Role of (F-18) Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Prediction of Response to Neoadjuvant Therapy in Esophageal Cancer: Correlation with Pathological Response and Survival

Purpose

The purpose of this study is to assess the correlation between metabolic response with fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and pathological response in patients with locally advanced esophageal cancer treated with neoadjuvant chemoradiotherapy and to study FDG-PET parameters for the prediction of pathological response and outcome.

Methods

Twenty-five patients with locally advanced esophageal cancer underwent two FDG-PET/CT scans for initial staging and after neoadjuvant chemoradiotherapy. FDG uptake in the primary tumor was calculated in both scans (SUVmax, SULpeak, and TLG). Metabolic response was assessed according to the reduction of PET parameters: complete response (mCR = 100%), partial response (mPR ≥50%), and no response (mNR ≤50%). Pathological response was also classified as complete (pCR), partial (pPR), or no response (pNR). Patients were followed up (range, 8-99 months) determining free-disease interval (FDI) and overall survival (OS).

Results

Two patients were excluded due to exitus for nonesophageal-related causes. The metabolic response was observed in 18/23 remaining patients (3mCR, 15 mPR), of which 12/18 patients showed a pathological response (3 pCR, 9 pPR). A major discrepancy was observed in 2 mNR patients who achieved pPR. FDI and OS were longer in patients with metabolic response than nonresponders, but no statistical difference was found. No significant correlation was found between PET parameters and pathological response, FDI, and OS.

Conclusions

FDG-PET/CT is a useful technique to assess response to neoadjuvant chemoradiotherapy in esophageal cancer. Although in this preliminary study, no correlation between metabolic and pathologic response was found and no statistical differences between responders and nonresponders were observed, a tendency of longer FDI and OS was apparently found in responders patients.

Development and validation of a gene expression signature based on RB1, PTEN,and TP53 in patients with metastatic hormone-sensitive prostate cancer (mHSPC)

236

Background: Alterations on the tumor suppressor genes (TSG) RB1, PTEN and TP53 are associated with treatment resistance and aggressive clinical evolution of prostate cancer patients (pts). We developed and assessed the role of a TSG gene expression signature in mHSPC pts. Methods: This is a multicenter retrospective biomarker study in mHSPC pts receiving different therapies. RB1, PTEN and TP53 mutations were assessed by targeted sequencing and its gene expression was determined by the nCounter platform in FFPE tumor samples. Normalized and transformed (z-score) expression data of a training cohort was used to establish the cut-off for RB1, PTEN and TP53 expression, those cut-offs were then applied to the other cohorts. TSGlow was considered when ≥2 out of 3 TSG presented low expression, and TSGwt in the remaining cases. TSG signature was correlated with castration resistance-free survival (CRPC-FS) (primary endpoint) and overall survival (OS) by Kaplan Meier and multivariate Cox analysis. Results: Overall, 297 pts (baseline characteristics are shown) were included: 125 treated with ADT+Docetaxel (ADT+D) (54 and 71 in training and validation cohorts, respectively), 93 with ADT, and 79 with ADT+Abiraterone or Enzalutamide (ADT+A/E). Training cohort pts were tested for both, gene expression and targeted sequencing of TSG. Pts with low expression of PTEN showed higher frequency of PTEN mutations (p<0.05). TSGlow (14 (25.9%) out of 54 pts) had a worse CRPC-FS (14.3 vs. 21.7 months (m); HR 2.2 (95% CI, 1.1 - 4.4), p=0.022). In the validation cohort, 7 (9.9%) pts were TSGlow and had a worse CPRC-FS (11.7 vs. 20 m, HR 2.5 (95% CI, 1.1 - 5.5), p=0.027) and OS (27.6 vs 58.1 m, HR 3.5 (95% CI, 1.3 - 9.5) p=0.012). TSGlow signature was independently associated with CPRC-FS (HR 2.66 (95% CI, 1.17 - 6.06), p=0.02) and OS (HR 3.67 (95% CI, 1.33 - 10.10), p=0.012). In the ADT and ADT+A/E cohorts, 20 (21.5%) and 14 (17.7%) pts were TSGlow, respectively. TSGlow was not predictive of either CRPC-FS (p=0.23 and p=0.242, respectively) or OS (p=0.091 and p=0.66, respectively). We analyzed together high-volume pts from both ADT+D and ADT cohorts. TSGlow pts (16, 10.74%) treated with ADT+D had a CRPC-FS (13.6 m) similar to pts treated with ADT (TSGlow = 14.5 m and TSGwt = 12.8 m). Moreover, TSGwt pts treated with ADT+D had a better CRPC-FS (19.3m) (p=0.022) and OS (ADT/TSGlow = 31.7 m, ADT/TSGwt = 38.6 m, ADT+D/TSGlow = 31.5 m, ADT+D/TSGwt = 52.2 m, p=0.07). Conclusions: A TSG gene expression signature is predictive of taxanes benefit in mHSPC pts and may be useful to personalize the treatment in this setting. [Table: see text]

