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Background Cabazitaxel was shown to improve overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) after abiraterone/enzalutamine and docetaxel failure, though benefit by the presence of DNA damage repair (DDR) defects is unknown. With the advent of poly(adenosine diphosphate–ribose) polymerase inhibitors (PARPi) in partially overlapping indications with cabazitaxel, we aimed to determine cabazitaxel activity in men with mCRPC according to their DDR status. Methods This is a retrospective multicenter study that enrolled patients with mCRPC treated with cabazitaxel who had undergone DDR tumour tissue profiling. Patients with at least one deleterious germline or somatic alterations were considered DDR positive (DDR+). Each DDR + patient has been matched with a DDR negative (DDR-) from the same institution who underwent the same test. An exploratory cohort of patients found to be DDR + by liquid biopsy was also included. Prostate specific antigen (PSA) decline≥50% (PSA50), PSA progression-free survival (PFS, PSA-PFS), radiographic PFS (rPFS), clinical PFS or radiographic PFS (c/rPFS) and OS were evaluated. Results Among 190 men (95 DDR+, 95 DDR-) with tissue sequencing, PSA50 was achieved with cabazitaxel in 29/92 (32%) and 33/92 (36%) in patients with DDR+ and DDR- (P = 0.64). The median rPFS was 5.33 months [95%CI 4.34–7.04] versus 5.75 months [95%CI 4.67–7.27] (P = 0.55). The median OS was 15.4 months [95%CI 12.16–26.6] and 11.5 months [95%CI 9.76–14.4] (P = 0.036), respectively. No PSA50 responses on cabazitaxel were observed in BRCA1/2 patients previously treated with PARPi (n = 10). Similar outcomes with cabazitaxel were observed in the liquid biopsy cohort (n = 63 DDR+). Conclusions Our study suggests that cabazitaxel is active in patients with mCRPC regardless of their DDR status, although its activity in men pretreated with a PARPi may be lower.

IntroductionUrachal cancer (UrC) is a rare, non-urothelial malignancy. Its natural history and management are poorly understood. Although localized to the bladder dome, the most common histological subtype of UrC is adenocarcinoma. UrC develops from an embryonic remnant, and is frequently diagnosed in advanced stage with poor prognosis. The treatment is not standardized, and based only on case reports and small series. This large retrospective multicentric study was conducted by the French Genito-Urinary Tumor Group to gain a better understanding of UrC.Material and Methodsdata has been collected retrospectively on 97 patients treated at 22 French Cancer Centers between 1996 and 2020.ResultsThe median follow-up was 59 months (range 44-96). The median age at diagnosis was 53 years (range 20-86), 45% were females and 23% had tobacco exposure. For patients with localized disease (Mayo I-II, n=46) and with lymph-node invasion (Mayo III, n=13) median progression-free-survival (mPFS) was 31 months (95% CI: 20-67) and 7 months (95% CI: 6-not reached (NR)), and median overall survival (mOS) was 73 months (95% CI: 57-NR) and 22 months (95% CI: 21-NR) respectively. For 45 patients with Mayo I-III had secondary metastatic progression, and 20 patients were metastatic at diagnosis. Metastatic localization was peritoneal for 54% of patients. Most patients with localized tumor were treated with partial cystectomy, with mPFS of 20 months (95% CI: 14-49), and only 12 patients received adjuvant therapy. Metastatic patients (Mayo IV) had a mOS of 23 months (95% CI: 19-33) and 69% received a platin-fluorouracil combination treatment.ConclusionUrC is a rare tumor of the bladder where patients are younger with a higher number of females, and a lower tobacco exposure than in standard urothelial carcinoma. For localized tumor, partial cystectomy is recommended. The mOS and mPFS were low, notably for patients with lymph node invasion. For metastatic patients the prognosis is poor and standard therapy is not well-defined. Further clinical and biological knowledge are needed.

Purpose: The phase III PROfound study (NCT02987543) evaluated olaparib versus abiraterone or enzalutamide (control) in metastatic castration-resistant prostate cancer (mCRPC) with tumor homologous recombination repair (HRR) gene alterations. We present exploratory analyses on the use of circulating tumor DNA (ctDNA) testing as an additional method to identify patients with mCRPC with HRR gene alterations who may be eligible for olaparib treatment. Patients and Methods: Plasma samples collected during screening in PROfound were retrospectively sequenced using the FoundationOne®Liquid CDx test for BRCA1, BRCA2 (BRCA), and ATM alterations in ctDNA. Only patients from Cohort A (BRCA/ATM alteration positive by tissue testing) were evaluated. We compared clinical outcomes, including radiographic progression-free survival (rPFS) between the ctDNA subgroup and Cohort A. Results: Of the 181 (73.9%) Cohort A patients who gave consent for plasma sample ctDNA testing, 139 (76.8%) yielded a result and BRCA/ATM alterations were identified in 111 (79.9%). Of these, 73 patients received olaparib and 38 received control. Patients’ baseline demographics and characteristics, and the prevalence of HRR alterations were comparable with the Cohort A intention-to-treat (ITT) population. rPFS was longer in the olaparib group versus control [median 7.4 vs. 3.5 months; hazard ratio (HR), 0.33; 95% confidence interval (CI), 0.21–0.53; nominal P < 0.0001], which is consistent with Cohort A ITT population (HR, 0.34; 95% CI, 0.25–0.47). Conclusions: When tumor tissue testing is not feasible or has failed, ctDNA testing may be a suitable alternative to identify patients with mCRPC carrying BRCA/ATM alterations who may benefit from olaparib treatment.

International audience; Background: Real-world data on cabozantinib in metastatic renal cell carcinoma (mRCC) is limited. This study (CABOREAL) reports treatment patterns and outcomes for patients treated with cabozantinib through the French Early Access Program.Patients and methods: This multicentre (n = 26), observational, retrospective study enrolled patients with mRCC who had received ≥1 dose of cabozantinib. Overall survival (OS) was estimated using the Kaplan-Meier method; subgroups were compared using the log-rank test. A multiple Cox regression model assessed predictive factors of OS after cabozantinib initiation.Results: Four hundred and ten recruited patients started treatment between September 2016 and February 2018: the Eastern Cooperative Oncology Group Performance Status ≥2, 39.3%; poor International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk, 31.7%; 0-1, 2 and ≥3 previous treatment lines, 25.3%, 33.4% and 41.2%, respectively; bone metastases, 55.9%; brain metastases, 16.8%. Median (min-max) follow-up was 14.4 (0-30) months. Overall, 57.0% of patients had a dose reduction, 15.6% an alternative dose schedule. The median average daily dose was 40.0 mg. Median (quartile [Q]1-Q3) treatment duration was 7.6 (0.1-29.1) months, median OS was 14.4 months, and the 12-month OS rate was 56.5% (95% confidence interval: 51.5-61.2). Most patients (54.4%) received subsequent treatment. Predictive factors associated with longer OS were body mass index ≥25 kg/m2 (p = 0.0021), prior nephrectomy (p = 0.0109), favourable or intermediate IMDC risk (p < 0.0001) and cabozantinib initiation at 60 mg/day (p = 0.0486).Conclusions: In the largest real-world study to date, cabozantinib was effective in unselected, heavily pretreated patients with mRCC. Initiation at 60 mg/day was associated with improved outcomes. CLINICALTRIALS.

More than 80 % of patient with metastatic germ cell tumor are cured with first line chemotherapy. Twenty to 30 % of patients will experience relapse or refractory disease with a very poor long-term prognosis. Most of them had metastatic germ cell tumors with a poor prognosis according to the international germ cell classification collaborative group (IGCCCG). The role of treatment intensification by high dose chemotherapy (HDCT) followed by stem cell rescue has not been demonstrated yet in the first line setting compared to standard chemotherapy. The role of HDCT in first or second salvage is also not yet demonstrated, many studies have been published in this situation with a lot of different regimen. Outside clinical trial, HDCT remains an option in salvage therapy, depending on many factors including prognostics factors, previous therapy, general condition and reference center consideration to select eligible patient who could benefit the most of this approach. Results from the international randomized trial TIGER will provide evidence-based information for HDCT strategy.

Resume Introduction Peu de donnees existent quant aux patients âges traites pour un cancer de la prostate resistant a la castration metastatique (CPRCM). L’objectif etait d’analyser la prise en charge des patients d’au moins 80 ans traites par docetaxel pour un CPRCM. Materiel et methodes Les donnees des octogenaires traites par docetaxel pour un CPRCM etaient recueillies de facon retrospective de 2009 a 2019 dans trois centres francais. La survie, les caracteristiques cliniques et pathologiques etaient recueillies ainsi que les traitements recus avant et apres docetaxel. Resultats Les donnees de 89 patients ont ete analysees. Au total, 20,2 % avaient recu le regime standard et 79,8 % ont une dose adaptee. Les patients du groupe adapte etaient significativement plus âges que les patients du groupe standard. Les autres caracteristiques cliniques et les scores geriatriques etaient similaires. Les reductions de dose pour toxicite etaient plus frequentes dans le groupe standard que dans le groupe adapte (p = 0,04). La survie globale mediane de la population totale etait de 13,3 mois. Elle etait plus longue dans le groupe standard que dans le groupe adapte (26,1 mois vs. 12,4 mois = 0,009). En analyse multivariee, le docetaxel employe a dose standard etait un facteur pronostic independant. Conclusion Cette etude suggere un reel benefice d’une prise en charge standard, meme chez les patients les plus âges. L’evaluation geriatrique doit permettre, parmi les patients definis comme fragiles par un score de depistage ou par l’oncologue, de depister les patients finalement eligibles au traitement standard.

