LSD1 inhibition suppresses ASCL1 and de-represses YAP1 to drive potent activity against neuroendocrine prostate cancer

Lysine-specific demethylase 1 (LSD1 or KDM1A ) has emerged as a critical mediator of tumor progression in metastatic castration-resistant prostate cancer (mCRPC). Among mCRPC subtypes, neuroendocrine prostate cancer (NEPC) is an exceptionally aggressive variant driven by lineage plasticity, an adaptive resistance mechanism to androgen receptor axis-targeted therapies. Our study shows that LSD1 expression is elevated in NEPC and associated with unfavorable clinical outcomes. Using genetic approaches, we validated the on-target effects of LSD1 inhibition across various models. We investigated the therapeutic potential of bomedemstat, an orally bioavailable, irreversible LSD1 inhibitor with low nanomolar potency. Our findings demonstrate potent antitumor activity against CRPC models, including tumor regressions in NEPC patient-derived xenografts. Mechanistically, our study uncovers that LSD1 inhibition suppresses the neuronal transcriptional program by downregulating ASCL1 through disrupting LSD1:INSM1 interactions and de-repressing YAP1 silencing. Our data support the clinical development of LSD1 inhibitors for treating CRPC - especially the aggressive NE phenotype.

Statement of Significance

Neuroendocrine prostate cancer presents a clinical challenge due to the lack of effective treatments. Our research demonstrates that bomedemstat, a potent and selective LSD1 inhibitor, effectively combats neuroendocrine prostate cancer by downregulating the ASCL1- dependent NE transcriptional program and re-expressing YAP1.

Transcriptional profiling of primary prostate tumor in metastatic hormone-sensitive prostate cancer and association with clinical outcomes: correlative analysis of the E3805 CHAARTED trial

BACKGROUND

The phase III CHAARTED trial established upfront androgen-deprivation therapy (ADT) plus docetaxel (D) as a standard for metastatic hormone-sensitive prostate cancer (mHSPC) based on meaningful improvement in overall survival (OS). Biological prognostic markers of outcomes and predictors of chemotherapy benefit are undefined.

PATIENTS AND METHODS

Whole transcriptomic profiling was performed on primary PC tissue obtained from patients enrolled in CHAARTED prior to systemic therapy. We adopted an a priori analytical plan to test defined RNA signatures and their associations with HSPC clinical phenotypes and outcomes. Multivariable analyses (MVAs) were adjusted for age, Eastern Cooperative Oncology Group status, de novo metastasis presentation, volume of disease, and treatment arm. The primary endpoint was OS; the secondary endpoint was time to castration-resistant PC.

RESULTS

The analytic cohort of 160 patients demonstrated marked differences in transcriptional profile compared with localized PC, with a predominance of luminal B (50%) and basal (48%) subtypes, lower androgen receptor activity (AR-A), and high Decipher risk disease. Luminal B subtype was associated with poorer prognosis on ADT alone but benefited significantly from ADT + D [OS: hazard ratio (HR) 0.45; P = 0.007], in contrast to basal subtype which showed no OS benefit (HR 0.85; P = 0.58), even in those with high-volume disease. Higher Decipher risk and lower AR-A were significantly associated with poorer OS in MVA. In addition, higher Decipher risk showed greater improvements in OS with ADT + D (HR 0.41; P = 0.015).

CONCLUSION

This study demonstrates the utility of transcriptomic subtyping to guide prognostication in mHSPC and potential selection of patients for chemohormonal therapy, and provides proof of concept for the possibility of biomarker-guided selection of established combination therapies in mHSPC.

Serial blood-based analysis of AR-V7 in men with advanced prostate cancer

BACKGROUND

We previously showed that pretreatment detection of androgen receptor splice variant-7 (AR-V7) in circulating tumor cells (CTCs) from men with castration-resistant prostate cancer is associated with resistance to abiraterone and enzalutamide, but not to taxane chemotherapies. Here, we conducted serial measurements of AR-V7 and evaluated patterns of longitudinal AR-V7 dynamics over the course of multiple sequential therapies.

PATIENTS AND METHODS

Metastatic prostate cancer patients treated at Johns Hopkins with AR-directed therapies or taxane chemotherapies underwent serial liquid biopsies for CTC-based AR-V7 analysis at baseline, during therapy, and at progression. We used a CTC enrichment platform followed by multiplexed reverse-transcription polymerase chain reaction analysis to detect full-length androgen receptor and AR-V7 transcripts. Patients selected for inclusion in this report were those who provided ≥4 CTC samples, at least one of which was AR-V7 positive, over the course of ≥2 consecutive therapies.

