Citations

Background: The Oncuria™ urine test for the detection of bladder cancer measures a multiplex protein signature. In this study, we investigated the influence of urinary cellularity, protein, and hematuria on the performance of the Oncuria™ test in an ex vivo experimental model. Materials and Methods: Pooled urine from healthy subjects was spiked with cultured benign (UROtsa) or malignant cells (T24), cellular proteins, or whole blood. The resulting samples were analyzed using the Oncuria™ test following the manufacturer’s instructions. Results: Urine samples obtained from healthy subjects were negative for bladder cancer by Oncuria™ test criteria. The majority of the manipulated conditions did not result in a false-positive test. The addition of whole blood (high concentration) did result in a false-positive result, but this was abrogated by sample centrifugation prior to analysis. The addition of cellular proteins (high concentration) resulted in a positive Oncuria™ test, and this was unaffected by pre-analysis sample centrifugation. Conclusions: The Oncuria™ multiplex test performed well in the ex vivo experimental model and shows promise for clinical application. The identification of patients who require additional clinical evaluation could reduce the need to subject patients who do not have bladder cancer to frequent, uncomfortable and expensive cystoscopic examinations, thus benefiting both patients and the healthcare system.

PURPOSE The ATEMPT trial was designed to determine if treatment with trastuzumab emtansine (T-DM1) caused less toxicity than paclitaxel plus trastuzumab (TH) and yielded clinically acceptable invasive disease-free survival (iDFS) among patients with stage I human epidermal growth factor receptor 2–positive (HER2+) breast cancer (BC). METHODS Patients with stage I centrally confirmed HER2+ BC were randomly assigned 3:1 to T-DM1 or TH and received T-DM1 3.6 mg/kg IV every 3 weeks for 17 cycles or T 80 mg/m 2 IV with H once every week × 12 weeks (4 mg/kg load →2 mg/kg), followed by H × 39 weeks (6 mg/kg once every 3 weeks). The co-primary objectives were to compare the incidence of clinically relevant toxicities (CRTs) in patients treated with T-DM1 versus TH and to evaluate iDFS in patients receiving T-DM1. RESULTS The analysis population includes all 497 patients who initiated protocol therapy (383 T-DM1 and 114 TH). CRTs were experienced by 46% of patients on T-DM1 and 47% of patients on TH ( P = .83). The 3-year iDFS for T-DM1 was 97.8% (95% CI, 96.3 to 99.3), which rejected the null hypothesis ( P < .0001). Serially collected patient-reported outcomes indicated that patients treated with T-DM1 had less neuropathy and alopecia and better work productivity compared with patients on TH. CONCLUSION Among patients with stage I HER2+ BC, one year of adjuvant T-DM1 was associated with excellent 3-year iDFS, but was not associated with fewer CRT compared with TH.

6076 Background: HCC is a rare subtype of follicular cell thyroid cancer that has been poorly studied in the past. Recent genomic studies have shown the PI3K/Akt/mTOR pathway is frequently altered in HCC. In addition, a phase II study of sorafenib (S) and everolimus (E) showed promising data in HCC. A study to evaluate this was initiated through Alliance and the International Thyroid Oncology Group. Methods: Patients (pts) were randomized to either sorafenib and everolimus (SE) vs. sorafenib alone (S). Inclusion criteria included; (1) diagnosis of HCC (confirmed through central review), no prior S or E, refractory to radioactive iodine, progressive disease by RECIST over prior 14 months. Primary endpoint was a comparison of progression-free survival (PFS) between SE and S using a stratified 1-sided log-rank test with 0.20 significance level and a power of 80%. 28 events were needed at final analysis. Secondary endpoints consisted of overall survival (OS), confirmed response rate (RR), and adverse events. Results: 35 pts were randomized from 10/2014 to 9/2019, 34 of which were evaluable for analysis (17-SE; 17-S) because 1 patient cancelled prior to receiving treatment. Median age was 66.5 years and 74% were male. ECOG performance status (PS) was 0 (47%) and PS 1 (53%). 41% had prior systemic treatment for HCC. No significant differences in baseline characteristics were observed between treatment arms. Median follow-up in 22 alive patients was 39.2 months (range: 15.1-64.9). Seven (21%) patients remain on treatment. PFS was significantly improved in the SE arm as compared to the S arm (HR=0.65 (95% CI: 0.26, 1.57); median PFS: SE=24.7 months (95% CI: 6.1-no upper), S=10.9 months (95% CI: 5.5-no upper); stratified 1-sided p=0.1662). OS was similar between the arms (2-sided p=0.4138). Confirmed response rate was similar between arms as well (SE: 18% (3 partial response (PR) vs. S: 24% (3 PR, 1 complete response)); Fisher’s exact p=1.00). Grade 3 adverse event (AE) rates (regardless of attribution) were similar between arms (SE: 77% vs. S: 77%; p=1.00). Each arm had 1 patient with at least one grade 4 AE (SE patient: cardiac arrest, tracheal obstruction, encephalopathy; S patient: mucositis oral) and no grade 5 AEs. Conclusions: PFS was improved with the addition of E to S in this small randomized multi-institutional phase II study done. Accrual was difficult, but these promising results suggest that this combination should be further studied. Support: U10CA180821, U10CA180882, U24CA196171; https://acknowledgments.alliancefound.org ; Novartis/GSK; ClinicalTrials.gov Identifier: NCT02143726. Clinical trial information: NCT02143726.

