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Objective To harness the frontline therapy in advanced penile squamous cell carcinoma (PSCC), for which chemotherapy exerts moderate activity but poor efficacy. Dacomitinib is an irreversible, pan-epidermal growth factor receptor (HER) inhibitor. Patients and Methods In a phase 2 study (NCT01728233), patients received dacomitinib 45 mg/day, orally, continuously. Inclusion criteria were SCC histology, clinical stage N2-3 or M1 (TNM 2009), and no prior chemotherapy administration. The primary endpoint was the objective response-rate (ORR, according to RECIST v1.1). Stopping rules based on the Bayesian posterior probability (PP) to demonstrate that the ORR exceeded 20% were set. Results From June 2013 to October 2016, 28 patients were treated. Eight (28.6%) had visceral metastases, 14 (50%) had pelvic and 17 (60.7%) clinically-involved bilateral lymph nodes. One complete and eight partial responses were obtained (ORR: 32.1%, 80% credibility interval 21.0-43.0%). The median follow-up duration was 19.8 months (IQR: 6.3-25.7); 12-month progression-free survival was 26.2% (95%CI: 13.2-51.9); 12-month overall survival (OS) was 54.9% (95%CI: 36.4-82.8). The median OS of locally-advanced patients was 20 months (IQR: 11.1-not reached). The Bayesian PP of exceeding the 20% ORR target was 92.3%. Grade 3 adverse events (skin rash) were seen in 3 patients (10.7%). Tissue samples from 25 patients were analyzed. Only two patients had HR-HPV-positive tumor. EGFR amplification was found in 4 patients (equally responders and non responders) and it was confirmed in all post-dacomitinib samples. TERT mutations (60%) were found in responders only, PI3K/mTOR pathway gene mutations in 42.9% responders versus 8.3% non responders. Conclusion Dacomitinib was active and well tolerated in patients with advanced PSCC and may represent an option when combination chemotherapy cannot be administered. Mutations in downstream effectors of EGFR signaling in relation to dacomitinib activity deserve further studies. This article is protected by copyright. All rights reserved.

Background Outcomes of neoadjuvant chemotherapy in patients with muscle-invasive urothelial bladder carcinoma (MIUBC) should be improved. Sorafenib was combined with gemcitabine and cisplatin chemotherapy (SGC) in an open-label, single-arm, phase 2 trial (NCT01222676). Patients and methods After transurethral resection of the bladder, T2–T4a N0 patients received four cycles of SGC followed by cystectomy. Sorafenib 400 mg q12h daily, continuously, was added to standard GC chemotherapy. In a Simon's 2-stage design, the primary endpoint was the pathologic complete response (pT0), assuming H0: ≤0.20 and H1: ≥0.40, with a type I and type II error of 5% and 10%, respectively. Results From April 2011 to June 2016, 46 patients were enrolled. Pathologic T0 response was obtained in 20 patients (43.5%, 95% CI: 28.9–58.9); pT ≤ 1 in 25 (54.3%, 95% CI: 39.0–69.1). After a median follow-up of 35 months, the median progression-free survival was not reached (NR, interquartile range: 23.6–NR), nor was median overall survival (interquartile range: 30.3–NR). Hematologic and extrahematologic grade 3 to 4 adverse events occurred in 45.6% and 26.1% of patients, respectively. In 29 samples from responders (pT ≤ 1) and nonresponders, different distribution of missense mutations involved DNA-repair genes, RAS-RAF pathway genes, chromatin-remodeling genes, and HER-family genes. ERCC1 immunohistochemical expression was associated with pT ≤ 1 response ( P = 0.047). The absence of a comparator arm prevented us to quantify sorafenib contribution. Conclusions SGC combination was active in MIUBC, and the identified molecular features included alterations that may help personalize treatment in MIUBC with new more potent targeted agents, combined with chemotherapy.

Background: Therapeutic options for patients with chemoresistant germ cell tumors (GCTs) are limited. Pazopanib is a selective tyrosine kinase inhibitor with distinct antiangiogenic activity. We aimed to evaluate pazopanib activity in patients with refractory GCT. Patients and methods: In the open-label, single-arm, phase 2 Pazotest study (NCT01743482), patient eligibility included failure of >= 2 platinum-based regimens, and allowed prior high-dose chemotherapy administration. Patients were given pazopanib 800 mg/day until disease progression (PD) or onset of unacceptable toxicity. Measurements of serum tumor markers (STM), computed tomography and FDG-PET were carried out at baseline, after 4 weeks of pazopanib treatment, and every 8 weeks thereafter. PD was defined as increasing levels of STM, increasing size of non-teratomatous masses, or appearance of new lesions. The study primary endpoint was progression-free survival (PFS, H0: 3-month PFS = 25%, alpha = 5%, beta = 20%). Results: Forty-three patients were enrolled from May 2013 to July 2016. The number of prior chemotherapy regimens was: 2 (11.6%), 3 (51.2%), >3 (37.2%). Grade 3 adverse events were observed in six patients (13.9%). Overall, 70.3% of patients had reduced levels of STM after 4 weeks. There were 2 partial responses (4.7%), 19 cases of stable disease, and 16 cases of PD (6 not evaluable by RECIST). The median follow-up duration was 29.6 months. The 3-month PFS probability was 12.8% [95% confidence interval (CI): 5.7%-28.9%]. The 24-month OS probability was 14.2% (95% CI: 6.0%-33.7%). In patients with a > 50% decline in STM, the 24-month OS probability was 24.1% (95% CI: 8.3%-69.6%). The small sample size was the major limitation. Conclusions: Despite pazopanib showed potent but short-lived activity in refractory GCT, long-term survival was obtained in a proportion of treated patients. According to the kinetics of pazopanib activity, this drug may be investigated in less pre-treated patients as an optimal bridging therapy preceding and/or combined with salvage chemotherapy.

