Reichert, Zachery R.

PURPOSE The continuous development of new imaging approaches, molecular phenotyping, genetic subtypes, prognosis assessments, and effective therapies across a range of disease states has created a need to redefine terminology and best practices for clinical trial conduct in patients with advanced prostate cancer. Methods We convened an international expert committee of diverse working groups, the Prostate Cancer Working Group 4 (PCWG4), between 2016 and 2025. Our objective was to formulate updated criteria based on emerging evidence and clinical trial data in a biomarker context to provide guidance for clinical trial design, eligibility, and end point assessments for patients with advanced prostate cancer. RESULTS PCWG4 redefines terminology around the disease state and previous therapies in a patient-centric context and terminology focused on androgen pathway modulation. We consider imaging, with a particular focus on positron emission tomography (PET)–defined disease. New recommendations are provided for disease state terminology, defining eligibility criteria, response and delay/prevent end points, intervals for reassessments including imaging, and patient-reported outcome determination. We provide recommendations in a biomarker-based context of use for the intended indication, reflective of patient benefit for specific interventions. We emphasize the need for development of validated PET imaging and molecular and phenotypic criteria as well as trial designs to appropriately risk stratify patients, predict and assess benefit, and measure post-treatment outcomes reliably in a trial framework. CONCLUSION PCWG4 updates recommendations on patient and tumor characterization, therapy development, and imaging criteria and extends guidance into earlier androgen pathway modulator–naïve/sensitive disease states to reflect an evolving, heterogeneous, and diverse patient population to optimize treatment benefits for all patients.

PURPOSE Previous studies suggest that SPOP mutations result in increased sensitivity to androgen receptor pathway inhibitors (ARPIs) but are limited by lack of granular data. We hypothesize that SPOP mutations are associated with improved outcomes across the spectrum of advanced prostate cancer (PC). METHODS Using the real-world clinicogenomic Prostate Cancer Precision Medicine Multi-Institutional Collaborative Effort database, we analyzed outcomes based on SPOP mutation status. The primary end point was overall survival (OS) from the diagnosis of metastatic disease. Secondary end points included real-world progression-free survival (PFS) and PSA90 response. RESULTS Among 2,097 patients with metastatic PC, 5.5% (N = 115) had SPOP -mutated tumors. Compared with SPOP wild-type, patients with SPOP mutations were older at diagnosis (median 65 v 63 years; P = .001) and had higher (≥8) Gleason sum (68% v 54%; P = .02), higher incidence of lung metastasis (17% v 6%; P = .001), and increased frequency of intraductal features (13% v 5%; P < .001). SPOP mutations were associated with improved PSA90 response with first ARPI exposure in the castrate-resistant setting (60% v 40.6%; OR, 2.20 [95% CI, 1.15 to 4.19]; P = .02) but not in the castrate-sensitive setting (78.9% v 71.5%; OR, 1.49 [95% CI, 0.66 to 3.37]; P = .43). Median PFS with first ARPI did not differ in SPOP- mutated versus wild-type group in both the castrate-sensitive (24.2 v 19.2 months; hazard ratio [HR], 0.80 [95% CI, 0.49 to 1.32]; P = .39) and castrate-resistant settings (15.0 v 12.4 months; HR, 0.81 [95% CI, 0.58 to 1.12]; P = .20). In multivariable analysis, SPOP mutations were associated with improved OS (HR, 0.65, P = .02). CONCLUSION SPOP mutations were associated with longer OS despite the presence of aggressive clinical features. The distinct clinical and molecular features of SPOP -mutated PC support its consideration as a unique molecular subtype with prognostic implications.