5001 Background: Tak is an oral selective nonsteroidal 17, 20-lyase inhibitor that blocks the synthesis of gonadal and adrenal androgens. We evaluated the clinical benefit of Tak with ADT in pts with newly diagnosed mHSPC. Methods: Pts with mHSPC with a Zubrod performance status (PS) of 0-2 and a PSA of ≥ 2 ng/ml were randomized 1:1 to ADT+Tak (300 mg twice daily) or ADT+Bic (50 mg daily). Stratification factors included PS (0-1 vs ≥2), extent of disease (minimal vs extensive), and receipt of ADT prior to registration (yes vs no). The primary endpoint was overall survival (OS). Secondary endpoints were progression free survival (PFS; based on PSA, imaging or clinical progression), PSA at 7 months (≤0.2 vs 0.2 < PSA; ≤-4 vs. > 4 ng/ml) and adverse event (AE) profile. With 2.75 yrs to accrue 1,186 eligible pts and 3 additional yrs of follow-up, we would have 90% power to determine a 33% improvement in OS from 54 to 72 mos (1-sided α = 0.025). A final analysis was pre-specified after 523 deaths using a 1-sided α = 0.022 to account for interim analyses. Results: Between 3/2013 and 7/2017, 1,313 pts were randomized and 1,279 were included in the intention-to-treat (ITT) analysis (32 pts were ineligible and 2 pts withdrew consent). Median age was 68 yrs and 10% of subjects were Black. Median PSA was 30 ng/mL (range 2-6710) and 49% of pts had extensive disease. After a median follow-up of 4.9 yrs, PFS and PSA response were significantly improved with Tak over Bic but no significant improvement in OS was observed (Table). More grade 3/4 AEs occurred in Tak vs. Bic arms (43% vs. 14%), and included hypertension (20% vs. 5%) and fatigue (5% vs. 2%). Five pts in Tak and 1 pt in the Bic arm had grade 5 AE. Conclusions: Despite clinically meaningful improvement in various outcome measures with Tak+ADT over Bic+ADT in this representative population of mHSPC, the improvement in OS did not meet the pre-specified criteria for statistical significance. The median OS of 70 mos in the control arm (standard ADT) was higher than that reported in contemporary phase 3 trials in this setting, and 16 mos higher than originally estimated. This trial sets a new landmark for survival estimates when pts with mHSPC have access to multiple approved subsequent life-prolonging therapies. Funding: NIH/NCI/NCTN grants U10CA180888, U10CA180819, U10CA180820; U10CA180821; and in part by Millennium Pharmaceuticals, Inc. (Takeda Pharmaceutical Company LTD) Clinical trial information: NCT01809691. [Table: see text]