Background: Treatment options for patients (pts) with heavily pretreated mCRPC are limited. Augmenting endocrine therapy by targeting CDK4/6 with abemaciclib has dramatically improved outcomes in HR+ breast cancer. Similar to ER, AR signaling activates CDK4 & 6 and abemaciclib showed preclinical anti-tumor activity in prostate cancer (PC). This signal seeking single arm Phase 2 study evaluated the safety and clinical activity of abemaciclib monotherapy in pts with heavily pretreated poor prognosis mCRPC who progressed after both a novel hormonal agent (NHA) and two taxanes. Methods: Eligible pts had progressive mCRPC, measurable disease by RECIST1.1, and previously received ≥1 NHA, docetaxel, and cabazitaxel for metastatic PC. Abemaciclib was administered at 200 mg BID on a continuous 28-day dosing schedule. The primary endpoint was investigator-assessed objective response rate without concurrent bone progression (ORR). A target ORR of ≥12.5% was deemed suitable to support further evaluation of abemaciclib monotherapy in this refractory mCRPC setting. Key secondary endpoints included disease control rate (DCR), time to PSA progression, radiographic progression-free survival (rPFS), overall survival (OS), and safety. Results: Forty-four pts (median age 68 yrs; 75% ECOG PS 1, median PSA of 96 ng/mL) were enrolled. In total, 46.5% had visceral metastasis, including 27.9% with liver metastases. Median time from development of mCRPC to study entry was 2.1 yrs and the median number of prior systemic regimens for mCRPC was 3. Median number of treatment cycles was 3 (1-13). Five pts (11.8%) had soft tissue response. The ORR without concurrent bone progression was 6.8%. Eighteen pts (40.9%) had stable disease, of which 6 (13.6%) lasted ≥6 months (mos); DCR was 47.7%. Median rPFS was 2.7 mos (95% CI 1.9, 3.7); 6-mos rPFS rate was 24.9% (95% CI 12.4, 39.5); median time to PSA progression was 6.5 mos. Median OS was 7.6 mos (95% CI 5.6, NE). Any grade (G) TRAEs experienced by ≥50% of pts were diarrhea (79.5%), decreased appetite (52.3%) and fatigue (50%); majority were G1/2. G3 TRAEs in ≥ 5% of pts were neutropenia (22.7%), anemia (6.8%), fatigue (6.8%) and diarrhea (6.8%). There were no G4 or G5 TRAEs. Discontinuation rate due to AE was 13.6%. Conclusions: Abemaciclib demonstrated modest but objective single-agent clinical activity in pts with very heavily pretreated progressive mCRPC. The safety profile of abemaciclib was consistent with the experience in breast cancer. Although the primary endpoint was not formally met, the single agent activity observed in this late line mCRPC setting validates CDK4/6 as a therapeutic target in advanced PC. The CYCLONE 2 and CYCLONE 3 studies are currently evaluating abemaciclib in combination with abiraterone/prednisone to leverage synergy of combined CDK4/6 and hormonal inhibition in first line mCRPC and mHSPC settings, respectively. Citation Format: Neeraj Agarwal, Daniel Castellano Guana, Teresa A. Gordoa, Jose A. Arija, Emeline Colomba, Gwenaelle Gravis, Loic Mourey, Stephanie Oudard, Aude Flechon, Macarena Gonzalez, Pablo Maroto-Rey, Michael Schweizer, Enrique Gallardo, Karim Nacerddine, Adams K. Appiach, Arjun Balar, Erica Johnston, José M. Piulats. CYCLONE 1: abemaciclib in men with heavily pretreated metastatic castration-resistant prostate cancer (mCRPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT159.

20 Background: Metastatic castration-sensitive prostate cancer (mCSPC) primarily affects older men (OM). In this post-hoc analysis we investigated the safety and efficacy of abiraterone acetate + prednisone (AAP) in older (≥ 70 years) and younger (< 70 years) patients in PEACE-1. Methods: Men with de novo mCSPC were allocated to standard of care (SOC), SOC + AAP, SOC + radiotherapy (RXT), or SOC + AAP + RXT in this 2x2 design phase 3 trial. SOC was initially androgen deprivation therapy (ADT) alone, then from Oct 2015 onwards, the use of docetaxel (D) was authorized as part of SOC (at the investigator’s discretion until 2017, then, following the publication of LATITUDE and STAMPEDE trials, accrual was restricted to men receiving ADT+ D). Efficacy and safety in OM included in PEACE-1 were analyzed with the same methods used in the overall trial (Lancet 2022; 399: 1695-1707). Results: A total of 741 younger men (YM) (63%) and 431 OM (37%) were randomized. OM presented with more altered PS (ECOG 1-2) (36% vs 26% p=0.0003) and less frequent use of docetaxel (D) as part of SOC (66% vs 51% p

471 Background: In the phase 3 JAVELIN Bladder 100 trial, avelumab 1L maintenance + best supportive care (BSC) significantly prolonged overall survival (OS) vs BSC alone in pts with aUC that had not progressed with 1L platinum-based chemotherapy (CTx). The JAVELIN Bladder regimen is now standard of care with level 1 evidence in international treatment guidelines. The AVENANCE study (NCT04822350), is investigating the efficacy and safety of avelumab 1L maintenance in a real-world population of pts with aUC in France. Data from the full analysis set are reported for the first time. Methods: In this ongoing, noninterventional, ambispective study, eligible pts have locally advanced or metastatic UC that has not progressed with 1L platinum-based CTx and previous, ongoing, or planned avelumab 1L maintenance treatment. The primary endpoint is OS from start of avelumab; secondary endpoints include progression-free survival (PFS), duration of treatment (DOT), and safety. Results: 591 pts received avelumab. At data cutoff (July 31, 2022), median follow-up was 12.0 mo (95% CI, 10.9-12.9). Median age was 73.1 y (IQR, 67.0-78.1). At start of 1L CTx (excluding pts with missing data), disease stage was metastatic in 524 pts (90.5%; visceral metastases in 426 [81.5%]) and locally advanced in 54 (9.3%). ECOG PS was 0-1 in 407 pts (85.3%) and 2-3 in 69 (14.5%). Tumor histology was pure UC in 528 pts (91.8%) and UC with variant or pure variant in 47 (8.2%). 1L CTx was gemcitabine + carboplatin (GemCarbo), gemcitabine + cisplatin (GemCis), dose-dense methotrexate + vinblastine + adriamycin + cisplatin (DD-MVAC), and other in 353 (61.0%), 170 (29.4%), 28 (4.8%), and 28 (4.8%) pts, respectively. Median number of cycles was 5 (range, 1-10). Median DOT with avelumab was 5.8 mo (95% CI, 5.2-7.0); 241 pts (40.8%) remained on treatment at data cutoff. The most common reasons for treatment discontinuation were disease progression (74.1% [n=258]), death (11.5% [n=40]), and adverse events ([AEs] 10.3% [n=36]). Median OS from start of avelumab was 18.4 mo (95% CI, 15.4-not estimable [NE]), the 12-month OS rate was 64.8% (95% CI, 60.0%-69.1%), and median PFS was 5.7 mo (95% CI, 5.3-7.0). In pts who had received GemCarbo, GemCis, or DD-MVAC, median OS (95% CI) was 16.2 mo (13.4-NE), not reached (NR; 18.1-NE), and NR (15.2-NE), respectively. Subgroups analyses will be presented. 218 pts received subsequent 2L, including CTx, antibody-drug conjugates, immunotherapy, and other in 186 (85.3%), 22 (10.1%), 6 (2.8%), and 4 (1.8%) pts, respectively. Any-grade treatment-related AEs (TRAEs) occurred in 217 pts (36.7%), including serious TRAEs in 29 (4.9%). Conclusions: Real-world data for avelumab 1L maintenance in pts with aUC from AVENANCE support the findings of JAVELIN Bladder 100 and confirm the clinical activity and acceptable safety profile of avelumab in a heterogeneous population. Clinical trial information: NCT04822350 .

526 Background: SG is an antibody-drug conjugate composed of an anti-Trop-2 antibody coupled to SN-38, a topoisomerase-I inhibitor, via a proprietary hydrolyzable linker. SG received accelerated FDA approval in April 2021 in pts with mUC who previously received PT-based therapy and a CPI based on the primary analysis of the pivotal TROPHY-U-01 Cohort 1 study. With 9.1 mo median (med) follow-up, SG monotherapy demonstrated a 27% objective response rate (ORR) and med overall survival (OS) of 10.9 mo in 113 pts with locally advanced or mUC progressing after receiving at least a PT-based therapy and a CPI (Tagawa, et al. J Clin Oncol. 2021). Here we report updated Cohort 1 outcomes. Methods: TROPHY-U-01 (NCT03547973) is a multicohort, open-label, phase 2 study. Cohort 1 pts (≥18 y) had progression of mUC following PT (as first-line metastatic therapy or as (neo)adjuvant therapy with recurrence/progression ≤12 mo) and CPI, had ECOG PS 0-1, and creatinine clearance ≥30 mL/min. Pts received 10 mg/kg of SG intravenously on D1 and D8 of 21-D cycles. The primary endpoint was ORR per central review by RECIST 1.1. Key secondary endpoints included duration of response (DOR), progression-free survival (PFS), clinical benefit rate (CBR), OS, and safety. Results: As of July 26, 2022, med follow-up was 10.5 mo (range, 0.3-40.9) for treated pts (N=113). As previously reported, pts (78% men; med age, 66 y; 66% with visceral metastases, 34% liver), were heavily pretreated with a med of 3 prior therapies (range, 1-8). Med time since last prior therapy was 1.5 mo (range, 0-60.0). At data cutoff, per central review, ORR was 28% (95% CI, 20.2-37.6); CBR was 38% (95% CI, 29.1-47.7), med DOR was 6.1 mo (95% CI, 4.7-9.7, n=32) and med PFS was 5.4 mo (95% CI, 3.5-6.9). Med time to response was 1.6 mo (range, 1.2-5.6) and med OS was 10.9 mo (95% CI, 8.9-13.8). DOR, PFS, and OS rates (95% CI) at 12 mo were 30% (13.6-48.8), 14% (7.2-23.3), and 45% (35.4-53.8), respectively, with 7 (6%) pts still receiving SG at 12 mo. In pts who received prior enfortumab vedotin (n=10) and prior PT in the (neo)adjuvant setting (n=39), results were consistent with the overall population. Grade ≥3 treatment-related adverse events (TRAEs) occurred in 65% of pts and were similar to prior reports; the most common Grade ≥3 TRAEs were neutropenia (35%), leukopenia (18%), anemia (14%), diarrhea (10%), and febrile neutropenia (10%). One treatment-related death occurred due to febrile neutropenia-related sepsis. Conclusions: At 10.5-mo med follow-up, the response rate remains high in pts with heavily pretreated mUC, including pts with visceral metastases, prior EV therapy and prior (neo)adjuvant PT therapy. No new safety signals were observed. These data support the use of SG in pts with mUC who received PT and a CPI and further evaluation of SG in earlier lines of therapy. Clinical trial information: NCT03547973 .

