Background

Several phase II trials in men with non-castrate PSA-recurrent prostate cancer have assessed the impact of novel non-hormonal agents on PSA kinetics. However, it is unknown whether changes in PSA kinetics influence metastasis-free survival (MFS).

Methods

We performed a retrospective post hoc analysis of 146 men treated in four phase II trials examining the investigational agents marimastat (a matrix metalloproteinase inhibitor; n=39), imatinib (a tyrosine kinase inhibitor; n=25), ATN-224 (a copper/zinc-superoxide dismutase inhibitor; n=22), and lenalidomide (an antiangiogenic/immunomodulatory drug; n=60). We investigated factors influencing MFS, including within-subject changes in PSA kinetics (PSA slope, doubling time, and velocity) before and after treatment initiation.

Results

After a median follow-up of 16.8 months, 70 patients (47.9%) developed metastases. In multivariable Cox regression models, factors that were independently predictive of MFS after adjusting for age and other clinical prognostic variables were baseline PSA doubling time (PSADT) (P=.05), baseline PSA slope (P=.01), on-study change in PSADT (P=.02), and on-study change in PSA slope (P=.03). In a landmark Kaplan-Meier analysis, median MFS was 63.5 months (95% CI 34.6–not reached) and 28.9 months (95% CI 13.5–68.0) for men with or without any decrease in PSA slope by 6 months after treatment, respectively.

Conclusions

This hypothesis-generating analysis suggests that within-subject changes in PSADT and PSA slope after initiation of experimental therapy may correlate with MFS in men with biochemically-recurrent prostate cancer. If validated in prospective trials, changes in PSA kinetics may represent a reasonable intermediate endpoint for screening new agents in these patients.

Purpose

AGS-1C4D4 is a human monoclonal antibody against prostate stem cell antigen (PSCA), a cell-surface protein expressed by most prostate cancers. AGS-1C4D4 is produced in Chinese hamster ovary (CHO) cells and has an identical sequence to AGS-PSCA, an anti-PSCA antibody produced in mouse hybridoma cells that has completed Phase I testing. Preclinical studies demonstrated comparability of AGS-1C4D4 to AGS-PSCA with respect to pharmacokinetics (PK) and tumor inhibition. However, because of differences in antibody-dependent cellular cytotoxicity between AGS-PSCA and AGS-1C4D4, a limited Phase I trial using AGS-1C4D4 was performed evaluating safety and PK.

Patients and method

Thirteen patients with metastatic castration-resistant prostate cancer were enrolled. AGS-1C4D4 was administered intravenously every 3 weeks for four planned doses at 6, 12, 24, or 48 mg/kg. Primary endpoints were safety and PK. Secondary endpoints were immunogenicity and clinical activity. Disease assessments were conducted every 12 weeks and included radiographic and PSA evaluations. Patients with stable disease could receive extended treatment beyond four infusions.

Results

Adverse events were primarily grade 1–2, without any grade 3–4 drug-related toxicities or infusion reactions. Anti-AGS-1C4D4 antibodies were not detected. Similar to AGS-PSCA, serum AGS-1C4D4 concentrations declined biphasically and elimination was characterized by slow clearance (CL) and a long terminal half-life (t1/2). Median CL for the four dose levels ranged from 0.10 to 0.14 ml/h kg, and t1/2 ranged from 2.2 to 2.9 weeks. No PSA reductions ≥50% were observed. Six patients (46%) had radiographically stable disease, lasting a median of 24 weeks.

Conclusion

AGS-1C4D4 was well-tolerated and demonstrated linear PK. Despite preclinical differences in antibody-dependent cellular cytotoxicity, AGS-1C4D4 and AGS-PSCA have similar safety and PK profiles. The recommended Phase II dose is 48 mg/kg.

BACKGROUND

Loss of the tumor suppressor PTEN is common in prostate cancer and may have prognostic significance. The authors examined PTEN and additional protein markers in primary tumors from patients with high-risk, localized prostate cancer who received adjuvant docetaxel in a prospective multicenter trial (TAX2501).

METHODS

Fifty-six of 77 patients enrolled in TAX2501 had primary prostatectomy specimens available for immunohistochemical analysis of PTEN, MYC, ERG, tumor protein p53 (p53), antigen KI-67 (Ki67), and phosphorylated forms of Akt, mammalian target of rapamycin (mTOR), and S6 ribosomal protein. Protocol-defined progression included a prostate-specific antigen (PSA) level ≥0.4 ng/mL, radiologic/clinical recurrence, or death. Univariate and multivariable proportional hazards regression analyses were used to investigate the influence of PTEN status (and other protein markers) on progression-free survival (PFS).

