Prior Platinum Therapy Research Articles

Efficacy and Safety of Salvage-line Nivolumab Monotherapy for Advanced Esophageal Squamous Cell Carcinoma: Comparison of 240 mg Versus 480 mg Doses

BackgroundNivolumab monotherapy is the standard second-line treatment for advanced esophageal squamous cell carcinoma (ESCC) after failure of platinum-based chemotherapy without anti-PD-1 antibody. Fixed dosing with 240 mg every 2 weeks was approved initially, followed by fixed dosing with 480 mg every 4 weeks based on pharmacokinetics data. However, information on the comparative efficacy and safety of the two doses remains limited.MethodsWe compared progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and the incidence of adverse events (AEs) between the two doses in 117 patients who received second-line (n = 85) or later-line (n = 32) nivolumab monotherapy at our institution between January 2016 and December 2021.ResultsIn the second-line group, patient characteristics for the 240 mg and 480 mg groups were as follows (240 mg vs. 480 mg): performance status (PS) 0/1/2 was 34/61/5% vs. 54/42/4%, and prior fluoropyrimidine plus platinum therapy (FP) was 81.3% vs. 42.3%. In the later-line group, the characteristics were: PS 0/1/2 was 28/60/12% vs. 14/86/0%, and prior FP was 60.0% vs. 42.8%. ORR was 11.9 vs. 24.0% in the second-line group (p = 0.19) and 0 vs. 14.3% in the later-line group (p = 0.22). Median PFS was 1.7 vs. 4.1 months on second-line (hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.35–1.01, p = 0.056) and 1.4 vs. 1.8 months on later-line (HR 0.58, 95% CI 0.23–1.46, p = 0.25); AEs of any grade were observed in 58.3 vs. 69.7%, respectively.ConclusionsThe efficacy and safety of the two doses of nivolumab monotherapy were comparable in patients with advanced ESCC.

Dual mTOR1/2 Inhibitor Sapanisertib (FTH-003/TAK-228) in Combination With Weekly Paclitaxel in Patients With Previously Treated Metastatic Urothelial Carcinoma: A Phase II Open-Label Study

BackgroundThe PI3K/AKT/mTOR pathway is frequently altered at genomic level in metastatic urothelial carcinoma (mUC). Since mTOR is the last protein in the PI3K signaling cascade, it may have the largest impact on the pathway and has been a focus of targeted therapies. Sapanisertib (FTH-003/TAK-228) is an oral highly selective mTOR1 and mTOR2 inhibitor. NFE2L2 mutations have been described as predictive biomarkers of response in patients with advanced squamous cell lung cancer treated with sapanisertib. Patients and MethodsThis was an open-label, investigator-initiated phase II study evaluating safety and efficacy of sapanisertib plus paclitaxel in patients with mUC who had progressed to prior platinum therapy, and the correlation with NFE2L2 mutations in responders. Primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS) and safety. Patients were treated with weekly paclitaxel at dose of 80 mg/m2 on days 1, 8, and 15 in combination with sapanisertib 4 mg administered orally 3 days per week on days 2-4, 9-11, 16-18, and 23-25 of a 28-day cycle. NFE2L2 mutations were analyzed by Sanger sequencing in responders. Results22 patients were enrolled from May 2018 to April 2020; the trial was halted early due to slow accrual and the COVID-19 pandemic. ORR was 18.2% (n = 4). Disease control rate was 50% (7 SD and 4 PR). Median PFS was 3.4 months (95% CI: 1.8-6.1) and median OS was 6.1 months (95% CI: 1.8-13.4). Adverse events (AE) of grade 3-4 were seen in 86% of patients, but no patients discontinued treatment due to AEs. NFE2L2 mutations were not found in responders. ConclusionsAlthough the primary endpoint was no met, sapanisertib and paclitaxel combination demonstrated clinical activity in a heavily pretreated population of mUC. This trial generates insight for future combination of sapaniserib with immunotherapy and/or antibody drug conjugates.

Preliminary efficacy, safety, and immunomodulatory effects of PT-112 from a phase 2 proof of concept study in patients (pts) with thymic epithelial tumors (TETs).

e20647 Background: Immune checkpoint inhibitors (ICIs) are associated with a high risk of immune-related adverse events (irAEs) in pts with TETs (thymoma and thymic carcinoma). PT-112, a novel inducer of immunogenic cell death, has demonstrated safety and efficacy in phase I trials. We present results of an unplanned interim analysis of a phase 2, NIH IRB-approved clinical trial to evaluate the clinical activity, tolerability, and correlative immunology of PT-112 in TETs (NCT05104736). Methods: Eligible pts with TETs with progression after prior platinum therapy were treated with PT-112 360 mg/m2 iv on days 1, 8 and 15 of a 28-day cycle until progression or development of intolerable toxicity. Prior history of autoimmunity (AI) or treatment with ICI was permitted. Primary objective is to determine the objective response rate. Immune activation was assessed by flow cytometry and multiplex immunofluorescence. Results: Ten pts have received treatment (median age 54, 3 females, 5 thymic carcinomas, 3 with prior TET-associated AI disease). Median number of prior systemic therapies is 2.5 (range, 1-4) and all pts have received cisplatin, paclitaxel, or both previously. Nine pts are evaluable for response, with stable disease in 8 (89%) and progressive disease in 1 (11%) pt. After a median potential follow-up of 7.4 months (mo) median progression-free survival is not reached in pts with thymoma and is 6.2 mo (95% CI: 1.8- 7.9 mo) in thymic carcinoma. All pts are evaluable for toxicity. The most common (all grades) treatment-related adverse events (TRAEs) are peripheral neuropathy (60%), anemia, fatigue and myalgias (each in 50%). Grade ≥ 3 TRAEs in more than one patient include anemia (30%) and neutropenia (20%). Two (20%) pts experienced relapse of AI: ocular myasthenia and immune cytopenias. The most common reason for treatment hold is peripheral neuropathy (40%). Treatment was discontinued due to TRAE (peripheral neuropathy) in 1 (10%) pt. There are no treatment related deaths. Treatment was associated with an increase in CD8+ T cells, activated CD4+ T cells and NK cells in peripheral blood. There was an increase in pro-inflammatory serum analytes (IFNg, TNFa, sCD27:sCD40L and sCD73) and a decrease in immunosuppressive analytes (VEGF, sCD40L and TGFb) compared with baseline. Paired tumor biopsies are being analyzed by multiplex immunofluorescence and results will be presented. Conclusions: PT-112 is safe and clinically active in pts with recurrent TETs. In contrast to ICIs, no new irAEs were observed. Immune analyses show evidence of early treatment-related immune activation and support the rationale underlying this novel treatment approach for TETs. Enrollment is ongoing with an accrual ceiling of 53. These initial results support further evaluation of PT-112 in TETs as monotherapy and in combination with other immunomodulatory interventions. Clinical trial information: NCT05104736 .

