Boorjian, Stephen A.

ABSTRACT Purpose The natural history of biochemical recurrence (BCR) after radical prostatectomy (RP) remains understudied, with limited long‐term data from large cohorts inclusive of both salvage radiotherapy (SRT)‐treated and untreated patients. Herein, we sought to evaluate the outcomes of patients with BCR and the impact of SRT on disease progression. Materials and Methods Patients undergoing RP who developed BCR (PSA ≥ 0.20 ng/mL) were included. Patients with BCR treated with SRT were compared to untreated patients using risk‐set matching with time‐dependent propensity scores. The primary outcome was metastases, analyzed using Kaplan–Meier and Cox models. The number needed to treat (NNT) with SRT to prevent progression was derived at 5 and 15 years. Results Among 6881 patients with BCR, 2109 received SRT. At a median follow‐up of 10.2 years, 1147 patients developed metastases. The median PSA at the time of SRT was 0.50 ng/mL. After 1:1 propensity score matching (2109 patients per cohort), SRT significantly reduced the risk of metastases at 5 (12.7% vs. 19.3%, p < 0.0001) and 15 years (28.6% vs. 31.5%, p < 0.001). On multivariable analysis, SRT independently reduced metastasis risk (HR 0.75, 95% CI 0.63–0.90, p = 0.002), translating to NNT of 23 and 15 at 5 and 15 years, respectively. Interaction analyses between SRT and nodal status ( p = 0.04) showed greater metastasis risk reduction in pN+ (HR 0.41, 95% CI 0.22–0.77, p = 0.005) compared to pN− disease (HR 0.81, 95% CI 0.67–0.97, p = 0.02). Conclusions Most patients with BCR post‐RP do not progress to metastasis. For those who do progress, SRT inarguably improves the oncologic outcomes in the BCR setting. However, careful patient selection and shared decision making should be encouraged in order to limit overtreatment and side effects.

Importance Trimodal therapy (TMT) is included as an alternative to radical cystectomy (RC) for definitive management of muscle-invasive bladder cancer (MIBC) in current clinical guidelines. Moreover, a 2023 retrospective analysis reported similar oncologic outcomes between these treatments among patients deemed fit for RC. Data regarding the comparative value of these treatments are lacking. Objective To evaluate the comparative cost-effectiveness of TMT and RC for treatment of MIBC. Design, Setting, and Participants This economic evaluation compared cost-effectiveness of treatments using a health transition state microsimulation model of patients with bladder cancer treated between 2005 and 2017 with 5- and 10-year horizons from a Medicare perspective. Model probabilities were informed by multicenter retrospective analyses published in 2023 comparing TMT with RC. The index patient was aged 71 years, with clinical stage T2-4aN0M0 MIBC, solitary tumor smaller than 7 cm, no or unilateral hydronephrosis, adequate bladder function, and lack of multifocal or extensive carcinoma in situ. Patients unfit for RC, radiation, or cisplatin-based chemotherapy were excluded. Exposures TMT and RC. Main Outcome and Measures Primary outcomes included effectiveness measured in quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICER) using a willingness-to-pay threshold of $100 000 per QALY. Sensitivity analyses were performed to assess the robustness of the model. Results For the index patient, at 5 years, the average cost was $30 525 higher for TMT than RC. Average QALYs were 3.87 and 3.94 for RC and TMT, respectively. As such, TMT was not cost-effective at 5-year (ICER, $464 291 per QALY) or 10-year (ICER, $308 638 per QALY) time horizons. On 1-way sensitivity analyses, TMT would become cost-effective if (1) TMT costs were less than $17 605; or (2) TMT resulted in an 11.6% improvement in metastasis-free survival relative to RC. Conclusions and Relevance In this economic evaluation study of TMT and RC for treatment of MIBC, TMT was associated with improved quality of life but was not cost-effective relative to RC at 5 and 10 years given higher treatment costs. These findings highlight the importance of developing policy initiatives that help reduce TMT costs and of providing patients with accurate expectations of long-term toxic effects to help guide preference-sensitive care.