RESULTS

In this exploratory, post hoc analysis, PTEN protein loss (vs presence) was observed in 61% of patients and was associated with lower preoperative PSA levels, higher clinical stage, lower Ki67 expression, the presence of p53, and the presence of ERG. In univariate analysis, the factors associated with PFS included Gleason sum, seminal vesicle invasion, PTEN status, MYC expression, and Ki67 expression. In multivariable analysis, only 3 variables emerged as independent prognostic factors for PFS: PTEN status (P = .035), MYC expression (P = .001), and Ki67 expression (P < .001). A prognostic model was constructed that incorporated clinical covariates as well as information on PTEN, MYC, and Ki67.

CONCLUSIONS

The current results indicated that PTEN status, MYC expression, and Ki67 expression in primary tumor samples may predict PFS more accurately than clinical factors alone in men with high-risk prostate cancer who receive adjuvant docetaxel after prostatectomy. If validated, these hypothesis-generating findings may have prognostic and therapeutic implications and may aid clinical trial design.

OBJECTIVE

To describe metastasis-free survival (MFS) in men with prostate-specific antigen (PSA) recurrence following radical prostatectomy, and to define clinical prognostic factors modifying metastatic risk.

PATIENTS AND METHODS

We conducted a retrospective analysis of 450 men treated with prostatectomy at a tertiary hospital between July 1981 and July 2010 who developed PSA recurrence (≥0.2 ng/mL) and never received adjuvant or salvage therapy before the development of metastatic disease.

We estimated MFS using the Kaplan–Meier method, and investigated factors influencing the risk of metastasis using Cox proportional hazards regression.

RESULTS

Median follow-up after prostatectomy was 8.0 years, and after biochemical recurrence was 4.0 years. At last follow-up, 134 of 450 patients (29.8%) had developed metastases, while median MFS was 10.0 years.

Using multivariable regressions, two variables emerged as independently predictive of MFS: PSA doubling time (<3.0 vs 3.0–8.9 vs 9.0–14.9 vs ≥15.0 months) and Gleason score (≤6 vs 7 vs 8–10).

Using these stratifications of Gleason score and PSA doubling time, tables were constructed to predict median, 5- and 10-year MFS after PSA recurrence. In different patient subsets, median MFS ranged from 1 to 15 years.

CONCLUSIONS

In men undergoing prostatectomy, MFS after PSA recurrence is variable and is most strongly influenced by PSA doubling time and Gleason score. These parameters serve to stratify men into different risk groups with respect to metastatic progression.

Our findings may provide the background for appropriate selection of patients, treatments and endpoints for clinical trials.

Background

This study was designed to evaluate toxicity and preliminary efficacy of 2 cycles of concomitant standard dose/schedule of 153Sm-lexidronam plus Q 3 weeks schedule escalating doses of docetaxel in metastatic castration-resistant prostate cancer (mCRPC).

Methods

mCRPC patients with progressive bone metastases were treated in 4 cohorts. Docetaxel doses were escalated from 50, 50, 0 mg/m2 (on days 1, 22, 43, per 12-week cycle) to 75, 75, 75 mg/m2. 153Sm-lexidronam was administered on days 2 (Q 12 weeks) at dose of 1 mCi/kg/cycle (maximum of 2 cycles).

Results

Thirteen patients received an average of 3.6 doses of docetaxel (range, 2–6 doses, median 4) and 1.5 doses of 153Sm-lexidronam (range, 1–2, median 2). Toxicity was primarily hematologic. There were total 35 episodes grade 3/4 neutropenia with a median 7 (range 7–14) days to recovery to ≤grade 1. One dose limiting grade 3 thrombocytopenia occurred on cohorts 3 and 4. Eight of 13 (62%) patients had PSA > 50% decrease as best response during the treatment. Median time to bone disease progression was 5.2 months (range 91 days–10 months+); 6/13 (46%) patients had stable/improved bone scans at 6 months and 6/6 (100%) symptomatic patients had improvement in pain.

Conclusions

Concurrent 6-month administration of 4 doses (75 mg/m2) of standard Q 3 weeks schedule of docetaxel with 2 Q 3 months infusions of 1 mCi/Kg 153Sm-lexidronam is feasible with reversible bone marrow suppression, and deserves further testing in mCRPC patients with extensive bone metastasis.

BACKGROUND

In men with metastatic castration-resistant prostate cancer (CRPC), the association of measurable tumor responses with overall survival (OS) is unknown. The authors retrospectively evaluated the TAX327 phase 3 trial to study this relation.