Clinical efficacy analysis of patients (pts) with HER-2 expressing metastatic urothelial carcinoma (mUC) treated with enfortumab vedotin (EV).

e16618 Background: EV, an antibody drug conjugate (ADC) targeting NECTIN-4, is an approved salvage treatment for unselected pts with mUC. ADCs targeting the human epidermal growth factor receptor-2 (HER-2) have also shown robust activity in clinical trials for mUC with tumor HER-2 expression. We investigated the interaction between HER-2 expression and clinical outcomes of pts treated with EV, which are currently unknown. Methods: We conducted a retrospective, single institution study analyzing pts with mUC who received EV. Immunohistochemistry (IHC) staining for HER-2 was completed with PATHWAY anti-HER2 (4B5) Antibody (Ventana Medical Systems, Tucson, AZ) using established breast cancer scoring algorithm. Wilcoxon rank sum and Fisher exact tests were used to compare continuous and categorical variables, respectively. Cox proportional hazards regression model was used to evaluate a variable’s ability to predict overall survival (OS). Variables with p-value ≤0.1 were included in the multivariate analysis (MVA). Results: We identified 158 pts with mUC who received EV. Median age at EV start was 70 (IQR 66-76), most pts were Caucasian (144, 91%), male (108, 68%), primary bladder tumors (113, 72%), and pure urothelial histology (95, 60%). 96 pts (61%) received prior platinum therapy and 117 pts (74%) had prior immunotherapy. ECOG scores ≥2 was seen in 54 pts (39%) while 75 pts (54%) had Bellmunt scores ≥2 (54%). Median follow up time was 12.5 months and median OS from EV start was 13 months. 94 pts (60%) had HER2 IHC staining. There was no association between HER2 intensity and any of the clinical variables. On univariate analysis (UVA): HER2 3 vs HER2 ≤2 HR was 0.38 (0.14, 0.98), male vs female HR=1.56 (0.94, 2.58), ECOG ≤1 vs ≥2 HR=0.6 (0.38,0.95), Bellmunt score 0-1 vs 2-3 HR=0.49 (0.3, 0.78), and hemoglobin (Hgb) HR=0.75 (0.67, 0.85). MVA showed HER2 3 vs HER2 ≤2 HR was 0.42 (0.16, 1.12), male vs female HR=2.3 (1.17, 4.42), ECOG ≤1 vs ≥2 HR=0.56 (0.30, 1.05), and Hgb HR=0.77 (0.65, 0.92). Conclusions: MVA of this single-site retrospective cohort did not show any association between HER2 expression and survival outcomes in pts with mUC who received EV. Further studies are needed to continue assessing the role of HER2 as a potential prognostic and predictive biomarker in UC, especially if HER-2 directed therapies become incorporated in the mUC treatment paradigm. [Table: see text]

Abstract P4-01-08: Efficacy of PARP Inhibitors in Patients With BRCA1/2-related Breast Cancer with Prior Platinum Exposure: A Systematic Review and Meta-Analysis

Abstract Background: Approximately 5% of breast cancer patients carry a deleterious germline BRCA1/2 mutation, which leads malignant cells to be deficient in the repair of DNA double-strand breaks via homologous recombination. The poly(adenosine diphosphate–ribose) polymerase (PARP) enzymes are important on DNA single-strand break repair and PARP inhibitors (PARPi) cause an accumulation of unresolved DNA damage in tumors with BRCA1/2 mutations, resulting in cell death. However, because platinum salts also ultimately cause double-strand DNA breaks and may have overlapping mechanisms of resistance with PARPi, the efficacy of PARPi in patients with prior platinum therapy is unknown. We sought to evaluate the efficacy of PARPi in patients with BRCA1/2-related breast cancer and previous platinum exposure. Methods: We performed a systematic review and meta-analysis of studies that evaluated the efficacy of PARPi in patients with advanced or metastatic breast cancer and germline BRCA1/2 mutations. Two independent investigators identified double-blind, randomized controlled trials (RCTs) that included the subgroup of previous exposure to platinum. PubMed, Embase, and Cochrane databases were searched for papers up to June 26, 2022. Data extraction from published reports and quality assessment were performed under Cochrane recommendations. Hazard ratios (HRs) with a 95% confidence interval (CI) were pooled, and a p-value of < 0.05 was considered statistically significant. The software Review Manager 5.3 was selected for conducting the statistical analysis. The primary endpoint of interest was progression-free survival (PFS). Results: Out of 2069 database results (487 on PubMed; 1376 on Embase; and 206 on Cochrane), 42 studies were selected for full review, and 4 RCTs, with a total of 249 patients, were included in the final investigation. The PARPi included were Olaparib, Talazoparib, Niraparib, and Veliparib. Pooled analysis showed that PARPi improved PFS in breast cancer patients with prior treatment with platinum-based therapy compared to the control group [HR = 0.72; 95% CI, 0.53-0.97; p = 0.03]. In comparison, the population without previous platinum exposure had a similar but slightly greater benefit from PARPi [HR = 0.68; 95% CI, 0.52-0.89; p = 0.005]. A subgroup analysis containing only the three randomized trials with PARPi monotherapy confirmed the central tendency favoring PARPi over physicians’ choice of single-agent chemotherapy in patients with prior platinum-therapy; however, because of small numbers and wide confidence interval it was not statistically significant [HR = 0.72; 95% CI, 0.51-1.01; p = 0.06]. Conclusions: Our findings suggest that PARPi are associated with longer PFS in patients with advanced breast cancer and previous exposure to platinum therapy, decreasing the concerns about cross-resistance between the drug classes. Nonetheless, more extensive studies are still necessary to investigate the efficacy of PARPi in patients with prior platinum exposure and truly platinum-resistant disease. Progression-free survival of included studies Citation Format: Alice D. Marinho, Beatriz Mella S. Pessoa, Gabriela R. Brandao, Caroliny H. Da Silva, Pedro A. Reis, Ana Carolina M. Comini, Felipe Batalini. Efficacy of PARP Inhibitors in Patients With BRCA1/2-related Breast Cancer with Prior Platinum Exposure: A Systematic Review and Meta-Analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-08.