518 Background: Pembro is standard of care for pts with mUC who progress after 1L PT therapy but only ~21% of pts respond, highlighting an unmet need (Bellmunt, et al. NEJM. 2017). SG is an antibody-drug conjugate composed of an anti-Trop-2 antibody coupled to SN-38 via a hydrolyzable linker. In Cohort 1 of the TROPHY-U-01 study, SG demonstrated a 27% objective response rate (ORR) with manageable safety in 113 pts with locally advanced or mUC who previously received PT and a checkpoint inhibitor (CPI; Tagawa, et al. J Clin Oncol. 2021), leading to accelerated FDA approval in this pt population. Preliminary results of the phase 2 TROPHY-U-01 Cohort 3 study showed that SG plus Pembro demonstrated a high ORR (34%) as a 2L therapy in 41 CPI-naive pts with mUC who progressed after PT (Grivas et al. J Clin Oncol. 2021). Here we present the primary analysis of Cohort 3. Methods: Cohort 3 pts (≥18 y) had progression of mUC following PT in the metastatic setting or following ≤12 mo of PT in the (neo)adjuvant setting and ECOG PS 0-1. Pts received 10 mg/kg of SG on D1 and D8 and 200 mg of Pembro on D1 of a 21-D cycle for ≤2 y. The primary endpoint was ORR [complete response (CR) + partial response (PR)] per central review by RECIST 1.1. Secondary endpoints include clinical benefit rate [CBR; CR + PR + stable disease for at least 6 mo], duration of response (DOR) and progression-free survival (PFS) per central review; and safety. Target enrollment was approximately 41 pts based on a Simon two-stage design for 90% power at one-sided α of 0.05 to demonstrate 21% improvement in ORR, with a null hypothesis of historical ORR ≤20% and an alternate hypothesis of ORR ≥41%. Results: As of July 26, 2022, median follow-up was 12.5 mo (range, 0.9-24.6) for treated pts (N=41); median age, 67 y (range, 46-86), 83% male, 61% ECOG PS 1, 76% ≥1 Bellmunt risk factors, and 78% visceral metastases (29% liver). Median duration of last prior anti-cancer therapy was 2.7 mo (range, 0-13). Per central review, ORR was 41% (95% CI, 26.3-57.9; 20% CR); CBR was 46% (95% CI, 30.7-62.6); median DOR was 11.1 mo (95% CI, 4.8-NE [not estimable]; n=17); and median PFS was 5.3 mo (95% CI, 3.4-10.2). Median time to response was 1.4 mo (95% CI, 1.3-2.7) and median OS was 12.7 mo (95% CI, 10.7-NE). Grade ≥3 treatment-related adverse events (TRAEs) occurred in 61% of pts; most common Grade ≥3 TRAEs were neutropenia (37%; 10% febrile neutropenia), leukopenia (20%), and diarrhea (20%). TRAEs led to a 15% discontinuation rate. Systemic steroid and G-CSF use were both 34%. No treatment-related death occurred. Conclusions: SG plus Pembro demonstrated a high ORR and CBR with a manageable safety profile in 2L mUC in CPI-naive pts who progressed after PT-based therapy. No new safety signals were observed with the combination. These data support further evaluation of SG plus CPI in mUC. Clinical trial information: NCT03547973 .

TPS434 Background: At diagnosis, 10 to 15% of testicular pure seminomas have a stage II defined by the presence of retroperitoneal lymph node metastases. The optimal choice of treatment modalities are associated with excellent efficacy but also acute and late toxicities. De-escalating treatment for seminoma patients with stage IIb, IIc and III and good prognosis according to IGCCCG (International Germ Cell Cancer Collaborative Group) based on negative FDG-PET (Fluorodeoxyglucose Positron Emission Tomography) after 2 cycles of EP (etoposide, cisplatine) chemotherapy seems feasible and safe according to SEMITEP cohort 2 results (Loriot Y, and al GETUG SEMITEP Trial: Eur Urol. 2022 Aug;82(2):172-179). Serum levels of microRNA (miR)-371a-3p (miRNA-M371) have been significantly associated with clinical stage and response to treatment in testicular germ cell tumors, with sensitivity and specificity higher than those of classic markers. The aim of the study NCT05529251 is to propose a new therapeutic approach for the stages IIa/IIb. Methods: This phase II, multicenter, prospective, randomized, non-comparative, de-escalation study will include patient with primary testicular seminomatous germ cell tumor with stage IIa/IIb < 3 cm in largest diameter seminoma, histologically proved after orchiectomy and good prognosis according to IGCCCG and LDH (Lactate DesHydogenase) < 2.5 x Upper Limit of Normal (ULN). They must have progressive disease and no prior treatment with radiotherapy or chemotherapy. In case of negative week-3 (after 1 EP cycle) PET-scan, patients will be randomized according to 2 arms ARM A: Boost of radiotherapy 20 to 30 Gray (Gy); ARM B Carboplatin AUC7 chemotherapy. In case of positive week-3 PET-scan: 3 courses of EP chemotherapy (ARM C). Primary outcome will include progression-free rate at 36 months. Secondary Outcome Measures will be serum level of miRNA M371, correlation with response to treatments and PET scan results, overall survival (OS), quality of life and tolerance to treatment. Blood samples (miRNA-M371) will be collected at screening, at the time of randomization before second cycle of chemotherapy or radiotherapy, at the end of treatment and at relapse. Enrollment has started in October 2022. A total of 90 patients will be included in the interventional study, leading to approximately 60 patients with negative FDG-PET randomized. Clinical trial information: NCT05529251 .

180 Background: Cabazitaxel and Lu-PSMA both improved survival in patients with mCRPC after docetaxel and an androgen receptor pathway inhibitor (ARPI), but there is limited data regarding Lu-PSMA activity after cabazitaxel. We aimed at assessing activity of Lu-PSMA and determinants of outcomes in this setting. Methods: Consecutive mCRPC patients from 6 European centers treated with Lu-PSMA after cabazitaxel were included in this retrospective study. Endpoints included radiographic progression-free survival (rPFS), time to PSA progression (PSA-TTP), PSA decline, objective response, overall survival, and safety. Results: Of 101 patients included (median age 67y), 64% had ISUP grade 4-5 disease; 71% had bone +/- nodal (LN) metastases, 22% visceral metastases, 7% LN only. All patients and 92% had received previous docetaxel and a prior ARPI (≥ 2 in 47%) before cabazitaxel respectively. Patients had received a median number of 6 cabazitaxel cycles (range 1-26). DNA damage repair alterations (DDR) were found in 11/48 (23%) patients with available testing. Patients received a median number of 3 Lu-PSMA cycles (range 1-14). With a median follow-up of 5.7 months, the median rPFS from Lu-PSMA initiation was 4.3 months (m, 95%CI 3.2-5.7) and median PSA-TTP was 3.5 m (95%CI 3.0-4.5). Overall, 44 patients (44%) experienced a PSA decline ≥ 50% (PSA50), 54 (53%) ≥ 30% (PSA30), and 67 (66%) any PSA decline. Objective response rate was 34%. Baseline characteristics associated with shorter rPFS on Lu-PSMA included ISUP grade 4-5 disease (median rPFS of 3.5 vs. 7.2m, p=0.02) and a time to castration resistance < 12 months (3.1m vs. 4.5m, p=0.04). Patients with LN only had longer rPFS compared to those with bone and visceral metastases (median NR vs. 3.6 and 3.7m, respectively, p=0.02). There was no association between activity of Lu-PSMA and DNA damage repair alterations, duration of previous cabazitaxel therapy, and number of previous ARPI. During Lu-PSMA, a profound PSA decline was associated with longer rPFS: patients achieving PSA50, PSA30 or any PSA decline had respective median rPFS rates of 9.0, 8.3 and 6.2 months, while those who did not experience any PSA decline had a median rPFS of only 2.6 months. Conclusions: Lu-PSMA demonstrated substantial PSA decline but limited duration of response after cabazitaxel in a real-life setting. Adverse baseline characteristics and absence of PSA decline may help early identification of poor responders.

618 Background: Muscle metastases (MM) are among rare secondary locations in renal cell carcinoma (RCC). Current guidelines do not provide specific advice on the management of these patients. There is a lack of scientific literature on the subject, mainly based on case reports or small retrospective monocentric cohorts. To date, therefore, there remains uncertainty about the clinical history, prognosis, and appropriate management of patients with MM. Methods: ARTEMIS is an ambispective national French multicenter, non-interventional study. It was opened to patients with metastatic RCC who had MM. The study was designed to assess overall survival (OS), progression-free survival (PFS), describe diagnostic and treatment modalities, and treatment-related serious adverse events in case of local treatments (TR-SAEs). Results: Median follow-up was 74.4 months IC95% [38.7-84.1]. The 146 enrolled patients were 73.6% male, with a median age of 57.6 years at diagnosis. They were initially diagnosed with stage IV RCC for 40.4% of them and had a favorable (36.2%), intermediate (45.7%), or poor (18.1%) IMDC risk score at the onset of metastases. Initially, metastases were mainly located in the lungs (55.5%), lymph nodes (26.7%), and bones (24.0%). Patients had a history of partial or total nephrectomy in 78.8% of cases. There were 30.0% of patients with synchronous MM. The median times from initial diagnosis or metastatic status to MM discovery were 25.5 [16.8-35.7] months and 8.4 [5.0-13.5] months, respectively. The majority (69.0%) of MM were discovered on conventional injected CT scans, whereas 8.3% were diagnosed clinically. Survival data are displayed on the table. Thirty-seven (25.3%) patients received local treatment of their MM which consisted of: external radiotherapy (48.6%), surgery (27.0%), cryotherapy (27.0%), stereotactic radiotherapy (5.4%), embolization (2.7%). Among them, local treatments prevented local relapse of MM in 28 patients (75.7%). Local TR-SAEs were seen in two patients (5.4%). Conclusions: ARTEMIS is the largest published cohort describing the disease history of patients with RCC suffering from MM. To our knowledge, this is the first study reporting the diagnostic and treatment modalities, also survival data. Despite its low incidence, the issue of these patients is not so rare in physicians’ practice. This work thus allows a greater understanding of clinical features and treatment of this pathology. [Table: see text]

Prostate-specific membrane antigen (PSMA) is highly expressed on the membrane of most prostate cancer cells and to a lesser extent in normal tissues. Many vectors targeting this protein have been created over the past decade and numerous clinical studies have positively demonstrated the tolerance and efficacy of radiolabeled prostate-specific membrane antigen ligands for PSMA radioligand therapy (PRLT). Preliminary results are encouraging that PRLT will become an important addition to the current therapeutic options in a number of settings. Improvement in radiopharmaceutical targeting and combination with other oncological agents are under investigation to further improve its therapeutic efficacy. These encouraging results have led to the development of other therapies using PSMA as a target, such as PSMA–targeted chimeric antigen receptor T-cells, PSMA–targeted antibody drug conjugates, and PSMA–targeted bi-specific T-cell-directed therapy. This narrative review details the current state and advancements in prostate-specific membrane antigen targeting in prostate cancer treatment.

