Second-line systemic therapies for metastatic urothelial carcinoma: a population-based cohort analysis

Introduction

Patients with urothelial carcinoma (uc) have a poor prognosis after progression on first-line cisplatin-based chemotherapy. Real-world data about second-line cytotoxic therapies are limited. We sought to characterize patients with metastatic uc who receive more than 1 line of systemic therapy and to describe their treatments and outcomes.

Methods

Using BC Cancer's pharmacy database, we identified patients with documented metastatic uc who had received more than 1 line of systemic therapy. A retrospective chart review was then performed to collect clinicopathologic, treatment, and outcomes data.

Results

The 51 included patients, of whom 42 were men (82%), had a median age of 65 years (range: 38-81 years). Sites of metastasis included lymph nodes (n = 30), bone (n = 7), lung (n = 9), and peritoneum (n = 2). Second-line chemotherapy regimens included gemcitabine-cisplatin [gc (n = 14)], paclitaxel (n = 24), docetaxel (n = 12), and an oral topoisomerase i inhibitor (n = 1). Median time to progression (ttp) and overall survival (os) were 2.0 and 6.83 months respectively. Compared with patients who received a different agent, patients who had experienced a prior response to first-line gc and who were re-challenged with second-line gc had a better median ttp (11.0 months vs. 6.0 months, p = 0.02) and survived longer (4.0 months vs. 1.0 months, p = 0.02). No differences in os between non-gc regimens were evident.

Conclusions

In patients with metastatic uc, overall outcomes remain poor, but compared with patients receiving other agents, the subgroup of patients re-challenged with second-line gc demonstrated improved ttp. Conventional chemotherapy regimens provide only modest benefits in the second-line setting and have largely been replaced with immunotherapy.

Borealis-1: a randomized, first-line, placebo-controlled, phase II study evaluating apatorsen and chemotherapy for patients with advanced urothelial cancer

Background

Five-year survival of patients with inoperable, advanced urothelial carcinoma treated with the first-line chemotherapy is 5%-15%. We assessed whether the Hsp27 inhibitor apatorsen combined with gemcitabine plus cisplatin (GC) could improve overall survival (OS) in these patients.

Patients and methods

This placebo-controlled, double-blind, phase II trial randomized 183 untreated urothelial carcinoma patients (North America and Europe) to receive GC plus either placebo (N = 62), 600 mg apatorsen (N = 60), or 1000 mg apatorsen (N = 61). In the experimental arm, treatment included loading doses of apatorsen followed by up to six cycles of apatorsen plus GC. Patients receiving at least four cycles could continue apatorsen monotherapy as maintenance until progression or unacceptable toxicity. The primary end point was OS.

Results

OS was not significantly improved in the single or combined 600- or 1000-mg apatorsen arms versus placebo [hazard ratio (HR), 0.86 and 0.90, respectively]. Exploratory study of specific statistical modeling showed a trend for improved survival in patients with baseline poor prognostic features treated with 600 mg apatorsen compared with placebo (HR = 0.72). Landmark analysis of serum Hsp27 (sHsp27) levels showed a trend toward survival benefit for poor-prognosis patients in 600- and 1000-mg apatorsen arms who achieved lower area under the curve sHsp27 levels, compared with the placebo arm (HR = 0.45 and 0.62, respectively). Higher baseline circulating tumor cells (≥5 cells/7.5 ml) was observed in patients with poor prognosis in correlation with poor survival. Treatment-emergent adverse events were manageable and more common in both apatorsen-treatment arms.

Conclusions

Even though apatorsen combined with standard chemotherapy did not demonstrate a survival benefit in the overall study population, patients with poor prognostic features might benefit from this combination. Serum Hsp27 levels may act as a biomarker to predict treatment outcome. Further exploration of apatorsen in poor-risk patients is warranted.

A prognostic index model for predicting overall survival in patients with metastatic castration-resistant prostate cancer treated with abiraterone acetate after docetaxel

A prognostic index model was developed, composed of six readily available and assessable factors and categorizing patients with metastatic castration-resistant prostate cancer treated with abiraterone–prednisone into distinct prognostic risk groups. This model could be useful for determining patient prognosis for follow-up, monitoring and patient stratification for clinical trials.

Background

Few prognostic models for overall survival (OS) are available for patients with metastatic castration-resistant prostate cancer (mCRPC) treated with recently approved agents. We developed a prognostic index model using readily available clinical and laboratory factors from a phase III trial of abiraterone acetate (hereafter abiraterone) in combination with prednisone in post-docetaxel mCRPC.