Background Progress in developing effective salvage therapies for UC is warranted. Alisertib is an orally available, selective inhibitor of the aurora kinase A. Methods A single-group, phase 2 trial was conducted with alisertib 50 mg orally BID for 7 days, with 14d rest until disease progression (PD) (NCT02109328). The primary endpoint (EP) was RECIST 1.1 objective response-rate (ORR, H-0 a parts per thousand currency sign 5 %, H-1 a parts per thousand yen 20 %, alpha = 10 % and beta = 20 %). Eligibility included failure of at least one platinum-based regimen. Results From 10/2014 to 04/2015, 22 patients were enrolled (20 evaluable for response), 8 (36.4 %) in second-line and 14 (63.6 %) beyond the second-line. Eight (36.4 %) had an ECOG-performance status 1-2. Two partial responses (PR, ORR: 9.1 %), 7 stable disease (SD) and 11 PD were obtained. Median follow-up was 8.3 months (IQR: 7-10.3), 6-month progression-free survival (PFS) was 13.6 % (95%CI: 4.8-39.0). Two SD are still receiving treatment after 11.5 and 6.3 months. Median overall survival (OS) was not reached (6-month OS: 59.1 %, 95%CI: 41.7-83.7). Hb < 10 g/dl was significantly associated with shorter PFS and OS multivariably (p = 0.031 and p = 0.033). Tissue of the case with 11.5 month SD harbored a missense mutation of mTOR (E1813D), the nonsense mutation Q527STOP of TSC1, HER3 and TAF1L missense mutations. Grade 3-4 adverse events (AE) were: 40.9 % mucositis, 36.4 % fatigue, 18.2 % neutropenia (13.6 % febrile neutropenia). There were 2 treatment-related deaths. Conclusions The study did not meet the primary EP, yet sustained disease control was obtained in about 14 % of patients. The incidence of AE and the issue of patient selection are two major concerns.

Background: The prognosis of patients (pts) with PSCC is primarily depending on the involvement of regional lymph nodes. Owing to the limited efficacy of chemotherapy, new drugs are warranted. Dacomitinib (Daco) is a potent, irreversible TKI of human EGFR/HER1, HER2 and HER4. Methods: In a phase 2 study (NCT01728233), pts received Daco 45 mg/d, orally, continuously. Inclusion criteria were SCC histology, and clinical stage N2-3 or M1; no prior chemotherapy was allowed. Computed tomography (CT) and PET/CT scans were repeated q8 weeks. Responding (R) pts with locally-advanced (LA) PSCC were offered radical surgery. The primary endpoint was the objective response-rate (ORR=CR+PR according to RECIST v1.1). Stopping rules based on the Bayesian posterior probability (PP) were set; the target was to demonstrate that the ORR exceeded 20%. Translational analyses on pre-Daco tumor samples included: EGFR and HER2 amplification, in-situ hybridization for HPV, and next generation sequencing. Results: From 06/13 to 010/16, 28 patients were treated. 8 (28.6%) had visceral metastases. 50% had pelvic and 60.7% clinically-involved bilateral LN. 1 CR + 8 PR were obtained (ORR=32.1%, 80% credibility interval 21.0-43.0%). The median follow up was 19.8 months (IQR: 6.3-25.7); 12-m PFS was 26.2% (95%CI: 13.2-51.9); 12-m OS was 54.9% (95%CI: 36.4-82.8). The median OS of LA pts was 20 months (IQR: 11.1-NR). The current Bayesian PP of exceeding the 20% ORR target is 92.3%. Grade 3 adverse events (skin rash) were seen in 3 pts (10.7%). The median drug exposure was 2.2 months. Tissue samples from 25 pts were analyzed. Only 2 pts were HPV+ (1SD, 1PD). EGFR ampl was found in 4 pts (1 CR, 1 PR, 2 SD) and it was confirmed in all post-Daco samples. TERT mutations (60%) were found in responders only, PI3K/mTOR pathway gene mutations in 42.9% R vs 8.3% non responders, IGF2R in 40% and 20%, respectively. Mutations were largely consistent between matched pre- and post-therapy samples in 7 evaluated pts. Conclusions: Daco was active in advanced PSCC and provided the best ORR with a single agent in PSCC. The biology underlying response to Daco seems to be independent from HER-pathway alterations. The frontline therapy can provide a suitable window of opportunity to test new drugs in PSCC. Note: This abstract was not presented at the meeting. Citation Format: Andrea Necchi, Salvatore Lo Vullo, Daniele Raggi, Patrizia Giannatempo, Nicola Nicolai, Giuseppina Calareso, Elena Togliardi, Maurizio Colecchia, Federica Perrone, Annunziata Gloghini, Luigi Mariani, Roberto Salvioni. First-line therapy with dacomitinib, an orally available pan-her tyrosine kinase inhibitor, for locally-advanced or metastatic penile squamous cell carcinoma: Results of an open label, single-arm, single-center, phase 2 study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT139. doi:10.1158/1538-7445.AM2017-CT139