Assessment of Durable Responses after Brexucabtagene Autoleucel (KTE-X19) in the ZUMA-2 Study in Relapsed/Refractory Mantle Cell Lymphoma (R/R MCL)

Introduction: Brexucabtagene autoleucel (brexu-cel, formerly known as KTE-X19) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved in the United States for the treatment of adults with R/R MCL and in the European Union for adults with R/R MCL after ≥2 prior therapies, including a Bruton tyrosine kinase inhibitor (BTKi). At a median 35.6-months (mo) follow-up in the Phase 2, multicenter ZUMA-2 study of brexu-cel in R/R MCL, the objective response rate was 91% (68% complete response [CR] rate), with a median duration of response (DOR) of 28.2 mo, and overall survival (OS) of 46.6 mo among all 68 treated patients (pts) and not reached in pts with a CR (Wang et al. J Clin Oncol. 2022). To identify factors associated with long-term response to KTE-X19, we evaluated patient and product characteristics by response status at 24 mo post infusion in ZUMA-2. Methods: Adults (≥18 years) with R/R MCL who had received ≤5 prior regimens including a BTKi underwent leukapheresis and conditioning chemotherapy followed by a single infusion of brexu-cel (2×106 anti-CD19 CAR T cells/kg). Post hoc assessments of patient, disease, pharmacokinetic, and product characteristics are reported by response status at 24 mo (ongoing vs relapsed). Results: At a median follow-up of 35.6 mo (range, 25.9-56.3), 62 pts had achieved a CR or partial response; 3 did not reach the 24-mo assessment visit and were excluded from this analysis. Of the 59 evaluable pts with response, 29 (49%) had ongoing responses at 24 mo (ongoing responders), and 30 (51%) had relapsed prior to 24 mo (relapsed responders). At baseline, the median age was 65 years and median number of prior therapies was 3 in both subgroups. Among ongoing vs relapsed responders, 66% vs 43% had ibrutinib as last prior therapy and 14% vs 13% had acalabrutinib as last prior therapy, with a median (range) time from last prior therapy of 63 (26-748) vs 64.5 mo (22-443), respectively. A smaller proportion of ongoing responders compared with relapsed responders received bridging therapy (21% vs 53%) and prior platinum therapy (10% vs 40%), respectively; while similar proportions received prior bendamustine therapy (45% vs 53%), prior proteosome inhibitor therapy (41% and 37%), and prior autologous stem cell transplant (48% vs 37%), respectively. At baseline, a greater proportion of ongoing responders had an ECOG score of 0 compared to relapsed responders (79% vs 57%, respectively), and the median (range) tumor burden (SPD) was 935.1 (260-6133) in ongoing responders and 4233.6 (386-14390) in relapsed responders. The incidence of high-risk features was similar between ongoing responders and relapsed responders, with 66% and 60% having a baseline Ki-67 proliferation index score of ≥30%, 10% of both subgroups having TP53 mutations, 45% and 37% having elevated lactose dehydrogenase levels (ULN to ≥1.5 ULN), and 10% and 13% having high-risk Simplified Mantle Cell Lymphoma International Prognostic Index scores (>6), respectively. The median (range) DOR in ongoing responders with CR (n=28) was not reached (46.7-not estimable) and was 8.3 mo (5-13.6) in relapsed responders with CR (n=15). Of the relapsed responders, 67% had received subsequent anticancer therapy by data cutoff, the most common of which were radiotherapy (23%), dexamethasone (23%), rituximab (23%), venetoclax (20%), and lenalidomide (20%; patients could have received multiple subsequent therapies and multiple lines of subsequent therapy). Median [range] peak (102.4 [0.3-2241.6] vs 59.9 [1.6-2589.5]) and area under the curve (1487 [3.8-16,700] vs 688.2 [19-27,200]) CAR T-cell levels were ~2x higher in ongoing responders than in relapsed responders, respectively. A modest increase in the median [range] total number of infused CCR7+ cells was observed in ongoing vs relapsed responders (119.8 [37-249.9] vs 89.1 [6.1-353.4]), suggesting a potential role of continuous memory T-cell differentiation in achieving durable responses. Conclusions: After ~3-years median follow-up, brexu-cel continues to demonstrate durable responses with 49% of patients in ongoing response at 24 mo post infusion. In summary, ongoing responders had lower ECOG scores and tumor burden, as well as less frequent use of bridging therapy and less intense regimens for previous relapses, suggesting the potential for greater benefit with brexu-cel if given in earlier course of disease.

Abstract CT007: PETRA: First in class, first in human trial of the next generation PARP1-selective inhibitor AZD5305 in patients (pts) with BRCA1/2, PALB2 or RAD51C/D mutations

Abstract Background: AZD5305 is a potent, highly selective PARP1 inhibitor and trapper with superior preclinical tolerability, target engagement and efficacy vs 1st generation dual PARP1/2 inhibitors (PARPi). This is the first report of the ongoing Phase 1/2a PETRA (NCT04644068) trial. Methods: Pts with advanced breast, ovarian, prostate or pancreatic cancer bearing germline or somatic BRCA1/2, PALB2 or RAD51C/D mutations received AZD5305 QD PO until disease progression. ECOG PS 0-2 and Hb ≥9.0 g/dL were required. Prior PARPi and platinum therapy were permitted. The primary objective was safety; secondary objectives included pharmacokinetics (PK) and pharmacodynamics in tumor and/or blood samples and response by RECIST v1.1, CA125 or PSA. Exploratory genomic analyses included zygosity evaluation and ctDNA response monitoring. Results: At data cutoff (Nov 17, 2021), 46 pts received AZD5305 10-90 mg QD (43.5% had prior PARPi; median 3.5 prior lines of therapy). AZD5305 was well tolerated across all doses without DLTs (Table). PK exposures were dose-proportional. Steady-state Ctrough was higher than 1st generation PARPi: specifically 6.3 and 31.9 fold above target effective concentration at 10 and 90 mg, respectively. PARylation inhibition was ≥90% at 10-40 mg QD (PBMCs) confirming target engagement. 7/25 (28%) pts had objective responses: 5 RECIST PRs (3 confirmed) and 2 additional pts with PSA50 responses (1 confirmed), including platinum- and PARPi-resistant pts. 13/22 (59%) RECIST-measurable pts had SD or PR up to 51+ weeks. ctDNA declined on treatment in 7/13 (54%) evaluable pts (3 complete, 4 >50% reductions) across doses. Conclusions: AZD5305 is a highly selective PARP1 inhibitor and trapper with excellent physiochemical properties and a wide therapeutic index. It led to maximal target engagement and showed promising clinical activity with favorable tolerability at exposures surpassing those of 1st generation PARPi. AZD5305 10 mg/d (n=8) AZD5305 20 mg/d (n=19) AZD5305 40 mg/d (n=13) AZD5305 60 mg/d (n=3) AZD5305 90 mg/d (n=3) Total (N=46) Most common (>10%) TRAEs, n (%) Any grade Any grade Any grade Any grade Any grade Grade ≥3 Any grade Nausea 3 (37.5) 5 (26.3) 1 (7.7) 1 (33.3) 0 0 10 (21.7) Anemia* 2 (25.0) 4 (21.1) 1 (7.7) 0 0 6 (13.0) 7 (15.2) Neutropenia* 3 (37.5) 2 (10.5) 1 (7.7) 0 1 (33.3) 2 (4.3) 7 (15.2) Thrombocytopenia* 1 (12.5) 2 (10.5) 2 (15.4) 0 0 1 (2.2) 5 (10.9) Fatigue and asthenia* 2 (25.0) 2 (10.5) 0 1 (33.3) 0 0 5 (10.9) Any TRAE leading to dose reduction 1 (12.5) 0 0 0 0 1 (2.2) Any TRAE leading to discontinuation 0 0 0 0 0 0 AE, adverse event; TRAE, treatment-related adverse event *Grouped Terms Citation Format: Timothy A. Yap, Seock-Ah Im, Alison M. Schram, Adam Sharp, Judith Balmana, Richard D. Baird, Jessica S. Brown, Maria Schwaederle, Elizabeth A. Pilling, Ganesh Moorthy, Spiros Linardopoulos, Adam Dowson, Carol Pound, Edit Lukacs, Sabina Cosulich, Stephen J. Luen. PETRA: First in class, first in human trial of the next generation PARP1-selective inhibitor AZD5305 in patients (pts) with BRCA1/2, PALB2 or RAD51C/D mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT007.