Background Metastatic germ cell tumor (mGCT) patients receiving chemotherapy have increased risk of life‐threatening venous thromboembolism (VTE). Identifying VTE risk factors may guide thromboprophylaxis in this highly curable population. Methods Data were collected from mGCT patients receiving first‐line platinum‐based chemotherapy at 22 centers. Predefined variables included International Germ Cell Cancer Collaborative Group (IGCCCG) risk classification, long‐axis diameter of largest retroperitoneal lymph node (RPLN), Khorana score, and use of indwelling vascular access device (VAD). VTE occurring at baseline, during chemotherapy and within 90 days, was analyzed. Results Data from 1135 patients were collected. Median age was 31 years (range 10‐74). IGCCCG risk was 64% good, 20% intermediate, and 16% poor. VTE occurred in 150 (13%) patients. RPLN >3.5 cm demonstrated highest discriminatory accuracy for VTE (AUC 0.632, P, Venous thromboembolism can cause morbidity in germ cell tumor patients receiving chemotherapy; large retroperitoneal lymphadenopathy (RPLN) and indwelling vascular access devices (VAD) are significant VTE risk factors. VAD insertion should be avoided and thromboprophylaxis can be considered for large RPLN.

Patients with smoldering multiple myeloma (SMM) are observed until progression, but early treatment may improve outcomes. We conducted a phase II trial of elotuzumab, lenalidomide, and dexamethasone (EloLenDex) in patients with high-risk SMM and performed single-cell RNA and T cell receptor (TCR) sequencing on 149 bone marrow (BM) and peripheral blood (PB) samples from patients and healthy donors (HDs). We find that early treatment with EloLenDex is safe and effective and provide a comprehensive characterization of alterations in immune cell composition and TCR repertoire diversity in patients. We show that the similarity of a patient's immune cell composition to that of HDs may have prognostic relevance at diagnosis and after treatment and that the abundance of granzyme K (GZMK)

PURPOSE Patients with metastatic urothelial carcinoma (mUC) who progress on platinum-based combination chemotherapy (PLT) and checkpoint inhibitors (CPIs) have limited options that offer objective response rates (ORRs) of approximately 10% with a median overall survival (OS) of 7-8 months. Sacituzumab govitecan (SG) is a TROP-2–directed antibody-drug conjugate with an SN-38 payload that has shown preliminary activity in mUC. METHODS TROPHY-U-01 (ClinicalTrials.gov identifier: NCT03547973 ) is a multicohort, open-label, phase II, registrational study. Cohort 1 includes patients with locally advanced or unresectable or mUC who had progressed after prior PLT and CPI. Patients received SG 10 mg/kg on days 1 and 8 of 21-day cycles. The primary outcome was centrally reviewed ORR; secondary outcomes were progression-free survival, OS, duration of response, and safety. RESULTS Cohort 1 included 113 patients (78% men; median age, 66 years; 66.4% visceral metastases; median of three [range, 1-8] prior therapies). At a median follow-up of 9.1 months, the ORR was 27% (31 of 113; 95% CI, 19.5 to 36.6); 77% had decrease in measurable disease. Median duration of response was 7.2 months (95% CI, 4.7 to 8.6 months), with median progression-free survival and OS of 5.4 months (95% CI, 3.5 to 7.2 months) and 10.9 months (95% CI, 9.0 to 13.8 months), respectively. Key grade ≥ 3 treatment-related adverse events included neutropenia (35%), leukopenia (18%), anemia (14%), diarrhea (10%), and febrile neutropenia (10%), with 6% discontinuing treatment because of treatment-related adverse events. CONCLUSION SG is an active drug with a manageable safety profile with most common toxicities of neutropenia and diarrhea. SG has notable efficacy compared with historical controls in pretreated mUC that has progressed on both prior PLT regimens and CPI. The results from this study supported accelerated approval of SG in this population.

Background High‐dose chemotherapy (HDCT) with TI‐CE regimen is a valid option for the treatment of relapsed advanced germ cell tumors (GCT). We report a phase II trial with therapeutic drug monitoring of carboplatin for optimizing area under the curve (AUC) of this drug. Methods Patients with unfavorable relapsed GCT were treated according to TI‐CE regimen: two cycles combining paclitaxel and ifosfamide followed by three cycles of HD carboplatin plus etoposide administered on 3 days. Carboplatin dose was adapted on day 3 based on carboplatin clearance (CL) at day 1 in order to reach a target AUC of 24 mg.min/mL per cycle. The primary endpoint was the complete response (CR) rate. Results Eighty‐nine patients who received HDCT were included in the modified intent‐to‐treat (mITT) analysis. Measured mean AUC was 24.4 mg.min/mL per cycle (22.4 and 26.8 mg.min/mL for 10th and 90th percentiles). Thirty‐five (44.3%) patients achieved a CR with or without surgery of residual masses and 20 patients achieved a partial response with negative tumor markers. With a median follow‐up of 44 months (m), median PFS was 12.3 m (95% CI: 7.5–25.9) and OS was 46.3 m (95% CI: 18.6–not reached). For high‐ and very high‐risk patients, according to the International Prognostic Score at first relapse or treated after at least one salvage treatment (n = 51), 2‐year PFS rate was 41.1%. Conclusion The rates of complete and favorable responses were clinically relevant in this very poor risk population. Individual monitoring of carboplatin plasma concentration permitted to control more accurately the target AUC and avoided both underexposure and overexposure to the drug., The superiority of HDCT over standard chemotherapy as initial salvage treatment of patients with relapsed or refractory germ cell tumors remains a valid question. In the TI‐CE regimen, TDM was demonstrated to be feasible in routine practice and really allowed to control target AUC more accurately compared to previous reports, avoiding both underexposure and overexposure to carboplatin. In our study, the rate of CR observed in this population with very poor prognosis was 44.3% and increased to 69.6% of favorable responses. Based on our study and if the benefit of HDCT is proven in the TIGER trial, we suggest that the use of carboplatin TDM for dose individualization in current practice should be considered.

Purpose Fumarate hydratase–deficient (FHdef) renal cell carcinoma (RCC) is a rare entity associated with the hereditary leiomyomatosis and RCC syndrome with no standard therapy approved. The aim of this retrospective study was to evaluate the efficacy of different systemic treatments in this population. Methods We performed a multicentre retrospective analysis of Fhdef RCC patients to determine the response to systemic treatments. The endpoints were objective response rate (ORR), time-to-treatment failure (TTF), and overall survival (OS). The two latter were estimated using the Kaplan–Meier method. Results Twenty-four Fhdef RCC patients were identified, and 21 under systemic therapy were included in the analysis: ten received cabozantinib, 14 received sunitinib, nine received “other antiangiogenics” (sorafenib, pazopanib, and axitinib), three received erlotinib-bevacizumab (E-B), three received mTOR inhibitors, and 11 received immune checkpoint blockers (ICBs). ORR for treatments were 50% for cabozantinib, 43% for sunitinib, 63% for “other antiangiogenics,” and 30% for E-B, whereas ORR was 0% for mTOR inhibitors and 18% for ICBs. The median TTF (mTTF) was significantly higher with antiangiogenics (11.6 months) than with mTOR inhibitors (4.4 months) or ICBs (2.7 months). In the first-line setting, antiangiogenics presented a higher ORR compared with nivolumab-ipilimumab (64% versus 25%) and a significantly superior mTTF (11.0 months vs 2.5 months; p = 0.0027). The median OS from the start of the first systemic treatment was 44.0 months (95% confidence interval: 13.0–95.0). Conclusions We report the first European retrospective study of Fhdef RCC patients treated with systemic therapy with a remarkably long median OS of 44.0 months. Our results suggest that antiangiogenics may be superior to ICB/mTOR inhibitors in this population.

Summary Metastatic castration-resistant prostate cancer (mCRPC) is immunologically "cold" and predominantly resistant to immune checkpoint therapy due to few tumor-infiltrating T cells. Ipilimumab (anti-CTLA-4) or anti-PD-1/PD-L1 monotherapy failed to show a significant benefit. Although the PD-1/PD-L1 pathway is minimally expressed in prostate tumors, we previously demonstrated that PD-1/PD-L1 expression increases as a compensatory inhibitory pathway in parallel with an ipilimumab-induced increase in tumor-infiltrating T cells. Here, we report the largest trial to date in mCRPC with anti-CTLA-4 plus anti-PD-1 (nivolumab 1 mg/kg plus ipilimumab 3 mg/kg; CheckMate 650, NCT02985957). With median follow-ups of 11.9 and 13.5 months in cohorts 1 (pre-chemotherapy; n = 45) and 2 (post-chemotherapy; n = 45), objective response rate was 25% and 10%, and median overall survival was 19.0 and 15.2 months, respectively. Four patients, two in each cohort, had complete responses. Exploratory studies identify potential biomarkers of response. Grade 3–4 treatment-related adverse events have occurred in ∼42%–53% of patients, with four treatment-related deaths. Therefore, dose/schedule modifications have been implemented.

521 Background: First-line treatment with pembrolizumab (pembro) monotherapy has shown durable clinical activity in selected patients (pts) with advanced/unresectable or metastatic urothelial carcinoma (UC). In a pooled population of pts with advanced UC from the single-arm phase 2 KEYNOTE-052 (NCT02335424) and the randomized, open-label, phase 3 KEYNOTE-361 (NCT02853305) studies, this exploratory analysis evaluated the relationship between baseline characteristics and clinical outcomes of first-line pembro monotherapy. Methods: Cisplatin-ineligible pts with advanced UC were enrolled in KEYNOTE-052 and chemotherapy-naive pts with advanced UC were enrolled in KEYNOTE-361. For analysis of predictive factors for ORR and OS in pembro-treated pts, the purposeful selection method was used to build the multivariable logistic regression model (ORR) and multivariable Cox model (OS), beginning with a univariable analysis of each independent variable. Any variable in the univariate model with P < 0.10 was a candidate for the multivariate model. The stepwise selection method was used to select the variables in the final model. Significance of the final model was set at P < 0.05. Data cutoff dates were September 26, 2020 (KEYNOTE-052) and April 29, 2020 (KEYNOTE-361). Results: This pooled analysis included 681 pts treated with pembro monotherapy (KEYNOTE-052, N = 374; KEYNOTE-361, N = 307 [170 were cisplatin ineligible]). Median follow-up was 51.9 mo (range, 22.0-65.3). ORR was 29.4% (95% CI, 26.0-32.9; 69 CRs, 131 PRs), and median DOR was 33.2 mo (range, 1.4+ to 60.7+). Median OS was 12.5 mo (95% CI, 11.0-14.6). By multivariate analysis, independent factors significantly associated with higher ORR were PD-L1 status (combined positive score [CPS] ≥10 vs CPS < 10; odds ratio [OR], 1.90 [95% CI, 1.33-2.71]; P = 0.0004), site of metastasis (lymph node only vs visceral disease; OR, 1.66 [95% CI, 1.06-2.59]; P = 0.0265), liver involvement (absent vs present; OR, 1.75 [95% CI, 1.06-2.89]; P = 0.0294), and baseline hemoglobin level ≥10 vs < 10 g/dL; OR, 2.17 [95% CI, 1.09-4.31]; P = 0.0276). Multivariate analysis of OS is displayed in the Table. Conclusions: This exploratory multivariate analysis identified numerous factors, including PD-L1–positive status (CPS ≥10), lymph node only metastasis, and lower ECOG PS score, associated with improved clinical outcomes in pts with advanced UC treated with first-line pembro monotherapy. Clinical trial information: NCT02335424 and NCT02853305. [Table: see text]