e16018 Background: S-GC neoadjuvant chemotherapy (NACT) was active in a phase 2 trial in MIBC, showing a response rate (downstaging to pT < 2) of 54.3% in 46 pts within a single-arm, phase 2 trial ( Necchi et al, GU ASCO 2017). The addition of S to GC may help investigators unravelling key molecular features underlying response in MIBC. Methods: Analyses were made on pre- and post-treatment TURB and cystectomy (Cy) specimens (10µm sections) and matched germline DNA of 29/46 pts. Analyses included measurements of ERCC1 (by immunohistochemistry, IHC) on TURB specimens, baseline circulating VEGF levels (ELISA), copy number variations (CNV, Affymetrix), and next generation sequencing (NGS, custom gene panels through the Ion AmpliSeq Library Kit2.0™ and the Ion Torrent Personal Genome Machine™ platform). Results: We analyzed TURB samples from 15 responders (R) and 4 non-R (NR). An additional 10 Cy samples were used for NR. Baseline VEGF levels were not associated with PFS or OS on univariable analyses (p = 0.943 and p = 0.669, respectively). Differences in R vs. NR pts were found according to CNVs and NGS. CN gains on regions of chromosome (chr) 18 and 20 and loss in chr 5 were found in 56-60% of R and in none of the NR. Gains on regions of chr 3 and losses in chr 1 and 20 were more frequent in the NR ( > 50%) vs. R ( < 20%). The median number of somatic mutations (mut) per sample was 3 (range, 0-19). Missense mut in DNA-repair genes ( POLK; FANCM; PRKDC; BLM; MSH2; MSH6; RAD50) were found in 63.6% R vs 16.7% NR, in RAS-RAF pathway genes ( CDKN2A; RAC1; KRAS; NF1) in 45.4% vs 7.1%, in chromatin-remodelling genes ( ARID1A; ARID2; KDM5C; SMARCA4; ATRX; KMT2C; DAXX; SETD2) in 54.5% vs 16.7%, and in HER-family genes in R only (36.4%). ERCC1 IHC expression was found in 55.6% R vs 93.3% NR (p = 0.047). Conclusions: We identified distinct molecular features of R vs NR to S-GC in MIBC. These features may be linked to a potentially-additive effect of S and CT. The identification of the targets of CNVs will further elucidate the underlying biology. These results may help developing personalized medicine in MIBC with new more potent targeted agents with CT. Clinical trial information: NCT01222676.

414 Background: Therapeutic options for patients (pts) with chemoresistant GCT are limited and prognosis is poor. PZP is a potent and selective tyrosine kinase inhibitor (TKI) with distinct antiangiogenic activity. Methods: In Pazotest trial (NCT01743482), pts were given PZP 800 mg/day until disease progression (PD) or unacceptable toxicity. Eligibility included failure of ≥ 2 platinum-based CT, including high-dose (HD)-CT. Baseline serum tumor markers (STM), computed tomography and FDG-PET were repeated after 4 wks and q8 weeks thereafter. The primary endpoint was PFS (H0: 3-m PFS ≤ 10%, H1: ≥ 25%, α = 5%/β = 20%). PD was defined as rising STM, increasing size of nonteratomatous masses (RECIST v1.1), or the appearance of new lesions. Translational analyses included circulating IL8 levels and next generation sequencing of pre-PZP tissue from extreme responders. Results: 43 pts were enrolled from 05/2013 to 07/2016. 35 pts (81.4%) had nonseminoma, 6 (14%) primary mediastinal GCT. The number of failed CT regimen was: 2 (11.6%), 3 (51.2%), > 3 (37.2%). 53.5% had failed HDCT. 39 pts had elevated STM: 56.4% AFP, 43.6% HCG. Grade 3-4 adverse events were seen in 4 pts (increased AST/ALT). 26/39 pts (66.7%) had STM reduction (38.5% > 50% from baseline) after 4 wks. RECIST results: 1 partial response, 20 stable disease, 16 PD (6 not evaluable). 12 (27.9%) had a decreased FDG uptake. Median follow-up was 29.6 months. 3-m PFS was 12.8% (95%CI: 5.7-28.9), median PFS was 2.5 m (IQR: 1.0-3.0). 24-m OS was 14.2% (95%CI: 6.0-33.7). In pts with > 50% STM decline, 24-m OS was 24.1% (95%CI: 8.3-69.6). Univariably, STM was associated with OS (HCG vs AFP: HR: 2.73, 95%CI: 1.24-6.02, p = 0.042). Baseline and +4wks IL8 levels did not predict for PFS/OS. In 2 responding pts, new mutations were found ( FLT3, G846V and RAD50 E448Q classified as damaging; TSC2, R197M and TNF A16V classified as benign). Conclusions: PZP was well tolerated and showed predictable activity, with early but short-living STM decline. Long term survival was obtained in a significant proportion of pts. Based on the present results, PZP may be investigated in earlier disease stages as an optimal bridging therapy preceding salvage curative treatment. Clinical trial information: NCT01743482.