Publisher Correction: Clinical efficacy and biomarker analysis of neoadjuvant atezolizumab in operable urothelial carcinoma in the ABACUS trial

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Clinical efficacy and biomarker analysis of neoadjuvant atezolizumab in operable urothelial carcinoma in the ABACUS trial

Antibodies targeting PD-1 or its ligand 1 PD-L1 such as atezolizumab, have great efficacy in a proportion of metastatic urothelial cancers^1,2. Biomarkers may facilitate identification of these responding tumors³. Neoadjuvant use of these agents is associated with pathological complete response in a spectrum of tumors, including urothelial cancer^4-7. Sequential tissue sampling from these studies allowed for detailed on-treatment biomarker analysis. Here, we present a single-arm phase 2 study, investigating two cycles of atezolizumab before cystectomy in 95 patients with muscle-invasive urothelial cancer (ClinicalTrials.gov identifier: NCT02662309). Pathological complete response was the primary endpoint. Secondary endpoints focused on safety, relapse-free survival and biomarker analysis. The pathological complete response rate was 31% (95% confidence interval: 21-41%), achieving the primary efficacy endpoint. Baseline biomarkers showed that the presence of preexisting activated T cells was more prominent than expected and correlated with outcome. Other established biomarkers, such as tumor mutational burden, did not predict outcome, differentiating this from the metastatic setting. Dynamic changes to gene expression signatures and protein biomarkers occurred with therapy, whereas changes in DNA alterations with treatment were uncommon. Responding tumors showed predominant expression of genes related to tissue repair after treatment, making tumor biomarker interpretation challenging in this group. Stromal factors such as transforming growth factor-β and fibroblast activation protein were linked to resistance, as was high expression of cell cycle gene signatures after treatment.

DUTRENEO Trial: A phase II randomized trial of DUrvalumab and TREmelimumab as NEOadjuvant approach in muscle-invasive urothelial bladder cancer (MIBC) patients prospectively selected by immune signature scores

TPS4588

Background: Cisplatin-based neoadjuvant chemotherapy (CT) followed by cystectomy improves overall survival in patients (pts) with MIBC. Immune checkpoint inhibitors as single agents are approved in pts with advanced UC. Combination of both programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) checkpoints might be synergistic. Durvalumab (DU) is a selective, engineered, human IgG1 monoclonal antibody (mAb) that blocks PD-L1 binding to PD-1 and CD80. Tremelimumab (TRE) is an anti-CTLA-4 mAb of the lgG2 isotype. Pembrolizumab and atezolizumab, have shown a promising activity (including significant pathologic complete responses (pT0)) in MIBC pts candidate to cistectomy, with better results in those pts with PD-L1 overexpression. It is expected that the dual targeting of the immune system with an anti-PDL1 + antiCTLA4 such as DU and TRE in the neoadjuvant setting may improve these outcomes. In addition, the most precise selection of pts according to a molecular INF-gamma signature is intended to increase the efficacy. Methods: This is a prospective and randomized phase II, open-label study conducted in urothelial MIBC pts diagnosed of T2-T4 and/or N+ candidates to cystectomy, ECOG 0-1 and adequate organ function. Pts will be treated according to the score of a pro-inflammatory signature (PIS) determined with Nanostring technology. Pts with a low PIS will receive standard cisplatin-based neoadjuvant therapy (22 pt). Pts with a high PIS will be randomized 1:1 to receive cisplatin-based neoadjuvant therapy (22 pt) or DU 1500 mg + TRE 75 mg every 4 weeks x 3 cycles (22 pt). If more than 8 responses (pT0) are observed in first 22 pts included in DU+TRE arm, 24 additional pts will be recruited in this arm. Primary objective is to assess the antitumor activity of DU+TRE measured as pT0 rate in pts with a positive PIS. Disease free survival and safety profile will be also evaluated. Tissue, plasma and urine samples will be collected for translational studies. Clinical trial information: NCT03472274.