TPS4630 Background: Bacillus Calmette-Guérin (BCG) is the standard first-line therapy for patients with high-risk non–muscle-invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) ± papillary tumors; however, patients whose disease is unresponsive to BCG therapy are unlikely to benefit from further courses of BCG. Bladder-preserving treatment options for patients with BCG-unresponsive NMIBC with CIS ± Ta/T1 include intravesical gene therapy (nadofaragene firadenovec-vncg), intravesical chemotherapy (gemcitabine and docetaxel), and immunotherapy (intravenous pembrolizumab and intravesical nogapendekin alfa inbakicept-pmln). In a pivotal phase 3 study, 53.4% of participants (55/103) with BCG-unresponsive NMIBC with CIS ± Ta/T1 achieved a complete response (CR) within 3 months of a single instillation of nadofaragene firadenovec, and of them, 45.5% (25/55) maintained a CR at 12 months. Nadofaragene firadenovec in combination with chemotherapy or immunotherapy may further improve clinical efficacy. ABLE-22 (NCT06545955) is an interventional study evaluating the safety and efficacy of nadofaragene firadenovec alone or in combination with chemotherapy (gemcitabine and docetaxel) or immunotherapy (pembrolizumab) in participants with high-risk BCG-unresponsive NMIBC. Participants not responding at month 3 will be offered reinduction. Methods: ABLE-22 will include approximately 40 to 75 sites across the United States and Canada; sites in Asia, Australia, and Europe may be included. Participants (anticipated N = 150) will be randomly assigned 1:1:1 to receive nadofaragene firadenovec (n = 50), nadofaragene firadenovec plus gemcitabine and docetaxel (n = 50), or nadofaragene firadenovec plus pembrolizumab (n = 50). Adults aged ≥18 years with documented NMIBC with CIS ± Ta/T1 that is unresponsive to ≥2 courses of BCG therapy within the last 12 months are eligible to enroll. The primary endpoint is CR (defined as absence of low- and high-grade NMIBC) at months 3 or 6, as participants with persistent NMIBC (any CIS, low-grade Ta, and > 3 cm or multifocal high-grade Ta) will be offered reinduction once, at month 3. Secondary endpoints include durability of CR, incidence of muscle-invasive progression, cystectomy-free survival, pathologic staging, overall survival, and safety. Durability of CR will be followed up to month 36 (assessed quarterly for the first 24 months); all other secondary endpoints will be assessed up to and including month 36. Exploratory endpoints include changes in expression of potential biomarkers in blood and urine. Results from this investigational, randomized, multicenter, open-label study evaluating the safety and efficacy of nadofaragene firadenovec alone or in combination with chemotherapy or immunotherapy are expected July 2028. Clinical trial information: NCT06545955 .

Abstract Objectives We aimed to assess the expression of biomarkers of response to antibody-drug conjugates (TROP2 and nectin-4) and immune microenvironment (NKG7, PD-L1, and B7-H3) in penile squamous cell carcinoma (pSCC). Methods Our archive was queried for patients who had a penectomy for pSCC between 2000 and 2022. Primary tumors were immunostained for B7-H3 and NKG7, while metastatic specimens were immunostained for TROP2 and nectin-4. Expression of PD-L1, TROP2, and nectin-4 in primary tumors was previously characterized. H-scores (0-300) were used to quantify expression. Associations between biomarkers, tumor-infiltrating lymphocytes (TILs), and clinicopathologic and outcome parameters were evaluated. Results For both TROP2 and nectin-4, H-scores within the lymph node metastases were higher compared to those within the primary tumors (mean, 264.5 vs 244.8, P = .0003; mean, 170.6 vs 146.7, P = .05, respectively; 33 paired specimens). For B7-H3 (n = 107), 32.7% of the primary tumors had an H-score of more than 0. In 34.8% of the cases, NKG7 expression was observed in 25% to 50% of the TILs. A significant association was noted between TIL density, B7-H3, NKG7, and PD-L1 expression. Conclusions Therapeutic strategies targeting TROP2 and nectin-4 hold promise for patients with advanced pSCC. The potential of PD-L1, B7-H3, and NKG7 for predicting response to immunomodulatory treatment warrants further research.

