPV+ oropharynx cancer patients who can safely receive RT dose de-escalation. Further work is needed to identify this population by other means, including radiographic and genomic factors.

Autoinfarction of a parathyroid adenoma can have an atypical clinicoradiologic features that can mimic an inflammatory process or malignancy. In addition, the associated fibrosis makes surgical resection more challenging than for regular parathyroid adenomas. The implications of these findings are that while autoinfarction of parathyroid adenomas is a rare phenomenon, this entity should be considered when there are heterogeneous and cystic components on imaging in patients without hypercalcemia. Ultimately, histopathology is necessary for definitive diagnosis.

Purpose/Objective(s) Systemic therapy plays a crucial role in the treatment of head and neck squamous cell carcinoma (HNSCC) in both the locoregionally advanced and recurrent/metastatic settings. The MACH-NC analysis demonstrates decreased overall survival benefit for chemotherapy in elderly patients treated definitively with chemoradiotherapy. Whether this is due to the detrimental effect of poor tolerability or a true difference in efficacy has not been well characterized. In order to examine this, we utilized HPV-positive oropharyngeal cancer (OPC) as a model with prospective data from patients enrolled on consecutive iterations of induction chemo- or chemoimmunotherapy (IC) response adaptive de-escalation trials. In addition to age, we hypothesized that body mass index (BMI), statin use, baseline tumor volume, and neutrophil- and platelet-lymphocyte ratios (NLR and PLR) may be potential predictors of response to IC. In order to examine this in a granular fashion, tumor volume was measured pre-and post-induction therapy. Materials/Methods Patients with locally advanced HPV+ OPC treated on three phase II institutional trials were included for analysis. In two of the trials, induction chemotherapy comprised of carboplatin (AUC 5 - 6 on day[d] 1) and (nab-)paclitaxel (100 mg/m2 on d 1, 8, 15) for three 21-d cycles. In the third trial, nivolumab (360 mg on d1) was added to the prior IC regimen. Primary and nodal tumor volumes were contoured on matched pre-and post IC diagnostic CT/MRI. A multilinear regression (MLR) was performed to evaluate potential predictors of volumetric response in the primary and nodes to IC. Results Of 148 evaluable patients, 138 (93%) were males with median age at diagnosis of 63 [56, 68]. The mean BMI was 29.3 (SD = 5) and about a third (n = 54, 36.7%) were on statins. The median NLR and PLR were 2.45 [1.8, 3.2] and 135 [109, 172] respectively. Median baseline total tumor volume was 27 cm3 [18.7, 38.6]. The median total volumetric change was a reduction by 79.4% [67.8, 86] following IC. MLR demonstrated age as the only significant negative predictor (B = -0.38, p = 0.039) of response to IC. Patients were then divided by the median age of 63. MLR showed the pre-IC volume of the primary (B = -0.19, p = 0.04) to be a significant negative predictor of response to IC in patients younger than 63. Conclusion Increased age is an independent predictor of worse volumetric response to systemic chemo(immuno) therapy. The underpinnings of this should be further explored. Furthermore, in the younger cohort, larger primary tumor volume was associated with poorer volumetric response. The role for cytoreductive radiotherapy to improve chemoimmunotherapy outcomes in the recurrent/metastatic setting should be investigated in clinical trials.

Purpose/Objective The standard of care for non-operative management of human papillomavirus-related oropharynx cancer (HPV-OPC) consists of concurrent cisplatin chemotherapy with radiotherapy (RT) to a total dose of 70 Gy. While the oncologic outcomes of this treatment approach have been excellent, there are considerable acute and late toxicities. Here, we report the 5-year survival and toxicity outcomes of 2 prospective HPV-OPC response-adapted de-escalation trials, in which low-risk (LR) patients were treated with volume- and dose-reduced RT to 50 Gy to involved sites, without elective nodal RT or concurrent chemotherapy. Material/Methods Patients with LR HPV-OPC and ≥50% response to induction by RECIST 1.1 treated per 2 prospective phase II trials as well as on a prospective cohort registry were included for analysis. Patients were considered LR if the following criteria were met: T1-T3, N0-N2b (AJCC 7th edition), and ≤20 pack-year smoking history. Patients were treated with induction chemo- or chemoimmunotherapy followed by RT alone to 50 Gy to involved sites. In the early trial iteration, patients underwent a planned neck dissection following RT to confirm pathologic clearance of lymph nodes. Clinicodemographic characteristics were summarized using descriptive statistics. Overall survival (OS), progression-free survival (PFS), and local control (LC) were estimated using the Kaplan-Meier method. Results From January 2015 through March 2020, 73 patients met LR criteria, of which, 54 (74%) had ≥50% response by RECIST and were de-escalated to RT alone. The median follow-up was 58 (range 10-92) months. The median age was 58 (range 38-84) years, and 92.6% were male. 57.4% of patients never smoked, and 42.6% smoked no more than 20 pack-years. The primary site was tonsil for 53.7% and base of tongue for 46.3%. 24.1% were T1, 53.7% were T2, and 22.2% were T3. 1.9% were N0, 5.6% were N1, 11.1% were N2a, and 81.5% were N2b. The 5-year OS, PFS, and LC were 96.3% (95% CI 91.3%-100%), 96.2% (95% CI 91.2%-100%), and 98.1% (95% CI 94.6%-100%), respectively. 2 (3.7%) patients required a G-tube during RT and none at 1 year following completion of RT. Of the 30 patients with a planned neck dissection, 2 (6.7%) had residual pathologic nodal disease. Conclusion With a median follow-up of 5 years, this analysis demonstrates excellent long-term local control, survival, and toxicity rates among patients with low-risk HPV+ oropharynx cancer treated with induction systemic therapy followed by radiotherapy to 50 Gy without concurrent chemotherapy, including a large proportion of patients with N2b disease. Chemo-selection provides a means of identifying a favorable cohort of HPV+ oropharynx cancer patients who can safely receive RT dose de-escalation. Further work is needed to identify this population by other means, including radiographic and genomic factors.

