EV-301 long-term outcomes: 24-month findings from the phase III trial of enfortumab vedotin versus chemotherapy in patients with previously treated advanced urothelial carcinoma

INTRODUCTION

This exploratory analysis evaluated efficacy and safety data for enfortumab vedotin versus chemotherapy over a median follow-up of ∼2 years from EV-301.

MATERIALS AND METHODS

Patients with locally advanced/metastatic urothelial carcinoma with prior platinum-containing chemotherapy and disease progression during/after programmed cell death protein 1/ligand 1 inhibitor treatment were randomized to enfortumab vedotin or chemotherapy (docetaxel, paclitaxel, vinflunine). Endpoints were overall survival (primary), progression-free survival (PFS), objective response, and safety.

RESULTS

In total, 608 patients were included (enfortumab vedotin, n = 301; chemotherapy, n = 307). With a median follow-up of 23.75 months, 444 deaths had occurred (enfortumab vedotin, n = 207; chemotherapy, n = 237). Risk of death was reduced by 30% with enfortumab vedotin versus chemotherapy [hazard ratio (HR) 0.70 (95% confidence interval [CI] 0.58-0.85); one-sided, log-rank P = 0.00015]; PFS improved with enfortumab vedotin [HR 0.63 (95% CI 0.53-0.76); one-sided, log-rank P < 0.00001]. Treatment-related adverse event rates were 93.9% for enfortumab vedotin and 91.8% for chemotherapy; grade ≥ 3 event rates were 52.4% and 50.5%, respectively. Grade ≥ 3 treatment-related decreased neutrophil count (14.1% versus 6.1%), decreased white blood cell count (7.2% versus 1.4%), and anemia (7.9% versus 2.7%) were more common with chemotherapy versus enfortumab vedotin; maculopapular rash (7.4% versus 0%), fatigue (6.8% versus 4.5%), and peripheral sensory neuropathy (5.1% versus 2.1%) were more common with enfortumab vedotin. Of special interest adverse events, treatment-related skin reactions occurred in 47.3% of patients receiving enfortumab vedotin and 15.8% of patients receiving chemotherapy; peripheral neuropathy occurred in 48.0% versus 31.6%, respectively, and hyperglycemia in 6.8% versus 0.3%.

CONCLUSIONS

After a median follow-up of ∼2 years, enfortumab vedotin maintained clinically meaningful overall survival benefit versus chemotherapy, consistent with findings from the EV-301 primary analysis; PFS and overall response benefit remained consistent. Adverse events were manageable; no new safety signals were observed.

EAU-ESMO consensus statements on the management of advanced and variant bladder cancer-an international collaborative multi-stakeholder effort: under the auspices of the EAU and ESMO Guidelines Committees†

BACKGROUND

Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.

OBJECTIVE

To bring together a large multidisciplinary group of experts to develop consensus statements on controversial topics in bladder cancer management.

DESIGN

A steering committee compiled proposed statements regarding advanced and variant bladder cancer management which were assessed by 113 experts in a Delphi survey. Statements not reaching consensus were reviewed; those prioritised were revised by a panel of 45 experts before voting during a consensus conference.

SETTING

Online Delphi survey and consensus conference.

PARTICIPANTS

The European Association of Urology (EAU), the European Society for Medical Oncology (ESMO), experts in bladder cancer management.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Statements were ranked by experts according to their level of agreement: 1-3 (disagree), 4-6 (equivocal), 7-9 (agree). A priori (level 1) consensus was defined as ≥70% agreement and ≤15% disagreement, or vice versa. In the Delphi survey, a second analysis was restricted to stakeholder group(s) considered to have adequate expertise relating to each statement (to achieve level 2 consensus).

RESULTS AND LIMITATIONS

Overall, 116 statements were included in the Delphi survey. Of these, 33 (28%) statements achieved level 1 consensus and 49 (42%) statements achieved level 1 or 2 consensus. At the consensus conference, 22 of 27 (81%) statements achieved consensus. These consensus statements provide further guidance across a broad range of topics, including the management of variant histologies, the role/limitations of prognostic biomarkers in clinical decision making, bladder preservation strategies, modern radiotherapy techniques, the management of oligometastatic disease and the evolving role of checkpoint inhibitor therapy in metastatic disease.

CONCLUSIONS

These consensus statements provide further guidance on controversial topics in advanced and variant bladder cancer management until a time where further evidence is available to guide our approach.