A phase II multicenter biomarker trial to study the predictive value of TMPRSS2-ERG before enzalutamide treatment in chemo-naïve metastatic castration-resistant prostate cancer

5040

Background: TMPRSS2-ERG fusion gene is a common driver of prostate cancer. The PREMIERE study is a phase II, single arm open-label, multicentre, clinical trial designed to analyse the predictive/prognostic value of TMPRSS2-ERG in first-line chemo-naïve mCRPC patients treated with enzalutamide. Methods: We centrally evaluated TMPRSS2-ERG in diagnostic samples using PCR, FISH and IHC for ERG. Among exploratory biomarkers we included plasma DNA, AR copy number by ddPCR and CTC by AdnaTest. PCWG2 criteria were used for outcome evaluation. We correlated TMPRSS2-ERGand other exploratory biomarkers with mCRPC outcomes. Results: Ninety eight patients with median age 77 y (range 59-95), ECOG 0/1 (54/46%) with mts located in bone (82%), LN (48%) and visceral (17%). With a median FU of 37.3 months, PSA response was PSA50: 82% and PSA90: 53%; median PSA-PFS was 13.7m (95%CI 10.2-19.0), Rad-PFS 26.7m (95%CI: 22.0-NA) and OS 37.5m (95%IC: 33.7-NA). TMPRSS2-ERG was detected in 32 pts (33%), AR gain in 11 pts and CTCs in 35 pts. No differences were observed based on TMPRSS2-ERG status for PSA response (PSA50: 81% vs 83%; p=0.8), PSA-PFS (median 12.8 vs 14.7m; HR 0.98; 95%CI 0.58-1.67; p=0.95), Rad-PFS (median 28.4 vs 26.4m; HR 1.02; 95% 0.53-1.96, p=0.95) or OS (median 36.9 vs 38.1m; HR 1.23; 95%CI 0.69-2.21, p=0.48). Plasma AR gain was associated with worse PSA-PFS (median 4.2 vs 14.7 m; p<0.0001), Rad-PFS (median 3.6 vs 28.4m; p<0.0001) and OS (median 12.7 vs 38.1m; p<0.0001). Plasma DNA and CTCs were also associated with worse outcome. Multivariate analyses of exploratory biomarkers are included in the table. Conclusions: The fusion gene TMPRSS2-ERG is not predictive nor prognostic on enzalutamide treatment in first-line chemo-naïve mCRPC patients. Plasma AR gain and CTCs are strong independent biomarkers associated with adverse outcome. Multivariate analysis of exploratory biomarkers. Clinical trial information: NCT02288936. [Table: see text]

Impact of the combination of durvalumab (MEDI4736) plus olaparib (AZD2281) administered prior to surgery in the molecular profile of resectable urothelial bladder cancer: NEODURVARIB Trial

TPS503

Background: Perioperative treatment of muscle-invasive bladder carcinoma (MIBC) remains cisplatin-based chemotherapy, but recent evidences suggest that immune checkpoint inhibitors could be incorporated in this setting. Durvalumab is a PD-L1 blocking antibody active in advanced urothelial carcinoma pretreated with platinum-containing chemotherapy and currently under evaluation in first-line, both as monotherapy and in combination with tremelimumab. Olaparib is a PARP inhibitor especially important in tumors with deficiencies in DNA repair mechanisms. Preliminary results from combination trials suggest that these drugs could have synergistic effect dependent on an immunogenic modulation related with STING pathway, and an increase of neoantigens. Unexpected toxicities have not been described. Methods: Design: Open label phase II single arm clinical trial. Primary Objective: To assess the impact of neoadjuvant treatment with durvalumab plus olaparib in the molecular profile of MIBC. Secondary Objectives: Efficacy (Radiological and pathological responses); Safety. Exploratory objective: To identify predictive and prognostic biomarkers. Key correlative studies: Independent central pathologist for histological review and assessment of immunohistochemistry for PD1, PD-L1 and PD-L2; Genomic characterization (WES) and Expression assessment (RNAseq) of the tumors pre and post treatment; Assessment of soluble biomarkers and their evolution during the treatment: flow cytometry for immune cells; immunoassays for cytokines; HLA genotyping. Treatment: Durvalumab 1500 mg iv Q4W & Olaparib 150 mg bid orally during 6 to a maximum of 8 weeks pre-cystectomy. Recruitment: 29 patients. Collaborating institutions: 10 (members of Spanish Oncology Genitourinary Group). Key Inclusion Criteria: Subjects with histological confirmation of T2-T4a MIBC aimed for cystectomy without neoadjuvant chemotherapy; Available samples for correlative studies; Adequate medullary, renal and hepatic function. Key Exclusion Criteria: Use of immunosuppressive medication; Documented autoimmune disorders. Clinical trial information: NCT03534492.