PURPOSE Preclinical studies suggest the combination of the poly(adenosine diphosphate[ADP]-ribose) polymerase (PARP) inhibitor olaparib and the ataxia telangiectasia–mutated and Rad3-related (ATR) inhibitor ceralasertib has synergistic antitumor activity in homologous recombination proficient (HRP) and homologous recombination repair gene mutation (HRRm) patients. This study aims to determine the efficacy of olaparib plus ceralasertib in metastatic castration-resistant prostate cancer (mCRPC) with and without HRRm. PATIENTS AND METHODS Thirty-five HRP and 12 HRRm PARP inhibitor–naïve patients with mCRPC progressing on ≥1 line of therapy or previous androgen receptor pathway inhibitor were enrolled. Patients received olaparib (300 mg twice daily) and ceralasertib (160 mg once daily, days 1-7) in 28-day cycles. HRRm was defined as biallelic inactivation of BRCA2 or BRCA1 , monoallelic inactivation of ATM , or germline inactivation of any of these genes. The primary end point was disease response rate (dRR; confirmed prostate-specific antigen decline ≥50% and/or complete/partial radiographic response by RECIST v1.1) in HRP patients. Secondary end points included dRR in HRRm patients, progression-free survival (PFS), and safety/toxicity. Two-stage designs were used. RESULTS Four of 35 (11%; 95% CI, 3.2 to 26.7) HRP and four of 12 HRRm patients responded. Median PFS was 8.2 months (95% CI, 5.3 to not reached) for HRP patients. Thirty-six percent of patients had ≥grade 3 toxicity, most commonly from anemia. Limitations include small, single-arm, nonrandomized trial design. CONCLUSION Combining ceralasertib with olaparib had limited activity in patients with HRP mCRPC. HRRm response rate was not greater than previous single-agent PARP inhibitor clinical trials.

The NCCN Guidelines for Testicular Cancer provide recommendations for the multidisciplinary approach to the diagnostic workup, treatment, and follow-up for testicular germ cell tumors, including both seminoma and nonseminoma. These NCCN Guidelines Insights discuss the current treatment recommendations and supporting clinical data for seminomas as presented in Version 2.2025 of the NCCN Guidelines for Testicular Cancer.

387 Background: Level 1 evidence supports treatment of high-risk and node positive PCa using 4-9 weeks of radiotherapy (RT) combined with 18-36 months of androgen deprivation therapy (ADT) with or without abiraterone acetate plus prednisone (AAP). While effective, some cancers recur, and this prolonged treatment is associated with inconvenience and variable morbidity. We aimed to determine whether the biological synergy of stereotactic body radiotherapy (SBRT) with a 6-month combination of ADT, AAP, and the PARP inhibitor niraparib, could enable a shorter intensified, yet safe and effective, therapeutic alternative. Methods: ASCLEPIuS (NCT04194554) is a multicenter investigator-initiated phase I/II trial in high-risk or node positive, homologous recombination unselected, PCa. Patients received 6 months of ADT, AAP, niraparib and SBRT to the prostate (37.5-40 Gy) +/- pelvic lymph nodes (25 Gy). Focal prostate/nodal boosting was permitted. The phase I primary endpoint was the maximum tolerated dose (MTD) of niraparib using the time-to-event continuous reassessment method (3 dose levels: 100 mg and 200 mg held during SBRT, or 200 mg concurrent with SBRT). Dose limiting toxicities (DLT) were any persistent grade 4+ hematologic toxicity or any grade 3+ rectal/urinary toxicity at least possibly related to treatment as assessed by CTCAE v5.0. Patient reported quality of life (QOL) was assessed with the EPIC-26 short form. Linear mixed models were used to compare scores over time. Results: Accrual began in Nov. 2020 with a transition from phase I to phase II in May 2023 after enrolling 54 men. Median follow-up of the phase I cohort is 12.1 months (IQR 9.4-18.9), 80% (n=43) had Grade Group 4-5, median PSA was 17 ng/mL (range, 1-73), 15% (n=8) had cN+ disease, and 76% (n=41) received nodal RT. There were 0 DLTs to date, no grade 3+ rectal or urinary toxicities, and 5 serious adverse events at least possibly attributable to study treatment (anemia, non-rectal gastrointestinal, syncope, infection, musculoskeletal). The most common grade 3 toxicities were hypertension (n = 11, 21%) and leukopenia (n=6, 11%). Transient dose reductions or holds of AAP or niraparib occurred in 10 and 11 patients, respectively. There were no statistically significant declines in patient reported urinary QOL at 6- or 12-months post-treatment compared to baseline (all p >0.15). A transient decline in bowel QOL at 6-months occurred (p<0.01), which improved by 12-months (p=0.16). Conclusions: Our phase I findings support the short-term safety and tolerability of the combination of SBRT to the prostate and nodes, ADT, AAP, and niraparib at an MTD of 200 mg in men with high-risk or node positive PCa. Our trial completed phase II enrollment in May 2024, and longer-term safety, efficacy, and genomic correlations will be presented in the future. Clinical trial information: NCT04194554 .