A phase 1a/b trial of imlunestrant (LY3484356), an oral selective estrogen receptor degrader (SERD) in ER-positive (ER+) advanced breast cancer (aBC) and endometrial endometrioid cancer (EEC): Monotherapy results from EMBER.

1021 Background: Imlunestrant is a novel, orally bioavailable SERD with pure antagonistic properties that result in sustained inhibition of ER-dependent gene transcription and cell growth. In dose escalation, imlunestrant showed favorable safety, pharmacokinetics (PK) and preliminary efficacy in patients with ER+, HER2- aBC and ER+ EEC (Phase 1a EMBER, Jhaveri 2021). Here we present updated data from the dose escalation (Phase 1a) and dose expansion (Phase 1b) of imlunestrant monotherapy in EMBER (NCT04188548). Methods: Phase 1a/1b enrolled patients with ER+ aBC (prior ET sensitivity; ≤3 prior therapies for aBC in Phase 1a following protocol amendment and ≤2 in Phase 1b) and ER+ EEC (prior platinum therapy; no prior fulvestrant or aromatase inhibitor). Premenopausal women received a concomitant GnRH agonist. Serial plasma samples were obtained for PK and ctDNA analysis. Key endpoints included recommended phase 2 dose (RP2D) determination, safety and tolerability, PK, objective response rate per RECIST v1.1 (ORR: complete response [CR] or partial response [PR]) in patients with measurable disease and ≥1 post-baseline tumor assessment or discontinued prior to tumor assessment, and clinical benefit rate (CBR: CR or PR, or stable disease ≥24 weeks) in patients enrolled ≥24 weeks prior to data cut. Results: As of January 14, 2022, 138 patients (n = 114 aBC, n = 24 EEC) received imlunestrant monotherapy at doses ranging from 200-1200 mg QD. Median age was 62.0 years (range 32-95). Median number of prior therapies for aBC and EEC was 2 (range 0-8) and 1 (0-5), respectively. aBC patients had received a prior ET (94.7%), CDK4/6 inhibitor (92.1%), fulvestrant (50.9%) and chemotherapy (26.3%). No dose-limiting toxicities were observed. Most treatment-emergent adverse events (TEAEs) were grade 1. At the RP2D (400 mg QD, n= 69), the most common all grade TEAE’s were nausea (33.3%), fatigue (27.5%), and diarrhea (23.2%). Across all doses, the incidence of treatment-related grade 3 AEs was low (3.6%). No patient discontinued due to a TEAE. In evaluable aBC patients, ORR was 8.0% (6/75) and CBR was 40.4% (42/104). In evaluable EEC patients, ORR was 5.0% (1/20 had a PR- ongoing pending confirmation) and CBR was 47.1% (8/17). Clinical benefit was observed regardless of baseline ESR1 mutation status as determined by ctDNA sequencing. Additional biomarker analyses will be presented at the meeting. Conclusions: Imlunestrant continues to demonstrate a favorable side effect profile, with no cardiac or opthalmic safety signals, and has continued evidence of clinical activity in heavily pre-treated ER+ aBC and EEC patients. Clinical trial information: NCT04188548.

Real-world PARPi treatment patterns and outcomes among patients with metastatic breast cancer.

e13005 Background: PARP inhibitors (PARPi) improves PFS among patients (pts) with HER2-ve metastatic breast cancer (MBC) and a BRCA1/2 mutation compared to physician choice of chemotherapy. The objective of this retrospective analysis was to look at the prognostic outcome associated with the use of PARPi therapy among pts with MBC in the real world setting. Methods: We utilized a federated network of de-identified health data representing approximately 84 million pt lives available through the TriNetX Research Network. We identified 767 pts with MBC treated with a PARPi. Overall survival (OS) was computed using the Kaplan Meier product limit method. Propensity score matching was performed on all comparisons of OS. Matching variables included age groups, prior platinum therapy, prior genitourinary malignancies, and secondary metastasis location. Results: Mean age was 56.3yrs. 718 pts had HER2- disease and 49pts had HER2+ disease. Median OS was 55.0m and 44.4m among pts with HER2- and HER2+ disease respectively. Median OS among was 58.3m and 48.6m among patients with HR+/HER2- and TNBC respectively(p = 0.18). Among pts with HR+/HER2- disease, 50.2% received PARPi in combination with endocrine therapy and 43.5% received CDK4/6i. Median OS among pts who received CDK4/6i + endocrine therapy prior to a PARPi and those that never received a CDK4/6i was 55.1m and 36.9m, respectively(p = 0.01). Among pts with TNBC, median OS among those that received PARPi prior to chemotherapy compared to those who received PARPi after chemotherapy was 52.5m and 47.6m respectively (p = 0.97). 169 HER2- pts had brain metastases. Median OS among pts who had brain metastases was 36.9m among pts with HR+/HER2- disease and 22.5m among pts with TNBC(p = 0.01). Among pts with no brain metastases, median OS was 60.6m among pts with HR+/HER2- disease and 56.3m among pts with TNBC(p = 0.91). Median OS among pts who were rechallenged with a PARPi compared to those who were not rechallenged with a PARPi was 58.3m vs 42m respectively (p = 0.05). Conclusions: To our knowledge this is the first data set to report activity of CDK4/6i among pts with HR+/HER2- MBC who received a PARPi, with an observed 18m OS advantage compared to pts who did not receive a CDK4/6i. In absence of brain metastases OS of pts with TNBC and HR+/HER2- is similar when treated with a PARPi.

