Citations

e17061 Background: ThePhase 3 VISION trial demonstrated that [177Lu]Lu-PSMA-617 prolonged overall survival (OS) in metastatic-castration resistant prostate cancer (mCRPC) patients who progressed on taxane-based chemotherapy and androgen receptor-signaling inhibitors (ARSi). The expanded access program (EAP) (NCT04825652) was opened to provide access to [177Lu]Lu-PSMA-617 for eligible patients until regulatory approval was obtained. The VISION trial required strict inclusion and exclusion criteria, which may not represent the patient population encountered in clinical practice. This study aimed to evaluate the efficacy and safety profile of [177Lu]Lu-PSMA-617 in a real-world setting within the EAP and compare the results with those from the VISION trial. Methods: Patients enrolled in the EAP between May 2021 and March 2022 at four institutions in the United States with available toxicity and outcome data were included. Outcome measures included overall survival (OS), ≥50% PSA decline rates (PSA-RR), and incidences of toxicity according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Differences in baseline characteristics, toxicity, and PSA-RR between the EAP and VISION were evaluated using a t-test of proportions. Results: 117 patients with mCRPC were eligible and included. Patients enrolled in the EAP were similarly pretreated with taxane-based chemotherapy regimens (>1 taxane: 47% vs 40%; p=0.16) and more heavily pretreated with ARSi (>1 ARSi: 70% vs 46%; p<0.001). EAP patients had similar levels of ≥3 grade anemia (18% vs 13%; p=0.15), thrombocytopenia (13% vs 8%; p=0.13), and neutropenia (3% vs 3%; p=0.85) and higher levels of ≥3 grade lymphopenia (34% vs 8%; p<0.001). Patients treated within the EAP experienced numerically shorter OS (median OS: 13.7 vs 15.3 months) and similar PSA-RR (40% vs 46%; p=0.29). Median follow-up was numerically shorter in the EAP compared with VISION (14.7 mo vs 20.3 mo). Conclusions: mCRPC patients treated with [177Lu]Lu-PSMA-617 in a real-world setting were more heavily pretreated with ARSi, had a similar safety profile, and experienced numerically shorter OS and similar PSA-RR compared with VISION trial patients. A major limitation of this study is that we did not have access to individual patient data from the VISION trial, so we were not able to assess whether differences in OS between VISION and the EAP were statistically significant.

e17059 Background: It is unclear if patients with different HRR gene-mutated mCRPC derive consistent benefit from treatment with PARPi and API combination. Approval labels for PARPi+API are inconsistent across regulatory bodies in the US (Food and Drug Administration, FDA) and Europe (European Medical Agency, EMA), adding to confusion among practicing clinicians. Therefore, we aimed to assess the differential efficacy of PARP+API therapy by different genes using up-to-date trial evidence. Methods: We maintain a living meta-analysis on mCRPC treatments that is updated when new data becomes available. Here, we report data from phase III randomized control trials (RCTs) assessing PARPi+API in 1L mCRPC. The outcomes of interest included radiographic progression-free survival (rPFS) and overall survival (OS). Hazard ratios (HR) for rPFS and OS by different genes were summarized using random effects meta-analysis via inverse variance approach. Results: We have screened 27376 references since the inception of this living review. Here, we report data from three trials (15 references) with a total of 1618 patients. Frequently reported HRR gene mutations in the included trials were BRCA2 (35%), ATM (21%), CDK12 (12.2%), CHEK2 (12.2%), BRCA1 (4.6%), and PALB2 (3.4%). In terms of rPFS, statistical benefit was observed in BRCA (0.28; 95% CI: 0.13-0.59) and CDK12 (0.58; 95% CI: 0.35-0.95) subgroups, whereas no statistically significant benefit was seen in PALB2 (0.53; 95% CI: 0.21-1.32), ATM (0.93; 95% CI, 0.57-1.53), and CHEK2 (0.92; 95% CI: 0.53-1.61) subgroups. For OS, benefit was observed in BRCA (0.47; 95%CI: 0.31-0.71) subgroup. While not statistically significant, a signal of meaningful OS benefit was observed in PALB2 (0.33; 95%CI: 0.10-1.16) but no OS benefit was observed in ATM (0.97; 95% CI: 0.57-1.67), CDK12 (0.80; 95% CI: 0.36-1.78), and CHEK2 (0.81; 95% CI: 0.37-1.75) subgroups. Conclusions: Current results show that mCRPC patients with BRCA and CDK12 alterations had delayed disease progression with PARPi+API as 1L therapy. BRCA mutations are also associated with improved OS, while patients with CHEK2 and ATM derived no significant benefit with PARPi+API combination. [Table: see text]