METHODS

Eligible patients for this analysis included those with World Health Organization (WHO)-defined measurable metastatic disease randomized to receive either docetaxel or mitoxantrone. OS was estimated by using the Kaplan-Meier method, and the prognostic relation of WHO-defined radiologic response with OS was performed by using Cox proportional hazards regression. Landmark analyses evaluated survival from baseline and at 2, 3, 4, and 6 months after baseline.

RESULTS

Four hundred twelve patients enrolled on the TAX327 trial had measurable tumors. Thirty-seven patients exhibited a complete or partial objective response (CR/PR, 9.0%), 116 had stable disease (SD, 28.2%), 99 had progressive disease (PD, 24%) and 160 (38.8%) did not have a after-baseline objective assessment. Partial responders demonstrated longer median OS (29.0 months) than patients with SD (22.1 months) or those with PD (10.8 months) or those who were not assessed (12.7 months). These results remained after landmark analysis. The authors found a significant association between ≥30% prostate-specific antigen (PSA) declines and radiologic response, with ≥30% PSA declines occurring in all patients with CR/PR, 79.8% of patients with SD, and 34.4% with PD. Radiologic response remained a significant but modest post-treatment prognostic factor for OS after adjusting for treatment, pain response, and ≥30% PSA decline (P = .009).

CONCLUSIONS

In men with metastatic CRPC and measurable disease receiving chemotherapy, objective tumor response was prognostic for OS and appeared to complement PSA assessment.

Background

The optimal number of 3-wk docetaxel plus prednisone (DP) cycles for metastatic castration-resistant prostate cancer (mCRPC) is unclear.

Objective

A retrospective analysis of two clinical trials was performed to evaluate the association of the number of cycles with overall survival (OS).

Design, setting, and participants

An exploratory analysis compared outcomes of 332 men who received DP in the TAX-327 trial, which stipulated up to 10 cycles, and 220 men who received DP in CS-205, a randomized phase 2 trial comparing DP plus AT-101 (bcl-2 inhibitor) versus DP plus placebo, which allowed up to 17 cycles.

Measurements

Patients who completed 10 cycles of DP without progression in both trials were included. Men in both arms of CS-205 were combined for analysis, as no significant differences in outcomes were observed. OS was estimated from the date of cycle 10 docetaxel infusion.

Results and limitations

The number of men receiving 10 cycles was similar (p = 0.26) in the two trials (166 [50.0%] in TAX-327 vs 99 [45.0%] in CS-205; the latter group received a median of five additional cycles). Six- and 12-mo estimated survival after cycle 10 was 92.2% (95% confidence interval [CI], 86.9–95.4%) and 74.6% (CI, 67.2–80.5%) in TAX-327, compared with 92.8% (CI, 85.5–96.5) and 63.4% (CI, 51.8–72.9%) in CS-205. Subanalyses suggested that <10 cycles may have a negative impact and prostate-specific antigen (PSA) declines at cycle 10 may carry a favorable impact. The significance of continued PSA declines up to 17 cycles is unclear. Limitations of a retrospective analysis apply.

Conclusions

A survival benefit was not detected with >10 cycles of DP in men with mCRPC in this retrospective hypothesis-generating analysis.

Background

Sunitinib is a standard treatment for metastatic renal cell carcinoma (mRCC). The neutrophil to lymphocyte ratio (NLR), an index of systemic inflammation, is associated with outcome in several cancer types.

Aims

To study the association of pre-treatment neutrophil to lymphocyte ratio with response rate, progression free survival (PFS) and overall survival (OS) of patients treated with sunitinib for mRCC.

Methods

We retrospectively studied an unselected cohort of patients with mRCC, who were treated with sunitinib. Logistic regression model was used to analyse response rate. Cox regression models were fitted to identify risk factors associated with PFS and OS. We investigated how pre-treatment NLR is associated with these clinical outcomes after adjusting for confounding covariates. Regression tree for censored data method was used to find the best NLR cut-off value.

Results

Between 2004 and 2011, 133 patients with mRCC were treated with sunitinib. One hundred and nine were included in the NLR analysis, from which were excluded patients without available data on pre-treatment NLR or with comorbidities/recent treatments known to be associated with a change of blood counts. Factors associated with PFS were low NLR ≥ 3 (HR = 0.285, p < 0.001), past nephrectomy (HR = 0.38, p = 0.035), sunitinib dose reduction/treatment interruption (HR = 0.6, p = 0.014), and the use of antiotensin system inhibitors (HR = 0.537, p = 0.008). Low NLR ≥ 3 was associated with OS (HR = 0.3, p = 0.043).

Conclusions

In patients with mRCC treated with sunitinib, pre-treatment NLR may be associated with PFS and OS. This should be investigated prospectively, and if validated applied in clinical practice and clinical trials.