Novel therapies in urothelial carcinoma: a biomarker-driven approach

Urothelial malignancies, including carcinomas of the bladder, ureters, and renal pelvis comprised ∼8% of new cancer cases in the USA in 2016. In the metastatic setting, 15% of patients exhibit long-term survival following cisplatin-based chemotherapy and in patients with recurrent disease, response rates to second-line chemotherapy are generally 15%-20% with a 3-month progression-free survival. However, recent advances in immunotherapy represent an opportunity to significantly improve patient outcomes. Moreover, the advent of next-generation sequencing has resulted in both an improved understanding of the fundamental genetic changes that characterize urothelial carcinoma (UC) and identification of several candidate biomarkers of response to various therapies. Incorporation of prospective genotyping into clinical trials will allow for the identification and enrichment of patients most likely to respond to specific targeted therapies and chemotherapy. Combining different therapeutic classes to enhance outcomes is also an area of active research in UC.

Commentary on "DNA damage response and repair gene alterations are associated with improved survival in patients with platinum-treated advanced urothelial carcinoma."

PURPOSE

Platinum-based chemotherapy remains the standard treatment for advanced urothelial carcinoma by inducing DNA damage. We hypothesize that somatic alterations in DNA damage response and repair (DDR) genes are associated with improved sensitivity to platinum-based chemotherapy.

EXPERIMENTAL DESIGN

Patients with diagnosis of locally advanced and metastatic urothelial carcinoma treated with platinum-based chemotherapy who had exon sequencing with the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) assay were identified. Patients were dichotomized based on the presence/absence of alterations in a panel of 34 DDR genes. DDR alteration status was correlated with clinical outcomes and disease features.

RESULTS

One hundred patients were identified, of which 47 harbored alterations in DDR genes. Patients with DDR alterations had improved progression-free survival (9.3 vs. 6.0 months, log-rank P = 0.007) and overall survival (23.7 vs. 13.0 months, log-rank P = 0.006). DDR alterations were also associated with higher number mutations and copy-number alterations. A trend toward positive correlation between DDR status and nodal metastases and inverse correlation with visceral metastases were observed. Different DDR pathways also suggested variable effect on clinical outcomes.

CONCLUSIONS

Somatic DDR alteration is associated with improved clinical outcomes in platinum-treated patients with advanced urothelial carcinoma. Once validated, it can improve patient selection for clinical practice and future study enrollment.

Atezolizumab in platinum-treated locally advanced or metastatic urothelial carcinoma: post-progression outcomes from the phase II IMvigor210 study

BACKGROUND

Conventional criteria for tumor progression may not fully reflect the clinical benefit of immunotherapy or appropriately guide treatment decisions. The phase II IMvigor210 study demonstrated the efficacy and safety of atezolizumab, a programmed death-ligand 1-directed antibody, in patients with platinum-treated locally advanced or metastatic urothelial carcinoma. Patients could continue atezolizumab beyond Response Evaluation Criteria In Solid Tumors (RECIST) v1.1 progression at the investigator's discretion: this analysis assessed post-progression outcomes in these patients.

PATIENTS AND METHODS

Patients were treated with atezolizumab 1200 mg i.v. every 3 weeks until loss of clinical benefit. Efficacy and safety outcomes in patients who experienced RECIST v1.1 progression and did, or did not, continue atezolizumab were analyzed descriptively.

RESULTS

In total, 220 patients who experienced progression from the overall cohort (n = 310) were analyzed: 137 continued atezolizumab for ≥ 1 dose after progression, 19 received other systemic therapy, and 64 received no further systemic therapy. Compared with those who discontinued, patients continuing atezolizumab beyond progression were more likely to have had a baseline Eastern Cooperative Oncology Group performance status of 0 (43.1% versus 31.3%), less likely to have had baseline liver metastases (27.0% versus 41.0%), and more likely to have had an initial response to atezolizumab (responses in 11.7% versus 1.2%). Five patients (3.6%) continuing atezolizumab after progression had subsequent responses compared with baseline measurements. Median post-progression overall survival was 8.6 months in patients continuing atezolizumab, 6.8 months in those receiving another treatment, and 1.2 months in those receiving no further treatment. Atezolizumab exposure-adjusted adverse event frequencies were generally similar before and following progression.

CONCLUSION

In this single-arm study, patients who continued atezolizumab beyond RECIST v1.1 progression derived prolonged clinical benefit without additional safety signals. Identification of patients most likely to benefit from atezolizumab beyond progression remains an important challenge in the management of metastatic urothelial carcinoma.