RESULTS

We identified 14 patients who received a total of 37 therapies and contributed 70 CTC samples for AR-V7 analysis during a median follow-up period of 11 months. Three patients remained AR-V7 positive during the entire course of therapy. The remainder underwent transitions in AR-V7 status: there were eight instances of 'conversions' from AR-V7-negative to -positive status (during treatment with first-line androgen deprivation therapy, abiraterone, enzalutamide, and docetaxel), and six instances of 'reversions' from AR-V7-positive to -negative status (during treatment with docetaxel and cabazitaxel).

CONCLUSIONS

AR-V7 is a dynamic marker, and transitions in AR-V7 status may reflect selective pressures on the tumor exerted by therapeutic interventions. While 'conversions' to AR-V7-positive status were observed with both AR-directed therapies and taxane chemotherapies, 'reversions' to AR-V7-negative status only occurred during taxane therapies. Serial blood-based AR-V7 testing is feasible in routine clinical practice, and may provide insights into temporal changes in tumor evolution.

Long-term survival and biomarker correlates of tasquinimod efficacy in a multicenter randomized study of men with minimally symptomatic metastatic castration-resistant prostate cancer

PURPOSE

Tasquinimod (Active Biotech) is an oral immunomodulatory, anti-angiogenic, and anti-metastatic agent that delayed metastatic disease progression in a randomized placebo-controlled phase II trial in men with metastatic castration-resistant prostate cancer (mCRPC). Here, we report long-term survival with biomarker correlates from this trial.

EXPERIMENTAL DESIGN

Two hundred and one (134 tasquinimod and 67 placebo) men with mCRPC were evaluated. Forty-one men randomized to placebo crossed over to tasquinimod. Survival data were collected with a median follow-up time of 37 months. Exploratory biomarker studies at baseline and over time were collected to evaluate potential mechanism-based correlates with tasquinimod efficacy including progression-free survival (PFS) and overall survival (OS).

RESULTS

With 111 mortality events, median OS was 33.4 months for tasquinimod versus 30.4 months for placebo overall, and 34.2 versus 27.1 months in men with bone metastases (n = 136), respectively. Multivariable analysis demonstrated an adjusted HR of 0.52 [95% confidence interval (CI), 0.35-0.78; P = 0.001] for PFS and 0.64 (95% CI, 0.42-0.97; P = 0.034) for OS, favoring tasquinimod. Time-to-symptomatic progression was improved with tasquinimod (P = 0.039, HR = 0.42). Toxicities tended to be mild in nature and improved over time. Biomarker analyses suggested a favorable impact on bone alkaline phosphatase and lactate dehydrogenase (LDH) over time and a transient induction of inflammatory biomarkers, VEGF-A, and thrombospondin-1 levels with tasquinimod. Baseline levels of thrombospondin-1 less than the median were predictive of treatment benefit.

CONCLUSIONS

The survival observed in this trial of men with minimally symptomatic mCRPC suggests that the prolongation in PFS with tasquinimod may lead to a survival advantage in this setting, particularly among men with skeletal metastases, and has a favorable risk:benefit ratio.

A phase I/IIA study of AGS-PSCA for castration-resistant prostate cancer

BACKGROUND

This first-in-human phase I/IIA study was designed to evaluate the safety and pharmacokinetics (PKs) of AGS-PSCA a fully human monoclonal antibody directed to prostate stem cell antigen (PSCA) in progressive castration-resistant prostate cancer.

PATIENTS AND METHODS

Twenty-nine patients were administered infusions of AGS-PSCA (1-40 mg/kg) every 3 weeks for 12 weeks; 18 final patients received a 40-mg/kg loading dose followed by 20-mg/kg repeat doses. Primary end points were safety and PK. Immunogenicity, antitumor activity and circulating tumor cells were also evaluated.

RESULTS

No drug-related serious adverse events were noted. Dose escalation stopped before reaching the maximum tolerated dose as target concentrations were achieved. Drug levels accumulated linearly with dose and the mean terminal half-life was 2-3 weeks across dose levels. The 40-mg/kg loading dose followed by repeated 20-mg/kg doses yielded serum drug concentrations above the projected minimum therapeutic threshold after two to three doses without excessive drug accumulation or toxicity. Significant antitumor effects were not seen.

CONCLUSIONS

A 40-mg/kg loading dose followed by 20-mg/kg infusions every 3 weeks is the recommended phase II dose of AGS-PSCA. PSCA is a promising drug target and studies in prostate and other relevant solid tumors are planned.

Phase I study of the histone deacetylase inhibitor entinostat in combination with 13-cis retinoic acid in patients with solid tumours

BACKGROUND

Preclinical studies suggest that histone deacetylase (HDAC) inhibitors may restore tumour sensitivity to retinoids. The objective of this study was to determine the safety, tolerability, and the pharmacokinetic (PK)/pharmacodynamic (PD) profiles of the HDAC inhibitor entinostat in combination with 13-cis retinoic acid (CRA) in patients with solid tumours.