Context

Androgen deprivation therapy (ADT) for prostate cancer (PCa) represents one of the most effective systemic palliative treatments known for solid tumors. Although clinical trials have assessed the role of ADT in patients with metastatic and advanced locoregional disease, the risk–benefit ratio, especially in earlier stages, remains poorly defined. Given the mounting evidence for potentially life-threatening adverse effects with short- and long-term ADT, it is important to redefine the role of ADT for this disease.

Objective

Review the published experience with currently available ADT approaches in various contemporary clinical settings of PCa and reported serious treatment-related adverse events. This review addresses the level of evidence associated with the use of ADT in PCa, focusing upon survival outcome measures. Furthermore, this paper discusses evolving approaches targeting androgen receptor signaling pathways and emerging evidence from clinical trials with newer compounds.

Evidence acquisition

A comprehensive review of the literature was performed, focusing on data from the last 10 yr (January 2000 to July 2011) and using the terms androgen deprivation, hormone treatment, prostate cancer and adverse effects. Abstracts from trials reported at international conferences held in 2010 and 2011 were also evaluated.

Evidence synthesis

Data from randomized controlled trials and population-based studies were analyzed in different clinical paradigms. Specifically, the role of ADT was evaluated in patients with nonmetastatic disease as the primary and sole treatment, in combination with radiation therapy (RT) or after surgery, and in patients with metastatic disease. The data suggest that in men with nonmetastatic disease, the use of primary ADT as monotherapy has not shown a benefit and is not recommended, while ADT combined with conventional-dose RT (<72 Gy) for patients with high-risk disease may delay progression and prolong survival. The postoperative use of ADT remains poorly evaluated in prospective studies. Likewise, there are no trials evaluating the role of ADT in patients with biochemical relapses after surgery or RT. In patients with metastatic disease, there is a clear benefit in terms of quality of life, reduction of disease-associated morbidity, and possibly survival. Treatment with bilateral orchiectomy, luteinizing hormone–releasing hormone agonist therapy, with and without antiandrogens has been associated with various serious adverse events, including cardiovascular disease, diabetes, and skeletal complications that may also affect mortality.

Conclusions

Although ADT is an effective treatment of PCa, consistent long-term benefits in terms of quality and quantity of life are predominantly evident in patients with advanced/metastatic disease or when ADT is used in combination with RT (<72 Gy) in patients with high-risk tumors. Implementation of ADT should be evidence based, with special consideration to adverse events and the risk–benefit ratio.

BACKGROUND

Adrenal/intratumoral androgen biosynthesis contributes to ligand-dependent androgen receptor activation in metastatic castration-resistant prostate cancer (mCRCP). Compounds targeting CYP-17 hydroxylase and lyase, as ketoconazole and abiraterone, block adrenal/intratumoral androgen biosynthesis, and are used as sequential endocrine approaches in mCRCP. We aimed to describe contemporary experience and association of clinical factors with Prostate specific antigen (PSA) response and disease progression, in mCRPC progressing on GnRH-agonist, antiandrogen, antiandrogen withdrawal, and treated with ketoconazole.

METHODS

Data were retrospectively analyzed in all mCRPC patients treated with ketoconazole. Patients continued GnRH-agonist, and treated with ketoconazole 200–400 mg 3× a day until dose-limiting toxicity or disease progression. A multivariate cox regression model was used to identify clinical factors associated with PSA response and disease progression.

RESULTS

From 1999 to 2010, 114 mCRPC patients were treated with ketoconazole. With a median follow-up time of 31 months (range 5–129), 25 patients (22%) had grade 3/4 toxicity, most commonly fatigue, abdominal discomfort, nausea, and dizziness. Sixty-one patients (54%) had ≥50% PSA decline. Median time to progression was 8 months (range 1–129). Factors associated with PSA response and disease progression were response to prior antiandrogen (≥6 vs. <6 months), pre-treatment PSADT (≥3 vs. <3 months) and extent of disease (limited-axial skeleton and/or nodal vs. extensive-appendicular skeleton and/or visceral).

CONCLUSIONS

Ketoconazole is effective and safe in mCRPC. Prior response to antiandrogen, pre-treatment PSADT, and disease extent are associated with PSA response and disease progression, and further supports a therapeutic role in suppressing adrenal androgens in mCRPC.

OBJECTIVE

To evaluate the pathologic outcome of prostate-specific antigen-screened patients with high-grade (Gleason score ≥ 8) prostate cancer limited to 1 biopsy core, without clinical evidence of disease.