BRCA reversion mutations mediated by microhomology-mediated end joining (MMEJ) as a mechanism of resistance to PARP inhibitors in ovarian and breast cancer.

5559 Background: PARP inhibitors exploit synthetic lethality in tumor cells with deficiency in homologous recombination repair (HRR). In line with this, most reported mechanisms of PARP inhibitor resistance restore HRR. Of multiple resistance mechanisms reported preclinically, reversion mutations in BRCA genes are the only confirmed mechanism of resistance to both platinum and PARP inhibitors in patients (pts) to date (Lin K et al. Cancer Discov 2019), with most studies focusing on ovarian cancer. MMEJ is an alternative DNA damage repair pathway, in which DNA polymerase θ (POLθ) has a key role; MMEJ has been suggested to play a role in BRCA reversion mutations (Tobalina L et al. Ann Oncol 2021). Methods: Targeted circulating tumor DNA (ctDNA) sequencing analyzed over 500 plasma samples collected at baseline and at progression to therapy in pts with ovarian or breast cancer and a mutation in BRCA1 and/or BRCA2 (BRCAm) who were treated with olaparib or chemotherapy in one of three Phase II/III clinical studies (LIGHT NCT02983799, SOLO3 NCT02282020, OlympiAD NCT02000622). Only pts with an original pathogenic BRCAm detected in ctDNA were evaluable. BRCA reversion mutations were identified using internal computational framework; DNA sequences surrounding BRCA reversion sites were analyzed for MMEJ signatures. Results: At baseline, in pooled data across treatment arms and across all available samples, BRCA reversion mutations were detected in 4/114 (3.5%) and 6/133 (4.5%) of breast and ovarian cancer pts, respectively, which may have developed on prior platinum therapy. At progression, BRCA reversion mutations were detected in 34/79 (43%) breast cancer pts and in 26/101 (26%) ovarian cancer pts who received olaparib, with at least 2/79 and 4/101 reversions already present at baseline, respectively. At progression, in the chemotherapy arm, BRCA reversion mutations were detected in 3/34 (9%) breast cancer pts and 1/29 (3%) ovarian cancer pts, with 2/34 and 0/29 reversions present at baseline, respectively. Reversion mutations varied in allelic frequency and were either present as single or multiple reversions, suggesting multiple events within the tumor were driving resistance. The location and type of reversion mutations reflected the functional importance of BRCA protein domains. A large proportion of BRCA reversion mutations (47/69 [68%] that were evaluable) were mediated by the MMEJ pathway based on the presence of MMEJ signatures around BRCA reversion sites. Conclusions: We detected BRCA reversion mutations in at least ̃40% of breast and ̃20% of ovarian cancer pts following treatment with olaparib. A large proportion of these reversion mutations are likely to have been mediated by MMEJ repair, suggesting that POLθ inhibitors in combination with platinum or PARP inhibitors might prevent or delay emergence of PARP inhibitor resistance. Clinical trial information: NCT02983799, NCT02282020, NCT02000622.

TROPiCS-04: Study of sacituzumab govitecan (SG) in patients (pts) with locally advanced (LA) unresectable or metastatic urothelial cancer (mUC) that has progressed after prior platinum (PLT) and checkpoint inhibitor (CPI) therapy.

TPS582 Background: Treatment options are limited for pts with LA unresectable or mUC who progress after prior PLT-based and CPI therapies. SG is an antibody-drug conjugate (ADC) composed of an anti-trophopblast cell surface antigen 2 (Trop-2) antibody coupled to SN-38 (a topoisomerase-I inhibitor) via a proprietary hydrolyzable linker. In the phase 2 registrational study TROPHY-U-01 (NCT03547973), SG demonstrated an objective response rate (ORR) of 27% and median overall survival (OS) of 10.9 months in pts with mUC who progressed after prior PLT-based and CPI therapies (n = 113; median, 3 prior lines of therapy; 84% with ≥1 Bellmunt risk factors; Tagawa et al, J Clin Oncol. 2021). These results compared favorably with historic data for single-agent chemotherapy (ORR, ̃18%; OS, 9 months; Powles et al. J Clin Oncol. 2021) and led to accelerated approval of SG by the US Food and Drug Administration for pts with LA or mUC who previously received a PLT-containing chemotherapy and CPI. The phase 3 TROPiCS-04 trial has been initiated to confirm these findings. Methods: TROPiCS-04 (NCT04527991) is a global, multicenter, open-label, randomized, controlled trial in pts with LA unresectable or mUC who progressed after prior PLT-based and CPI therapies. Key eligibility requirements include Eastern Cooperative Oncology Group performance status 0-1; no prior CPI or ADC therapy within 4 weeks of study drug initiation; no history of active interstitial lung disease or noninfectious pneumonitis; and adequate hematologic, hepatic, and renal function. Pts will be randomly assigned 1:1 to receive SG 10 mg/kg intravenously (IV) on days 1 and 8 of 21-day cycles or single-agent treatment of physician’s choice (paclitaxel 175 mg/m2, docetaxel 75 mg/m2, or vinflunine 320 mg/m2 IV on day 1 of 21-day cycles) until progressive disease, unacceptable toxicity, or withdrawal of consent. Treatment beyond progressive disease may be permitted in pts deemed to be receiving clinical benefit per investigator assessment. Approximately 600 pts will be enrolled across ̃280 sites in 3 regions (North America, Europe, and Asia-Pacific) to provide 90% power on the primary endpoint of OS. Secondary endpoints include progression-free survival, ORR, clinical benefit rate, duration of response (all per Response Evaluation Criteria in Solid Tumors version 1.1 by blinded independent central review and investigator assessment), safety, and quality of life. Study enrollment started in January 2021 and is ongoing with pts currently enrolled at 30 sites across all 3 regions. Clinical trial information: NCT04527991.

Validation of Prognostic Scores in Patients With Metastatic Urothelial Cancer Enrolling in Phase I Targeted Therapy or Next Generation Immunotherapy Trials.