A phase I-II study to evaluate safety and efficacy of the combination of niraparib plus cabozantinib in patients with advanced kidney/urothelial carcinoma

TPS501

Background: Niraparib (N) is an orally selective poly(ADP-ribose) polymerase (PARP)-1/-2 inhibitor approved for maintenance treatment of patients (pt) with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer after complete or partial response to platinum-based chemotherapy (CT). Cabozantinib (C) is a tyrosine kinase (TK) inhibitor with activity against TKs including VEGFR2, MET and AXL, approved on kidney cancer pt after TK failure, that has demonstrated clinical activity in heavily pretreated, advanced UC pt. c-Met receptor TK is activated in urothelial carcinoma (UC) cells. c-Met activity can decrease response to PARP inhibitors, whereas treatment with c-Met inhibitors renders cells more sensitive to PARP inhibition. UC pt with tumors overexpressing c-Met may benefit from the combination of c-Met and PARP inhibitors. This multicenter, open-label phase (ph) I-II study is to explore the maximum-tolerated dose (MTD) of N + C combination in pt with advanced genitourinary malignancies (UC and kidney cancer) follow by a preliminary efficacy of the combination in advanced UC. Methods: Eligible pt have confirmed histopathology of UC or clear cell renal cell carcinoma, advanced or metastatic disease, age ≥18 years, ECOG PS ≤1, progressive disease after platinum-based CT, measurable lesions, no prior therapy with PARP or c-Met inhibitors and adequate bone marrow, liver and renal functions. The ph I portion is enrolling ≈24 pt to identify the MTD proposed to use in a ph II (RP2D). Pt will receive N and C p.o. once daily in 28-day cycles: Dose level 1 (DL1) N/C 100/20 mg; DL2 200/20 mg; DL3 200/40 mg; DL4 200/60 mg. Pt will be accrued to each dose level in cohorts of 6 pt until the MTD is achieved (the highest dose at which ≤1 out of 6 pt experience a dose-limiting toxicity [DLT]). DLT will be evaluated during the first 2 cycles. The ph 2 portion will enroll 51 UC pt to receive the RP2D. Tumor response will be assessed per RECIST v1.1. Endpoints of the ph 2 are 6-month PFS (primary), overall response rate, disease control rate, duration of response, PFS and OS. Tissue and plasma sample will be collected for translational study. Clinical trial information: NCT03425201.

NGS, RNA-Seq, TIL, and PTEN analyses in prostate cancer specimens from patients enrolled in the study of the Akt inhibitor ipatasertib (Ipat) combined with abiraterone acetate (AA)

310

Background: In Phase III studies, ipilimumab did not extend OS in unselected populations with metastatic castration-resistant prostate cancer (mCRPC) (Kwon, 2014; Beer, 2014), suggesting that successful cancer immunotherapy development strategies require the evaluation of treatment effects in biomarker-driven segments. In addition, PTEN loss has been identified as a potential mechanism of resistance to immunotherapy (Peng, 2016). Therefore, we explored possible associations between cancer immunity (CI)-related biomarkers and PTEN loss in mCRPC samples. Methods: Tumor samples obtained in the Phase II study of AA ± Ipat in patients with mCRPC (de Bono, ESMO 2016) were retrospectively profiled. DNA alterations and tumor mutational burden (TMB) were assessed by FoundationOne. RNA-seq analysis of multiple CI-related expression signatures was performed. Tumor-immune lymphocyte (TIL) scores were analyzed in 3 compartments (stromal, sTIL; intratumoral, iTIL; peritumoral, pTIL) based on H&E stained specimens. Up to 10 evenly distributed fields were examined; the average of these fields was used to estimate the %TILs for each compartment. Results: Strong associations were observed between multiple CI-related signatures (e.g., INFγ-induced, immune checkpoints, Treg, checkpoint inhibitors). Fewer than 10% of the samples had a high level (≥ 10% of the tumor area) of TIL infiltration in any compartment (Table). TIL scores, TMB values, PTEN status and Gleason score all appeared to be independently associated, and none were associated with CI-related gene signatures, except for a possible association between pTILs and the B-cell signature (ρ = 0.49, P < 0.0001). Conclusions: Comprehensive high-content profiling of prostate cancer samples suggests that PTEN status and CI-related biomarkers were independently associated, while TMB and TIL values were generally not associated with CI-related signatures. Clinical trial information: NCT01485861. [Table: see text]