CLINICALTRIALS.GOV ID

NCT02108652.

The impact of prior platinum therapy on survival in patients with metastatic urothelial cancer receiving vinflunine

Background:

A phase III trial demonstrated an overall survival advantage with the addition of vinflunine to best supportive care (BSC) in platinum-refractory advanced urothelial cancer. We subsequently examined the impact of an additional 2 years of survival follow-up and evaluated the influence of first-line platinum therapy on survival.

Methods:

The 357 eligible patients from the phase III study were categorised into two cohorts depending on prior cisplatin treatment: cisplatin or non-cisplatin. Survival was calculated using the Kaplan–Meier method.

Results:

The majority had received prior cisplatin (70.3%). Survival was higher in the cisplatin group (HR: 0.76; CI 95% 0.58–0.99; P=0.04) irrespective of treatment arm. Multivariate analysis including known prognostic factors (liver involvement, haemoglobin, performance status) and prior platinum administration did not show an independent effect of cisplatin. Vinflunine reduced the risk of death by 24% in the cisplatin-group (HR: 0.76; CI 95% 0.58–0.99; P=0.04) and by 35% in non-cisplatin patients (HR: 0.65; CI 95% 0.41–1.04; P=0.07).

Interpretation:

Differences in prognostic factors between patients who can receive prior cisplatin and those who cannot may explain the survival differences in patients who undergo second line therapy. Prior cisplatin administration did not diminish the subsequent benefit of vinflunine over BSC.

Long-term survival results of a randomized phase III trial of vinflunine plus best supportive care versus best supportive care alone in advanced urothelial carcinoma patients after failure of platinum-based chemotherapy

BACKGROUND

To compare long-term, updated overall survival (OS) of patients with advanced transitional cell carcinoma of the urothelium (TCCU) treated with vinflunine plus best supportive care (BSC) or BSC alone, after failure of platinum-based chemotherapy.

PATIENTS AND METHODS

Three hundred and seventy patients were randomly assigned in a phase III trial and allocated (2:1) to vinflunine (320 or 280 mg/m(2)) plus BSC or BSC alone. The first report (Bellmunt J, Theodore C, Demkov T et al. Phase III trial of vinflunine plus best supportive care compared with best supportive care alone after a platinumcontaining regimen in patients with advanced transitional cell carcinoma of the urothelial tract. J Clin Oncol 2009; 27(27): 4454-4461) had a median follow-up of 22.1 m and the current report has a follow-up of 45.4 m.

RESULTS

Three hundred and fifty-two patients had died (censoring rate 5%). In the intention-to-treat (ITT) population, the median OS was 6.9 m and 4.6 m for vinflunine plus BSC versus BSC alone, respectively (n.s.). In multivariate Cox analysis, the addition of vinflunine was independently correlated with improved survival (HR: 0.719; 95% CI:0.570-0.906, P = 0.0052). In the eligible population, the median OS in both the arms was 6.9 and 4.3 m, respectively (HR: 0.78; 95% CI:0.61-0.96; P = 0.0227), indicating an estimated 22% reduction in the risk of death.

CONCLUSIONS

The updated OS data confirm the positive treatment effect of vinflunine on survival that was previously reported. These results are consistent over time and confirm that vinflunine is a valuable option for second-line treatment in patients with advanced TCCU after failure of platinum-based regimens.

A double-blind randomized trial of docetaxel plus vandetanib versus docetaxel plus placebo in platinum-pretreated advanced urothelial cancer

LBA239

Background: Vandetanib (V) is a novel small-molecule inhibitor that targets key signaling pathways in cancer including VEGF and EGF. V in combination with docetaxel (D) was assessed in patients (pts) who received prior platinum-based chemotherapy for advanced urothelial cancer (UC).

Methods: Patients eligible for this randomized, multicenter, double-blind, investigator-initiated trial had metastatic UC after failure of prior platinum-based chemotherapy. Up to 3 prior therapies were allowed including paclitaxel. The primary objective was to determine whether once-daily oral V (100 mg) + D (75 mg/m2 IV q21 days) prolonged progression-free survival (PFS) vs. placebo (P) + D (80% power to detect 60% improvement in median PFS with 1-sided α=0.05). Patients on D+P, had the option to cross over to single agent V. Overall survival (OS), overall response rate (ORR), stable disease (SD), and safety were secondary objectives.