5074 Background: PC commonly expresses PSMA and has dose-responsive radiosensitivity. 177Lu-based radioligands usually use an empiric dosing regimen. This 1st dose-escalation study of 177Lu-PSMA-617 employed a dose-dense fractionation schedule intended to allow delivery of higher total doses to overcome radioresistance due to repopulation. Here, we report mature results of the study. Methods: Progressive mCRPC following > 1 potent ARPI (e.g., abi/enza) and chemo (or unfit/refuse taxane) without limit of # prior therapies provided adequate organ function and ECOG PS 0-2. Treatment: single cycle of fractionated dose 177Lu-PSMA-617 on D1 and D15. In Ph I dose-escalation, patients (pts) received one cycle of 7.4 - 22 GBq followed by Simon 2-stage Ph II at 22.2 GBq. PSMA expression was not required for treatment, but pre- and post-treatment 68Ga-PSMA11 PET/CT and/or 177Lu-PSMA-617 SPECT done. Primary efficacy by PSA changes with 2ndary outcomes with CT/bone scans, PSMA PET, circulating tumor cell (CTC; CellSearch) counts, plasma DNA (PCF_SELECT), and survival. Results: Between 1/2017 – 2/2021, 50 pts treated with median PSA 164.3, 35 (70%) CALGB (Halabi) poor risk. 47 (94%) bone, 38 (76%) nodal, 12 (24%) lung, 5 (10%) liver mets (4 additional pts with PSMA PET+ liver mets not apparent on CT). 29 (58%) with prior >2 ARPI, 29 (58%) with >1 chemo, 14 (28%) with Ra-223, 2 (4%) with 177Lu-J591. 27 (54%) treated at 22 GBq. No dose-limiting toxicity during Ph I. 38 (76%) with any PSA decline, 27 (54%) with >50% PSA. Median rPFS 8.3 mo [5.6-16.7], and OS 15.7 mo [10.9-20.6]. Of 17 RECIST measurable, 6 (35.3%) responded, 7 (41.2%) stable, 4 (23.5%) progressed. Of 31 with paired CTC counts, 16 (52%) decreased, 5 (16%) were stable; 10 (32.3%) converted to favorable/undetectable. Plasma DNA with high allele-specific ploidy and ARcopy number gain associated with OS (univariate). Treatment emergent adverse events (TEAE): 32 (64%) dry mouth, 22 (44%) pain flare, 22 (44%) fatigue, 19 (38%) nausea, 15 (30%) anemia, 15 (28%) thrombocytopenia (plts), 9 (18%) neutropenia (ANC). All TEAEs restricted to grade (Gr) 1-2 except 6 (12%) with Gr 3 anemia, 2 (4%) Gr 3/4 plts, 1 (2%) Gr 3 ANC. TEAE incidence and Gr were not related to dose. On multivariable analysis, 177Lu dose administered (p=0.09), CALGB risk (p=0.04), prior chemo (p=0.009), associated with OS; dose (p=0.1), CALGB risk (p=0.2), and AR copy number (p=0.2) associated with PSA50 decline. Baseline PSMA imaging (by imaging score or SUVmax) was not associated with OS or response. Conclusions: A single-cycle of fractionated-dose 177Lu-PSMA-617 is safe. Despite no pre-selection for PSMA expression, most had PSA decline with favorable PFS and OS compared to historical controls and similar to PSMA-selected targeted radionuclide studies administering multiple cycles in a less dose-intense approach. Clinical trial information: NCT03042468 .