4541 Background: Radical cystectomy (RC) is the standard of care for patients with BCG-unresponsive high risk non-muscle invasive bladder cancer (NMIBC), but many patients are unfit for surgery or elect bladder preservation. This trial was designed to evaluate the activity of atezolizumab in BCG-unresponsive high risk NMIBC. Methods: This single arm phase II registration trial testing systemic atezolizumab (1200 mg IV) every 3 weeks for one year aimed to enroll 135 (70 CIS and 65 non-CIS) eligible patients with histologically proven BCG-unresponsive high risk NMIBC who were unfit for or declined RC. Here we report the 18 month results for all eligible patients who received at least one protocol treatment. The co-primary endpoints were pathological complete response (CR) rate at 6 months in patients with CIS (reported at ASCO 2020), and event-free survival (EFS) in all patients at 18 months using Kaplan-Meier methods (KM), conditional on a positive CIS response rate. A sample size of 135 evaluable patients provided 93% statistical power for detecting a 30% 18-month EFS rate versus 20% using a one-sided alpha = 0.05. EFS in the subset with Ta/T1 disease and duration of response in CIS patients were secondary endpoints. Results: 172 patients were enrolled, 166 received at least one dose of atezolizumab and are included in the safety analysis, and, of those, 128 were eligible and included in the efficacy analysis. As previously reported, 20 (27%) out of 74 patients with CIS attained a pathologic CR at 6 months. The KM estimate of 12 month (actual 11.9 mo) duration of response after 6 month CR for CIS patients was 54% (95% CI 30%, 78%) and the median duration of response was 16.5 months. The KM EFS rate at 18 months in 74 patients with CIS was 17% (90% CI 9%, 25%). The 18 month KM EFS rate in the overall population of 128 patients with Ta, T1 and CIS was 29% (90% CI 22%, 36%). The 18 month actuarial EFS rate in 54 patients with Ta/T1 disease was 45% (90% CI 34, 57%). Any possibly or probably treatment-related adverse event (TRAE) was observed in 142 out of 166 (86%) patients who received any atezolizumab regardless of eligibilty. The most frequent TRAEs were fatigue 72 (43%), diarrhea 34 (20%), and anemia 38 (23%). Grade 3-5 TRAEs occurred in 28 (17%) patients, including rash in 4 (2%), hyponatremia in 4 (2%), hypertension in 3 (2%) and elevated liver function tests in 3 (2%). There were two treatment-related deaths (sepsis and respiratory failure due to myasthenia gravis). Conclusions: The observed response of atezolizumab at 6 and 18 months in patients with BCG-unresponsive CIS suggests that this could be a valuable treatment to address a critical unmet need in this patient population. The 18 month EFS in patients with Ta/T1 disease suggests activity in this patient subset. This trial provided no new safety concerns. Funding: NIH/NCI grants: CA180888, CA180819, CA180820, CA180821, CA180863 and in part by Genentech. Clinical trial information: NCT02844816.

TPS595 Background: Patients (pts) with HER2+ early breast cancer (EBC) and invasive residual disease (RD) after neoadjuvant therapy (NAT) have a higher risk of relapse than pts with a pathologic complete response (pCR). Post neoadjuvant T-DM1 has improved invasive disease-free survival (iDFS), but pts with estrogen receptor (ER)-negative or nodal RD have suboptimal outcomes and recurrences in the central nervous system are a problem. More effective treatment strategies are needed. The CompassHER2 trials, EA1181 and A011801, leverage pCR to tailor post neoadjuvant therapy in HER2+ EBC. EA1181 is a NAT de-escalation trial of a taxane, trastuzumab and pertuzumab (THP) in clinical stage II-III HER2+ EBC; pts with a pCR complete HP +/- adjuvant radiation (RT) +/- endocrine therapy (ET). A011801 is an escalation trial for pts with high risk HER2+ RD after NAT, examining addition of the HER2 selective tyrosine kinase inhibitor (TKI) tucatinib to adjuvant T-DM1. Methods: Eligibility and Intervention: Pts. with high-risk HER2+ RD (e.g. ER-,node-positive, or both) after a predefined course of neoadjuvant HER2-directed treatment are randomized 1:1 to adjuvant T-DM1+ placebo (pb), vs. T-DM1 and tucatinib with adjuvant RT +/- ET. Eligibility criteria include completion of ≥ 6 cycles of NAT, including ≥ 9 weeks of T and H +/- P. All chemotherapy (CT) must be completed preoperatively unless participating in EA1181 (̃15-30% enrollees); these pts must receive postoperative CT to complete ≥ 6 cycles prior to enrollment on A011801. Pts who received prior HER2-targeted TKIs or antibody-drug conjugates are ineligible. Objectives: The primary objective is to determine if iDFS is higher with addition of T-DM1 to tucatinib in pts with HER2+ EBC with RD after NAT; secondary endpoints include overall survival, breast cancer free survival, distant recurrence-free survival, brain metastases-free survival and disease-free survival. Correlative objectives include the association of i) tumor infiltrating lymphocyte (TILs) levels in the primary tumor and RD with iDFS, ii) TILs with tucatinib benefit, iii) iDFS and circulating tumor cells (CTC) at serial timepoints and iv) the magnitude of benefit of tucatinib (iDFS) in pts with/without detectable pretreatment CTCs. Quality of life and pharmacokinetic endpoints will also be evaluated. Statistics: A011801 is a prospective, double-blind, randomized, phase III superiority trial; stratified by i) receipt of postoperative CT (Y/N), ii) hormone receptor-status (+/-),and iii) pathologic lymph node status (+/-). The study targets an absolute difference of 5% in iDFS (control vs. experimental arm 82% & 87%, HR = 0.7), with a two-sided alpha of 0.05 and power of 80%. The sample size is 981; target accrual = 1031 pts; activation and completion dates are 01/6/21 and ̃ 01/2028. Support: U10CA180821, U10CA180882; Seagen Inc; ClinicalTrials.gov Identifier: NCT04457596 Clinical trial information: NCT04457596.

