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91
Background: Resistance to androgen receptor (AR) targeted therapies is common in mCRPC. Glucocorticoid receptor (GR) expression increases with AR inhibition in patients (pts) and ...blockade of GR signaling inhibits CRPC growth in preclinical models when combined with AR blockade. We thus conducted a phase I/II open label trial of Enz combined with Mif, a GR, AR, and progesterone receptor antagonist for pts with mCRPC to assess the feasibility and impact on disease progression with dual AR/GR antagonism. Methods: The phase I dose escalation portion assessed the safety of the two-drug combination and a recommended phase II dose (R2PD) was determined based on safety, pharmacokinetic and endocrine assessments. In the phase II portion, patients (pts) received 12 weeks of Enz (160mg/day) followed by randomization to Enz alone or Enz plus Mif with PSA-progression free survival (PFS) as the primary endpoint. 42 pts were to randomize to each arm to provide 80% power to detect a hazard ratio of 0.6, with a one-sided alpha of 0.1; there was a planned interim futility analysis after 50% of progression events. Results: 106 pts (18 phase I/88 phase II) were enrolled. Pts had a median age of 70 (range 53-89) and baseline PSA of 12.8 (range 0.1-755). 34% of pts received prior docetaxel. The RP2D was 120mg/day Enz and 300mg/day Mif. In phase II, 33 patients were randomized to each arm, with well-balanced baseline demographics. 22 pts were not randomized (15 due to disease progression, 2 due to toxicity, and 5 due to the interim study analysis). The interim analysis showed no difference between arms in PSA-PFS (hazard ratio = 1.34, p=0.395), 12-month PSA-PFS of 31% in both arms, and per-protocol, the trial was stopped. Toxicities were similar in the arms, e.g. fatigue (12% vs. 14%), hot flashes (6% vs. 5%), and pain (4% vs. 4%). Conclusions: The addition of Mif to Enz following a 12-week Enz lead-in did not delay time to PSA progression. Further analyses of secondary endpoints, including translational biomarkers such as hormone levels, GR/AR-v7 expression in circulating tumor cells and cell free DNA analyses are ongoing. Clinical trial information: NCT02012296.
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306
Background: Approved rapalogs inhibit mTORC1 and have limited activity in mRCC, possibly due to compensatory feedback loops. Sapanisertib addresses the incomplete inhibition of the ...mTOR pathway through targeting of both mTORC1 and mTORC2 with antitumour activity demonstrated in patients with mRCC. In this multicenter, single arm phase II trial, we evaluated the efficacy of sapanisertib in patients with mRCC progressing on standard therapies (NCT03097328). Methods: Eligible mRCC patients had an ECOG performance status of 0-2 and had progressed on standard therapies. Prior therapy with rapalogs (everolimus, temsirolimus) and variant RCC histologies were permitted. Patients had a baseline biopsy and received treatment with sapanisertib 30 mg by mouth weekly until unacceptable toxicity or disease progression. The primary endpoint was overall response rate (ORR) by RECIST 1.1. Tissue biomarkers of mTOR pathway activation were explored. Results: We enrolled 38 mRCC patients (clear cell = 28; variant histology = 10) between August 2017 and November 2019. The majority had intermediate (76%) or poor risk (11%) by IMDC criteria. Twenty (53%) had received ≥ 3 lines of therapy; 13 (34%) patients received prior rapalogs. Median follow-up was 10.4 months (range 1-27.4) and median duration of therapy was 1.6 (range 0.3-13.8) months. ORR by central review was 2 of 38 (5.3% 90%CI: 1%-15.6%). 31.6% of all patients and 30.7% of those with prior rapalog exposure had some tumor shrinkage during course of treatment. Median progression free survival (PFS) was 2.5 months (95% CI 1.8,3.7). Twelve patients (32%) developed treatment-related grade 3 adverse events (AEs) with no grade 4 or 5 toxicity reported; 6 patients (16%) required dose reduction and 4 (11%) discontinued therapy for AEs. Oncopanel tumor sequencing identified alterations in the mTOR pathway in 6 of 29 patients ( MTOR n = 2, PTEN n = 3, TSC1 n = 1.) Reduced PTEN expression by immunohistochemistry was seen in 7 of 19 patients. There was no association between mTOR pathway mutations or PTEN loss and response to sapanisertib. Conclusions: In this study we demonstrate minimal activity of sapanisertib in patients with treatment refractory mRCC with no clear benefit among patients with mTOR/PTEN pathway alterations. Additional treatment strategies are needed for patients with refractory mRCC.