Patients and methods

Baseline data were available from 762 patients treated with abiraterone–prednisone. Factors were assessed for association with OS through a univariate Cox model and used in a multivariate Cox model with a stepwise procedure to identify those of significance. Data were validated using an independent, external, population-based cohort.

Results

Six risk factors individually associated with poor prognosis were included in the final model: lactate dehydrogenase > upper limit of normal (ULN) [hazard ratio (HR) = 2.31], Eastern Cooperative Oncology Group performance status of 2 (HR = 2.19), presence of liver metastases (HR = 2.00), albumin ≤4 g/dl (HR = 1.54), alkaline phosphatase > ULN (HR = 1.38) and time from start of initial androgen-deprivation therapy to start of treatment ≤36 months (HR = 1.30). Patients were categorized into good (n = 369, 46%), intermediate (n = 321, 40%) and poor (n = 107, 13%) prognosis groups based on the number of risk factors and relative HRs. The C-index was 0.70 ± 0.014. The model was validated by the external dataset (n = 286).

Conclusion

This analysis identified six factors used to model survival in mCRPC and categorized patients into three distinct risk groups. Prognostic stratification with this model could assist clinical practice decisions for follow-up and monitoring, and may aid in clinical trial design.

Trial registration numbers

NCT00638690.

A phase II study of the HDAC inhibitor SB939 in patients with castration resistant prostate cancer: NCIC clinical trials group study IND195

BACKGROUND

SB939 is a potent oral inhibitor of class 1, 2, and 4 histone deacetylases (HDACs). These three HDAC classes are highly expressed in castration resistant prostate cancer (CRPC) and associated with poor clinical outcomes. We designed a phase II study of SB939 in men with metastatic CRPC.

METHODS

Patients received SB939 60 mg on alternate days three times per week for 3 weeks on a 4-week cycle. Primary endpoints were PSA response rate (RR) and progression-free survival (PFS). Secondary endpoints included objective response rate and duration; overall survival; circulating tumor cell (CTC) enumeration and safety. Exploratory correlative studies of the TMPRSS2-ERG fusion and PTEN biomarkers were also performed.

RESULTS

Thirty-two patients were enrolled of whom 88 % had received no prior chemotherapy. The median number of SB939 cycles administered was three (range 1-8). Adverse events were generally grade 1-2, with five pts experiencing one or more grade three event. One patient died due to myocardial infarction. A confirmed PSA response was noted in two pts (6 %), lasting 3.0 and 21.6 months. In patients with measurable disease there were no objective responses. Six patients had stable disease lasting 1.7 to 8.0 months. CTC response (from ≥5 at baseline to <5 at 6 or 12 weeks) occurred in 9/14 evaluable patients (64 %).

CONCLUSION

Although SB939 was tolerable at the dose/schedule given, and showed declines in CTC in the majority of evaluable patients, it did not show sufficient activity based on PSA RR to warrant further study as a single agent in unselected patients with CRPC.

A phase 2 study of patupilone in patients with metastatic castration-resistant prostate cancer previously treated with docetaxel: Canadian Urologic Oncology Group study P07a

BACKGROUND

The purpose of this study was to determine the clinical activity of patupilone in patients with metastatic castration-resistant prostate cancer previously treated with docetaxel.

PATIENTS AND METHODS

Eligible patients had progressive disease within 6 months of receiving docetaxel. Patupilone was administered 10 mg/m2 i.v. every 3 weeks. The primary end point was the proportion of patients with a confirmed≥50% prostate-specific antigen (PSA) decline.

RESULTS

Eighty-three patients were enrolled. At baseline, the median time to progression after prior docetaxel was 1.4 months (range 0-5.7). Gastrointestinal serious adverse events occurred in four of the six initial patients leading to a reduction of the starting dose of patupilone to 8 mg/m2 for subsequent patients. Grade 3-4 toxicity at this dose included diarrhea (22%), fatigue (21%), and anorexia (10%). One patient experienced grade 3-4 hematologic toxicity. A PSA decline of ≥50% occurred in 47% of patients. A partial measurable disease response occurred in 24% of assessable patients. A patient-reported pain response was observed in 59% of assessable patients. Median time to PSA progression was 6.1 months [95% confidence interval (CI) 4.7-8.0] and median overall survival was 11.3 months (95% CI 9.8-15.4).