Enrolling patients with metastatic urothelial carcinoma (mUC) in phase I trials provides an opportunity to identify biological drug activity. Developing prognostic scores may aid in patient selection for phase 1 trials. We analyzed records of patients with mUC who participated in targeted therapy and immunotherapy phase I clinical trials at MD Anderson Cancer Center (MDACC). The Bellmunt and Bajorin scores were calculated as bladder cancer-specific prognostic scores. The Royal Marsden Hospital (RMH) and MDACC scores were calculated as phase I prognostic scores. Hazard ratios (HR) were calculated using the Cox proportional hazard model. The prognostic value of the Bellmunt, Bajorin, RMH, and MDACC scores were assessed using the Likelihood ratio (LR) χ2 test and the c-index. Between 2015 and 2019, 43 patients were enrolled in phase I trials and 12 were enrolled in >I trial leading to a total of 57 trial participants (TPs). Ninty-seven percent of TPs received prior platinum therapy and 60% received a prior checkpoint inhibitor. Median overall survival (OS) and progression-free survival (PFS) were significantly shorter with increasing Bajorin, RMH, or MDACC scores, but not with increasing Bellmunt score. The RMH (c-index=0.658, LR χ2=11.8, P=.008) and MDACC scores (c-index =0.66, LR χ2=12.76, P=.01) outperformed the Bajorin score (c-index=0.522, LR χ2=1.22, P=.5) and the Bellmunt score (c-index=0.537, LR χ2=0.36, P=.9) in predicting overall survivalover. The Bajorin, RMH, and MDACC scores, but not the Bellmunt score, were also predictive of progression-free survival (PFS)prog. The RMH and MDACC scores again outperformed the Bajorin scoreand the Bellmunt score for predicting PFS. The RMH and MDACC phase I prognostic scores accurately predicted survival in patients with mUC and outperformed the bladder cancer-specific scores at time of enrollment on phase 1 clinical trials. The RMH and MDACC scores could optimize selection of patients with mUC for phase I clinical trials.

Rucaparib is a safe and effective maintenance therapy for advanced pancreatic cancer

Select patients with advanced pancreatic cancer may have another effective treatment option for maintenance therapy. New data show that rucaparib is effective in stopping tumor growth or substantially shrinking tumors in the majority of patients with select biomarkers enrolled in a phase II trial by researchers at the Abramson Cancer Center at the University of Pennsylvania in Philadelphia.1 The open-label, single-arm, single-stage, phase II study was conducted to test the hypothesis that rucaparib, a poly(adenosine diphosphate ribose) polymerase inhibitor (PARPi), would confer at least 60% progression-free survival at 6 months as maintenance therapy in patients with platinum-sensitive advanced pancreatic cancer with select biomarkers. The study included 46 patients with locally advanced or metastatic pancreatic cancer with confirmed or likely pathogenic germline or somatic pathogenic variants in BRCA1, BRCA2, or PALB2 genes. Patients were aged at least 18 years and had received prior treatment with platinum-based chemotherapy; 34 patients received at least 16 weeks or more, whereas 8 patients received less than 16 weeks. All patients were treated with rucaparib at a dose of 600 mg delivered orally twice a day during every day of a 28-day cycle until disease progression or unacceptable toxicity. For the 42 patients available for evaluation, the progression-free survival rate at 6 months was 59.5%, and the median progression-free survival was 13.1 months. When disease control was examined, 41.7% of the patients, including 3 of 6 patients with the variant PALB2 and 1 of 2 patients with a somatic BRCA2 mutation, experienced either a complete response or a partial response. Kim A. Reiss, MD, assistant professor at the Abramson Cancer Center and lead author of the study, says that these findings expand on prior results from the phase III POLO study showing the efficacy of maintenance olaparib, the first poly(adenosine diphosphate ribose) polymerase 1 (PARP1) agent to be used as maintenance therapy for advanced pancreatic cancer, in select patients with germline BRCA mutations and platinum-sensitive metastatic pancreatic cancer.2 “Our study showed efficacy in patients with additional variants,” she says. “The role of maintenance PARP inhibition may possibly be expanded to patients with germline PALB2 mutations and those with somatic BRCA mutations.” Dr. Reiss also notes the efficacy of rucaparib for patients with locally advanced disease and patients who did not receive a full 4 months of prior platinum therapy. “Although platinum sensitivity is key for PARPi efficacy, a full 4 months of treatment may not be required prior to switching to maintenance therapy,” she says. This finding is important because of toxicities of platinum-based chemotherapy that typically emerge before the completion of 16 weeks of therapy.

272P Outcomes of patients (pts) who had received prior platinum (PP) therapy in the phase III EMBRACA trial of talazoparib (TALA) vs physician’s choice of chemotherapy (PCT) in patients with germline BRCA1/2 mutated (gBRCA1/2mut) advanced breast cancer (ABC)

TALA is a poly (ADP-ribose) polymerase inhibitor approved in the US, EU, and other countries for the treatment of deleterious/suspected deleterious gBRCA1/2mut HER2-negative ABC. While TALA treatment in the phase 3 EMBRACA trial (NCT01945775) benefited pts regardless of PP, greater improvements in clinical outcomes for TALA vs PCT (capecitabine, eribulin, gemcitabine, or vinorelbine) were seen for pts not treated with PP (PFS hazard ratio [95% CI] 0.76 [0.40–1.45], P = 0.41 for PP vs 0.52 [0.39–0.71], P < 0.0001 for no-PP subgroups).

Effect and Safety of Therapeutic Regimens for Patients With Germline BRCA Mutation-Associated Breast Cancer: A Network Meta-Analysis

PurposeBreast cancer type 1 susceptibility (BRCA) mutations not only increase breast cancer (BC) risk but also result in poor survival and prognosis for BC patients. This study will analyze the effect and safety of therapeutic regimens for the treatment of BC patients with germline BRCA (gBRCA) mutations by network meta-analysis.MethodsPublic databases were searched from inception to 29 April 2021. Frequentist network meta-analysis was conducted to analyze the benefit of chemotherapy and targeted drug-related strategies.ResultsSeventeen articles were included in the analysis. For progression-free survival (PFS), olaparib (hazard ratio (HR): 0.58; 95% confidence interval (CI): 0.43 – 0.79), platinum (HR: 0.45; 95% CI: 0.22 – 0.89), and talazoparib (HR: 0.54; 95% CI: 0.41 – 0.71) were significantly better than platinum-free chemotherapy (Chemo). The results based on indirect comparisons showed that veliparib (Vel) + platinum + Chemo was also significantly better than Chemo (HR: 0.37; 95% CI: 0.20 – 0.69). For overall survival (OS), olaparib was significantly better than Chemo only in the population who did not receive prior chemotherapy. For pathologic complete response (pCR), bevacizumab+Chemo had a significant advantage over platinum agents (OR: 3.64; 95% CI: 1.07 - 12.39). Olaparib and talazoparib both showed significantly higher objective response rates (ORRs) than Chemo.ConclusionThe PFS results suggested that olaparib, talazoparib, and Vel+platinum agent+Chemo were ideal regimens for overall, TNBC, and advanced BC patients with gBRCA mutations. Whether PARPis are suitable for patients with gBRCA mutations who have received prior platinum therapy still needs to be clarified.