METHODS

Ninety-two patients with only 1 biopsy core with cancer and treated by radical prostatectomy were divided into 4 groups according to the biopsy Gleason score: 3 + 3 = 6 (23 cases), 3 + 4 = 7 (25 cases), 4 + 3 = 7 (20 cases), and ≥8 (24 cases).

RESULTS

Cases with Gleason score ≥8 showed a significantly higher proportion of extraprostatic extension (50%), positive surgical margins (21%), and seminal vesicle invasion (12%) when compared with the other groups. Patients with Gleason score ≥8 in the biopsy had a 25-fold increased in the odds ratio for extraprostatic extension in the prostatectomy. The incidence of extraprostatic extension was higher in those with prostatic cancer involving ≥50% of one core (88%) compared with cases involving <50% (32%).

CONCLUSION

In patients with prostate cancer limited to 1 biopsy core, the presence of Gleason score ≥8 significantly increased the incidence of extraprostatic extension, positive surgical margins, and seminal vesicle invasion. The odds ratio was substantially higher in patients with ≥50% of Gleason ≥8 in the biopsy core. These data might be taken into account for proper clinical management of this set of patients.

OBJECTIVES

To determine the agreement between the local pathologist findings and central pathologist findings using data from the TAX 3501 trial. TAX 3501 was a randomized, multinational trial comparing the outcomes of patients with high-risk prostate cancer treated with androgen deprivation with or without docetaxel after radical prostatectomy (RP). Patient eligibility was determined by a minimal 5-year progression-free survival estimate of 60% using Kattan’s nomogram.

METHODS

The pathologic findings were reassessed in 257 consecutive RP specimens by 2 central pathologists and compared with the local pathologist data.

RESULTS

For the Gleason score, agreement was found in 181 (70%) of 257 cases, upgrading in 57 (75%), and downgrading in 25% of the RP specimens The most frequent upgrade was from Gleason score 7 to 8 or 9 and downgrading from Gleason score 8 to 7. Of the upgrades and downgrades, 37% and 21% were of 2 Gleason score points, respectively. For the tumor extent, agreement was found in 179 (70%) of 256 specimens, with upstaging in 70 (91%) and downstaging in 9%. The most frequent upstage was from focal to extensive extraprostatic extension (45%). For seminal vesicle invasion, agreement was found for 238 (93%) of 256 RP specimens Almost equal rates of underdiagnosing and overdiagnosing seminal vesicle invasion was observed. For margin status, agreement was present for 229 (89%) of 256 cases. The central pathologist review led to reclassification as a positive margin in 17 cases and a negative margin in 10. For lymph node status, 2 (1%) of 210 RP specimens had positive nodes identified only by the central pathologist. Agreement was observed in 154 negative and 54 positive cases.

CONCLUSIONS

Significant interobserver variations were found between the central and local pathologists. From the central pathologist review, the progression-free survival estimates were altered in 31 patients (13%), including 22 who were reassigned a greater risk estimate, rendering them study eligible. Thus, interobserver variability affected prognostication and trial accrual.

Purpose

To evaluate the safety and activity of 6 months of treatment with lenalidomide at 5 or 25 mg/d in nonmetastatic biochemically relapsed prostate cancer.

Experimental Design

Sixty men with non-castrate, nonmetastatic, biochemically relapsed prostate cancer were stratified by prostate-specific antigen (PSA) doubling time, surgery/radiation therapy, prior androgen deprivation therapy (ADT), and randomized to lenalidomide 5 mg (n = 26) or 25 mg/d (n = 34) for 3 weeks repeated monthly for 6 months or until dose-limiting toxicity or disease progression. Toxicity was evaluated monthly, and PSAs and X-rays/scans every 6 months. Study size was determined to detect a progression rate of 40% at 6 months in either arm with 85% power (compared with a rate of 80% in the population receiving no treatment). Changes in PSA slopes were calculated using the regression of the log PSA for each patient before and during the initial 6 months and compared by t test.

Results

Baseline variables were balanced between arms. Grade 3/4 toxicity rates were 12% (n = 3) with 5 mg and 29% (n = 10) with 25 mg (P = 0.1), most commonly neutropenia (five patients, all on 25 mg). Two patients per arm had thromboembolic events. The change in PSA slope was greater with 25 mg versus 5 mg [−0.172 (−0.24 to −0.11) versus −0.033 (−0.11 to 0.04); P = 0.005]. With a mean follow-up of 31.4 months (range 14–44), five patients on 25 mg and one patient on 5 mg remain on the study.

Conclusions

Lenalidomide has acceptable toxicity and is associated with long-term disease stabilization and PSA declines. Randomized studies evaluating conventional clinical disease end points in this patient population are planned.