Phase II trial of afatinib in patients with advanced/metastatic urothelial carcinoma (UC) with genetic alterations in ERBB receptors 1-3 who failed on platinum-based chemotherapy (CT)

TPS540

Background: First-line treatment of patients (pts) with advanced/metastatic UC consists of platinum-based CT, with no well-established subsequent therapy for platinum-refractory disease. Although checkpoint inhibitors have shown promising results recently, targeted agents have generally not demonstrated significant clinical activity in this setting. Around 20% of UC harbor ERBB family genetic alterations, as such it may be a suitable therapeutic target (Knowles, Nat Rev Cancer 2015;15:25–41). The irreversible ERBB family blocker, afatinib, has shown activity in a Phase II trial in a subset of pts with UC who had ERBB2/ERBB3 aberrations (Choudhury, J Clin Oncol 2016;34:2165–71). This Phase II trial will evaluate afatinib in pts with UC molecularly selected for ERBB receptor alterations. Methods: This single-arm trial will assess the efficacy and safety of afatinib in pts with UC harboring ERBB2/ERBB3 mutations or ERBB2 amplification (Cohort A), or EGFR (ERBB1) amplification (Cohort B). Eligible pts are ≥18 years of age with ECOG PS 0–1, histologically confirmed advanced/metastatic UC of the bladder, upper tract or urethra, not amenable to surgery and progressing during or after platinum-based CT, with available archival tissue samples for pre-screening biomarker analysis. Pts will receive oral afatinib 40 mg/day until disease progression or discontinuation. Cohort A is enrolling in two stages, with Stage 2 enrollment based on anti-tumor activity observed. The primary endpoint is progression-free survival (PFS) rate at 6 months; secondary endpoints include objective response rate, PFS, overall survival, disease control rate, duration of response and tumor shrinkage. Trial objectives will be analyzed separately for the two cohorts. Safety and biomarker assessments will also be performed. The trial commenced in June 2016; as of October 4, 2017, 201 samples have been analyzed, with 24.3% and 8% of pts with genetic alterations potentially eligible for inclusion in Cohort A and B, respectively. To date, 12 pts have received study treatment in Cohort A and 6 in Cohort B; recruitment is ongoing. Clinical trial information: NCT02780687.

Association of CTC detection by AdnaTest with outcome on enzalutamide in chemotherapy-naïve castration-resistant prostate cancer: Exploratory results from PREMIERE—A SOGUG trial

5052

Background: Circulating tumor cells (CTCs) enumeration using CellSearch correlates with clinical outcome in prostate cancer, but is limited for gene expression analysis. AdnaTest ProstateCancer is a commercially available CTC immune-enrichment and PCR-related detection method that allows gene expression studies (Antonarakis E, NEJM 2014). It has demonstrated incremental detection of CTCs in patients with no CTCs identified by CellSearch (Samoila A, ASCO 2013) but needs to be clinically qualified. There is a strong need for studies to assess the association with the clinical outcome in CRPC. Methods: Between February and November 2015, 98 asymptomatic or oligo-symptomatic chemotherapy-naïve mCRPC pts were recruited in 16 institutions. Although initially designed to study the predictive value of TMPRSS2-ETS, data emerging after the trial was initiated led the group to prioritize alternative predefined exploratory biomarkers, including plasma AR (Grande E, ASC0 2017 #) and CTC characterization (Grande E, ESMO 2016). Outcome measures included PSA-PFS (sPFS), radiographic PFS (rPFS) and OS. Cox regression was used for survival analyses and Fisher’s exact test for PSA response. Results: Ninety-eight patients had CTC blood samples available. CTCs were detected at baseline, 12 weeks and progression in 36% (35/98), 27% (26/95) and 78% (32/41), respectively. The CTC conversion rate (positive to negative after 12 w) was 43% (15/35). All CTC conversions had ≥50% decline in PSA (15/15) whereas only 35% (7/20) of pts with persistent CTCs. At first interim analysis, with a median follow-up of 10.6 months, detection of CTCs at baseline was associated with worse sPFS (median, 7.59 m versus NR, HR, 3.67; 95% CI 1.90-7.10; P < 0.001), rPFS (median, 12.9 m versus NR; HR, 7.61; 95% CI, 2.80-20.64; P < 0.001) and OS (medians NR, HR, 9.51; 95% CI, 1.11-81.52; P = 0.0398). CTC positive pts were less likely to have a ≥90% decline in PSA (OR, 2.88; 95% CI, 1.13-7.72; P = 0.02). Conclusions: CTC detection using AdnaTest is associated with an adverse outcome in chemotherapy-naïve asymptomatic or oligo-symptomatic mCRPC pts. Clinical trial information: NCT02288936.