Importance:Immune checkpoint inhibitors improve survival in recurrent and/or metastatic head and neck cancer, yet their role in curative human papillomavirus-positive oropharyngeal cancer (HPV+ OPC) remains undefined. Neoadjuvant nivolumab and chemotherapy followed by response-adaptive treatment in HPV+ OPC may increase efficacy while reducing toxicity. Objective:To determine the deep response rate and tolerability of the addition of neoadjuvant nivolumab to chemotherapy followed by response-adapted locoregional therapy (LRT) in patients with HPV+ OPC. Design, Setting, and Participants:This phase 2 nonrandomized controlled trial conducted at a single academic center enrolled 77 patients with locoregionally advanced HPV+ OPC from 2017 to 2020. Data analyses were performed from February 10, 2021, to January 9, 2023. Interventions:Addition of nivolumab to neoadjuvant nab-paclitaxel and carboplatin (studied in the first OPTIMA trial) followed by response-adapted LRT in patients with HPV+ OPC stages III to IV. Main Outcomes and Measures:Primary outcome was deep response rate to neoadjuvant nivolumab plus chemotherapy, defined as the proportion of tumors with 50% or greater shrinkage per the Response Evaluation Criteria in Solid Tumors 1.1. Secondary outcomes were progression-free survival (PFS) and overall survival (OS). Swallowing function, quality of life, and tissue- and blood-based biomarkers, including programmed death-ligand 1 (PD-L1) expression and circulating tumor HPV-DNA (ctHPV-DNA), were also evaluated. Results:The 73 eligible patients (median [range] age, 61 [37-82] years; 6 [8.2%] female; 67 [91.8%] male) started neoadjuvant nivolumab and chemotherapy. Deep responses were observed in 51 patients (70.8%; 95% CI, 0.59-0.81). Subsequent risk- and response-adaptive therapy was assigned as follows: group A, single-modality radiotherapy alone or transoral robotic surgery (28 patients); group B, intermediate-dose chemoradiotherapy of 45 to 50 Gray (34 patients); and group C, regular-dose chemoradiotherapy of 70 to 75 Gray (10 patients). Two-year PFS and OS were 90.0% (95% CI, 0.80-0.95) and 91.4% (95% CI, 0.82-0.96), respectively. By response-adapted group, 2-year PFS and OS for group A were 96.4% and 96.4%, and group B, 88.0% and 91.0%, respectively. Lower enteral feeding rates and changes in weight, as well as improved swallowing, were observed among patients who received response-adapted LRT. Pathologic complete response rate among patients who underwent transoral robotic surgery was 67.0%. PD-L1 expression was nonsignificantly higher for deeper responses and improved PFS, and ctHPV-DNA clearance was significantly associated with improved PFS. Conclusions and Relevance:This phase 2 nonrandomized controlled trial found that neoadjuvant nivolumab and chemotherapy followed by response-adapted LRT is feasible and has favorable tolerability, excellent OS, and improved functional outcomes in HPV+ OPC, including among patients with high-risk disease. Moreover, addition of nivolumab may benefit high PD-L1 expressors, and sensitive dynamic biomarkers (eg, ctHPV-DNA) are useful for patient selection. Trial Registration:ClinicalTrials.gov Identifier: NCT03107182.

Supplementary Figure S3. Overall survival (OS) and progression free survival (PFS) in different subgroups. (A) Subgroup analysis by HPV status and oropharyngeal primary site, (B) subgroup analysis by PIK3CA mutational status and oropharyngeal primary site, and (C) Subgroup analysis by TP53 mutational status and oropharyngeal primary site.