Context

We have recently witnessed a rapid increase in the number of effective systemic agents for men with metastatic castration-resistant prostate cancer (CRPC), including novel hormonal therapies (abiraterone acetate and MDV3100), immunotherapies (sipu-leucel-T), chemotherapies (cabazitaxel), and bone microenvironment targeting agents (denosumab, radium 223). Given the increasing complexity of treatment decisions for this disease, major research and clinical priorities are (1) finding biomarkers that enable an understanding of the natural history and complex biology of this heterogeneous malignancy, (2) defining predictive biomarkers that identify men most likely to benefit from a given therapy, and (3) identifying biomarkers of early response or progression to optimize outcomes.

Objective

In this review, we discuss existing and potential biomarkers in CRPC and how they may currently inform prognosis, aid in treatment selection (predictive value), and relate to survival outcomes (surrogacy).

Evidence acquisition

PubMed-based literature searches and abstracts through September 2011 provided the basis for this literature review as well as expert opinion.

Evidence synthesis

We address blood and urine-based biomarkers such as prostate-specific antigen, lactate dehydrogenase, total and bone alkaline phosphatase and other bone turnover markers, hemoglobin, and circulating tumor cells in the context of prognosis, prediction, and patient selection for therapy. Given the inherent problems associated with defining progression-free survival in CRPC, the importance of biomarker development and the needed steps are highlighted. We place the discussion of bio-markers within the context of the design/intent of a trial and mechanism of action of a given systemic therapy. We discuss novel biomarker development and the pathway for surrogate or predictive biomarkers to become credentialed as useful tests that inform therapeutic decisions.

Conclusions

A greater understanding of biomarkers in CRPC permits a more personalized approach to care that maximizes benefit and minimizes harm and can inform clinical trials tailored to men most likely to derive benefit.

OBJECTIVE

To describe metastasis-free survival (MFS) and overall survival (OS) among men with prostate-specific antigen (PSA)-recurrent prostate cancer after radical prostatectomy who did not receive additional therapy until metastasis, using a multicentre database capturing a wide ethnic mix.

PATIENTS AND METHODS

A retrospective analysis of the Center for Prostate Disease Research National Database (comprised of five US military hospitals and one civilian centre) was performed for patients with PSA relapse (≥0.2 ng/mL) after radical prostatectomy who had no additional therapy until the time of radiographic metastatic disease.

We investigated factors influencing metastasis and all-cause mortality using univariate and multivariate Cox regression analysis.

RESULTS

There were a total of 346 men who underwent radical prostatectomy between May 1983 and November 2008 and fulfilled the entry criteria. All patients had information on survival and 190 men had information on metastasis. Among patients with survival data (n = 346), 10-year OS was 79% after a median follow-up of 8.6 years from biochemical recurrence.

Among men with metastasis data (n = 190), 10-year MFS was 46% after a median follow-up of 7.5 years.

In Cox regressions, four clinical factors (Gleason score, pathological stage, time to PSA relapse and PSA doubling time), as well as age, were predictive of OS and/or MFS in univariate analysis, although only PSA doubling time (≥9 vs 3–8.9 vs <3 months) remained independently predictive of these outcomes in multivariate analysis (P < 0.001).

CONCLUSIONS

This multicentre multi-ethnic dataset shows that OS and MFS can be extensive for men with PSA-recurrent prostate cancer, even in the absence of further therapy before metastasis.

This unique patient cohort, the second largest of its type after the Johns Hopkins cohort, confirms that PSA doubling time is the strongest determinant of OS and MFS in men with PSA-recurrent disease.

Longer follow-up and more events will be required to determine whether other variables may also contribute to these outcomes.

BACKGROUND

Antiandrogen withdrawal is a potential therapeutic maneuver for patients with progressive prostate cancer. This study was designed to examine antiandrogen withdrawal effects within the context of a large multi-institutional prospective trial.

METHODS

Eligibility criteria included progressive prostate adenocarcinoma despite combined androgen blockade. Eligible patients received prior initial treatment with an antiandrogen plus orchiectomy or luteinizing hormone-releasing hormone (LHRH) agonist. Patients were stratified according to type of antiandrogen, type of progression (prostate-specific antigen [PSA] or radiographic), presence or absence of metastatic disease, and prior LHRH agonist versus surgical castration.