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TPS191
Background: Recent updates to genetic testing recommendations and approved treatment options for prostate cancer (PCa) patients (pts) have clarified the need for comprehensive ...genetic registries. Germline DNA damage repair (DDR) defects are present in over 10% of pts who develop metastatic castration-resistant prostate cancer (mCRPC) while 5-10% of pts with localized PCa have germline pathogenic variants in DDR genes. NCCN guidelines have recently expanded to address genetic testing to include high risk localized, node positive and metastatic disease, in addition to family cancer history criteria. In May 2020, the FDA approved 2 PARP inhibitors for mCRPC treatment. Genetic registries can address the critical need to identify pts for recently approved targeted treatments, understand real-world effects of targeted therapies, and expand clinical trials examining less common mutations. PROMISE is a prospective genetic registry equipped to meet these needs. Methods: 5,000 PCa pts will be screened via the online study portal and at-home germline testing to identify and enroll 500 eligible pts with germline pathogenic variants, likely pathogenic variants, and variants of uncertain significance (VUS) in the genes of interest: ATM, ATR, BRCA1, BRCA2, BRIP1, CHEK2, FAM175A, GEN1, HOXB13, MRE11A, MLH1, MSH2, MSH6, NBN, PALB2, PMS2, PTEN, RAD51C, RAD51D, TP53 and XRCC2. Additional genes may be added as evidence emerges. Eligible pts must be assigned male at birth and have documented PCa through tissue biopsy, and/or PSA >100ng/dL, and/or radiographic evidence of disease. Pts with or without prior genetic testing, including those with known pathogenic variants, are encouraged to enroll. Exclusion criteria are: inability or unwillingness to provide information for eligibility and incomplete inclusion criteria. Following germline testing, all pts will be offered genetic counseling and periodic newsletters with updates on treatments and clinical trials. Every 6 months, eligible pts will complete a patient-reported outcome (PRO) survey (EORTC QLQ-C30) and updated medical records will be obtained for clinical data abstraction. Eligible pts will enter long-term follow-up. The primary endpoint is the creation of a prospective genetic registry of PCa pts. Additional endpoints include: frequency of pathogenic or likely pathogenic germline variants of interest, recruitment of a control group with a VUS in the genes of interest, association between disease characteristics and germline testing results, comparison of PROs between disease subpopulations, longitudinal outcomes, and overall survival. Study duration will be 20 years (active recruitment: 5 years, follow-up: 15 years). PROMISE is recruiting at 10 US sites and has 282 subjects enrolled in the screening phase to date. PROMISE is sponsored and managed by the Prostate Cancer Clinical Trials Consortium. Clinical trial information: NCT04995198.
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213
Background: Cabozantinib (C) is a small molecule inhibitor of receptor tyrosine kinases including VEGFR-2, c-MET. C trials have shown significant improvements in bone pain and bone ...scintigraphy in mCRPC patients (pts). We hypothesized that functional imaging using MRI could elucidate underlying biological processes by demonstrating an early decrease in vascular permeability (decrease in transfer consant - Ktrans) and subsequent decrease in cell density (increase in apparent diffusion coefficient - ADC) within bone metastases. Methods: mCRPC pts received C 60 mg daily. The primary endpoint was change in Ktrans at 2 weeks (wks) of treatment. Secondary endpoints included Ktrans and ADC longitudinal changes, and correlation with bone scan, PSA, RECIST, and changes in reported pain. All pts underwent MRI at baseline, day 0, day 15 and every 12 wks. Results: 17 pts were treated at two sites. Median age: 68 yrs (range:51-83), baseline PSA 94.78 ng/mL (7.4-2971), number of prior CRPC therapies 2 (1-8). Median progression free survival was 5.1 months; 5 pts discontinued therapy for adverse events, and 12 for progressive disease. The most common grades 3/4 toxicities were fatigue (24%) and palmarplantar erythrodysesthesia (12%). 14 pts were evaluable for the primary endpoint. At 2 wks, Ktrans decreased an average 35%, 0.074 to 0.048 min
-1
(SD=0.016, p<0.0001). There was no change in Ktrans between wk 2 and end of study. There was an increase in median ADC of 150 at wk 12. There were no RECIST or 50% PSA responses. Conclusions: Ktrans decreased significantly after 2 wks of treatment, consistent with antiangiogenic properties of C. Compared to wk 2, K trans at disease progression is unchanged, which could signify that adaptive vascular change is not the primary mechanism of tumor resistance to the drug. Contrary to our hypothesis, ADC increased during the trial, which perhaps correlates with the short median time to progression. Still, MRI of bone metastases could benefit drug development for other agents in mCRPC or interrogation of bone metastases, notoriously challenging for disease response analysis, in other cancers. Clinical trial information: NCT01599793.