Results: One-hundred and forty-two pts were enrolled at 16 institutions, 68% men; median age 65y; ECOG PS 0/1: 52%/48%; visceral involvement: 66%. 80% of patients had ECOG PS 1 and/or visceral metastases. 44% of patients had 2 or more prior systemic therapies and 15% had prior paclitaxel. Baseline characteristics were balanced in both arms. Median PFS was 11.1 weeks (wks) for D+V arm vs. 6.9 wks for D+P arm (HR=1.04, p=0.92). Median OS was 25.4 wks for the D+V arm vs. 30.6 wks for the D+P arm (HR 1.21, p=0.35). ORR was 7.1% for the D+V arm vs. 11.1% for the D+P arm (OR=0.6, 90% CI [0.2–1.6]). SD or better rates were 50.0% vs. 37.5% on D+V and D+P, respectively. As of December 2010, 5 pts were on therapy and 70% of pts died. Median follow-up for pts still alive is 7.2 months. Treatment-related grade >3 toxicities for D+V arm was 60% vs. 36% for the D+P arm (p=0.055) and were generally manageable (grade 4, 14% vs. 11%). Grade >3 toxicities that were more commonly seen in the D+V arm were rash/photosensitivity (11% vs. 0%) and diarrhea (7% vs. 0%).

Conclusions: In this platinum-pretreated population of advanced UC, the addition of vandetanib to docetaxel did not result in a significant improvement in PFS, ORR or OS. Toxicities were greater but manageable.

[Table: see text]

Intermittent chemotherapy (ICh) for metastatic castration-resistant prostate cancer (mCRPC): Results of a prospective randomized phase II trial of the DoD Prostate Cancer Clinical Trials Consortium

133

Background: Docetaxel remains the standard of care for patients (pts) with mCRPC. However, the optimal duration of chemotherapy (Ch) is not known. Providing Ch holidays is often undertaken, but is not well characterized. A randomized phase II trial was undertaken to test two ICh regimens.

Methods: Pts with Ch naive mCRPC and KPS > 60% were eligible. Pts were treated with “induction” docetaxel 75 mg/m2 q3 weeks, and prednisone 5 mg po bid. After 6 cycles, responding pts (PSAWG1 criteria) stopped Ch and were randomized to observation (Obs) or to GM-CSF, 250 mcg/m2 sq daily for 14 days out of every 28 day cycle. Pts were followed with monthly PSA and imaging every 2 cycles until progressive disease (PD) by PSAWG1 criteria, at which point they resumed treatment with Ch, again for 6 cycles, followed by the same “off Ch” regimen. The primary endpoint was the time to PD while on Ch (time to Ch resistance.)

Results: Of 97enrolled pts to date, 94 are evaluable (3 are still undergoing induction). 69 pts completed induction (25 did not due to PD, adverse events (AE), or MD choice), of which 27 had PD after 6 cycles. Thus, 42/94 evaluable pts (45%) were eligible for randomization. Of these, 21 pts underwent Obs and 21 received GM-CSF. To date, 23/42 (55%) pts who underwent a Ch holiday restarted Ch, all for PSA PD. 8/23 (35%) had a response to Ch re-initiation. (15 pts did not re-start Ch because of AE, other therapy being started, or patient choice, and 4 pts are still undergoing either Obs or GM-CSF.) Obs pts were “off Ch” for a median of 2 months (range 2-4), compared with 3 months (range 2-8) for GM-CSF pts.

Conclusions: While feasible, only 45% of pts met criteria for ICh. 35% of pts responded to Ch re-initiation. Insufficient data exist to assess the impact of GM-CSF on time off Ch or time to Ch resistance.

No significant financial relationships to disclose.

Defining “cisplatin ineligible” patients with metastatic bladder cancer

238

Background: Cisplatin-based chemotherapy is standard first-line treatment for patients (pts) with metastatic urothelial carcinoma (UC). However, a large proportion of pts with UC are considered “unfit” for cisplatin, leading to clinical trials designed specifically for cisplatin-ineligible pts, with substantial variability in eligibility criteria. A clear and consistent definition of pts “unfit” for cisplatin-based therapy will aid in the development of standard eligibility criteria.

Methods: We assembled a panel of GU medical oncologists and followed a three-fold approach. First, we surveyed 120 international GU medical oncologists. Subsequently, we reviewed the literature regarding ‘cisplatin ineligibility‘ in solid tumors. Finally, the panel reconciled the survey results and available literature and generated a consensus definition.