345 Background: Despite cisplatin-based chemotherapy (CT) is recommended in MIUBC, an unmet need is to identify new drugs or combinations to improve the outcomes. SGC combination was evaluated in an open-label, single-arm, phase 2 trial (NCT01222676). Methods: After TURB, pts with T2-T4a N0 MIUBC received 4 cycles of cisplatin 70 mg/m2 d1, gemcitabine 1000 mg/m2d1 and 8, q3 wks. Sorafenib 400 mg q12h was administered daily from day 1 until radical cystectomy. In a Simon’s 2-stage design, the primary endpoint was pathologic complete responses (pT0). Residual carcinoma in situ was considered pT0. ITT analysis was applied. Statistical hypothesis assumed H0: ≤0.20 and H1: ≥0.40 (α and β of 5% and 10%). ERCC1 immunohistochemistry (IHC) and next-generation sequencing (NGS) of TURB tissue, and measurement of baseline circulating VEGF levels, were planned. Results: From 04/2011-06/2016, 45 pts were enrolled. 28 pts (62.2%) had macroscopical residual disease after TURB, 17 (37.8%) presented with clinical stage T3-4. pT0 was obtained in 19 pts (42.2%, 95%CI: 27.6-57.9); pT≤1 in 24 (53.3%, 95%CI: 37.9-68.3). After median follow-up of 35 months, median PFS was not reached (IQR: 29.4-NE), like median OS (IQR: 30.3-NE). Pathological response (pT0 vs pT≤1 vs other) predicted for both PFS (p=0.015) and OS (p=0.046). Hematologic (hem) G3-4 adverse events (AE): platelet 28.9%, neutrophils 15.6%, Hb (4.4%). Extra-hem AEs were seen in 9 pts (20%). 24 (53.3%) pts needed S temporary interruption (5 cases discontinuation). Tumor samples were available from 23 pts for ERCC1-IHC, 24 for NGS: ERCC1 IHC expression was associated with non response (pT≥2, p=0.033). ERBB2/ERBB3 mutations were found only in responders (pT≤1, 20%). PIK3CA/AKTmutations (missense, and newly-identified mutations) were more frequent in pT≥2 pts (35.7% vs 20%). Baseline VEGF levels did not predict for PFS/OS. NGS of the remaining pts of the trial is ongoing. Conclusions: SGC combination was active and effective in MIUBC. Translational analyses are providing information to develop combination of CT with new more potent and selective TKIs, possibly in more selected pts. Clinical trial information: NCT01222676.

399 Background: The prognosis of patients (pts) with PSCC is primarily depending on the involvement of regional lymph nodes (LN). Owing to the limited efficacy of chemotherapy (ChT), new drugs are warranted. Daco is a potent, irreversible TKI of human EGFR/HER1, HER2 and HER4. Methods: In a phase 2 study (NCT01728233), pts received Daco 45 mg/d orally continuously. Inclusion criteria were SCC histology, and clinical stage N2-3 or M1; no prior ChT was allowed. Computed tomography (CT) and PET/CT scans were repeated q8 wks. Responding pts with LA-PSCC were offered radical surgery. The primary endpoint was the objective response-rate (ORR = CR+PR according to RECIST v1.1). The study was conducted according to a Bayesian design, based on predictive probability; the target was to demonstrate that the ORR exceeded 20%. Translational analyses on pre-Daco tumor samples included: EGFR and HER2 amplification (ampl), in-situ hybridization for HPV, and next generation sequencing. Results: From 06/13 to 09/16, 26 pts were treated. 7 (26.9%) had visceral metastases. 50% had pelvic and 57.7% clinically-involved bilateral LN. 1 CR + 7 PR were obtained (ORR = 30.4%, 95% credibility interval 14.9-48.6%). Median follow up = 16.6 months; 12-m PFS = 24.1% (95%CI: 11.1-52.3); 12-m OS = 50.7% (95%CI: 31.7-80.9). The current Bayesian posterior probability of exceeding the 20% ORR target is 89%. Tissue samples from 23 pts were analyzed. Only 2 pts were HPV+ (1SD, 1PD). EGFR ampl was found in 4 pts (1 CR, 1 PR, 2 SD) and it was confirmed in all post-Daco samples. TERT mutations (60%) were found in responders (R) only. Mutations in genes potentially associated with resistance to EGFR inhibitors ( HRAS, BRAF, PIK3CA, PTEN, STK11) were found in 47% non responders (NR) vs 25% R. HRAS and BRAF mutations segregated with NR (20%). Additional unfrequent mutations of druggable targets were found: RAC1, TSC1 and mTOR in R, FGFR2, RAD50, PDGFRB and FLT4 in NR, IGF2R in both. Conclusions: Dacomitinib was active in HPV-negative, advanced PSCC. Among multiple altered pathways, we were able to delineate the possible molecular profile of responders. An expansion cohort to confirm the translational findings is planned. Clinical trial information: NCT01728233.