430 Background: Primary urethral cancer (PUC) is a rare and heterogeneous malignancy. Due to its scarcity, little data are available on the optimal treatment sequence and survival, especially in metastatic patients. Methods: Data from patients diagnosed with a PUC between 01/01/2000 and 12/31/2018 were retrospectively collected from nine French referral centers. Survival rate were estimated with the Kaplan-Meier method and prognostic factors were analyzed using the Cox proportional hazards model and the log-rank test. In order to increase the statistical power of survival analysis in the metastatic stage, patients with synchronous and metachronous metastatic disease were pooled. Results: We identified 44 (62%) males and 27 (38%) females with a PUC. The most frequent histological types were urothelial carcinomas (40.0%), squamous cell carcinomas (34.3%) and adenocarcinomas (14.3%). Twenty-five (35.2%) patients were diagnosed at a localized stage (≤ T2, N0, M0); 35 (49.3%) at a locally advanced stage (≥ T3 or ≥ N1, M0) and 11 (15.5%) at a distant stage (M1). Twenty-seven patients had a metachronous metastatic cancer. Multimodality therapy was used in 24.0% and 57.1% of the patients with a localized and locally advanced disease, respectively. In the entire cohort, median overall survival (OS) was 52.5 months (IC95% 32.2 – 64.1) and stage at diagnosis was a predictor of OS (p < 0.0001). For the 60 patients with a non-metastatic disease, 39 (65%) had a recurrence or were dead and the median disease-free survival (DFS) was 21.2 months (IC95% 16.8 – 34.5). Nodal involvement was the only factor associated with DFS (HR: 2.03, p = 0.0390). Multimodal treatment compared with unimodal treatment was not significantly associated with DFS (HR: 1.22, p = 0.5419). Regarding survival of the 38 metastatic patients, the median OS was 15.2 months (IC95% 8.2 – 23.5) and the median progression-free survival was 6.4 months (IC95% 4.4 – 9.8). Conclusions: This retrospective study showed an important heterogeneity in terms of histology, stage at diagnosis, and treatment of PUC. In this cohort, the multimodal approach did not show any improvement in survival of non-metastatic patients. This study is one of the few to describe the survival in metastatic patients.

540 Background: The 3-arm, open-label, phase 3 KEYNOTE-361 study (NCT02853305) evaluated first-line pembro ± chemo vs chemo in advanced UC regardless of PD-L1 status. The trial did not meet its primary end points of superior PFS and OS with pembro + chemo vs chemo and thus analysis of pembro monotherapy (mono) vs chemo was exploratory. We explored the association of TMB status and PD-L1 combined positive score (CPS) with clinical outcomes in KEYNOTE-361. Methods: In pts with TMB and/or PD-L1 data, the association between TMB (via whole exome sequencing) and PD-L1 (via PD-L1 IHC 22C3 pharmDx) and clinical outcomes (ORR, PFS, and OS) was evaluated. In each treatment arm, the hypotheses regarding the associations were evaluated using logistic regression (ORR) and Cox proportional hazards regression (PFS; OS), and 1-sided (pembro; pembro + chemo) and 2-sided (chemo) P values were calculated; significance was prespecified at α = 0.05 without multiplicity adjustment. Clinical utility was assessed using prespecified cutoffs of 175 mut/exome (TMB) and CPS 10 (PD-L1). Clinical data cutoff was April 29, 2020. Results: 820/993 pts (82.6%) had evaluable TMB data (pembro, 252; pembro + chemo, 282; chemo, 286). TMB (log10) was significantly positively associated with ORR, PFS, and OS for pembro ( P < 0.001, < 0.001, and 0.007, respectively) and PFS and OS for pembro + chemo ( P= 0.007 and 0.010, respectively). The area under the receiver operating characteristics (AUROC) curve (95% CI) for discriminating response was 0.64 (0.56-0.71) for pembro, 0.53 (0.46-0.60) for pembro + chemo, and 0.52 (0.45-0.59) for chemo. Efficacy by TMB cutoff is reported in the Table. All 993 pts had PD-L1 data (pembro, 302; pembro + chemo, 349; chemo, 342). PD-L1 was significantly positively associated with PFS for pembro ( P= 0.006) and ORR for pembro + chemo ( P= 0.042) but not chemo. Efficacy by PD-L1 CPS is reported in the Table. Conclusions: Strong associations were observed between TMB and all 3 clinical outcomes (ORR, PFS, and OS) with pembro mono in the first-line setting and a reduced association was observed between TMB and clinical outcomes with pembro + chemo. No consistent associations were observed between PD-L1 and clinical outcomes with pembro mono or pembro + chemo. Clinical trial information: NCT02853305. [Table: see text]

492 Background: Immune checkpoints inhibitors (ICIs) have recently changed therapeutic landscape of la/mUC. Recent studies suggested an improvement of response to salvage chemotherapy (CT) after ICIs in several cancer types including urothelial carcinoma. We assumed that efficacy of CT rechallenge after ICIs may be improved compared to second-line CT without previous ICIs in patients (pts) with la/mUC. Methods: CIMUC is a French multicentric retrospective study including all pts with la/mUC initiating second or third-line CT from January 1st 2015 to June 30th 2020. Two groups of pts were defined: pts in group 1 (G1) were treated with a second-line CT without previous ICIs; pts in group 2 (G2) were treated with third line CT after ICIs. Primary endpoint was objective response rate (ORR: proportion of patients with complete or partial response, according to RECIST 1.1 criteria) in G2 versus G1. Secondary endpoints were progression-free survival (PFS), defined as time from initiation of second or third-line CT to disease progression or death from any cause, and toxicities. This study is supported by the French Genito Urinary Group (GETUG). Results: 553 pts were included. Baseline characteristics of the 2 groups are summarized in the Table. ORRs were 31% (95%CI [26.5-35.5]) and 29.2% (95%CI [21.9-36.6]) respectively in G1 and G2, without statistically significant difference (p=0.617), even after adjustment for Bellmunt risk factors (p=0.3214). In subgroups analysis, no difference in ORR was observed by type of CT (platinum or taxanes), duration of response (DOR) to first-platinum-based CT (< 12 months or ≥ 12 months) and FGFR-status. We did not identify any predictive factor of OR in G2 in multivariate analysis. Median PFS were 4.6 months (95%CI [3.88; 5.06]) and 4.86 months (95%CI [4.11; 5.45]), respectively in G1 and G2. Grade 3/4 hematologic toxicity occurred in 35% and 22.4%, respectively in G1 and G2. Conclusions: While ORR was not superior in G2 versus G1, pts derive comparable benefit in a further line of treatment (G2) in terms of ORR and PFS. Despite limits inherent to any retrospective study, CIMUC represents one of the largest retrospective studies in this setting.[Table: see text]

Purpose To define characteristics, treatment response, and outcomes of men with brain metastases (BM) from germ cell tumors (GCT). Patients and Methods Data from 523 men with BM from GCT were collected retrospectively from 46 centers in 13 countries by using standardized questionnaires. Clinical features were correlated with overall survival (OS) as the primary end point. Results BM were present at initial diagnosis in 228 men (group A) and at relapse in 295 men (group B). OS at 3 years (3-year OS) was superior in group A versus group B (48% v 27%; P < .001). Multiple BM and the presence of liver or bone metastasis were independent adverse prognostic factors in both groups; primary mediastinal nonseminoma (group A) and elevations of α-fetoprotein of 100 ng/mL or greater or of human chorionic gonadotropin of 5,000 U/L or greater (group B) were additional independent adverse prognostic factors. Depending on these factors, the 3-year OS ranged from 0% to 70% in group A and from 6% to 52% in group B. In group A, 99% of patients received chemotherapy; multimodality treatment or high-dose chemotherapy was not associated with statistically improved survival in multivariable analysis. In group B, only 54% of patients received chemotherapy; multimodality treatment was associated with improved survival compared with single-modality therapy (hazard ratio, 0.51; 95% CI, 0.36 to 0.73; P < .001), as was high-dose compared with conventional-dose chemotherapy (hazard ratio, 0.41; 95% CI, 0.24 to 0.70; P = .001). Conclusion Men with BM from GCT have poor OS, particularly if additional risk factors are present. High-dose chemotherapy and multimodality treatment seemed to improve survival probabilities in men with BM at relapse.

Background The GETUG 13 phase III trial tested personalised chemotherapy based on tumour marker decline in patients with poor-prognosis germ-cell tumour (GCT) and demonstrated that a dose-dense regimen improves progression-free survival in patients with an unfavourable decline. We investigated the pattern of relapse for patients included in GETUG 13. Methods We conducted an analysis of relapse events in patients from GETUG 13. Baseline procedures before inclusion in the trial comprised a thoraco-abdomino-pelvic computed tomography scan and a magnetic resonance imaging of the brain. Results With a median follow-up of 4.1 years (0.3; 8.8 years), a progression event was observed in 109/254 patients (43%). First event consisted in a marker progression only in 47 patients (43%), a radiographic progression only in 35 patients (32%), a mix progression on both markers and imaging in 12 patients (11%) and death in 15 patients (14%). In patients with radiographic progression only, brain was the predominant site (n = 19/35, 54%). Among patients with unfavourable decline who experienced a radiographic progression (as first and subsequent progression event, n = 58), brain was a site of progression in 28 patients (48%): 12/30 (40%) in patients treated with cisplatin, bleomycin and etoposide and 16/28 (57%) in those treated with dose-dense chemotherapy. Conclusions Brain metastases develop often, early and frequently as the only site of relapse in the course of poor-prognosis GCT. This raises the question of early detection and optimal treatment of brain metastases in these patients, e.g. by integrating a systematic brain MRI after 2–3 months of chemotherapy.