CONCLUSIONS

Patupilone at 8 mg/m2 was tolerable, had antitumor activity, and was associated with symptomatic improvement in patients previously treated with docetaxel.

A phase II study of sunitinib (SU) for maintenance therapy in metastatic castration-resistant prostate cancer (mCRPC) after response to docetaxel (D)

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Background: After treatment with D based chemotherapy, there is currently no standard therapy although new options are emerging. Due to its mechanism of action, acceptable toxicity profile and simple administration, SU has potential for therapeutic activity in the setting of maintenance therapy for patients with mCRPC who have responded to D based chemotherapy.

Methods: Patients with mCRPC who had evidence of responding or stable disease at completion of D treatment were enrolled in this phase II multicentre trial. Patients received 50mg of SU daily on 4 week on/2 week off cycles. The primary endpoint was effect of SU maintenance on PFS. Because of potential effects of SU on PSA kinetics, clinical progression was defined independent of PSA. PSA response rate was a secondary endpoint. PSA-progression (PSA-P) was defined as a 25% PSA increase over baseline.

Results: Thirteen patients have been enrolled and treated to date. Mean age was 63 years (47-76). ECOG scores of 0, 1, and 2 were reported for 4, 8 and 1 patients respectively. Mean number of prior cycles of D given was 9.5. A total of 28 cycles of SU were administered. A total of 291 adverse events (AEs) were recorded, of which 66%, 27%, and 7% were classified as Grades 1, 2, and 3, respectively. No Grade 4 AEs were seen. AEs were of a type and severity expected for SU. The most frequent grade 3 AEs were fatigue (n=3) and hand foot syndrome (n=3). No PSA responses have been documented. Most patients had immediate PSA increases without evidence of clinical progression. The mean PSAs increased by 159%, 396%, and 853% in Cycles 1, 2, and 3, respectively, corresponding to p-values of 0.18, 0.03, and 0.01 when compared to the PSA-P threshold of 25%. The trial will continue to complete its planned accrual of 26 evaluable patients and updated results, along with PFS, will be presented at the meeting.

Conclusions: SU is well tolerated as maintenance therapy after D in men with mCRPC, with a predictable side-effect profile. PSA values after treatment with SU may not reflect progression in patients with mCRPCas significant increases were observed as early as Cycle 2 without clinical evidence of worsening disease.

[Table: see text]

The neoadjuvant management of bladder cancer in Canada: A survey of genitourinary medical oncologists

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Background: The uptake of neoadjuvant chemotherapy (NC) for the treatment of stage II/III bladder cancer remains variable despite evidence supporting its use. The aim of this study is to better understand the use of NC in Canada to facilitate standardization of practice and develop a platform for clinical trials.

Methods: The survey was initially tested on a subset of medical oncologists. It was then e-mailed to 30 medical oncologists across Canada who primarily treat bladder cancer.

Results: In total, 25 (83%) surveys were completed. Respondents were 92% academic based, 100% full time, and 52% in practice for >10 years. The majority of referrals for all stages came from urologists with 4 respondents (16%) seeing 5-10 cases/yr, 10 (40%) seeing 11-15/yr, 5 (20%) seeing 16- 20/yr and 6 (24%) seeing >20/yr. Of these 8 reported having only 1-2 referrals for NC; 7 had 3-4 NC referrals; 7 had 5-6 NC referrals; and 2 reported seeing >6 referrals/year. Patients referred for NC tended to be younger (50-65); Performance Status (PS) 0/1; T-stage T3a/T3b; or nodal status N1/N2. 96% indicated they do offer NC to selected patients as both standard of care and to downsize tumors. Key factors cited for not offering NC were: Age >85, PS 3/4; T-stage T2a or T4a; Nodal status: N3; GFR <40ml/min. Main baseline staging modalities included CT chest/abdomen/pelvis, bone scan and cystoscopy. Gemcitabine/cisplatin was most commonly used with 20% using high-dose MVAC. Six (27%) reported doing midway staging with CT abdomen/pelvis and cystoscopy; 36% report staging after completion of chemo. Average time from last chemotherapy to cystectomy was 4-6 wks, with no patients being offered adjuvant chemotherapy postoperatively.

Conclusions: The majority of GU MO in Canada would offer NC. Stage, PS, renal function, and comorbidities were the biggest determinants of offering NC, while age played a lesser role. The number of overall referrals for NC, however, remains relatively low. We plan to survey urologists in Canada to determine if differences in attitudes about NC or barriers to referrals account for the low number of referrals.