METHODS

Patients with advanced solid tumours were treated with entinostat orally once weekly and with CRA orally twice daily × 3 weeks every 4 weeks. The starting dose for entinostat was 4 mg m(-2) with a fixed dose of CRA at 1 mg kg(-1) per day. Entinostat dose was escalated by 1 mg m(-2) increments. Pharmacokinetic concentrations of entinostat and CRA were determined by LC/MS/MS. Western blot analysis of peripheral blood mononuclear cells and tumour samples were performed to evaluate target inhibition.

RESULTS

A total of 19 patients were enroled. The maximum tolerated dose (MTD) was exceeded at the entinostat 5 mg m(-2) dose level (G3 hyponatremia, neutropenia, and anaemia). Fatigue (G1 or G2) was a common side effect. Entinostat exhibited substantial variability in clearance (147%) and exposure. CRA trough concentrations were consistent with prior reports. No objective responses were observed, however, prolonged stable disease occurred in patients with prostate, pancreatic, and kidney cancer. Data further showed increased tumour histone acetylation and decreased phosphorylated ERK protein expression.

CONCLUSION

The combination of entinostat with CRA was reasonably well tolerated. The recommended phase II doses are entinostat 4 mg m(-2) once weekly and CRA 1 mg kg(-1) per day. Although no tumour responses were seen, further evaluation of this combination is warranted.

The effect of PSA doubling time (PSADT) and Gleason score on the PSA at the time of initial metastasis in men with biochemical recurrence after prostatectomy

16

Background: We previously reported on a cohort of men with biochemical recurrence after prostatectomy (n=430) who underwent observation until metastatic progression. Here, we describe the PSA at metastasis for those patients who developed metastatic disease.

Methods: PSA at metastasis was defined as the PSA value collected at the time of the first occurrence of metastasis as determined by CT or bone scan. We calculated the median PSA at metastasis and the interquartile range (IQR) for the entire cohort of men with metastatic progression, and also across different strata of PSADT (≤3 vs 3-9 vs 9-15 vs ≥15 mo) and Gleason score (≤7 vs 8-10). We used Pearson's correlation coefficient (r) to examine the relationship between PSADT or Gleason score and PSA at metastasis.

Results: With a median follow-up of 4 years after biochemical recurrence, 126/430 men (29.3%) had developed metastases. Sites of first metastasis included bone in 114 men (90.5%), extra-pelvic lymph nodes in 5 men (4.0%), lung in 3 men (2.4%), liver in 3 men (2.4%), and brain in 1 man (0.8%). The median PSA at the time of initial metastasis was 31.4 ng/mL (IQR, 8.8–87.5). Median PSA at metastasis across different PSADT strata is shown below (Table). There was a weak but statistically significant correlation between PSADT and 1/PSA at metastasis (r=0.20, P=0.02). There was no correlation between Gleason score and PSA at metastasis (r=0.01, P=0.83). Median PSA at metastasis was 30.3 ng/mL (IQR, 8.6–74.9) for men with Gleason ≤7 (n=69) and 34 ng/mL (IQR, 7.9–115) for men with Gleason 8-10 (n=57).

Conclusions: In patients with biochemical recurrence after prostatectomy, there is an inverse correlation between PSADT and PSA at metastasis, while Gleason sum has no effect on PSA at metastasis. These data may be used by clinicians to estimate at what PSA level metastases are likely to first develop across different strata of PSADT, helping to determine when/if to initiate therapy.

[Table: see text]

No significant financial relationships to disclose.

PSA doubling time (PSADT) and serum testosterone (T) during intermittent androgen deprivation (IAD) in patients with biochemically relapsed prostate cancer (BRCP; M0): Potential predictive implications

150

Background: The systemic management of patients with BRPC remains controversial. IAD is commonly employed. Aims: To evaluate the PSA dynamics and serum T in pts with BRPC treated with IAD until the development of PSA refractoriness or clinical evidence of metastatic disease.

Methods: Data were retrospectively analyzed in all pts with BRCP treated with GnRH at PSA thresholds according to pre-treatment PSADT (10-15ng/mL, 15-20, and 20-30 for PSADT ≤3 mos, 3-9 mos, and ≥ 9 ms, respectively) and continued until PSA nadir. Antiandrogen (AA) was added for PSA > 1.0 ng/mL after 3 mos). Follow-up (FU) consisted of PSA and T q3 mos. Cycles were repeated at the above preselected PSA thresholds and continued until lack of PSA response. Scans were obtained prior to cycles and at the time of CRPC state. Mixed effects model was used to study PSADT change over cycles. Multivariate cox regression model was used to identify prognostic variables.