Despite a compelling preclinical rationale for the use of anti-angiogenic drugs in urothelial cancer (UC), short-living responses have been observed in clinical trials. PF-03446962 is a novel monoclonal antibody against Activin Receptor-Like Kinase-1 (ALK1), a type I subclass of the TGF beta receptor, with dose-dependent anti-angiogenic activity. An open label, single-group, phase 2 trial of PF-03446962 was conducted in salvage setting. Patients failing at least one chemotherapy regimen were eligible. Design provided PF-03446962 10 mg/Kg intravenously fortnightly until disease progression (PD) or unacceptable toxicity. Two-month progression-free survival (PFS) was the primary endpoint. The trial was registered with ClinicalTrials.gov, number NCT01620970. Fourteen patients were enrolled from October 2012 to July 2013. Median age was 64 years (interquartile range [IQR]: 58.2-69.5), 9 patients had a Bellmunt score of 1-2, median number of prior drugs was 3. One stable disease and 13 PD were recorded and the study met the futility stopping rule of interim analysis. Median PFS was 1.8 months (95 %CI, 1.4-2.0). After a median follow up of 7.4 months (IQR 4.5-10.9), 8 patients are alive. Median overall survival (OS) was 8 months (95 %CI, 2.9-not estimable). Most common toxicities were thrombocytopenia (G1-2 in 5 cases, persistent G3 in one, with 3 dose delays and 1 dose interruption), fatigue and abdominal pain (G1-2 in 4 cases each). Impairment of quality of life (ESAS score) was observed as well as an increase from baseline to +2 month median levels of vascular endothelial growth factor (VEGF) and interleukin-8. PF-03446962 had no activity as single drug in refractory UC and we do not recommend further investigation outside of the combination with agents targeting the VEGF receptor axis. Despite a compelling preclinical rationale for the use of anti-angiogenic drugs in urothelial cancer (UC), short-living responses have been observed in clinical trials. PF-03446962 is a novel monoclonal antibody against Activin Receptor-Like Kinase-1 (ALK1), a type I subclass of the TGFβ receptor, with dose-dependent anti-angiogenic activity. An open label, single-group, phase 2 trial of PF-03446962 was conducted in salvage setting. Patients failing at least one chemotherapy regimen were eligible. Design provided PF-03446962 10 mg/Kg intravenously fortnightly until disease progression (PD) or unacceptable toxicity. Two-month progression-free survival (PFS) was the primary endpoint. The trial was registered with ClinicalTrials.gov, number NCT01620970. Fourteen patients were enrolled from October 2012 to July 2013. Median age was 64 years (interquartile range [IQR]: 58.2-69.5), 9 patients had a Bellmunt score of 1-2, median number of prior drugs was 3. One stable disease and 13 PD were recorded and the study met the futility stopping rule of interim analysis. Median PFS was 1.8 months (95 %CI, 1.4-2.0). After a median follow up of 7.4 months (IQR 4.5-10.9), 8 patients are alive. Median overall survival (OS) was 8 months (95 %CI, 2.9-not estimable). Most common toxicities were thrombocytopenia (G1-2 in 5 cases, persistent G3 in one, with 3 dose delays and 1 dose interruption), fatigue and abdominal pain (G1-2 in 4 cases each). Impairment of quality of life (ESAS score) was observed as well as an increase from baseline to +2 month median levels of vascular endothelial growth factor (VEGF) and interleukin-8. PF-03446962 had no activity as single drug in refractory UC and we do not recommend further investigation outside of the combination with agents targeting the VEGF receptor axis.