Results: Responses were received from 65/120 (54%) of those surveyed. The survey results are shown in the Table . Reconciling the survey results with the available literature, the panel recommended the following be used to consistently define pts with metastatic UC “unfit” for cisplatin-based chemotherapy for clinical trial purposes: (1) ECOG performance status of 2 and/or (2) creatinine-clearance < 60 ml/min and/or (3) CTCAE Gr ≥ 2 hearing loss and/or (4) CTCAE Gr ≥ 2 neuropathy.

Conclusions: Substantial variability exists in investigators' definitions of pts with metastatic UC “unfit” for cisplatin. A consensus definition is proposed for standardization of eligibility criteria.

[Table: see text]

No significant financial relationships to disclose.

A phase I study of sorafenib and RAD001 for metastatic clear cell renal cell carcinoma

5104

Background: Both RAD001 and sorafenib have activity against advanced clear cell renal cell carcinoma (ccRCC). Inhibition of both mTOR and angiogenesis may improve outcomes; therefore, a phase I trial combining sorafenib and RAD001 was undertaken. Methods: Cohorts of 3 or 6 patients with ccRCC were treated with a 7 day run-in period of sorafenib 400 mg PO BID continuously followed by RAD001 (dose level I: 2.5 mg, dose level II: 5 mg) PO QD and sorafenib 400 mg PO BID continuously. Pharmacokinetic sampling of sorafenib was obtained on day -1, and of both RAD001 and sorafenib on day 15 of combination therapy. Dose-limiting toxicity (DLT) was defined as occurring within the first 28 days of therapy. Results: Fifteen patients with a median age of 65 (range 51–75) have been enrolled. Two patients were not evaluable for response or DLT evaluation. Five pts were treated with sunitinib previously. Zero of 6 pts on dose level 1 experienced a DLT. Two of 9 pts treated at dose level II have experienced protocol-defined DLTs (grade 4 uric acid and grade 3 lipase with grade 2 pancreatitis). Independently-reviewed best objective responses in 13 evaluable pts include 3 confirmed partial responses (10, 17+, and 23+ months), 6 stable disease (2+, 4+, 4.5, 6+, 13, and 23+ months), and 4 progressive disease. Steady state dosing of RAD001 demonstrated a steady state AUC0–24h of RAD001 of 193.3 (± 32.9) ng h/mL at a dosage of 5 mg QD, comparable to the single agent 5 mg QD steady state dosing AUC0–24h of 238 (± 77) ng h/mL, suggesting there is no pharmacokinetic interaction between RAD001 and sorafenib. Linear pharmacokinetics between the 2.5 and 5 mg QD dosages of RAD001 were observed. The AUC0–24h of sorafenib was not significantly changed by concomitant dosing with RAD001 with a steady state AUC0–24h of 134600 (±42072) ng h/mL pre-RAD001 and a post-sorafenib steady state AUC0–24h of 131451 (±53838) ng h/mL. Conclusions: Combination therapy with sorafenib and RAD001 is safe and feasible. No clinically relevant pharmacokinetic interaction was observed. Activity for the combination has been observed and a phase II study is planned at the 5 mg QD dosage of RAD001.

No significant financial relationships to disclose.

Phase II study of bortezomib in patients with previously treated advanced urothelial tract transitional cell carcinoma: CALGB 90207

BACKGROUND

There is no standard second-line treatment for advanced urothelial carcinoma (UC). Response rates to second-line chemotherapy for advanced UC are low and response duration is short. Bortezomib is a proteasome inhibitor with preclinical activity against UC.

PATIENTS AND METHODS

Treatment consisted of bortezomib 1.3 mg/m(2) i.v. twice weekly for two consecutive weeks, followed by a 1-week break. The primary end point was objective response rate (complete response + partial response) by Response Evaluation Criteria in Solid Tumors criteria. Secondary end points included safety, toxicity, and progression-free and overall survival.

RESULTS

In all, 25 patients with advanced UC previously treated with combination chemotherapy were enrolled in a multi-institutional single-arm trial from December 2003 through April 2005. Only 29% of patients had node-only metastases. Grade 3/4 drug-related toxic effects included thrombocytopenia (4%), anemia (8%), lymphopenia (8%), sensory neuropathy (6%), hyperglycemia (4%), hypernatremia (4%), fatigue (4%), neuropathic pain (6%), dehydration (4%), and vomiting (4%). No objective responses were observed [95% confidence interval (CI) = 0-12]. The median time to progression was 1.4 months (95% CI = 1.1-2.0 months), and the median survival time was 5.7 months (95% CI = 3.6-8.4 months). There were no treatment-related deaths.