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5005
Background: Nivo + Ipi is an established first-line treatment (tx) for advanced RCC. We hypothesized that the addition of CTLA-4 blockade may not be required for all patients ...(pts). Furthermore, the optimal duration of Nivo maintenance in responding pts is unknown. In this phase II response-adaptive trial, we investigate the sequential addition of 2 doses of Ipi to induce response in Nivo non-responders (NR) and duration of Nivo in responding pts (NCT03203473). Methods: We enrolled pts with advanced RCC with no prior checkpoint inhibitor exposure. All pts received Nivo alone with subsequent arm allocation based on RECISTv1.1 response within 6 months (mos) of tx. Pts with a confirmed partial response (PR) or complete response (CR) within 6 months (mos) discontinued Nivo and were observed (Arm A). Arm A pts reinitiated Nivo if they developed progressive disease (PD); Ipi was added to Nivo if PD persisted or recurred. Pts with stable disease (SD) or PD after no more than 6 mos of Nivo alone received 2 doses of Ipi (Arm B). The primary endpoints were the proportion with PR/CR at 1-year (yr) after Nivo discontinuation (Arm A) and proportion of Nivo NR who convert to PR/CR after adding Ipi (Arm B). Results: 83 pts initiated tx of whom 99% had ECOG 0-1, 96% clear cell RCC, 51% tx-naïve, and 69% IMDC intermediate/poor risk. Median follow-up was 17.0 mos. 15 pts were not allocated to an arm 7 withdrew for PD, 7 withdrew for toxicity, 1 still on tx with unconfirmed PR (uPR). At 6 mos, induction Nivo resulted in a confirmed PR in 11% of pts (n=9/83): 12% (n=5/42) tx-naïve, 10% (4/41) prior tx, 8% (n=1/13) favorable risk, 11% (n=8/70) intermediate/poor risk (Table). 11 pts (13%: 9 PR, 1 uPR, 1 SD) were allocated to Arm A, of whom 5 (45%, 90% CI 20-73%) remained off Nivo at ≥ 1 yr. Of 57 pts (69%) allocated to Arm B, 2 pts converted to a PR (4%, 90% CI 1-11%), both of whom had prior tx and PD as best response to Nivo alone. Grade 3-4 treatment related adverse events (TrAE) occurred in 7% (n=6/83) on induction Nivo and in 23% (n=13/57) on Arm B (Nivo + Ipi). Conclusions: We cannot currently recommend a strategy of Nivo followed by response-based addition of Ipi due to the absence of CR and low PR/CR conversion rate (4%). Though a subset of pts treated with Nivo alone can maintain durable responses off tx at 1-yr, early Nivo discontinuation in the absence of toxicity cannot currently be recommended. Investigation into biomarkers to guide tx is ongoing. Clinical trial information: NCT03203473 . Table: see text
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4501
Background: Dysregulated metabolism is a hallmark of RCC, driven by overexpression of glutaminase (GLS), a key enzyme of glutamine metabolism. Telaglenastat (Tela) is an ...investigational, first-in-class, selective, oral GLS inhibitor that blocks glutamine utilization and critical downstream pathways. Preclinically, Tela synergized w/ cabozantinib (Cabo), a VEGFR2/MET/AXL inhibitor, against RCC tumors. In a Ph 1 study cohort, Tela+Cabo showed encouraging safety/efficacy as 2L+ therapy for mRCC. This trial compared Tela+Cabo vs Pbo+Cabo in previously treated pts w/ clear-cell mRCC (NCT03428217). Methods: Eligible pts had 1-2 prior lines of systemic therapy for mRCC, including ≥1 anti-angiogenic therapy or nivolumab + ipilimumab (nivo/ipi), KPS ≥70%, measurable disease (RECIST 1.1), no prior Cabo or other MET inhibitor. Pts were randomized 1:1 to receive Cabo (60 mg PO QD) with either Tela (800 mg PO BID) or Pbo, until disease progression/unacceptable toxicity, and were stratified by prior PD-(L)1 inhibitor therapy (Y/N) and IMDC prognostic risk group. Primary endpoint was progression-free survival (PFS; RECIST 1.1) by blinded independent radiology