480 Background: Prognosis of patients (pts) failing multiple chemotherapy (CT) regimens is quite dismal. CD30 is expressed and prognostic in embryonal carcinoma, hence it is a rational target for treatment. Brentuximab Vedotin (BV) is an antibody-drug conjugate consisting of the chimeric anti-CD30 antibody SGN-30 conjugated to an antitubulin synthetic analog (MMAE). A phase 2 trial is ongoing in GCT (NCT01851200). Methods: 24 pts with biopsy-proven CD30+ GCT will receive BV 1.8 mg/Kg IV q3 weeks until disease progression or onset of unacceptable toxicity. Eligibility will include failure of 2 or 3 platinum-based CT (including HDCT). All pts will undergo measurement of serum tumor markers (STM), a computed tomography and a PET scan q6 weeks. An optimal Simon’s 2-stage design will be applied. The primary endpoint is the objective response-rate (ORR; H0: ≤ 5%, H1: ≥ 25%, α and β = 10%). In stage 1, 9 evaluable patients will be accrued. Sequential peripheral blood samples are being collected for immune profiling by flow cytometry of immune cell subsets. Results: From 07/13 to 04/15, 9 pts have been treated, 3 in third-line, and 6 beyond the third-line. 5 had received HDCT. STM decline was obtained in 7 pts (77.8%) after the first dose and in 4 pts (44.4%) after 2 doses (with normalized [1] or still positive [3] STM). ORR was 22.2% (1 CR+1 PR) according to RECIST v1.1, and there were 3 metabolic PR. 3-month PFS was 11.1% (95%CI: 0.6-38.8), 6-month OS was 85.7% (95%CI: 33.4-97.9). 1 case of reversible G3 hyperglycemia was recorded. No BV discontinuation due to toxicity occurred. In 7 evaluable pts, a trend to increasing expression of activation (HLA-DR), proliferation (Ki67), and functional differentiation (Granzyme B) markers in CD4 and CD8 T cells was observed during BV. In CR patient, an increased frequency of naive and central memory T cells was observed after the first cycle of BV, as well as a reduction in the fraction of PD1+/CD8+ T cells. Conclusions: Brentuximab is endowed with potent antitumor activity and meaningful immunomodulatory effects in GCT. The rapid development of resistance is a concern. ORR is pending confirmation in the whole sample size. Clinical trial information: NCT01851200.

382 Background: Progress in developing effective salvage therapies for UC is warranted. AAK overexpression has been described in UC and spindle checkpoint (SC) dysregulation is a common feature. Alisertib is an orally available, selective TKI of AAK. Methods: A single-group, Ph2 trial was conducted with Alisertib 50 mg orally BID for 7 days, with 14d rest until disease progression (PD) (NCT01653028). The primary endpoint was RECIST 1.1 objective response-rate (ORR), and ≥ 3/20 responses were required (H0 ≤ 5%, H1 ≥ 20%, α = 5%/β = 20%) to move to a randomized trial of paclitaxel plus either Alisertib or placebo. Eligibility included failure of ≤ 2 platinum-based regimens. Cox regression analyses were done. Targeted sequencing of pts is being performed through the Ion AmpliSeq Comprehensive Cancer Panel (Life Technologies). Results: From 10/2014 to 04/2015, 22 pts were enrolled (20 evaluable for response), 8 (36.4%) in 2nd line and 14 (63.6%) > 2ndline. 8 (36.4%) had an ECOG-PS 1-2, 3 (13.6%) had Hb < 10mg/dl, 9 (40.9%) had liver metastases. 2 PR (ORR: 10%), 7 stable disease (SD) and 11 PD were recorded. Median FUP was 6.3 mos (IQR: 4.5-8.0). 6m-PFS was 18.2% (95%CI: 7.5-44.1), including 2 pts with 9.7 and 9.5 mos FUP (still ongoing, both > 2nd line). Median PFS was 1.8 mos (IQR: 1.3-3.4), but median OS was not reached (6m-OS: 63.6%, 95%CI: 46.4-87.3). Hb < 10gr/dl was significantly associated with shorter PFS and OS multivariably (p = 0.031 and p = 0.033). AAK-IHC expression did not correlate with outcome. Tissue of pt with 9.7 month SD harbored a missense mutation of mTOR (E1813D*) and the nonsense mutation Q527STOP* of TSC1, together with HER3 and TAF1Lmissense mutations. Grade 3-4 adverse events (AE) were: 54.5% alopecia, 41% mucositis, 36.4% fatigue, 18% neutropenia (14% febrile neutropenia). There were 2 treatment-related deaths (septic shock). Conclusions: Preliminary data suggest the possibility for sustained disease control in about 20% of pts, including very long term PR/SD. Hb ≥ 10 and mutations of TSC1/mTOR (TAF1L?) might be the clinical and biological markers for patient enrichment design with SC inhibitors like Alisertib, although the incidence of AE is a major concern. Clinical trial information: NCT01653028.