Abstract CT115: Phase I trial of the triplet berzosertib (M6620, VX-970), veliparib and cisplatin (BVP) in patients with advanced solid tumors

Abstract Background: Ataxia-telangiectasia-related (ATR) protein kinase is central to the repair of damaged DNA through the homologous recombination (HR) pathway. We conducted a phase I trial of cisplatin in combination with the ataxia-telangiectasia-related (ATR) protein kinase inhibitor berzosertib (M6620) and the poly (ADP-ribose) polymerase (PARP) 1/2 inhibitor veliparib, postulating that simultaneous PARP and ATR inhibition impairs DNA repair and induces a “BRCA null”-like phenotype which could potentiate the antitumor activity of cisplatin. We evaluated the safety, maximal tolerated dose (MTD) and preliminary anti-tumor activity of this treatment triplet. The study was conducted through the Experimental Therapeutics Clinical Trials Network (ETCTN). Methods: This open label trial used a 3+3 design. Cisplatin and berzosertib were each administered intravenously on separate, sequential days for two continuous weeks [day (D) 1 and 8; D2 and 9 respectively], together with veliparib orally twice daily during IV therapy and for 24 hours after (D1-3 and 8-10) in 21-day cycles. Prior platinum and PARP inhibitor therapy were permitted. Tumor expression of DNA damage repair (DDR) biomarkers was assessed at the MTD using validated, quantitative immunofluorescence assays. Results: Fifty-three patients (pts) enrolled, 46 pts evaluable for response. The MTD and RP2D dose is cisplatin 40 mg/m2 D1 and D8, berzosertib 210 mg/m2 D2 and D9, and veliparib 200mg BID (D1-3, D8-10). Three patients achieved a confirmed partial response (PR; 5.6%). A further 2 patients had an unconfirmed PR (breast carcinoma, -30%; HGS carcinoma, -36%). Four responders (3 PR and 1 uPR) received prior platinum. Median time on study: 4 cycles (range 1-25). Genomic data was available on four pts achieving a response: ovarian cancer (BRCA-wildtype, ATM unknown; 25 cycles), breast carcinoma (ATM mutation; 14 cycles), SCC of the tongue (Chek2 mutation; 20 cycles), and HGS carcinoma (ATM/BRIP1 mutation; 4 cycles). Twenty-six pts (56.5%) had stable disease. Thirty-five patients (66.0%) required dose reduction in at least 1 agent, most commonly veliparib (25; 47.2%). Most common grade 3 and 4 adverse events were related to myelosuppression: anemia (20; 37.7%), thrombocytopenia (17; 32.1%), leukopenia (13; 24.5%), neutropenia (12; 22.6%), and lymphopenia (11; 20.8%). Ongoing pharmacodynamic analyses of tumor biopsies collected on C1D1 (post-veliparib/cisplatin) and C1D9 (post-veliparib/cisplatin/M6620) have demonstrated a combination-induced increase in RAD51, indicative of replication stress. Conclusions: The BVP combination shows anti-tumor activity in HR-compromised tumors and M6620 further increases the DDR response elicited by combination cisplatin/veliparib. Citation Format: Geraldine O'Sullivan Coyne, Khanh T. Do, Shivaani Kummar, Naoko Takebe, Sarina Piha-Paul, Richard Piekarz, Deborah Wilsker, Brandon Miller, Katherine Ferry-Galow, Ralph Parchment, Lamin Juwara DNP, Mary Jane Ong, Arjun Mittra, James H. Doroshow, Alice P. Chen. Phase I trial of the triplet berzosertib (M6620, VX-970), veliparib and cisplatin (BVP) in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT115.

A first-in-human phase 1a/b trial of LY3484356, an oral selective estrogen receptor (ER) degrader (SERD) in ER+ advanced breast cancer (aBC) and endometrial endometrioid cancer (EEC): Results from the EMBER study.

1050 Background: Novel degraders and antagonists of ER are under evaluation in aBC, to overcome both ER mediated resistance and the bioavailability and dosing limitations of fulvestrant, the only approved SERD. ER is also overexpressed in ̃80% of EEC and endocrine therapy (ET) is utilized for these patients (pts). LY3484356, a novel, orally bioavailable SERD with pure antagonistic properties results in sustained inhibition of ER-dependent gene transcription and cell growth. Preclinically, LY3484356 shows favorable efficacy and pharmacokinetic (PK) properties, including antitumor activity in ESR1 mutants. Here we present the initial clinical data from EMBER, an ongoing first-in-human phase 1a/b trial of this novel agent. Methods: Phase 1a evaluated LY3484356 dose escalation (i3+3 design) in women with ER+, HER2- aBC (≤3 prior therapies for aBC following protocol amendment; prior ET sensitivity) and ER+ EEC (prior platinum therapy). Premenopausal women received a concomitant GnRH agonist. Key endpoints included determination of the recommended phase 2 dose, safety and tolerability, PK, and objective response rate and clinical benefit rate per RECIST v1.1. Results: As of the data cut (November 9, 2020), 28 pts (n = 24 aBC, n = 4 EEC) were enrolled at doses ranging from 200-1200 mg QD. Median age was 59 years (range, 35-80). Median number of prior therapies for aBC was 2 (range, 1-8; 6 pts enrolled prior to protocol amendment had received ≥4 prior therapies), including prior fulvestrant (46%), a CDK4/6 inhibitor (83%), and chemotherapy (33%). No dose-limiting toxicities were observed. Treatment-emergent adverse events (TEAEs) were mostly grade 1-2, including nausea (32%), fatigue (25%), and diarrhea (18%). The only grade 3 treatment-related AE was diarrhea (n = 1). TEAEs of bradycardia and QTc prolongation were not observed despite intensive central ECG monitoring. Dose-proportional increases in LY3484356 exposures were observed across all evaluated doses and t1/2 was 25-30 hours. At the starting dose level (200 mg QD), unbound LY3484356 exposures exceeded those achieved with fulvestrant. 16 of 28 pts were efficacy evaluable, with the remaining 12 pts ongoing prior to first scan. Among 16 evaluable pts, 11 (8 aBC, 3 EEC) had stable disease (10 pts ongoing), and 5 had progressive disease. RECIST responses were observed after the data cut and will be detailed at the meeting. Plasma ctDNA analysis indicated decreases in mutant allele frequencies, including mutant ESR1 in 9/12 (75%) evaluable pts across all dose levels. Conclusions: LY3484356 QD dosing shows favorable safety and PK properties, along with preliminary efficacy in pts with heavily pretreated ER+ aBC and EEC. Updated data will be presented at the meeting. Clinical trial information: NCT04188548 .

A phase Ib study of TQB2450 plus anlotinib in patients with advanced triple-negative breast cancer.