Resume Introduction Les therapies orales ont deplace le suivi des patients atteints de cancer, de l’hopital au domicile. Aussi, le nombre d’appels entrants a augmente dans les services. Pour comprendre l’origine, les raisons, la prise en charge et l’impact des appels, nous avons conduit une enquete nationale francaise. L’objectif etait de decrire la facon dont les appels telephoniques sont geres dans les services d’oncologie. Methodes Etude prospective menee sur un echantillon representatif de specialistes francais en oncologie, utilisant des therapies orales. Resultats Au sein des 51 departements impliques, 86 % des specialistes etaient des oncologues ou hematologues et 14 % des oncologues-radiotherapeutes. Quatre-vingt pour cent des centres etaient publics et 20 % prives. Le nombre median d’appels/semaine etait 110. Soixante-six pour cent des appels provenaient de patients ou des familles et 23 % des medecins generalistes. A reception par les secretaires, la moitie des appels correspondaient a une question medicale. Soixante-cinq pour cent des centres n’avaient pas de procedure et 70 % des repondants indiquaient ne pas former specifiquement leurs equipes pour repondre. Soixante-cinq pour cent des specialistes y consacraient plus de 30 minutes/jour. La plupart d’entre eux consideraient les appels comme perturbant les activites medicales. Soixante-six pour cent des appels de patients etaient lies a des effets indesirables des traitements. Vingt-deux pour cent des specialistes declaraient au moins un effet indesirable grave lie a l’interpretation erronee d’un appel. Discussion L’augmentation des traitements par voie orale genere une charge de travail importante en appels telephoniques entrants. Pour en ameliorer la gestion, des adaptations des organisations sont necessaires.

International audience; Introduction: Papillary renal cell carcinoma (PRCC) represents 10%e15% of renal carcinomas. No standard treatments exist for metastatic PRCC (mPRCC) patients. Axitinib is indicated as second-line treatment in metastatic clear cell renal carcinoma, and we aim to assess the efficacy of this vascular endothelial growth factor receptor inhibitor in front line for mPRCC. Methods: This French multicentre phase II study AXIPAP enrolled untreated mPRCC patients, with measurable disease, Eastern Cooperative Oncology Group performance status 1 and Vascular endothelial growth factor; VEGF inhibitor; Targeted therapy adequate organ functions. PRCC had to be confirmed by histology expert central review. Axi-tinib was administered orally 5 mg twice daily. Primary end-point was progression-free rate at 24 weeks (24w-PFR) by central review. Results: Fifty-six patients were screened, and 44 included (13 type 1, 30 type 2 and 1 non-specified). The median follow-up was 32.0 (13.1e39.9) months. The 24w-PFR was 45.2% (95% confidence interval [CI], 32.6% to þN), the objective response rate was 28.6% (95% CI, 15.7%e44.6%) (type 1: 7.7%; type 2: 35.7%). The overall median progression free survival was 6.6 months (95% CI, 5.5e9.2), 6.7 months (95% CI, 5.5e9.2) and 6.2 months (95% CI, 5.4 e9.2) for type 1 and 2, respectively. Median overall survival was 18.9 months (95% CI, 12.8enot reached). Adverse events were as expected; grade 3e4 treatment-related adverse events were rare except hypertension (27%). Conclusions: Axitinib demonstrated encouraging efficacy in mPRCC patients, especially in type 2 PRCC. Toxicity was manageable. Axitinib appears as an interesting option for first-line treatment and to be worth further investigation in combination with immunotherapy in these patients. Expert pathology review should be recommended in this setting. Clinical trial registration: ClinicalTrials.gov, NCT02489695.

The emergence of oral cancer treatment in oncology has shifted patient follow-up from the hospital to the home. This trend has resulted in an increase in phone and e-mail interactions initiated by patients, but also by pharmacists, by liberal nurses, by general practitioners, and an increase in calls to the emergency response services (SAMU) both for real or perceived emergencies. This increased volume of patient and pharmacist communication has caused significant disruption in the daily activity of affected oncology departments and in particular of the secretariats. The procedures for formulating and securing appropriate responses within a short time frame are generally not established, and as a result, there is a risk that decisions made could be inappropriate for the patient's situation, especially in the case of complications.. Tracking responses to phone calls is necessary and answers should be noted in the medical file, including side effects, in particular the serious AEs for a good quality of care. This guideline describes best practices for oncologists who manage "incoming" calls from patients or professionals involved in the care pathway.

5000 Background: Historically, androgen deprivation therapy (ADT) was the standard of care (SOC) for men with mCSPC. Since 2015, combining ADT with either docetaxel, novel hormonal therapies, or radiotherapy to the primary tumor (RXT) (for those with low burden metastases) was shown to improve overall survival (OS) and thus has become the new SOC. It is unknown whether combining these new treatments on top of ADT further increments outcomes. Methods: Men with de novo mCSPC were randomized to SOC, SOC + abiraterone acetate-prednisone (abiraterone), SOC + RXT, or SOC + abiraterone + RXT. SOC was initially ADT alone, then from Oct 2015 onwards the use of docetaxel was authorized as part of SOC (at the investigator’s discretion until 2017, then, following the publication of the LATITUDE and STAMPEDE trials, accrual was restricted to men receiving ADT+docetaxel). The trial has two co-primary endpoints of radiographic progression-free survival (rPFS) and OS with type I error of 0.1% and 4.9%, respectively. The required number of rPFS events to achieve 80% power has been reached for the abiraterone question (not yet for the RXT question). The interaction between abiraterone and RXT was first tested using a Cox model adjusted for stratification factors (performance status, type of castration, metastatic burden, and when applicable, docetaxel). A hierarchical testing was used to test the effect of abiraterone: overall population, then ADT+docetaxel population. Results: From Nov 2013 to Dec 2018, 1173 men were enrolled (SOC was ADT+docetaxel in 710 pts and ADT alone in 463 pts), median age 67y (IQR: 60-72), high volume 57%, low volume 43%. The median follow-up is 3.5y. No interaction was detected between the effect of abiraterone and that of RXT (p = 0.64), allowing to pool abiraterone arms for comparisons. rPFS was significantly improved in the abiraterone arm in the overall population (HR: 0.54 (0.46-0.64), p < 0.0001; medians: 2.2 vs 4.5 years) and in the ADT+docetaxel population: (HR: 0.50 (0.40-0.62), p < 0.0001; medians: 2.0 vs 4.5 years). bPFS (PFS including PSA progression as an event) also significantly favored abiraterone in the overall population (HR: 0.40 (0.35-0.47), p < 0.0001; medians: 1.5 vs 3.8 years) and in the ADT+docetaxel population (HR: 0.38 (0.31-0.47), p < 0.0001; medians: 1.5 vs 3.2 years). OS is maturing. Grade 3-4 adverse events reported in > 5% of pts within the first 6 months in the ADT+docetaxel population included neutropenic fever (4.5% vs 5.4%), liver toxicity (19.7% vs 13%), and hypertension (12.2% vs 8.6%) in the abiraterone and control arms, respectively. Conclusion: Adding abiraterone to ADT + docetaxel significantly improves rPFS in men with de novo metastatic prostate cancer, with about 2.5 years of absolute benefit in medians, and no meaningful additional short-term toxicity. Clinical trial information: NCT01957436.

5044 Background: CheckMate 9KD is a phase 2 trial of NIVO (anti-PD-1) combined with either rucaparib, docetaxel, or enzalutamide for mCRPC. PARP inhibitors, like rucaparib, increase cellular DNA damage, particularly in tumors with DNA repair defects, leading to genomic instability and cell death. This DNA damage promotes immune priming and adaptive PD-L1 upregulation. Consequently, dual PD-(L)1 and PARP inhibition is a plausible therapeutic strategy for mCRPC. We report final results for cohort A1 (NIVO + rucaparib for post-CT mCRPC) of CheckMate 9KD. Methods: Cohort A1 enrolled patients (pts) with post-CT mCRPC (1–2 prior taxane regimens), ongoing ADT, ≤ 2 prior novel hormonal therapies (abiraterone, enzalutamide, etc) for mCRPC, and no prior PARP inhibitor treatment. Pts received NIVO 480 mg Q4W + rucaparib 600 mg BID until disease progression/unacceptable toxicity (NIVO dosing limited to 2 yrs). Coprimary endpoints: objective response rate (ORR) per PCWG3 criteria and prostate-specific antigen response rate (PSA-RR; ≥ 50% PSA reduction) in all treated pts and pts with homologous recombination deficiency positive (HRD+) tumors, determined before enrollment. Secondary endpoints included radiographic progression-free survival (rPFS), overall survival (OS), and safety. Results: Of 88 treated pts, median age 66 yrs (range, 46–85), 34.1% had visceral metastases and 65.9% had measurable disease. Median follow-up was 11.9 mo. Pts had a median of 4.5 NIVO doses and 3.8 mo of rucaparib. The table summarizes primary and key secondary efficacy results, and shows better outcomes for HRD+ vs HRD–/not evaluable (NE) tumors. In pts with BRCA2 mutations, confirmed ORR was 37.5% (3/8 pts) and confirmed PSA-RR was 45.5% (5/11 pts). Any-grade treatment-related AEs (TRAEs) occurred in 93.2% of pts, most commonly nausea (40.9%) and fatigue (33.0%). Grade ≥ 3 TRAEs occurred in 54.5% of pts, most commonly anemia (20.5%) and neutropenia (10.2%). TRAEs led to discontinuation in 27.3% of pts. One pt had a stroke, considered related to rucaparib by the investigator, after 28 days on rucaparib and 2 NIVO doses and died 2 months later due to post-thrombolysis hematoma. Conclusions: NIVO + rucaparib is active in pts with HRD+ post-CT mCRPC, although the trial design and short follow-up limit assessment of benefits of the combination vs individual components. Pts with HRD– tumors did not appear to benefit from either drug. No new safety signals were observed with NIVO + rucaparib. Additional biomarker analyses are ongoing. Clinical trial information: NCT03338790. [Table: see text]

TPS5086 Background: In cancer cells, the cyclin-dependent kinases 4 and 6 (CDK4 & 6)/retinoblastoma protein (Rb) pathway is commonly altered, resulting in uncontrolled cell cycle entry and proliferation. CDK4 & 6 inhibitors represent a major advance in the management of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer (ABC or MBC, respectively). Abemaciclib is an oral selective inhibitor of CDK4 & 6 administered on a continuous dosing schedule, approved in combination with endocrine therapy for HR+, HER2- ABC or MBC. In addition, abemaciclib is also approved by the FDA as monotherapy for HR+, HER2- ABC or MBC following endocrine therapy and prior chemotherapy in the metastatic setting. Similar to the estrogen receptor signaling pathway in breast cancer cells, there is evidence that the androgen receptor axis activates CDK4 & 6 to sustain prostate cancer cell proliferation and survival. Preclinical studies in prostate cancer cell lines and xenograft models showed that abemaciclib exhibits single agent activity by inducing cell cycle arrest and tumor growth inhibition. Clinical activity of abemaciclib in combination with abiraterone and prednisone is investigated in a randomized phase 2 study in the first-line mCRPC setting (CYCLONE 2, NCT03706365). Despite recent advances, management of heavily pretreated mCRPC remains a major clinical challenge. Herein, we hypothesize that mCRPC patients whose disease progressed after novel hormonal agents (NHA) and taxane therapies may derive therapeutic benefit from single agent abemaciclib. Methods: CYCLONE 1 is a phase 2, single-arm, multicenter study to assess the safety and efficacy of abemaciclib monotherapy in 40 patients with mCRPC progressing after ≥1 NHA and 2 taxane regimens. Patients will be enrolled at time of prostate specific antigen (PSA) or radiographic progression per PCWG3 criteria and have at least 1 measurable lesion per RECIST 1.1. Metastatic tumor tissue (fresh biopsy or archival material