RESULTS

A total of 210 eligible and evaluable patients had a median follow-up of 5.0 years; 64% of patients previously received flutamide, 32% bicalutamide, and 3% nilutamide. Of the 210 patients, 21% of patients had confirmed PSA decreases of ≥50% (95% CI, 16% to 27%). No radiographic responses were recorded. Median progression-free survival (PFS) was 3 months (95% CI, 2 months to 4 months); however, 19% had 12-month or greater progression-free intervals. Median overall survival (OS) after antiandrogen withdrawal was 22 months (20 and 40 months for those with and without radiographic evidence of metastatic disease, respectively). Multivariate analyses indicated that longer duration of antiandrogen use, lower PSA at baseline, and PSA-only progression at study entry were associated with both longer PFS and OS. Longer antiandrogen use was the only significant predictor of PSA response.

CONCLUSIONS

These data indicate a relatively modest rate of PSA response in patients who were undergoing antiandrogen withdrawal; however, PFS can be relatively prolonged (≥1 year) in approximately 19% of patients.

Purpose

BMS-641988 is an androgen receptor antagonist with increased potency relative to bicalutamide in both in vitro and in vivo prostate cancer models. A first-in-man phase I study was conducted to define the safety and tolerability of oral BMS-641988 in patients with castration-resistant prostate cancer (CRPC).

Experimental Design

Doses were escalated from 5 to 150 mg based on discrete pharmacokinetic parameters in cohorts of 3 to 6 subjects. After establishing safety with 20 mg of BMS-641988 in the United States, a companion study was opened in Japan to assess differences in drug metabolism between populations.

Results

Sixty-one men with CRPC were treated with daily BMS-641988. The pharmacokinetics of BMS-641988 and its active metabolites were proportional to dose. One patient experienced an epileptic seizure at a dose of 60 mg administered twice. Despite achieving target drug exposures, anti-tumor activity was limited to 1 partial response. Seventeen of 23 evaluable patients (74%) exhibited stable disease on imaging (median 15 weeks; range 8–32), and 10 of 61 patients (16%) achieved a ≥30%. decline in levels of prostate-specific antigen (PSA). Partial agonism was seen within the context of this study upon removal of the drug as evidenced by a decrease in PSA.

Conclusions

Although the clinical outcomes of predominantly stable disease and partial agonism were similar to what was observed in the preclinical evaluation of the compound, the limited anti-tumor activity of BMS-641988 at therapeutic dose levels coupled with an episode of seizure activity led to study closure.

BACKGROUND

We sought to determine the change of PSA doubling time (PSADT) and its association with disease progression during intermittent androgen deprivation (IAD) therapy for prostate cancer.

METHODS

Data were retrospectively analyzed in 96 patients with biochemically relapsed prostate cancer (BRPC) treated with IAD since 1995. IAD consisted of LHRH-agonists ± antiandrogen given usually at PSA threshold (ng/ml) of 10–20, for 6–9 months. Cycles were repeated until the development of castration resistance. Mixed effects model was used to study PSADT change over cycles. Multivariate cox regression model was used to identify outcome-associated variables.

RESULTS

Patients received a mean of 2.8 treatment cycles over a mean follow-up time of 71 months. Fifty-seven (59%) remain on treatment and 39 (41%) developed PSA refractoriness (n = 8) or positive scans (n = 31). First off treatment interval PSADT (median 2.3 months) was significantly shorter than the baseline (median 7.34) but remained stable in subsequent cycles. Off treatment interval PSADT adjusted for testosterone recovery (median 3.7) was significantly longer than that based on all PSA determinations (median 2). Factors associated with disease progression were pre-treatment PSADT (≥6 vs. <6), first off treatment interval PSADT (≥3 vs. <3), and PSA nadir during the first treatment interval (<0.1 vs. ≥0.1).

CONCLUSIONS

During IAD for BRPC, PSADT becomes shorter, and is associated with testosterone recovery. PSADT before treatment and during the first off treatment interval is associated with disease progression. If prospectively validated these data may guide treatment with IAD and clinical trial design.

Background

Sunitinib is a standard treatment for metastatic renal cell carcinoma. Angiotensin system inhibitors, including angiotensin converting enzyme inhibitors and angiotensin II receptor blockers, are widely used in hypertension, kidney disease, and heart failure. Data suggests that they may inhibit tumourigenesis.

Aims

To study the effect of angiotensin system inhibitors on sunitinib treatment outcome in metastatic renal cell carcinoma.

Methods

We performed a retrospective study of an unselected cohort of patients with metastatic renal cell carcinoma who were treated with sunitinib. Patients were divided into angiotensin system inhibitors users (group 1) and non-users (group 2). The effect of angiotensin system inhibitors on objective response, time to disease progression and overall survival, was tested with adjustment for known confounding risk factors through logistic regression model and Cox regression model.