Abstract Addressing the limited responsiveness to immune checkpoint blockade (ICB) in human cancers remains a critical challenge. Efforts over the past two decades have primarily focused on enhancing CD8 T cell function and preventing their exhaustion. However, less attention has been given to understanding the molecular mechanisms that contribute to the immunosuppressive tumor microenvironment (TME), which impedes CD8 T cell infiltration and fosters ICB resistance. The TME in ICB-resistant tumors is characterized by Transforming Growth Factor beta (TGF-β) cytokine signaling, leading to a fibrotic extracellular matrix (ECM) and the accumulation of immunosuppressive fibroblasts and myeloid cells. These features hinder CD8 T cell penetration, thereby promoting immune escape. The immune checkpoint molecule B7-H3, overexpressed in ICB-resistant cancers, has been linked to impaired CD8 T cell infiltration and poor prognosis. However, the molecular mechanisms governing B7-H3 function remain poorly understood. We investigated the relationship between B7-H3 gene expression and ICB response using transcriptomic data from two randomized phase 3 trials (IMvigor010 and IMvigor210). Bulk RNAseq data, tissue staining, and spectral flow cytometry were used to characterize the TME composition of B7-H3 high and low tumors. Multi-omic profiling of tumor cell lines with manipulated B7-H3 expression was performed to identify downstream targets of B7-H3. Syngeneic mouse tumor models were used to assess the impact of B7-H3 on tumor growth and antitumor immunity. High B7-H3 expression was associated with shorter overall survival in both IMvigor010 (HR=0.48, 95% CI: 0.33-0.70, p&lt;0.0001) and IMvigor210 trials (HR=0.68, 95% CI: 0.51-0.92, p=0.01). In ICB-refractory cancers, B7-H3 expression correlated with high levels of fibroblasts, collagen deposits, and M2 macrophages. Gene set enrichment analysis revealed a positive association between B7-H3 and TGF-β signaling. Genetic deletion of B7-H3 in tumor cells reduced the surface expression of MMP14, a metalloprotease that activates TGF-β. Pan-cancer analysis identified MMP14 as the gene most correlated with B7-H3 (Pearson r=0.69, p&lt;0.0001). TGF-β activation was reduced by 70% in B7-H3 knockout cells compared to wild-type. Loss of B7-H3 led to MMP14 accumulation in lysosomes, resulting in its degradation. We generated a B7-H3 inhibitor, 5D10, which promotes MMP14 degradation and inhibits TGF-β activation. In humanized B7-H3 mouse models, 5D10 significantly reduced TGF-β activation, enhancing CD8 T cell infiltration and impairing tumor growth. Our research identifies B7-H3 as a driver of immune exclusion and ICB resistance. We describe a novel, receptor-independent mechanism where B7-H3 promotes TGF-β activation via stabilization of MMP14. Targeting B7-H3 represents a strategy to modulate the TME, transforming immune-excluded tumors into immune-inflamed states that may respond better to ICB. Citation Format: Fabrice Lucien, Roxane Lavoie, Jack Korleski, Yohan Kim, Bharath Wootla, Liguo Wang, Ava Farrell, Kelly Harper, Martine Charbonneau, Claire Dubois, Igor Frank, Sounak Gupta, John Cheville, Jacob Orme, Stephen Boorjian, Parash Shah, Eugene Kwon, Sean Park, Haidong Dong. The immune checkpoint molecule B7-H3 is a driver of tumor immune exclusion by mediating TGF-β activation [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr B034.