Predictors of radiologic progression free survival (rPFS) during abiraterone acetate (AA) treatment in a randomized phase II study of AA maintenance in combination with docetaxel (D) after disease progression to AA in metastatic castration resistant prostate cancer (mCRPC): ABIDO-SOGUG trial

e16536

Background: AA improves OS and rPFS in asymptomatic/minimally symptomatic mCRPC patients. D is currently one of the standard treatments after progression to AA. However, the value of maintaining AA along with D despite progression to AA has not been tested. ABIDO trial aims to evaluate efficacy and safety of AA + D maintenance after disease progression to first line AA in mCRPC. Clinicopathologic features associated with rPFS during first line AA are presented. Methods: ABIDO trial is a randomized, phase II, open-label study with two stages. In stage I pts receive AA (1000 mg + prednisone (P) 10 mg qd) until progressive disease. In the stage II pts will be randomized to receive three-weekly D 75 mg/m2plus P 10 mg/d with (arm A) or without (arm B) AA 1000 mg/d. Pts had no visceral metastases, ECOG PS 0-1, and adequate organ functions. Clinicopathological predictors for rPFS to first line AA were estimated using the Kaplan-Meier method and independent associations were evaluated using Cox regression models. Results: 143 pts were included. Analyzed variables were: median age was 70y, 60% of pts had ECOG 0, 84% bone metastases (18% > 4), 42% BPI score 2-3, 53% Gleason > = 8, 30% PSA > 80 ng/mL, 38% node involvement and 11% had at least one lymph node > = 3 cm; 53% of pts achieved 4 weeks PSA reduction > 50%.Median rPFS was 18 months. Univariate analysis identified as significant variables: PSA, BPI, Gleason, node involvement, 4 weeks PSA reduction > 50%, and total volume of lymph node metastasis. On multivariate analysis, BPI (0-1 vs 2-3) (hazard ratio [HR] 1.81; p = 0.039), Gleason ( < 8 vs > = 8) (HR 2.51; p = 0.005), node involvement (no nodes, nodes < 3 cm and at least 1 node > = 3 cm (HR 2.8; p = 0.001 and 3.57; p = 0.009) and PSA reduction > 50% (HR 3.06; p < 0.001) were independently associated with rPFS. Median rPFS was superior in pts with 3 or more good prognostic factors (14m vs not reached; p < 0.001). Conclusions: BPI, Gleason, node involvement and 4-week PSA response were identified as independent prognostic factors for rPFS in first line AA treated patients. Clinical trial information: NCT02036060.

Association of androgen receptor (AR) gene status in plasma DNA with outcome on enzalutamide in chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC): Exploratory results from the PREMIERE trial—On behalf of SOGUG