review. The study was designed to detect a PFS hazard ratio (HR) of 0.69 w/ alpha 0.05 and 85% power. Data cutoff date: August 31, 2020. Results: 444 pts were randomized (221 Tela+Cabo; 223 Pbo+Cabo). Baseline characteristics were balanced between arms. Median follow-up was 11.7 mo; 276 pts received prior ICI, including 128 w/ prior nivo/ipi. Median PFS (mPFS) was 9.2 mo for Tela+Cabo vs 9.3 mo for Pbo+Cabo (HR = 0.94; 95% CI: 0.74, 1.21; stratified log-rank P= 0.65) with overall response rates (ORR; confirmed) of 31% with Tela+Cabo vs 28% Pbo+Cabo, respectively. Overall survival was not mature at data cutoff. In a prespecified subgroup analysis in pts w/ prior ICI, mPFS was numerically longer w/ Tela+Cabo than Pbo+Cabo (11.1 vs 9.2 mo, respectively; unstratified HR = 0.77; 95% CI: 0.56, 1.06). In the Pbo+Cabo arm, mPFS was 9.2 mo for pts w/ prior ICI exposure and 9.5 mo for pts without, and ORR was 32% and 20%, respectively; if ICI included nivo/ipi, ORR was 37%. Rates of adverse events (AEs) were similar between arms.Grade 3-4 AEs occurred in 71% of Tela+Cabo pts and 79% of Pbo+Cabo pts and included hypertension (17% vs 18%) and diarrhea (15% vs 13%). Cabo was discontinued due to AEs in 10% of Tela+Cabo pts and 15% of Pbo+Cabo pts. Conclusions: The addition of Tela did not improve the efficacy of Cabo in mRCC in this study. Tela+Cabo was well tolerated with AEs consistent with known risks of both agents. The study provides valuable insight on efficacy outcomes of a contemporary population of pts w/ mRCC who receive Cabo in the 2/3L setting. Clinical trial information: NCT03428217.
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4503
Background: The combination of gemcitabine (G) and cisplatin (C) is a standard therapy for metastatic urothelial carcinoma (mUC). Based on data that angiogenesis plays a role in UC ...growth and progression, a randomized placebo-controlled trial was performed. Methods: Patients mUC, no prior chemotherapy for metastatic disease and >12 months from prior (neo)adjuvant chemotherapy and ECOG PS 0-1 were randomized 1:1 to G 1000 mg/m
2
IV days 1 and 8 and C IV 70 mg/m
2
day 1 with bevacizumab (GCB) 15 mg/kg IV or placebo (GCP) day 1 every 21 days. Randomization was stratified by the presence of visceral metastases and prior chemotherapy. The primary endpoint was overall survival (OS) defined as the time from randomization to death or last follow-up (FU). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and ≥ grade 3 toxicity. With 445 deaths, the log-rank test had an 87% power to detect a hazard ratio (HR) of 0.74 with a 2-sided α=0.05. The primary analysis was based on the stratified log-rank test adjusting on stratification factors. Alliance Data Safety and Monitoring Board approved the final OS analysis be performed at 420 events due to lower than expected event rates. Results: 506 patients were randomly assigned (252 GCB, 254 GCP) stratified by the presence of visceral disease and prior chemotherapy for UC. The median FU for patients still alive was 46.2 months. Median OS was 14.5 months for patients treated with GCB and 14.3 months for patients treated with GCP with a HR of 0.87 (95%CI 0.72-1.06; 2-sided Wald p=0.17). The HR for PFS was 0.77 (95%CI 0.63-0.93) in favor of GCB (p=0.0074). Grade 3 or greater adverse event rate was 83.5% with GCB compared to 80.7% with GCP. Conclusions: The addition of bevacizumab to GC chemotherapy did not result in improved OS (primary endpoint) in patients with mUC but there was a PFS improvement. The observed median OS of about 14 months is consistent with prior phase III trials of cisplatin-based chemotherapy. Support: U10CA180821, U10CA180882, U10CA180820, U10CA180853, U10CA180888, Genentech https://acknowledgments.alliancefound.org. Clinical trial information: NCT00942331.