5010 Background: hK2 (encoded by the KLK2gene) is a novel target expressed on the cell surface of prostate cancer cells with restricted expression elsewhere. JNJ-6420 is a first-in-class anti-hK2 antibody–based targeted radiotherapy delivering 225Ac, a high-energy short-range alpha-particle emitter, to prostate cancer cells. Here we report the first-in-human study evaluating JNJ-6420 in heavily pretreated biomarker-unselected participants (pts) with mCRPC who received ≥1 prior androgen receptor pathway inhibitor. Methods: Intravenous JNJ-6420 was escalated from 50 μCi to 400 μCi every 8-12 weeks in the outpatient setting with no residential radioprotective restrictions. Prior radioisotopic therapy was an exclusion criterion. Primary objectives were safety and defining a recommended phase 2 dose (RP2D). Secondary objectives included preliminary assessment of clinical activity. Results: As of January 5, 2024, 67 pts received ≥1 JNJ-6420 dose. Exposure and clinical activity for the 57 pts in the ≥150 μCi JNJ-6420 cohorts are summarized (see Table); 35/57 (61.4%) experienced grade ≥3 TEAEs, and 21 (36.8%) had a serious TEAE. TEAEs of note included thrombocytopenia (63.2%) and interstitial lung disease (ILD, 9%). All instances of ILD occurred at cumulative doses ≥500 μCi and prior to implementation of pulmonary function surveillance. Grade ≥3 TEAEs (≥10%) included anemia (26.3%), thrombocytopenia (17.5%), lymphopenia (10.5%), and leukopenia (10.5%). 9/57 (15.8%) pts discontinued treatment due to TRAEs; 4 TRAEs resulted in death. At doses ≥150 μCi, the PSA50 rate was 45.6%. To date, across all dose cohorts, 31 pts (46%) remained on treatment for ≥24 weeks. Prolonged clinical, biochemical, and radiographic responses were noted in pts receiving doses of 150 μCi and higher. Durable responses included pts on treatment for 112 weeks (96 weeks since last dose), 88 weeks (13 weeks since last dose), and 46 weeks (after a single dose). Conclusions: In this first-in-human study, key TEAEs of JNJ-6420 were thrombocytopenia and ILD, both associated with repeated dosing. At ≥150 μCi, 1-2 doses of JNJ-6420 elicited profound and durable biochemical and radiographic responses. Evaluation of the RP2D is ongoing. These data highlight hK2 as a novel target for targeted alpha-particle therapy. Clinical trial information: NCT04644770 . [Table: see text]

5008 Background: [177Lu]Lu-PSMA-617 (177Lu-PSMA-617) prolonged radiographic progression-free survival (rPFS) versus androgen receptor pathway inhibitor (ARPI) change in taxane-naive patients with metastatic castration-resistant prostate cancer (mCRPC) in PSMAfore (NCT04689828). In this exploratory analysis, associations between baseline circulating tumor DNA (ctDNA) and outcomes were assessed. Methods: Patients were randomized 1:1 to 177Lu-PSMA-617 (7.4 GBq Q6W; 6 cycles) or ARPI change (abiraterone/enzalutamide). Patients known to have actionable mutations (e.g. BRCA) were excluded. The primary endpoint was rPFS. Baseline plasma ctDNA was analyzed using a customized 585-gene sequencing assay. ctDNA fraction was assessed in all samples passing quality control. Alterations in key prostate cancer drivers (prevalent in >10% participants) were assessed in samples with ctDNA fraction >1%. Univariate Cox regression (reference: ARPI change) was used to assess association of ctDNA fraction or alterations with rPFS, prostate-specific antigen response (≥50% decline; PSA50) and RECIST response (RR) at the June 21, 2023 data cutoff. Results: Of 360 samples from 468 patients, 255 passed quality control and 156 had ctDNA fraction >1% (median 5.85%; range 0–85). Detection of ctDNA alterations was comparable between arms and with published data. Median rPFS was shorter for patients with ctDNA fraction > versus ≤1% (HR 2.753; 95% CI 1.957–3.872; p<0.0001) (Table); ctDNA fraction >1% was also associated with worse RR and PSA50 response. Median rPFS was shorter for patients with detected versus undetected AR(HR 1.954; 95% CI 1.333–2.865; p<0.001), TP53(1.655; 1.13–2.426; p<0.01) and PTEN(1.62; 1.018–2.578; p<0.05) alterations. Median rPFS was longer with 177Lu-PSMA-617 versus ARPI change in patients with detected AR, TP53, PTEN(Table) , PI3K pathway and DNA repair pathway alterations. There was no significant association between ctDNA alterations and PSA50 or RR. Conclusions: ctDNA fraction >1% and AR, TP53and PTENalterations were associated with worse outcomes in PSMAfore regardless of treatment. Nonetheless, patients with these negative prognostic biomarkers did better with 177Lu-PSMA-617 than with ARPI change. Clinical trial information: NCT04689828 . [Table: see text]