5016

Background: Building on previous discoveries studying AR status in plasma (Carreira S, Sci Transl Med 2014, Romanel A, Sci Transl Med 2015) and following a road-map for biomarker development, we aimed to clinically qualify AR status in chemotherapy-naïve mCRPC using an optimized multiplex droplet digital PCR (ddPCR) assay (Condeduca et al.;ASCO2017;Abstract#). Methods: Between February and November 2015, 98 asymptomatic or oligo-symptomatic chemotherapy-naïve mCRPC patients were recruited in 16 Spanish hospitals. Tissue and blood samples were required at study entry. Although initially designed to study the predictive value of TMPRSS2-ETS, data emerging after the trial was initiated led the group to prioritize alternative predefined exploratory biomarkers, including plasma ARand CTC characterization (Grande E. ESMO 2016 & Font A. et al; ASCO2017; Abstract #). Outcome measures included PSA-progression-free survival (sPFS), radiographic progression-free survival (rPFS) and overall survival (OS). Cox regression was used for survival analyses and Fisher’s exact test for PSA response. Results: Ninety-four patients had plasma DNA available for analysis. At baseline, AR gain was present in 11 pts (12%) and CTCs in 35 (37%). AR gain in CTC-positive and negative patients was 20% and 7%, respectively. At first interim analysis and with a median follow-up of 10.6 months, detection of AR gain was associated with worse sPFS (median, 3.60 versus 15.5 m, HR, 4.33; 95% CI 1.94-9.68; P < 0.001), rPFS (median, 3.90 m versus not reached HR, 8.06; 95% CI, 3.26-19.93; P < 0.001) and OS (medians not reached, HR, 11.08; 95% CI, 2.16-56.95; P = 0.004). These results were independently associated in multivariate analysis including cfDNA and CTCs for all described endpoints. AR gain patients were less likely to have a ≥50% decline in PSA (OR, 4.93; 95% CI, 1.30-18.75; P = 0.025). Conclusions: Detection of AR gain in plasma using a robust multiplex ddPCR method predicts an adverse outcome in chemotherapy-naïve mCRPC. Further prospective randomized studies are warranted. Clinical trial information: NCT02288936.

Phase II clinical and pharmacokinetic (PK) trial of zalypsis (Z) in patients with urothelial carcinoma (UC) progressing after a first-line platinum-based regimen

e15001

Background: Platinum-based chemotherapy (CT) is beneficial as first-line treatment of advanced UC. However, the majority of patients develop recurrent disease with poor long-term survival rates. Attempts to improve second-line treatments have evaluated single agents and multi-drug combinations, neither of which has managed to improve survival or achieve durable responses. Z is a cytotoxic agent that induces apoptosis by acting at cell cycle level, has DNA-binding properties and inhibits transcriptional responses. Z has shown anti-tumor activity in vitro and in vivo in xenograft models. Based on the activity observed in a phase I study (1PR and 2 SD) in advanced bladder cancer, we have designed a phase II study to explore the efficacy of Z in this setting. Methods: Patients with histologically-confirmed advanced or metastatic UC, who had failed one prior line of platinum-based CT, with proven progression or relapse before study entry, were included. Patients were treated with a Z intravenous infusion of 3 mg/m2 over 1-hour and every 3 weeks. A two-stage design was chosen; at least four (of 17) evaluable patients had to reach the primary endpoint during the first stage in order to progress into a second stage of up to 37 patients. The primary endpoint was tumor control rate (TCR): percentage of patients with objective response (OR) of any duration or patients alive and progression-free (PFS) at three months. Results: Twenty patients of a median age of 71 years (r: 54-83) were enrolled after a median of one prior treatment line (r:1-2). One patient was considered non-evaluable. No ORs were observed and only one patient had PFS ≥ 3 months. The median time on treatment was 1.68 months (r: 0.76-4.21). Toxicity consisted mostly of grade 1-2 fatigue, anorexia and nausea. Five patients had isolated troponin I increases (with no ECG or LVEF findings). Hematological toxicity was mild, one patient had grade 3 neutropenia and one patient had grade 3 thrombocytopenia. Conclusions: Only one patient reached the primary endpoint (TCR) during the first stage; consequently, the study was closed and no further development was considered.

BRCA1, RAP80, and AEG-1 mRNA expression in resectable muscle-invasive bladder cancer (MIBC) patients (p) treated with neoadjuvant cisplatin-based chemotherapy

4579

Background: Cystectomy remains the standard treatment in MIBC and only a minority of p are treated with neoadjuvant chemotherapy, suggesting that predictive markers of chemotherapy outcome are needed. Low BRCA1 mRNA expression is associated with an improvement in survival in bladder cancer p treated with cisplatin-based chemotherapy. However, BRCA1 function can be modulated by other DNA repair genes. RAP80 is required for the accumulation of BRCA1 to sites of DNA breaks, and cells depleted of RAP80 exhibit hypersensitivity to irradiation. AEG-1 can induce BRCA1 expression and cause chemoresistance. Methods: Paraffin-embedded pre-treatment tumor samples were collected by transurethral resection from 65 p with resectable MIBC stage T2-4N0M0 treated with neoadjuvant cisplatin-based chemotherapy. Gene expression levels of BRCA1, RAP80 and AEG-1 were quantified by real-time quantitative PCR. Expression levels were divided into terciles and correlated with median survival (MS). Results: 33 p were treated with cisplatin, methotrexate and vinblastine (CMV) and 32 p with cisplatin and gemcitabine. Chemotherapy was followed by cystectomy in 60 p. Overall MS was not reached and 5-year survival was 51%. MS was 45 months (m) and 5-year survival was 27% in 21 p with high BRCA1 mRNA levels vs 168 m and 59% in 44 p with low and intermediate levels (p=0.05). MS was 50 m in 15 p with high AEG-1 levels, 45 m in 15 p with intermediate levels, and was not reached in 18 p with low levels, although these differences were not statistically significant (p=0.3). No differences in MS were observed according to RAP80 mRNA levels. Conclusions: BRCA1 can be a useful marker to predict the efficacy of neoadjuvant chemotherapy. Cisplatin-based chemotherapy should be recommended in p with low/intermediate BRCA1 expression. Further studies with larger numbers of p are warranted to elucidate the role of AEG-1 in this setting.