LBA531 Background: Muscle-invasive urothelial carcinoma (MIUC) is an aggressive disease with high relapse rates. Neoadjuvant platinum-based chemotherapy (NAC) is the standard of care in patients (pts) who are cisplatin (Cis)-eligible. However, many pts are Cis-ineligible or have persistent muscle-invasive disease after NAC and surgery. We evaluated pembrolizumab (Pembro) as adjuvant therapy in pts with high-risk MIUC following surgical resection. Methods: The AMBASSADOR study is an open-label, randomized, phase III trial that enrolled pts with histologically confirmed MIUC of the bladder, upper tract, or urethra who (1) had ≥ pT2 and/or pN+ or margins+ at surgery (radical cystectomy, nephrectomy, nephroureterectomy, or ureterectomy) following NAC or (2) ≥ pT3 and/or pN+ or margins+ at surgery without NAC and were either Cis-ineligible or declined adjuvant Cis-based therapy. Pts were registered ≥4 to 16 weeks after surgery and randomized 1:1 to receive Pembro 200 mg every 3 weeks for 1 year or observation (Obs). Randomization was stratified by pathologic stage, centrally tested PD-L1 status, and prior NAC. The dual primary endpoints were disease-free survival (DFS) and overall survival (OS) with a target sample size of 739 pts and required 387 DFS and 320 OS events for final analysis. Secondary objectives included evaluation of DFS and OS in PD-L1-positive and -negative pts and assessing safety. Here we present the interim DFS and OS results. Results: Between 09/2017 and 08/2021 a total of 702 pts were randomized prior to early closure due to US FDA approval of nivolumab for MIUC pts: 354 pts to Pembro and 348 pts to Obs; 13.0% vs 21.6% withdrew from study without event in the Pembro vs Obs arms, respectively. 74 pts (21%) in the Obs arm received an immune checkpoint inhibitor. Median follow-up was 22.3 months (mos) for DFS and 36.9 mos for OS. The DFS endpoint (based on 319 events needed for interim analysis) crossed the efficacy boundary. Median DFS was 29.0 months (95% confidence interval (CI) 21.8‒not evaluable (NE)) with Pembro and 14.0 months (95% CI 9.7‒20.20) with Obs (hazard ratio (HR) 0.69 [95% CI 0.55–0.87]; p=0.0013). At the interim analysis (n = 257 events), median OS was 50.9 months (95% CI 43.9‒NE) with Pembro and 55.8 months (95% CI 53.3‒NE) with Obs (HR 0.98 [95% CI 0.76–1.26]; p=0.88). Grade 3+ adverse events occurred in 48.4% and 31.8% of pts in the Pembro and Obs arms, respectively. Conclusions: Adjuvant Pembro demonstrated a statistically significant and clinically meaningful improvement in DFS vs Obs for high-risk MIUC pts after radical surgery. The OS endpoint may have been impacted by pts on the Obs arm receiving a checkpoint inhibitor. Pembro was tolerable with no new safety signals. These results support adjuvant Pembro as a new therapeutic option for pts with MIUC with high risk for recurrence. Additional follow-up is ongoing for the final DFS/OS, PD-L1 subgroups, and ctDNA analyses. Clinical trial information: NCT03244384 .

The substantial biological heterogeneity of metastatic prostate cancer has hindered the development of personalized therapeutic approaches. Therefore, it is difficult to predict the course of metastatic hormone-sensitive prostate cancer (mHSPC), with some men remaining on first-line androgen deprivation therapy (ADT) for several years while others progress more rapidly. Improving our ability to risk-stratify patients would allow for the optimization of systemic therapies and support the development of stratified prospective clinical trials focused on patients likely to have the greatest potential benefit. Here, we applied a liquid biopsy approach to identify clinically relevant, blood-based prognostic biomarkers in patients with mHSPC. Gene expression indicating the presence of CTCs was greater in CHAARTED high-volume (HV) patients (52% CTChigh) than in low-volume (LV) patients (23% CTChigh; * p = 0.03). HV disease (p = 0.005, q = 0.033) and CTC presence at baseline prior to treatment initiation (p = 0.008, q = 0.033) were found to be independently associated with the risk of nonresponse at 7 months. The pooled gene expression from CTCs of pre-ADT samples found AR, DSG2, KLK3, MDK, and PCA3 as genes predictive of nonresponse. These observations support the utility of liquid biomarker approaches to identify patients with poor initial response. This approach could facilitate more precise treatment intensification in the highest risk patients.