No significant financial relationships to disclose.

Cost of care for prostate cancer patients: An observational cohort study comparing clinical trials to standard care

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Background: Monetary support of clinical trials is a fundamental necessity for improving treatment and prevention methods; however, current economic data pertaining to the per-patient costs of treating prostate cancer are limited. A concurrent lack of certainty regarding the cost requirements of standard care patients makes it difficult for healthcare professionals and policy makers to generate informed decisions regarding budgets and funding needs. Prostate cancer clinical trials are facing a national funding crisis due to the perception that patients enrolled in clinical trials consume more resources than patients receiving standard care.

Methods: A retrospective observational cohort study was conducted to examine the costs incurred by prostate cancer patients at the Tom Baker Cancer Center over one year. Costs for 36 patients enrolled in one of nine cancer trials were compared with costs for 36 matched control subjects who received standard care. Resource utilization was tracked using medical charts and quantified by prices listed in the TBCC's 2009 Clinical Trials Budget template.

Results: No evidence was found to support a difference in overall resource utilization between clinical trial patients and standard of care patients (Paired two-tailed t- test, N= 36, p =0.90). There was, however, variability in the types of resources used by each patient population, indicating that, while trial patients may take up significantly more clinic time (p =0.04), undergo more tests and procedures (p < 0.001) and require more diagnostic imaging (p = 0.01), standard care patients are more likely to receive costly interventions such as radiation therapy (p =0.06). Pharmaceutical costs have not yet been included in the analysis and could drastically alter the final results.

Conclusions: This study revealed differences in the cost distribution of clinical trials patients versus standard of care patients, which could be used by administrators to improve budgeting and time allocation. The lack of difference in overall cost may be helpful to research advocates attempting to encourage centers to take on more trials. Further analysis is required before definitive conclusions can be drawn.

No significant financial relationships to disclose.

A randomized phase II study of OGX-011 in combination with docetaxel and prednisone or docetaxel and prednisone alone in patients with metastatic hormone refractory prostate cancer (HRPC)

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Background: Clusterin, a cytoprotective chaperone protein that promotes cell survival, is associated with androgen independent progression and overexpressed in HRPC. OGX-011 (OGX, developed by OncoGenex Technologies/Isis Pharmaceuticals) is a 2’- methoxyethyl modified phosphorothioate antisense that inhibits clusterin expression in humans at doses of ≤640 mg and potentiates chemotherapy activity in prostate xenografts. The objective of this study was to determine the anti-tumor activity of OGX in combination with docetaxel (DOC) in patients (pts) with HRPC. Methods: Chemo-naive pts with metastatic HRPC were randomized to receive DOC 75mg/m2 q3 weeks + OGX 640mg weekly as a 2-hour IV infusion (Arm A) + prednisone or DOC + prednisone (Arm B). Serum levels of clusterin were assessed serially. A single stage randomized phase II design was employed with PSA response rate (RR) as the primary endpoint (Bubley et al, J Clin Oncol 1999;17:3461). Planned sample size was 40 per arm: Arm A the hypotheses (H0:PSA RR<40% vs. H1:PSA RR>60%) could be tested at 10% β and 10% a, Arm B the true PSA RR could be estimated with half-width of the 90% confidence interval <13% if observed PSA RR was 40%. Results: 82 pts (41/arm) were enrolled from September 2005 to December 2006 at 12 centers. Baseline characteristics are similar in both arms (available to date for 63 pts): median age 67 (range: 49–84), PSA 110 μg/L (5.6–1261), hemoglobin 128 g/L (96–158), alkaline phosphatase 133 U/L (47–1294), LDH 193 U/L (120–741). ECOG performance status was 0 in 49% and 1 in 51%; 67% had bone/nodal disease only and 33% had other metastatic sites. To date, 56 pts have received ≥2 cycles. Toxicity due to OGX included grade 1/2 fevers and rigors in 37% and 67% pts respectively, but other adverse events were similar in both arms. PSA response has occurred in 43%, progression in 9%, and 48% have not yet met criteria for response or progression. Conclusions: Combined docetaxel and OGX is well tolerated in pts with metastatic HRPC and PSA responses have been observed. Pt treatment, follow-up and analysis of serum clusterin levels continue. Results by arm will be available by June 2007. Supported by a grant from the NCI-Canada/Canadian Cancer Society.

No significant financial relationships to disclose.