Phase II trial of cabazitaxel in patients with advanced or metastatic transitional cell carcinoma of the urothelial tract who have progressed within less than 12 months after cisplatin-based chemotherapy: A Spanish Oncology Genitourinary Group (SOGUG) study

TPS4672

Background: Advanced transitional cell carcinoma of the urothelium (TCCU) on progression after previous cisplatin-based combination is generally an incurable disease. The appropriate management of these patients is still an unmet need. Many drugs have shown modest or no activity in previous phase 2 trials. Population heterogeneity in these studies emerges as one of the key determinants that could explain the variable outcomes. Recently, in a phase III study in this setting, prognostic factors (PF) for overall survival were identified (Bellmunt J et al, JCO 2010). Taxanes are active drugs in 2nd-line metastatic TCCU. Cabazitaxel (C) is a semi-synthetic taxane that is a poor substrate for the multidrug resistance system. C could be a valid alternative in this patient population. Methods: This is an open label phase II study of C in patients (pts) with advanced or metastatic TCCU who have progressed within 12 months after receiving a 1st-line platinum based chemotherapy. There are three treatment arms as patients will be assigned to one of three groups previously defined based on the presence of 0, 1 or 2-3 PFs as defined by Bellmunt et al. The activity of C will be assessed separately in each group and overall. The primary endpoint is response rate (RR) evaluated according to RECIST 1.1, a maximum of 35 pts are needed in each subgroup (maximum number of pts required: 105). Secondary objectives are RR in the whole population, toxicity, progression-free survival and overall survival. In addition, an external validation of the prognostic model proposed by Bellmunt will be conducted, as well as a pharmacogenomic study in order to better define the toxicity profile of the drug and the potential responders.

Vinflunine maintenance therapy versus best supportive care (BSC) after platinum combination in advanced bladder cancer: A phase II, randomized, open-label study (MAJA study)—SOGUG 2011-02

TPS4674

Background: Vinflunine is a novel microtubule inhibitor currently approved by EMA as treatment after platinum progression, in metastasic bladder cancer. It is distinguished from the other vinca-alkaloids because it binds relatively weakly to tubulin, suggesting an improved tolerance profile as a result of less neuropathy. Based on the fact that no cumulative toxicity is expected and the results reported in second-line, we aim to test the role of vinflunine in first line therapy, as maintenance treatment for patients who obtain clinical benefit after platinum. Methods: This is a multicenter, randomized, open label, proof-of-concept study that will be performed in 20 institutions members of the Spanish Oncology Genitourinary Group (SOGUG). Subjects will be randomized in a 1:1 ratio to receive vinflunine 320 mg/m2 every 21 days plus BSC vs BSC alone until disease progression. Vinflunine dose will be 280mg/m2 for patients with PS=1, age ≥ 75 years, prior pelvic radiotherapy or creatinine clearance Cr <60ml/min. Stratification factors are: 1) Scheduled dose at randomization (320 vs 280mg/m2) 2) Liver metastasis (Y/N). Main inclusion criteria are: Subjects ≥18 and< 80 years of age with histological diagnosis of transitional cell carcinoma of the urothelial tract and measurable disease with radiological response or stabilization after 6 cycles of a platinum containing doublet for metastasic/advanced disease. Primary objective will be progression free survival (PFS), considering as clinically relevant 6 months in experimental arm. To guarantee an overall type-1 α error (one side) no greater than 0.05 and a type II (β) error 0.1 for the primary endpoint of PFS, a sample size of 86 patients allocated in a 1:1 ratio is planned. Recruitment is scheduled to start by February 2012. A pharmacogenomic translational study will also be conducted.