5003 Background: [177Lu]Lu-PSMA-617 (177Lu-PSMA-617) prolonged radiographic progression-free survival vs change of androgen receptor pathway inhibitor (ARPI) in taxane-naïve patients with metastatic castration-resistant prostate cancer (mCRPC) in PSMAfore (NCT04689828). We now present health-related quality of life (HRQoL) and pain outcomes at second interim analysis. Methods: Eligible patients had mCRPC, were candidates for change of ARPI after progression on one prior ARPI, and had ≥1 PSMA-positive and no exclusionary PSMA-negative metastatic lesions by [68Ga]Ga-PSMA-11 PET/CT. Ineligible patients were candidates for PARP inhibition or had received prior systemic radiotherapy, immunotherapy or chemotherapy. Patients were randomized 1:1 to open-label 177Lu-PSMA-617 (7.4 GBq/6 weeks; 6 cycles) or ARPI change (abiraterone/enzalutamide). Patients with confirmed radiographic progression on ARPI change could cross over to 177Lu-PSMA-617. Secondary endpoints included time to worsening (TTW) in self-reported HRQoL (FACT-P, EQ-5D-5L) and pain (BPI-SF), defined as a composite of score worsening (prespecified thresholds), clinical progression (including new anti-cancer treatment) or death. Post hoc analyses of TTW in FACT-P and BPI-SF excluded clinical progression and death. The study was not powered for these endpoints and type I error was not controlled. Results: We randomized 468 patients (234/arm) with a median age of 72 years (range, 43–94). Median duration of exposure was 8.4 months for 177Lu-PSMA-617 and 6.5 months for ARPI change. 177Lu-PSMA-617 delayed TTW in FACT-P, EQ-5D-5L and BPI-SF scales and subscales vs ARPI change (Table). Results were similar in non-composite analyses. Incidence of grade ≥3 adverse events (AEs), serious AEs and AEs leading to discontinuation for 177Lu-PSMA-617 and ARPI change were 34% vs 44%, 20% vs 28% and 5.7% vs 5.2%, respectively. Conclusions: 177Lu-PSMA-617 delayed TTW in self-reported pain and HRQoL vs change of ARPI in taxane-naïve patients with PSMA-positive mCRPC. Clinical trial information: NCT04689828 . [Table: see text]

Abstract Background The role of Th17 cells in prostate cancer is not fully understood. The transcription factor BATF controls the differentiation of Th17 cells. Mice deficient in Batf do not produce Th17 cells. Methods In this study, we aimed to characterize the role of Batf-dependent Th17 cells in prostate cancer by crossbreeding Batf knockout mice with mice conditionally mutant for Pten. Results We found that Batf knockout mice had changes in the morphology of prostate epithelial cells compared with normal mice, and Batf knockout mice deficient in Pten (called Batf-) had smaller prostate size and developed fewer invasive prostate adenocarcinomas than Pten-deficient mice with Batf expression (called Batf+). The prostate tumors in Batf- mice showed reduced proliferation, increased apoptosis, decreased angiogenesis and inflammatory cell infiltration, and activation of nuclear factor–κB signaling. Moreover, Batf- mice showed significantly reduced interleukin 23 (IL-23)-IL-23R signaling. In the prostate stroma of Batf- mice, IL-23R–positive cells were decreased considerably compared with Batf+ mice. Splenocytes and prostate tissues from Batf- mice cultured under Th17 differentiation conditions expressed reduced IL-23/IL-23R than cultured cells from Batf+ mice. Anti–IL-23p19 antibody treatment of Pten-deficient mice reduced prostate tumors and angiogenesis compared with control immunoglobulin G–treated mice. In human prostate tumors, BATF messenger RNA level was positively correlated with IL-23A and IL-23R but not RORC. Conclusion Our novel findings underscore the crucial role of IL-23-IL-23R signaling in mediating the function of Batf-dependent Th17 cells, thereby promoting prostate cancer initiation and progression. This finding highlights the BATF–IL-23R axis as a promising target for the development of innovative strategies for prostate cancer prevention and treatment.