Abstract Purpose Intensive multi-modal regimens have improved survival for patients with atypical teratoid rhabdoid tumor, however relapse rates remain high. A better understanding of clinical and pathologic features associated with tumor relapse is critical to risk-stratifying patients. Patients and Methods ACNS0333 treatment consisted of multi-agent chemotherapy, high-dose chemotherapy, and radiation therapy, lasting approximately 6 months. Variables including patient age, sex, tumor location, M-stage, degree of resection, order of therapy, germline status, and molecular subgroup were analyzed. Cumulative incidence (CI) of event free survival due to relapse was evaluated for each variable. Results Thirty-three of 65 evaluable patients had tumor relapse. For the entire cohort, the CI of relapse was 21.8% at 6 months, 40.6% at one year and 50.3% at 4 years. For patients with infratentorial tumors, CI of relapse was 26.3%, 34.2% and 37.2%, at 6 months, 1 and 4 years respectfully compared to 15.3%, 49.9%, and 69.7% for those with supratentorial tumors (p 0.051). Patients with SHH subtype had no relapses in the first 6 months and CI of relapse of 37.5% at 4 years, while those with TYR and MYC subgroups had CI of relapse of 33.3% and 26.7% at 6 months and 46.3% and 73.3% at 4 years respectfully (p 0.088). Patients with germline mutations had a cumulative incidence of relapse of 20% at 6 months and 60% at 12 months compared to 22.6% and 37.7% respectfully for those without. No obvious trends were noted based on other analyzed variables. Conclusions ACNS0333 was not powered to determine prognostic indicators of relapse, however, this data suggest interesting trends based on tumor location, subtype and germline status. Infratentorial location and SHH subtype maybe associated with lower risk of relapse. Larger data sets must be compiled to further investigate these variables, perform multivariate analyses and inform risk-stratification on future trials.

Abstract Background Antibody drug conjugates (ADCs) targeting the epidermal growth factor receptor (EGFR), such as depatuxizumab mafodotin (Depatux-M), is a promising therapeutic strategy for glioblastoma (GBM) but recent clinical trials did not demonstrate a survival benefit. Understanding the mechanisms of failure for this promising strategy is critically important. Methods PDX models were employed to study efficacy of systemic vs intracranial delivery of Depatux-M. Immunofluorescence and MALDI-MSI were performed to detect drug levels in the brain. EGFR levels and compensatory pathways were studied using quantitative flow cytometry, Western blots, RNAseq, FISH, and phosphoproteomics. Results Systemic delivery of Depatux-M was highly effective in nine of 10 EGFR-amplified heterotopic PDXs with survival extending beyond one year in eight PDXs. Acquired resistance in two PDXs (GBM12 and GBM46) was driven by suppression of EGFR expression or emergence of a novel short-variant of EGFR lacking the epitope for the Depatux-M antibody. In contrast to the profound benefit observed in heterotopic tumors, only two of seven intrinsically sensitive PDXs were responsive to Depatux-M as intracranial tumors. Poor efficacy in orthotopic PDXs was associated with limited and heterogeneous distribution of Depatux-M into tumor tissues, and artificial disruption of the BBB or bypass of the BBB by direct intracranial injection of Depatux-M into orthotopic tumors markedly enhanced the efficacy of drug treatment. Conclusions Despite profound intrinsic sensitivity to Depatux-M, limited drug delivery into brain tumor may have been a key contributor to lack of efficacy in recently failed clinical trials.