PURPOSEThere remains a lack of clarity regarding the influence of sequencing of androgen deprivation therapy (ADT) and radiotherapy (RT) on outcomes in prostate cancer (PCa). Herein, we evaluate the optimal sequencing of ADT with prostate-directed RT in localized PCa.METHODSMEDLINE (1966-2018), Embase (1982-2018), ClinicalTrials.gov, and conference proceedings (1990-2018) were searched to identify randomized trials evaluating the sequencing, but not duration, of ADT with RT. Two randomized phase III trials were identified, and individual patient data were obtained: Ottawa 0101 and NRG Oncology's Radiation Therapy Oncology Group 9413. Ottawa 0101 randomly assigned patients to neoadjuvant or concurrent versus concurrent or adjuvant short-term ADT. Radiation Therapy Oncology Group 9413, a 2 × 2 factorial trial, included a random assignment of neoadjuvant or concurrent versus adjuvant short-term ADT. The neoadjuvant or concurrent ADT arms of both trials were combined into the neoadjuvant group, and the arms receiving adjuvant ADT were combined into the adjuvant group. The primary end point of this meta-analysis was progression-free survival (PFS).RESULTSThe median follow-up was 14.9 years. Overall, 1,065 patients were included (531 neoadjuvant and 534 adjuvant). PFS was significantly improved in the adjuvant group (15-year PFS, 29% v 36%, hazard ratio [HR], 1.25 [95% CI, 1.07 to 1.47], P = .01). Biochemical failure (subdistribution HR [sHR], 1.37 [95% CI, 1.12 to 1.68], P = .002), distant metastasis (sHR, 1.40 [95% CI, 1.00 to 1.95], P = .04), and metastasis-free survival (HR, 1.17 [95% CI, 1.00 to 1.37], P = .050) were all significantly improved in the adjuvant group. There were no differences in late grade ≥ 3 gastrointestinal (2% v 3%, P = .33) or genitourinary toxicity (5% v 5%, P = .76) between groups.CONCLUSIONThe sequencing of ADT with prostate-directed RT has significant association with long-term PFS and MFS in localized PCa. Our findings favor use of an adjuvant over a neoadjuvant approach, without any increase in long-term toxicity.

PURPOSE In prostate cancer, inactivating CDK12 mutations lead to gene fusion–induced neoantigens and possibly sensitivity to immunotherapy. We aimed to clinically, pathologically, and molecularly characterize CDK12-aberrant prostate cancers. METHODS We conducted a retrospective multicenter study to identify patients with advanced prostate cancer who harbored somatic loss-of-function CDK12 mutations. We used descriptive statistics to characterize their clinical features and therapeutic outcomes (prostate-specific antigen [PSA] responses, progression-free survival [PFS]) to various systemic therapies, including sensitivity to poly (ADP-ribose) polymerase and PD-1 inhibitors. RESULTS Sixty men with at least monoallelic (51.7% biallelic) CDK12 alterations were identified across nine centers. Median age at diagnosis was 60.5 years; 71.7% and 28.3% were white and nonwhite, respectively; 93.3% had Gleason grade group 4-5; 15.4% had ductal/intraductal histology; 53.3% had metastases at diagnosis; and median PSA was 24.0 ng/mL. Of those who underwent primary androgen deprivation therapy for metastatic hormone-sensitive disease (n = 59), 79.7% had a PSA response, and median PFS was 12.3 months. Of those who received first-line abiraterone and enzalutamide for metastatic castration-resistant prostate cancer (mCRPC; n = 34), 41.2% had a PSA response, and median PFS was 5.3 months. Of those who received a first taxane chemotherapy for mCRPC (n = 22), 31.8% had a PSA response, and median PFS was 3.8 months. Eleven men received a PARP inhibitor (olaparib [n = 10], rucaparib [n = 1]), and none had a PSA response (median PFS, 3.6 months). Nine men received a PD-1 inhibitor as fourth- to sixth-line systemic therapy (pembrolizumab [n = 5], nivolumab [n = 4]); 33.3% had a PSA response, and median PFS was 5.4 months. CONCLUSION CDK12-altered prostate cancer is an aggressive subtype with poor outcomes to hormonal and taxane therapies as well as to PARP inhibitors. A proportion of these patients may respond favorably to PD-1 inhibitors, which implicates CDK12 deficiency in immunotherapy sensitivity.