CONCLUSION

Although bortezomib is well tolerated, it does not have antitumor activity as second-line therapy in UC.

Sunitinib therapy for patients (pts) with metastatic renal cell carcinoma (mRCC): Updated results of two phase II trials and prognostic factor analysis for survival

5095

Background: Two single-arm phase 2 trials reported a 42% objective response rate (ORR) with sunitinib as second-line therapy in mRCC pts (JAMA 2006;295:2516–24). Efficacy results were updated and an analysis of prognostic factors for survival was performed on pooled data. Methods: Eligibility criteria and treatment plan were nearly identical for both trials. Pts with mRCC who failed =1 prior cytokine-based therapy received sunitinib in repeated 6-week cycles of 50 mg/day orally for 4 weeks, followed by 2 weeks off treatment. Response was assessed by investigators according to RECIST. Pretreatment clinical and biochemical features were examined for prognostic factors by univariate and multivariate analysis (p<0.05 significance level was used in the backward stepwise selection procedure). Results: Updated efficacy data for 168 evaluable pts showed an ORR of 45% (95% CI: 39%, 54%), median progression-free survival (PFS) of 8.4 months (95% CI: 7.9, 10.7), and median overall survival (OS) of 22.3 months (95% CI: 14.8, 36.0). Twenty pts remain on treatment with sunitinib with the longest pt on the drug for >3.5 years with partial response for >3 years. The median duration of response was 11.6 months (95% CI: 9.9, 15.2), and included 1 pt with a complete response for >2 years. The proportion of pts alive at 2 years is 48%. Final prognostic factors for survival in the multivariate model were ECOG PS 0 vs. =1 (p=0.0034); time interval from diagnosis to sunitinib treatment =1 yr vs. <1 yr (p=0.0002); hemoglobin =13 vs. <13 g/dL for males and =11.5 vs. <11.5 g/dL for females (p=0.0002). Conclusions: Median survival is nearly 2 years, which compares favorably to the historical experience (12.7 months) in second-line therapy with other agents (JCO 2004;22:454–63). The influence of sunitinib therapy on patient survival is being investigated in a randomized phase 3 trial compared to interferon-a in first-line therapy for mRCC. Further study of prognostic factors to sunitinib therapy is warranted in the first-line setting.

No significant financial relationships to disclose.

Phase II trial of sunitinib in bevacizumab-refractory metastatic renal cell carcinoma (mRCC): Updated results and analysis of circulating biomarkers

5035

Background: Sunitinib malate is an oral, multitargeted tyrosine kinase inhibitor with antiangiogenic and antitumor activity. This study evaluated the safety and activity of sunitinib in mRCC patients (pts) previously treated with the VEGF-neutralizing antibody, bevacizumab. Levels of angiogenic biomarkers, including plasma VEGF and soluble VEGFR-3 (sVEGFR-3), were assessed for predictive significance with clinical response. Methods: Pts were required to have mRCC with disease progression following bevacizumab- based therapy, measurable disease, ECOG performance status 0 or 1, and adequate organ function. Pts were treated with sunitinib 50 mg daily in 6-week cycles (4 weeks on, followed by 2 weeks off). The primary endpoint was objective response according to RECIST. Plasma VEGF and sVEGFR-3 levels were measured in pre-treatment samples and at multiple timepoints on study. Results: A total of 61 pts were enrolled. The objective partial response rate was 23% (95% CI: 13%, 36%); 35 pts (57%) demonstrated stable disease. The median duration of response was 36 weeks (95% CI: 26, NA) and progression-free survival was 30 weeks (95% CI: 18, 34). Plasma VEGF levels increased from baseline (3-fold mean elevation), while plasma sVEGFR-3 levels decreased from baseline (40% mean reduction). Pre-treatment VEGF levels were significantly higher in pts (n=34) with <10 weeks between cessation of bevacizumab and start of sunitinib (p<0.001); ELISA specificity suggests that detected VEGF is not bevacizumab-bound. Pre-treatment sVEGFR-3 levels were significantly lower at baseline in responding pts vs. non-responding pts (p<0.0318). A greater reduction in sVEGFR-3 levels was seen in responding pts vs. non-responding pts (p<0.10). Pretreatment VEGF and VEGF fold-changes did not differ according to clinical response. Conclusions: Sunitinib has significant antitumor activity in bevacizumab-refractory mRCC pts, suggesting absence of cross-resistance between bevacizumab and sunitinib. Biomarkers including plasma VEGF and sVEGFR-3 may have predictive potential in sunitinib-treated patients.