450 Background: 1L pembro is approved in advanced UC for cisplatin-ineligible pts with PD-L1 combined positive score (CPS) ≥10 and any platinum-ineligible pts regardless of CPS in the United States based on single-arm trial data. In the phase III KEYNOTE-361 study, 1L pembro + chemo did not statistically significantly improve PFS or OS vs chemo for pts with advanced UC; formal testing of 1L pembro vs chemo was not performed. We present an exploratory analysis of outcomes with pembro vs chemo for choice-of-carboplatin (carbo) pts in KEYNOTE-361 (NCT02853305). Methods: At randomization, choice of platinum agent (cisplatin or carbo) plus gemcitabine for each pt was selected based on investigator’s assessment of cisplatin ineligibility. ORR/DOR per RECIST v1.1 by blinded independent central review and OS were determined for all pts selected for carbo (“choice-of-carbo”) and also choice-of-carbo pts with CPS ≥10. Risk difference assessment for select AEs for pembro vs chemo was conducted in choice-of-carbo pts who received ≥1 dose study treatment. Results: As of Apr 29, 2020, the median (range) time from randomization to data cutoff in the full study cohort was 31.7 (22.0-42.3) mo. At randomization, renal impairment was the most common reason for choice of carbo by investigators (36% of all pts). 170 choice-of-carbo pts were randomized to the pembro arm, and 196 choice-of-carbo pts to the chemo arm. Median OS in this subgroup was 14.6 mo with pembro vs 12.3 mo with chemo (HR 0.83 [95% CI 0.65-1.06]). 18-mo OS rate was 42% with pembro vs 40% with chemo. ORR to pembro vs chemo was 27.6% vs 41.8%. Median (range) DOR with pembro vs chemo was not reached (NR) (3.2+-36.1+ mo) vs 6.3 (1.8+-33.8+) mo. 84/170 (49%) and 89/196 (45%) choice-of-carbo pts in the pembro and chemo arms, respectively, had CPS ≥10. In this subgroup, median OS was 15.6 mo with pembro vs 13.5 mo with chemo (HR 0.82 [95% CI 0.57-1.17]). 18-mo OS rate was 44% with pembro vs 43% with chemo. ORR to pembro vs chemo was 29.8% vs 46.1%. Median (range) DOR with pembro vs chemo was NR (4.2-36.1+ mo) vs 8.3 (2.1+-33.8+) mo. Among treated pts (N=166 for pembro, N=190 for chemo), 112 pts (68%) in the pembro arm and 163 pts (86%) in the chemo arm had grade 3-5 AEs of any cause. Pembro was associated with a higher risk of pruritus, while chemo was associated with a higher risk of decreased white blood cell, neutrophil, and platelet counts, nausea, thrombocytopenia, neutropenia, and anemia. Conclusions: Due to the trial design, this subset was not statistically tested and is exploratory. Median OS and 18-mo OS rates did not appear markedly different in the two arms; some parameters such as DOR favored pembro, although longer follow-up is needed to determine median DOR for pembro. The PD-L1 CPS ≥10 did not clearly enrich for responders to pembro in choice-of-carbo pts. Pembro was associated with a lower rate of grade 3-5 AEs of any cause than chemo. Clinical trial information: NCT02853305.

27 Background: ctDNA testing offers additional opportunities for homologous recombination repair (HRR) gene alteration determination in patients who are not able to access tumor tissue testing. Alteration testing in ctDNA, for BRCA1, BRCA2 and ATM alterations was performed retrospectively in the PROfound study (phase 3 trial of olaparib versus physician’s choice of abiraterone or enzalutamide in men with HRR gene-mutated mCRPC [NCT02987543]). Methods: ctDNA samples were sequenced at FMI, using the FoundationOne Liquid CDx assay for alterations in BRCA1, BRCA2 (BRCA) and ATM, using plasma samples collected during screening in PROfound. Only patients who consented and provided plasma samples from Cohort A (BRCA/ ATM alteration positive by tissue testing) were tested for ctDNA alterations. Radiographic progression-free survival (rPFS) assessed by blinded independent central review (BICR) in patients positive for alterations in ctDNA was analysed via stratified log-rank test. Additional efficacy endpoints (Objective Response Rate [ORR], Overall Survival[OS]) were also assessed. Results: In total, 181/245 (73.9%) Cohort A patients consented and provided a plasma sample for ctDNA testing, of which 139/181 (76.8%) had a ctDNA result reported (either mutation positive or mutation negative) and 42 patient samples failed testing due to insufficient DNA yield or a technical failure of the test.BRCA/ ATM alterations were identified in111/139 (79.9%) patients and 28/139 patients did not report a BRCA/ATM mutation either due to lack of ctDNA shedding from the tumour or ctDNA levels below the sensitivity of the assay. Patients who carried BRCA/ ATM ctDNA alterations had comparable demography, baseline characteristics and proportions of BRCA1, BRCA2 and ATM mutated patients to the overall Cohort A patients. rPFS by BICR results, in patients with BRCA/ ATM alterations in ctDNA, are presented in the Table. Key secondary efficacy endpoints (ORR, OS) will also be reported for ctDNA alteration positive patients. Conclusions: ctDNA testing in patients with mCRPC is feasible and most, but not all patients have concordant results. Patients who were positive for alterations in BRCA1, BRCA2 or ATM showed a consistent rPFS improvement (hazard ratio [HR] 0.33 [0.21, 0.53]) when compared with the ITT population identified by tumor tissue testing (HR 0.34 [0.25, 0.47]). This suggests that using ctDNA to identify patients carrying BRCA1, BRCA2 or ATM alterations who will benefit from olaparib may be beneficial. Clinical trial information: NCT02987543. [Table: see text]

448 Background: 1L pembro + chemo did not show statistically superior PFS and OS vs chemo for pts with advanced UC in the phase III KEYNOTE-361 study; OS for pembro vs chemo was not formally tested. We analyzed PFS2 (time from randomization to progressive disease [PD] on first subsequent therapy, or death from any cause, whichever occurs first) by study treatment and subsequent therapy in KEYNOTE-361 (NCT02853305) to determine the effects, if any, of therapy sequence on PFS2. Methods: PFS2 was estimated for pts in each treatment arm, who received any subsequent therapy including any anti–PD-(L)1, any therapy other than anti–PD-(L)1, or no therapy. These were exploratory analyses; no formal comparisons were done. Results: 1010 pts were randomized: 351 pts to receive pembro + chemo, 307 to pembro, and 352 to chemo. As of Apr 29, 2020, the median (range) time from randomization to data cutoff was 31.7 (22.0-42.3) mo. Subsequent therapy was received by 124/351 (35%), 126/307 (41%), and 215/352 (61%) pts in the pembro + chemo, pembro, and chemo arms, respectively. Subsequent anti–PD-(L)1 therapy was received by 169/352 (48%) pts in the chemo arm vs 23/351 (7%) in the pembro + chemo arm and 14/307 (5%) in the pembro arm. Of pts in the pembro arm who received subsequent therapy, >90% received 2L cisplatin-based or carboplatin-based treatment. Median (m) PFS2 (95% CI) for all pts by treatment arm was 14.1 mo (12.6-16.2) with pembro + chemo, 10.9 mo (9.5-12.9) with pembro, and 10.4 mo (9.8-11.2) with chemo. Across treatment arms, pts in the pembro + chemo arm had the longest mPFS2 with any subsequent therapy (14.5 mo [95% CI 13.1-16.6]) (Table). Pts in the pembro arm who received no subsequent therapy had a longer mPFS2 (12.9 mo [95% CI 8.1-17.9]) vs pts in the chemo arm who received no subsequent therapy (9.4 mo [95% CI 7.6-10.6]). Finally, pts treated with 1L pembro in the trial followed by 2L therapy other than anti−PD-(L)1 had comparable mPFS2 (10.2 mo [95% CI 8.6-12.1]) to pts treated with 1L chemo in the trial followed by 2L anti−PD-(L)1 (11.1 mo [95% CI 10.2-12.9]). Conclusions: In this exploratory analysis, treatment sequence of chemo followed by anti−PD-(L)1 upon PD vs anti–PD-(L)1 followed by chemo upon PD did not appear to impact mPFS2. Among pts who did not receive 2L therapy, 1L pembro appeared to be associated with longer mPFS2 than chemo, potentially driven by long-term responders to pembro. Clinical trial information: NCT02853305 . [Table: see text]

429 Background: Patients (pts) with advanced UTC who fail first-line therapy have poor prognoses. Durvalumab (D; anti-PD-L1) 10 mg/kg every 2 weeks is approved for treatment of metastatic urothelial carcinoma (mUC) after progression on platinum-based chemotherapy (CT). Further understanding of long-term safety and efficacy of D in platinum and non-platinum pretreated pts, using a fixed dose every 4 weeks (Q4W), is of value. Methods: Module A of the phase IIIb STRONG study (NCT03084471) investigated the safety of fixed-dose D (1500 mg, Q4W) in pts with urothelial and nonurothelial UTC who progressed on or after platinum/non-platinum CT. The primary endpoint was the number of pts with adverse events of special interest (AESIs) – events with an inflammatory or immune-mediated mechanism that may require interventions (eg, steroids/immunosuppressants), including immune-mediated adverse events (imAE). AEs with onset date on or after the date of first dose and up to 90 days after study discontinuation were included. Secondary endpoints included serious AEs and overall survival (OS). Exploratory endpoints included objective response rate (ORR) and disease control rate (DCR) (investigator assessed per RECIST 1.1). Results: A total of 867 pts received D monotherapy. Median age was 68.1 yr and 80.0% were male; 87.1% had an ECOG PS 0-1 and 12.7% had ECOG PS 2. Most (96.3%) had urothelial UTC, including urothelial variants. Tumor PD-L1 expression was high (≥25%) in 239/577 (41.4%) pts with available data. Median treatment and follow-up duration were 12.1 wk (range 1-128) and 13.8 mo (range 0.0-28.8), respectively. Safety data are reported in the table. Deaths related to study treatment occurred in 9 pts (1.0%). At data cutoff (March 31, 2020), 30.8% of pts were in survival follow-up. Median OS was 7.0 mo (95% CI: 6.4-8.2); OS rate at 1 and 2 yr was 35.8% (95% CI: 32.5-39.2) and 20.2% (95% CI: 16.5-24.1), respectively. ORR was 17.7% with complete responses in 5.1% of pts. DCR at 6 mo was 33.0%. Median OS of subgroups: PD-L1 high or low: 9.3 mo (95% CI: 6.7-12.7) and 6.5 mo (95% CI: 5.8-8.1); ECOG PS 0-1 or 2: 8.4 mo (95% CI: 7.2–9.8) and 3 mo (95% CI: 2.0-4.1); urothelial and nonurothelial UTC: 7.0 mo (95% CI: 6.4-8.2) and 7.0 mo (95% CI: 2.7-10.2), respectively. Conclusions: Fixed-dose D monotherapy Q4W is convenient with an acceptable safety profile in previously treated pts for UTC. Long-term safety and efficacy data reported are consistent with published studies of D and other IO agents in this setting. Clinical trial information: NCT03084471 . [Table: see text]