1074 Background: TQB2450 is a humanized monoclonal antibody targeting programmed death-ligand 1 (PD-L1). Anlotinib is an antiangiogenic small molecule, multi-target tyrosine kinase inhibitor that has improved clinical outcomes in various solid tumors. This phase 1b study aims to evaluate the safety and efficacy of TQB2450 plus anlotinib for patients with advanced triple-negative breast cancer (TNBC) after the failure of standard therapy. Methods: This ongoing study included a dose-escalation phase and an expansion phase. Advanced TNBC patients with prior anthracyclines and/or taxanes treatment and failed at least first-line therapy were enrolled. In the dose-escalation phase, eligible patients received anlotinib (8mg, 10mg, and 12mg, qd, days 1-14; 21 days per cycle) plus TQB2450 (1200mg, day 1; 21 days per cycle) following the conventional 3+3 design. If the starting dose of 10mg anlotinib led to ≥2 dose-limiting toxicities (DLTs), 8mg anlotinib would be administered. After the dose-escalating phase, eligible patients were enrolled into the expansion cohort. The primary endpoint was objective response rate (ORR), and the secondary endpoints were overall survival (OS), disease control rate (DCR), progression-free survival (PFS), and safety. Results: Between May 29, 2019, and December 31, 2020, in the dose-escalation phase, three patients receiving 10mg anlotinib plus 1200mg TQB2450 had no DLTs in the first cycle, neither did three patients with 12mg anlotinib plus TQB2450. Next, 28 patients with advanced TNBC received 12 mg anlotinib plus TQB2450 in the expansion phase. Finally, a total of 34 patients were included with median age of 49.5 (32-70) and median prior lines of 2 (1-6). Numbers of patients with prior platinum therapy: 16, prior anthracycline therapy: 32. The ORR was 26.47% (9/34) and DCR was 82.35% (28/34). The median PFS was 8.57 months. Seventeen patients experienced grade 3 treatment-related AEs (TRAEs). Most frequently occurring (&gt;5%) grade 3 TRAEs were QT interval prolongation (17.65%), hypertension (14.71%), diarrhea (8.82%), hand-foot syndrome (HFS) (8.82%), and hypertriglyceridemia (5.88%). Conclusions: TQB2450 plus anlotinib showed an acceptable safety profile with promising activity for previously anthracyclines and/or taxanes-treated advanced TNBC patients. Clinical trial information: NCT03855358 .[Table: see text]

SAUL, a single-arm study of atezolizumab for chemotherapy-pretreated locally advanced or metastatic carcinoma of the urinary tract: outcomes by key baseline factors, PD-L1 expression and prior platinum therapy

BackgroundThe impact of pretreatment factors on immune checkpoint inhibition in platinum-refractory advanced urothelial cancer (aUC) deserves further evaluation. The aim was to study the association of Bellmunt risk factors, time from last chemotherapy (TFLC), previous therapy and PD-L1 expression with atezolizumab efficacy in platinum-refractory aUC.Patients and methodsThis was a post-hoc analysis of patients who had received prior cisplatin or carboplatin in the prospective, single-arm, phase IIIb SAUL study (NCT02928406). Patients were treated with 3-weekly atezolizumab 1200 mg intravenously. The primary outcome was overall survival (OS). Relationships were analysed using Cox regression and long-rank test.ResultsOf 997 patients in SAUL, 969 were eligible for this analysis. The number of Bellmunt risk factors was associated with OS (P < 0.001); median OS (mOS) for 0, 1 and 2-3 risk factors was 17.9, 8.9 and 3.3 months, respectively. Significant associations were also observed between OS and TFLC (P < 0.001), programmed death-ligand 1 (PD-L1) expression (P = 0.002), and prior perioperative chemotherapy (P = 0.013); mOS was 6.97 versus 11.63 months for TFLC ≤6 versus >6 months, 7.75 versus 11.6 months for PD-L1 expression on <1% of tumour-infiltrating immune cells (ICs) (IC0)/expression on 1% to <5% of tumour-infiltrating ICs (IC1) versus expression on ≥5% of tumour-infiltrating ICs (IC2/3) and 10.2 versus 7.8 months for prior versus no prior perioperative chemotherapy, respectively. The type of platinum compound and number of previous treatment lines were not associated with outcomes.ConclusionsPost-platinum atezolizumab is active in aUC, irrespective of previous platinum compound and lines of therapy. Bellmunt risk stratification, PD-L1 expression, TFLC and perioperative chemotherapy were identified as prognostic factors for OS with second-line atezolizumab, indicating the need for novel prognostic signatures for immunotherapy-treated patients with aUC.

Adjuvant T-DM1 versus trastuzumab in patients with residual invasive disease after neoadjuvant therapy for HER2-positive breast cancer: subgroup analyses from KATHERINE

In the KATHERINE study (NCT01772472), patients with residual invasive early breast cancer (EBC) after neoadjuvant chemotherapy (NACT) plus human epidermal growth factor receptor 2 (HER2)-targeted therapy had a 50% reduction in risk of recurrence or death with adjuvant trastuzumab emtansine (T-DM1) versus trastuzumab. Here, we present additional exploratory safety and efficacy analyses. KATHERINE enrolled HER2-positive EBC patients with residual invasive disease in the breast/axilla at surgery after NACT containing a taxane (± anthracycline, ± platinum) and trastuzumab (± pertuzumab). Patients were randomized to adjuvant T-DM1 (n= 743) or trastuzumab (n= 743) for 14 cycles. The primary endpoint was invasive disease-free survival (IDFS). The incidence of peripheral neuropathy (PN) was similar regardless of neoadjuvant taxane type. Irrespective of treatment arm, baseline PN was associated with longer PN duration (median, 105-109 days longer) and lower resolution rate (∼65% versus ∼82%). Prior platinum therapy was associated with more grade 3-4 thrombocytopenia in the T-DM1 arm (13.5% versus 3.8%), but there was no grade ≥3 hemorrhage in these patients. Risk of recurrence or death was decreased with T-DM1 versus trastuzumab in patients who received anthracycline-based NACT [hazard ratio (HR)= 0.51; 95% confidence interval (CI): 0.38-0.67], non-anthracycline-based NACT (HR= 0.43; 95% CI: 0.22-0.82), presented with cT1, cN0 tumors (0 versus 6 IDFS events), or had particularly high-risk tumors (HRs ranged from 0.43 to 0.72). The central nervous system (CNS) was more often the site of first recurrence in the T-DM1 arm (5.9% versus 4.3%), but T-DM1 was not associated with a difference in overall risk of CNS recurrence. T-DM1 provides clinical benefit across patient subgroups, including small tumors and particularly high-risk tumors and does not increase the overall risk of CNS recurrence. NACT type had a minimal impact on safety.