No significant financial relationships to disclose.

Clinical outcome of taxane-resistant (TR) hormone refractory prostate cancer (HRPC) patients (pts) treated with subsequent chemotherapy (ixabepilone (Ix) or mitoxantrone/prednisone (MP)

4558

Background: The clinical course of TR HRPC pts has not previously been evaluated in a large, prospective study. No standard treatment exists for this pt population, although MP is frequently used. Ix is an epothilone B analogue with activity against TR cell lines. Methods: Metastatic HRPC pts with disease progression during or within 60 days of stopping T chemotherapy were eligible. In a 2-arm, non-comparative randomized phase II study, pts were assigned to receive either: 1) M 14 mg/m2 IV q3wks and P 5 mg PO BID or 2) I × 35 mg/m2 IV q3wks. Crossover was allowed for progression or toxicity. The study’s primary endpoint was to detect a ≥ 50% PSA decline by Consensus Criteria in at least 25% of 2nd-line pts (H0 = 10%, α = 0.04, β = 0.18 for each arm). Pts were followed for survival. Results: Forty-one evaluable pts each were accrued to Ix and to MP. The median follow-up is 5.0 months (range: 0.3–19.5). The median number of cycles administered to each 2nd-line arm is 3 (range: Ix: 1–8, MP: 1–12). Median survival from protocol entry is 13.0 months with Ix and 12.5 months with MP. Confirmed 2nd-line post-therapy (rx) ≥50% PSA declines were observed in 17% of Ix pts (95% CI = 7–32) and 20% of MP pts (95% CI = 9–35). Of pts with measurable disease, partial responses were observed in 1/18 pts on 2nd-line Ix (6%; 95% CI = 0.1–27.3) and in 1/15 pts on 2nd-line MP (7%; 95% CI = 0.2–31.9). Median duration on 2nd-line Ix and MP was 2.2 months and 2.3 months, respectively. Crossover to 3rd-line rx occurred in 39% of Ix pts and 68% of MP pts. Confirmed 3rd-line post-rx ≥50% PSA declines were observed in 3/24 Ix pts and in 4/13 MP pts. The most common grade 3/4 toxicity associated with 2nd-line rx was neutropenia as previously reported (41% of Ix pts, 54% of MP pts). Conclusions: This prospective trial has characterized TR HRPC pts as having an observed median survival of approximately 1 year. This may be a useful reference for the screening of effective agents in the 2nd-line setting for TR HRPC. Both Ix and MP appear to have only modest activity as 2nd- and 3rd-line rx in this highly selected TR HRPC population. This study was supported by Bristol-Myers Squibb and the Prostate Cancer Foundation.

No significant financial relationships to disclose.

CALGB 90207: Phase II trial of bortezomib in patients with previously treated advanced urothelial tract transitional cell carcinoma (TCC)

4582

Background: No standard 2nd-line chemotherapy exists for metastatic TCC. Response rates to 2nd-line chemotherapy for advanced TCC are low and response duration tends to be short. Bortezomib is a proteasome inhibitor with preclinical activity against TCC. Methods: Twenty-five patients with advanced TCC who had been previously treated with combination chemotherapy were enrolled in a multi-institutional single-arm trial from December 2003 through April 2005. Treatment consisted of bortezomib 1.3 mg/m2 intravenously twice weekly for two consecutive weeks, followed by a 1-week rest period. The primary endpoint was objective response rate by RECIST criteria. Secondary endpoints included safety, toxicity, progression-free survival, and overall survival. Results: The median age was 65.5 yrs (59–7-74.9) and the median number of years since diagnosis was 1.4 (0.9–3.6). 72% of patients were male. 65% of patients had visceral metastases, and 20% of patients had lymph node-only metastases. Prior chemotherapy regimens included gemcitabine/cisplatin (50%), gemcitabine/carboplatin (25%), paclitaxel/carboplatin (5%), single agent paclitaxel (5%), and other multi-agent regimens (15%). Median hemoglobin was 11.4 g/dL (inter-quartile range 10.6–12.3). No objective responses were observed. The median time to progression was 2.1 months (95% CI= 1.4–5.5). Median overall survival was 5.5 months (95% CI= 3.6–8.1). Toxicity was modest. Grade 3/4 drug-related toxicities included thrombocytopenia (6%), sensory neuropathy (6%), hyperglycemia (6%), neuropathic pain (6%), dehydration (6%) and vomiting (6%). There were no treatment-related deaths. Conclusions: Although bortezomib is well tolerated in patients with previously treated advanced TCC, it does not have anti-tumor activity as 2nd-line therapy in TCC.