Abstract Objectives There is limited research on suicide risk screening (SRS) among head and neck cancer (HNC) patients, a population at increased risk for suicide. To address this gap, this single-site mixed methods study assessed oncology professionals' perspectives about the feasibility, acceptability, and appropriateness of an electronic SRS program that was implemented as a part of routine care for HNC patients. Methods Staff who assisted with SRS implementation completed (e.g., nurses, medical assistants, advanced practice providers, physicians, social workers) a one-time survey (N = 29) and interview (N = 25). Quantitative outcomes were assessed using previously validated feasibility, acceptability, and appropriateness measures. Additional qualitative data were collected to provide context for interpreting the scores. Results Nurses and medical assistants, who were directly responsible for implementing SRS, reported low feasibility, acceptability, and appropriateness, compared with other team members (e.g., physicians, social workers, advanced practice providers). Team members identified potential improvements needed to optimize SRS, such as hiring additional staff, improving staff training, providing different modalities for screening completion among individuals with disabilities, and revising the patient-reported outcomes to improve suicide risk prediction. Conclusion Staff perspectives about implementing SRS as a part of routine cancer care for HNC patients varied widely. Before screening can be implemented on a larger scale for HNC and other cancer patients, additional implementation strategies may be needed that optimize workflow and reduce staff burden, such as staff training, multiple modalities for completion, and refined tools for identifying which patients are at greatest risk for suicide.

AbstractBackgroundDespite the overall safety and efficacy of COVID‐19 vaccinations, rare cases of systemic autoimmune diseases (SAIDs) have been reported post‐vaccination. This study used a global survey to analyze SAIDs in susceptible individuals' post‐vaccination.MethodsA cross‐sectional study was conducted among participants with self‐reported new‐onset SAIDs using the COVID‐19 Vaccination in Autoimmune Diseases (COVAD) 2 study dataset—a validated, patient‐reported e‐survey—to analyze the long‐term safety of COVID‐19 vaccines. Baseline characteristics of patients with new‐onset SAIDs and vaccinated healthy controls (HCs) were compared after propensity score matching based on age and sex in a 1:4 ratio.ResultsOf 16 750 individuals, 74 (median age 52 years, 79.9% females, and 76.7% Caucasians) had new‐onset SAID post‐vaccination, mainly idiopathic inflammatory myopathies (IIMs) (n = 23, 31.51%), arthritis (n = 15; 20.53%), and polymyalgia rheumatica (PMR) (n = 12, 16.40%). Higher odds of new‐onset SAIDs were noted among Caucasians (OR = 5.3; 95% CI = 2.9–9.7; p < .001) and Moderna vaccine recipients (OR = 2.7; 95% CI = 1.3–5.3; p = .004). New‐onset SAIDs were associated with AID multimorbidity (OR = 1.4; 95% CI = 1.1–1.7; p < .001), mental health disorders (OR = 1.6; 95% CI = 1.3–1.9; p < .001), and mixed race (OR = 2.2; 95% CI = 1.2–4.2; p = .010), where those aged >60 years (OR = 0.6; 95% CI = 0.4–0.8; p = .007) and from high/medium human development index (HDI) countries (compared to very high HDI) reported fewer events than HCs.ConclusionThis study reports a low occurrence of new‐onset SAIDs following COVID‐19 vaccination, primarily IIMs, PMR, and inflammatory arthritis. Identified risk factors included pre‐existing AID multimorbidity, mental health diseases, and mixed race. Revaccination was well tolerated by most patients; therefore, we recommend continuing COVID‐19 vaccination in the general population. However, long‐term studies are needed to understand the autoimmune phenomena arising post‐vaccination.