481 Background: Therapeutic options for pts with chemoresistant GCT are limited and prognosis is poor. Pazopanib (PZP) is a potent and selective tyrosine kinase inhibitor (TKI) with distinct antiangiogenic activity. Methods: Pazotest-01 enrolled pts who were given PZP 800 mg/day orally until disease progression (PD) or unacceptable toxicity. Eligibility included failure of ≥ 2 platinum-based regimens, including high-dose chemotherapy (HDCT). Baseline serum tumor markers (STM), a computed tomography and a FDG-PET were repeated after 4 wks of PZP and q8 weeks thereafter. The primary endpoint was PFS (H0: 3-month PFS ≤ 10%, H1: ≥ 25%, α = 5%/β = 20%). PD was defined as rising STM, an increase in tumour size, or the appearance of new lesions. An enrolment of 43 pts was planned from a single center (NCT01743482). Results: From 05/2013 to 07/2015, 32 pts were enrolled (27 [84.4%] with nonseminoma, including 5 [15.6%] with malignant transformation, and 5 seminomas). 5 (15.6%) had primary mediastinal nonseminoma (PMNSGCT). 3 had failed two prior regimens, 15 (46.9%) three, and 14 (43.7%) > 3 regimens, including HDCT in 15 (46.9%). 20 (62.5%) had liver, bone, or brain metastases. 29 pts had elevated STM: 18 of them (62.1%) had a STM decline (mean: -53.5%). 1 PR, 19 SD (64.5% clinical benefit) and 12 PD were obtained according to RECIST v1.1. 8 pts (25%) had a densitometric and 10 (29%) a metabolic partial response. The kinetics of response was predictable in all pts: best response was seen within 4wks of starting PZP, neither PR nor STM decline occurred > 4wks. Median follow up was 15.7 months. Median PFS was 2.73 months, 3-month PFS was 28% (95%CI: 13.3-44.8). 4 pts (12.5%) were progression-free at > 5 months FUP (including 1 PMNSGCT). Median OS was 4.9 months. 4 cases (12.5%) of G3 AST/ALT increase, and 1 case of G3 diarrhea and vomiting each have been observed. 7 pts (21.9%) had G2 asthenia. Conclusions: PZP is endowed with potent anti-tumor activity in extensively pretreated patients with GCT. PZP was well tolerated, and the combination with paclitaxel is a rational next step to improve the response duration. The primary endpoint is pending confirmation in the full sample-size, and mature results will be presented. Clinical trial information: NCT01743482.

483 Background: Prognosis of pts with advanced/metastatic PSCC is poor and chemotherapy exerts a low efficacy. Targeting HER pathway is rational and promising in PSCC. Two companion trials are enrolling in the 1st-line/neoadjuvant setting (Dacomitinib, NCT01728233) and salvage setting (Afatinib, NCT02541903). Here we present the ongoing results of the former study. Dacomitinib is a potent, irreversible TKI of human EGFR/HER1, HER2 and HER4. Methods: 37 pts with clinical N2-3 or M1 disease receive oral Dacomitinib 45 mg daily until surgery or disease progression (PD)/unacceptable toxicity. No prior systemic therapy is allowed. Computed tomography and PET scan are repeated q2 months. Simon’s Optimal 2-stage design is applied. The primary endpoint is the objective response-rate (ORR = CR/PR according to RECIST v1.1: H0 ≤ 5%, H1 ≥ 20%, α and β = 10%). Next generation sequencing (NGS) with “Hot-spot cancer panel” (Ion Torrent, Life Technologies) is being performed for all enrolled pts. Results: From 06/13 to 05/15, 14 pts were treated. Median age was 57 yrs (IQR: 54-72). 4 had received inguinal/pelvic lymphadenectomy, 4 had inguinal+pelvic nodes, 10 bilateral disease, and 4 distant mets. Two pts achieved a PR (ORR: 14.3%), 8 a SD, 4 a PD. 8 pts (57.1%) had a metabolic PR. 9 pts underwent post-Dacomitinib lymphadenectomy: > 90% necrosis was seen in one patient. After a median follow-up of 6.97 months, 6 pts (42.8%) were progression-free (median PFS was 4.47 months). Median OS was 11.9 months, 1-year OS was 50% (95%CI: 8.05-82.63). Skin toxicity was observed in 7 pts (6 G1, 1 G3), G2 diarrhea in two, and bleeding of cutaneous mets in one. Tissue from one PR pt harbored missense mutations in FBXW7 (R505S), PTEN (A3T), and TP53 (R273H, loss of function mutation) genes. Conclusions: Dacomitinib is endowed with antitumor activity in PSCC. Results are pending confirmation in the whole sample size. Dacomitinib and Afatinib trials will provide insights into the targeting of HER pathway in PSCC based on prior chemotherapy administration. Preliminary data on molecular alterations linked to clinical benefit are being observed. Clinical trial information: NCT01728233.

TPS4570 Background: The paradigm shift in the treatment of urothelial cancer (UC) is perceived by the oncology community as a long-standing medical need under multiple aspects. For patients (pts) w...