No significant financial relationships to disclose.

Efficacy and safety of sunitinib malate (SU11248) in bevacizumab-refractory metastatic renal cell carcinoma (mRCC)

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Background: Sunitinib malate (SU11248) is an oral, multitargeted tyrosine kinase inhibitor of the vascular endothelial growth factor receptor (VEGFR) family, platelet-derived growth factor receptor (PDGFR) and other related receptors. It has demonstrated anti-tumor activity in cytokine-refractory mRCC patients (pts). The activity of sunitinib in pts refractory to VEGF binding agents such as bevacizumab, however, has not been evaluated. It was hypothesized that tumor resistance to bevacizumab may be driven, in part, through pathways sensitive to inhibition by sunitinib. A phase II study evaluating the activity of sunitinib in bevacizumab-refractory mRCC was thus conducted. Methods: Pts with mRCC who demonstrated RECIST-defined disease progression within 3 months after bevacizumab-based therapy were treated with sunitinib (50 mg daily, 4 weeks of a 6-week cycle). Additional eligibility included measurable disease, clear cell histology, ≤ 2 prior systemic regimens, prior nephrectomy, performance status 0 or 1 and adequate organ function. The primary endpoint was objective response by RECIST criteria. A single-stage design was employed to test the null hypothesis that the true response rate is ≤ 5% versus the alternative hypothesis that the true response rate is ≥ 15%. Results: Accrual of 60 patients has been completed. Baseline characteristics include a median age of 59 years; 92% of pts had ≥ 2 metastatic sites and 23% had prior radiotherapy. Thirty-two of 60 pts enrolled are evaluable for response; 28 pts are too early for assessment. Twenty-six pts (81%) demonstrated some degree of tumor shrinkage, including, 4 pts (13%; 95% CI 4%, 29%) demonstrating an objective partial response. The most common treatment-related adverse events (AEs) included fatigue, diarrhea, dysgeusia, and nausea. Serious treatment-related AEs included fatigue, diarrhea, nausea and one fatal cerebral hemorrhage; 3 pts withdrew due to an AE. Conclusions: Sunitinib has substantial antitumor activity in bevacizumab-refractory mRCC pts, suggesting that sunitinib may inhibit signaling pathways involved in bevacizumab resistance. The precise mechanisms of response to sunitinib in bevacizumab-refractory tumors will require additional studies.

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Refined deletion mapping of the chromosome 19q glioma tumor suppressor gene to the D19S412-STD interval

Allelic loss of chromsome 19q occurs frequently in malignant gliomas, suggesting the presence of a chromosome 19q glioma tumor suppressor gene. Deletion mapping studies have delineated a 3.5 Mb candidate region between D19S219 and HRC. Cloned sequences from the proximal 425 kb of this interval, however, have not shown tumor-specific alterations. To refine the location of the tumor suppressor gene further, we conducted loss of heterozygosity studies on 191 malignant gliomas using nine PCR-based polymorphisms. These included the previously identified and physically mapped markers D19S219, DM, D19S112, HRC and the recently physically mapped polymorphisms at D19S412, STD, D19S596 and GYS. In addition, we isolated a novel microsatellite polymorphism that maps 400 kb telomeric to D19S112. Oligodendroglial tumors showed frequent loss of heterozygosity in all grades, and typically displayed allelic loss at all studied markers. Astrocytomas, however, showed frequent loss primarily in anaplastic astrocytomas and displayed deletion breakpoints within the candidate region. Deletion mapping revealed a minimal region of overlap between D19S412 and STD, a distance of 900 kb. These data suggest that the D19S412-STD interval represents the most likely location for a chromsome 19q glioma tumor suppressor gene involved in astrocytoma, and perhaps oligodendroglioma, tumorigenesis.

Relation of free silicone to human breast carcinoma

Of 12 women with carcinoma of the breast and coexistent silicone mastopathy, nine had had injections of liquid silicone for breast augmentation; three had leaking silicone-gel prostheses. The clinical findings indicated that early diagnosis was obscured by the silicone-induced mastopathy, which rendered the interpretation of physical findings and mammograms difficult. The pathologic findings were suggestive of a possible adverse effect of the presence of free silicone within the breast tissue, axillary nodes, and axillary fat. Although no causal relationship between silicone and breast carcinoma is implied, a heightened awareness of the possible coexistence of silicone mastopathy and breast carcinoma is necessary.