385 Background: Personalized chemotherapy based on tumor marker decline is the new standard in poor prognosis germ-cell tumor in Europe since 2014 (GETUG 13, Lancet, Fizazi et al). The purpose of this study was to analyze the reproducibility of the princeps study in patients not selected in clinical routine between 2014 and 2018. Methods: Patients (pts) were eligible if they had at least one criteria of IGCCCG classification for poor prognosis group. They had to be treated according the study terms of GETUG 13 study and did not received prior treatment. They had to received 1 BEP (Bleomycin, Etoposide, Cisplatin). Tumor markers (HCG and AFP) were dosed between day 18 and 21. Then, they received 3 additional BEP if they had favorable tumor marker decline or intensive chemotherapy if they had unfavorable decline. Results: This retrospective study included 104 patients in 14 french centers treated between 2013 and 2018: 22,1 % (n = 23) in the favorable group (Fav), 77,9 % (n = 81) in the unfavorable group (Unfav). Thirty-two pts had PS ≥ 2. In Unfav, there were more pts with HCG > 50 000 UI/L (44,2 % vs 13 %, p = 0,0067), neutrophil-to-lymphocyt ratio was also higher (median 6,4 vs 4,5, p = 0,0199). At cycle 1, all pts received BEP in Fav and 87,5 % (n = 70) in Unfav. After chemotherapy and surgery, 65,2 % in Fav and 41,3 % in Unfav obtained complete response. At 30 months (median follow-up), Fav-OS was 80,5 % (IC95% 55,8 – 92,2) and Unfav-OS was 64,4 % (IC95% 52 – 74,4). At 30 months, rates were 69,6 % (IC95% 46,6 -84,2) and 63.5 % (IC95% 51,9 – 73) respectively. In GETUG 13 study, 3-years OS was 84 % in Fav and 73 % on Unfav; 3-years PFS was 70 % and 59 % respectively. Seven pts died because of toxicity in Unfav (No one in Fav). Neuropathy, anemia and thrombopenia were more frequent in Unfav. Salvage high-dose chemotherapy with stem-cell transplant was required in 4 (66,7 %) pts in Fav and 8 (36,4 %) pts in Unfav. Conclusions: This study showed a reproducibility of the princeps study in terms of PFS and OS. Toxicity seemed more important in real world. For the congress, results will be reported with 50 additional pts.

439 Background: The phase III KEYNOTE-361 study examined the efficacy and safety of 1L pembro + chemo or pembro alone vs chemo for pts with advanced UC. The PFS and OS benefit of pembro + chemo vs chemo did not reach statistical significance; no further formal tesing was done. We present an exploratory analysis of OS by subsequent therapy in KEYNOTE-361 (NCT02853305) to assess how 1L and 2L therapy selection affected survival outcomes; no formal comparisons were conducted. Methods: OS was estimated for pts by whether they received subsequent therapy, and by whether subsequent therapy included an anti–PD-(L)1 agent. Results: 351 pts were randomized to pembro + chemo, 307 pts to pembro, and 352 pts to chemo. As of Apr 29, 2020, the median (range) time from randomization to data cutoff was 31.7 (22.0-42.3) mo. 124/351 pts (35%) in the pembro + chemo arm, 126/307 pts (41%) in the pembro arm, and 215/352 pts (61%) in the chemo arm received any subsequent therapy. Similar rates of subsequent therapy (pembro + chemo: 32%; pembro: 43%; chemo: 59%) were observed for pts who experienced progressive disease (PD) by blinded independent central review (BICR). A higher rate of pts (169/352 [48%]) in the chemo arm received subsequent anti–PD-(L)1 therapy than in either the pembro + chemo arm (23/351 [7%]) or pembro arm (14/307 [5%]). Due to the small pt numbers, pts in the pembro + chemo or pembro arms who received subsequent anti−PD-(L)1 were not considered further. This analysis included all pts who received 2L therapy (465/1010 pts [46%]); the rate of 2L therapy was similar in pts with PD by BICR (274/615 [45%]). Chemo agents alone or in combination, specifically carboplatin, cisplatin, docetaxel, doxorubicin, gemcitabine, and paclitaxel, were the most commonly received subsequent therapies for pts who did not receive anti–PD-(L)1 in 2L. Pts who received 1L chemo followed by subsequent anti–PD-(L)1 had longer mOS (19.1 mo [95% CI 16.2-22.2]) than pts with 1L pembro followed by 2L therapy not including an anti−PD-(L)1 agent (16.0 mo [95% CI 11.8-19.2]) (Table). Conclusions: In this exploratory analysis, favorable survival outcomes were observed for pts who received 1L chemo followed by anti–PD-(L)1 compared with pts who received 1L pembro followed by 2L therapy not including an anti–PD-(L)1 agent. These data underline the continued importance of immunotherapy as 2L therapy for advanced UC. Clinical trial information: NCT02853305 . Research Sponsor: Merck & Co., Inc[Table: see text]

435 Background: The phase III KEYNOTE-361 study compared efficacy and safety of 1L pembro + chemo or pembro vs chemo in pts with advanced UC. The trial did not meet its primary endpoints of PFS or OS superiority for pembro + chemo vs chemo; formal testing for OS for pembro vs chemo was not performed. We present a post hoc landmark analysis to examine the durability of CR/PR/SD and long-term survival in pts with CR, PR, or SD to pembro vs chemo at week 9 in KEYNOTE-361 (NCT02853305). Methods: Landmark analyses of OS by CR/PR/SD at 9 weeks after randomization in the ITT population were performed. Pts were included if they had a best response of CR/PR/SD per RECIST v1.1 by blinded independent central review at the landmark date of week 9 (first imaging assessment per study protocol). Duration of CR/PR/SD and OS were estimated by the Kaplan-Meier method. No formal comparisons were performed. Results: 307 pts were randomized to receive pembro and 352 pts to receive chemo in the KEYNOTE-361 study. As of Apr 29, 2020, the median (range) time from randomization to data cutoff was 32.5 (22.0-42.4) mo for the pembo arm and 31.4 (22.1-41.6) mo for the chemo arm. In the landmark analysis, fewer pts had CR/PR/SD at week 9 with pembro (n=137 [45%]) than with chemo (n=253 [72%]). Median (range) duration of response for pembro vs chemo was 18.7 (4.4+-35.4+) vs 12.3 (0.0+-29.7+) mo for pts with CR, and 35.0 (1.1-36.1+) vs 6.1 (0.0+-36.3+) mo for pts with PR. Median (range) duration of SD was 4.8 mo (0.0-38.2+) with pembro and 4.6 mo (0.0-16.1+) with chemo. Median OS (95% CI) for pembro vs chemo was not reached (NR) (25.5-NR) vs NR (19.1-NR) for pts with CR; NR (NR-NR) vs 14.8 mo (12.1-21.0) for pts with PR; and 18.5 mo (13.8-28.8) vs 11.1 mo (8.1-14.6) for pts with SD, respectively. Long-term OS rates were higher with pembro vs chemo across all groups (CR/PR/SD) at week 9 (Table). Conclusions: In this post hoc landmark analysis, chemo was associated with more initial responses than pembro, whereas pembro was associated with longer median duration of CR and PR, and generally longer median OS than chemo. Among pts who achieved CR/PR/SD at week 9, the relative OS benefit for pembro vs chemo increased over time. Clinical trial information: NCT02853305. [Table: see text]

384 Background: Stage I testicular germ cell tumor (TGCT) has excellent cure rates and surveillance is fully included in patient’s management, particularly during the first years of follow-up. Surveillance guidelines differ between the academic societies, with different recommendations concerning clinical and imaging frequency de-escalation and long term follow-up. We evaluated surveillance practice and schedules followed by French specialists and set up a DELPHI method to obtain a consensual surveillance program with an optimal schedule for patients with localized TGCT. Methods: An online survey on surveillance practice of stage I TGCT based on clinical-cases was conducted among urologists, radiotherapists and oncologists. Results were compared to AFU, ESMO and EAU guidelines. Then a panel of experts assessed surveillance proposals following a formal consensus method (DELPHI method). Statements were drafted after analysis of the previous survey and systematic literature review, with 2 successive rounds to reach a consensus. Results: Survey and DELPHI were conducted between July 2018 and May 2019. Sixty-one (12.2%) participated to the survey (69% oncologists, 15% urologists, 16% radiotherapists). For the first 5 years of follow-up we observed 30 to 50% of adherence to AFU’s guidelines, 20 to 36% of adherence to ESMO’s guidelines and 6 to 45% of practices not corresponding to any of the guidelines depending on clinical situations. Only 25% of practitioners stopped surveillance after the 5th year, as recommended. No physician followed the ESMO guidelines of de-escalation chest imaging. For the Delphi study, a panel of 32 experts (78% oncologists, 16% urologists, 6% radiotherapists) was asked about 38 statements. Consensus was reached for 26 statements concerning clinico-biological surveillance modalities and end of surveillance after the 5th year of follow-up. For seminoma, abdominal ultrasound was proposed as an option to the abdominopelvic (AP) scan for the 4th year of follow-up. No consensus was reached regarding de-escalation of chest imaging. Conclusions: The survey proved that French TGCT specialists do not follow current guidelines. With DELPHI method, a consensus was obtained for frequency of clinico-biological surveillance, discontinuation of surveillance after the 5th year and stop of AP scan on the 4th year of follow-up for seminoma. Questions remains concerning type and frequency of chest imaging.