Results

Between 2004 and 2010, 127 patients with metastatic renal cell carcinoma were treated with sunitinib, 44 group 1 and 83 group 2. The groups were balanced regarding known clinicopathologic prognostic factors. Objective response was partial response/stable disease 86% versus 72% and progressive disease 14% versus 28% (p = 0.07) in group 1 versus 2, respectively. Median progression free survival was 13 versus 6 months (HR 0.537, p = 0.0055), and median overall survival 30 versus 23 months (HR 0.688, p = 0.21), in favour of group 1.

Conclusions

Angiotensin system inhibitors may improve the outcome of sunitinib treatment in metastatic renal cell carcinoma. This should be investigated prospectively, and if validated applied in clinical practise and clinical trials.

Background

Small cell carcinoma of the prostate is an uncommon neoplasm, the origin of which has been controversial. To address this, we performed transcriptome profiling and TP53 sequencing of concurrent small cell and prostatic adenocarcinoma to determine the relationship between these entities.

Methods

We identified an unusual case of primary prostate cancer that contained adjacent acinar adenocarcinoma (Gleason score 4+3=7) and small cell carcinoma. We performed laser capture microdissection to isolate tumor components and performed gene expression and TP53 gene sequence analysis on each component, with results validated by immunohistochemistry for PSA, PSAP, PSMA, androgen receptor, NKX 3.1 and neuroendocrine markers.

Results

Transcriptome profiling of the carcinoma components identified 99 genes with a greater than 10-fold differential expression between prostatic adenocarcinoma and small cell carcinoma, many of which have not been previously reported in prostate cancer. The small cell carcinoma component demonstrated upregulation of proliferative and neuroendocrine markers and tyrosine kinase receptors, and downregulation of cell adhesion molecules, supporting the aggressive nature of this form of carcinoma. Sequencing of the TP53 gene suggested a common clonal origin for both components.

Conclusions

This is the first report of a primary small cell carcinoma of the prostate subjected to extensive molecular analysis and the first to show a clonal relation between two morphologically distinct prostate cancer types. The evidence of progression to small cell carcinoma may yield important insights into the pathogenesis of this entity and provide a novel spectrum of molecular markers to further dissect cellular pathways important in tumor progression.

Purpose

We evaluated rapid androgen cycling in combination with docetaxel for men with progressive non-castrate prostate cancers.

Methods

Non-castrate patients with ≤ 6 months of hormones were eligible. Cohort 1 (63 patients ) received 6 28-day cycles of docetaxel (75 mg/m2), leuprolide and 7 days of topical testosterone. Cohort 2 (39 patients) received 9 21-day cycles of docetaxel (70 mg/m2), leuprolide and 3 days of testosterone. The primary endpoint was the proportion of patients at 18 months who achieved non -castrate testosterone levels (>150 ng/dl) and an undetectable PSA (≤ 0.05, ≤0.5, or ≤2.0 ng/ml with prior prostatectomy, radiotherapy, or no definitive therapy, respectively). Cytochrome P450 3A4 (CYP3A4) activity and docetaxel pharmacokinetics were evaluated.

Results

A higher proportion of patients achieved the undetectable PSA outcome at 18 months in cohort 2 relative to cohort 1 (13% vs. 0%). The 16% incidence of febrile neutropenia was higher than observed in patients was castration-resistant disease, which may have been related to a 50% reduction in overall docetaxel clearance in the non-castrate group. There was no alteration in CYP3A4 activity (P=0.87) or docetaxel clearance (P=0.88) between cycles.

Conclusions

The undetectable PSA endpoint allows for a rapid screening of interventions for further study. Increasing the number of docetaxel cycles following a shorter period of testosterone repletion, and a longer duration of testosterone depletion, increased the proportion of men who achieved an undetectable PSA. The higher-than-expected incidence of febrile neutropenia may have been related to the reduced overall docetaxel clearance in patients with non-castrate vs castrate testosterone levels.

Purpose

To find the maximum tolerated dose (MTD) of OSI-461 in combination with mitoxantrone in patients with advanced solid tumors.

Methods

This was a Phase I study using cohort dose escalation of OSI-461 dosed orally twice daily in combination with mitoxantrone 12 mg/m2 given on Day 1 of each 21-day cycle.

Results

OSI-461 dose was escalated to 1,000 mg po bid. One patient experienced a dose-limiting toxicity (DLT). Three patients discontinued the study due to adverse events (AE). Two patients (10%) had a partial response, and ten patients (50%) had stable disease as best response.

Conclusion

The combination of OSI-461 and mitoxantrone was well tolerated. Dose escalation was stopped because of toxicities in a concurrent Phase I trial. The response rate seen in patients with prostate cancer was comparable to response rates seen in trials of mitoxantrone and prednisone alone, and further studies of the combination of OSI-461 and mitoxantrone were not pursued.