384 Background: Prognosis of pts with advanced/metastatic PSCC is poor and chemotherapy exerts a low efficacy. PSCC is consistently depending on the epidermal growth-factor receptor (EGFR) pathway and early signals of activity of anti-EGFR targeting have been reported. Dacomitinib is a potent, irreversible TKI of human EGFR/HER1, HER2 and HER4. The primary objective of the trial will be to investigate the activity of PF-0299804 until surgical removal of nodal disease (locally-advanced setting) or until disease progression/onset of unacceptable toxicity (metastatic setting) (ClinicalTrials.gov NCT01728233). Methods: 37 pts with clinical N2-3or metastatic disease will receive oral dacomitinib 45 mg daily. Further eligibility requirements are ECOG-PS≤1, locoregional relapse after prior surgery, and no prior systemic therapy. Computed tomography (CT) and PET scans are scheduled at baseline and every 2 months. Simon’s Optimal 2-stage design is applied. The primary endpoint is the response-rate (CR/PR according to RECIST v1.1, H1:20%, H0: 5%). In stage 1, 12 evaluable patients will be accrued. Results: From 06/13 to 07/14, 9 pts were enrolled. Median age was 55 yrs (IQR: 54-72). 4 had received inguinal/pelvic lymphadenectomy, 4 had inguinal+pelvic nodes, 7 bilateral disease, and 2 distant mets. One patient achieved a PR, 6 a SD, 2 PD. 5 pts had a metabolic PR. After a median follow-up of 5 months, 4 pts (44.4%) are still progression-free (2-month PFS was 77.8%, 95%CI: 36.5-93.9). Skin toxicity was observed in 5 cases (4 G1, 1 G3), G2 diarrhea in two, and bleeding of cutaneous mets in one case. Conclusions: The minimum requirements to move to the second stage and full accrual have been met. Dacomitinib is showing activity in patients with PSCC. Further understanding of drug activity will come from the body of translational imaging and molecular characterization of tumors from enrolled patients. Clinical trial information: NCT01728233.

e15529 Background: Patients (pts) with GCT who fail to be cured following multiple chemotherapy (CT) courses (± high-dose CT) have an extremely poor prognosis and long-term remissions are anecdotal. Pazopanib (PZP) is a potent and selective, orally available, TKI of VEGFR1, 2, and 3, PDGFRα, PDGFRβ, and cKit. We updated the initial results of the ongoing open-label, single-group, phase 2 study which is sponsored by INT Milano. Methods: Patients failing at least 2 platinum-based CT (including high-dose CT) received PZP 800 mg/day orally until disease progression (PD) or evidence of unacceptable toxicity/side effects. All pts underwent measurement of serum tumor markers (STM), a computed tomography and a FDG-PET after 1 month and q2 months thereafter. In a Simon’s 2-stage design, the primary endpoint is 3-month progression-free survival (PFS). In stage 1, 18 evaluable patients will be accrued. If ≥ 3 pts will be progression-free at 3 months, enrolment will be extended to the 2ndstage. Results: From 06 to 12...

TPS4592 Background: Progress in developing new effective therapies in advanced and relapsing urothelial cancer has been stagnant in the last few decades and a paradigm shift is desperately needed. ...

376 Background: Patients (pts) with germ cell tumors (GCT) who fail to be cured following multiple chemotherapy (CT) courses (± high-dose CT) have an extremely poor prognosis and long-term remissions are anecdotal. Pazopanib (PZP) is a potent and selective, orally available, TKI of VEGFR1, 2, and 3, PDGFRα, PDGFRβ, and cKit. Here we report the initial results of the ongoing open-label, single-group, phase II study which is sponsored by INT Milano (ClinicalTrials.gov NCT01743482). Methods: Pts with refractory GCT received pazopanib 800 mg/day orally until disease progression or evidence of unacceptable toxicity/side effects. Eligibility requirements included failure of at least two platinum-based CT, including high-dose CT. All pts underwent measurement of serum tumor markers (STM), a computed tomography and a FDG-PET after one month of treatment and q2 months thereafter. Results: From May 2013 to July 2013, five pts were enrolled, three in fourth, and two in fifth-line. Median age was 39 (IQR: 33 to 48). Three out of five had failed high-dose chemotherapy (HDCT), two had an extragonadal primary, all pts had at least one elevated STM at baseline, the sole parameter in one patient, two had liver metastases, four pts had a retroperitoneal relapse. Four had elevation of alfafetoprotein (AFP), one of human choriogonadotropin (HCG). Four were nonseminomas, one a pure seminoma. After the first month of treatment, four out of five pts had a decrease in marker levels, one patient had disease progression (PD). Two of the responding pts had a necrotic evolution of disease at computed tomography corresponding to a RECIST and metabolic (PET/CT) progression, two had a stable disease. Two-month follow up is available for three out of four responders: one interrupted PZP for toxicity and had a marker PD, another an increase to baseline levels and the last one a further reduction (pure seminoma, one out of five confirmed response at two months). There were two cases of hepatic toxicities (one G2 and one G3-4 with dose interruption). Conclusions: PZP is endowed with preliminary activity in extensively pretreated patients with GCT. The unique availability of STM in interpreting densitometric and metabolic response might provide insights into response assessment of solid tumors under antiangiogenic therapy. Clinical trial information: NCT01743482.