Results: From 1995-2010, with a mean FU of 71 mos (range 22-183 months), 96 pts received a mean of 2.8 cycles (range 1-9) of IAD; 58 (60%) remain on treatment and 38 (40%) were switched to continuous ADT due to PSA refractoriness (n=11) or positive scans (n=27). PSADT at the first off treatment (tx) interval (mean 3.1, 0.59-30.5 range, median 2.3) was significantly shorter than the baseline (p<0.0001; mean 9.7, range 0.27-53.9, median 7.34) but remained relatively stable (p=0.29) in subsequent cycles. PSADT adjusted for T recovery (≥3 ms after T recovery to ≥ 150 ng/dL) was significantly longer (p=0.006) than that based only on all PSA determinations (mean 5.4, range 1.31-30.5, median 3.7 versus mean 3.1, range 0.59-30.5, median 2.3). Significant factors associated with probability of PSA refractoriness were pre-IAD PSADT (≥ 6 vs <6 ms), first off tx interval PSADT (≥3 ms vs <3m), the use of AA during first tx cycle, and PSA nadir during the first tx interval (<0.1 vs ≥0.1 ng/mL).

Conclusions: Our data suggest that PSADT becomes shorter after the initial cycle of IAD and correlate with T recovery. PSA dynamics and need for AA to enhance PSA nadir are associated with PSA refractoriness in pts BRPC treated with IAD.

No significant financial relationships to disclose.

A phase II study of pomegranate extract for men with rising prostate-specific antigen following primary therapy

11

Background: Pomegranate extract (POMx) demonstrates promising antitumor effects in prostate cancer (PCA). Prior published work reveals an increase in PSA doubling time (PSADT) in a single arm study of pomegranate juice (POM) in PCA patients (pts) with a rising PSA after local therapy. We sought to determine the effects of low (1 gram) or high (3 grams) daily POMx on PSADT in a similar but broader population of men seeking to defer androgen deprivation therapy.

Methods: Our multi-center, double bind phase II trial randomized men with rising PSA and without metastases to receive high or low dose POMx, stratified by baseline PSADT and Gleason score, and with no restrictions for PSADT and no upper limit PSA value. Men were treated until progression or for 18 months. PSA levels were obtained every 3 months. This study was designed to detect a 6 month increase in PSADT from baseline.

Results: 104 patients were enrolled and treated for up to 6 (92%), 12 (70%) and 18 months (36%). Median PSADT lengthened in the Intent to treat population (96% white, median age 74.5 years, median Gleason score 7) from baseline 11.9 (range 1.6-54.6) compared to 18.5 (2-1523) months after treatment (p<.001).There was no significant treatment difference on PSADT between the dose groups (p=.920). Declining PSA levels were observed in 13 pts (13%) during the study. No significant changes occurred in testosterone in either group. Although no clinically significant toxicities were seen, mild to moderate diarrhea was seen in 8 pts (7.7%).

Conclusions: POMx treatment significantly increased the PSADT by over 6 months in both treatment arms, with no effect on testosterone. This IND-conducted study confirms slowing of PSADT after treatment with POMx as was found with POM, yet in a PCA patient population with greater high risk progression features.

[Table: see text]

Phase II study of tasquinimod in chemotherapy-naive patients with metastatic castrate-resistant prostate cancer (CRPC): Safety and efficacy analysis including subgroups

126

Background: Tasquinimod (TASQ) is an oral quinoline-3-carboxamide derivative that binds to S100A9 and displays anti-angiogenic and anti-tumor activity in prostate cancer (PC) models. In a randomized blinded phase II study, 206 (136 TASQ, 70 placebo [P]) men with metastatic castrate resistant (CRPC) were assigned to TASQ/P once-daily at an initial dose level of 0.25 mg/day escalating to 1.0 mg/day over 4 weeks. The primary endpoint to demonstrate an improvement in PCWG2 criteria-defined progression at 6 months was met and presented at ASCO 2010. This abstract provides an update on safety and efficacy including CRPC subgroups.

Methods: Subgroups of patients based on baseline criteria were investigated for safety using NCI CTC v 3.0 criteria, PK and efficacy.

Results: 201 (134 TASQ, 67 P) pts with a median age of 72.6 years received treatment and were evaluable for efficacy and safety. The updated analysis based on 5 additional PFS events confirmed an improved PFS of 7.6 vs. 3.3 months for pts on TASQ vs. P. Most progression events in both arms were radiological, but more pts progressed on bone scan in the P group. Radiographic PFS was 8.8 vs 4.4 months. Significant PFS improvements were observed in the PCWG2 risk groups with bone metastatic and visceral disease. TASQ treatment led to a transient increase in inflammatory lab markers such as CRP and fibrinogen, as well as asymptomatic increases in amylase/lipase. CRP increase was associated with adverse events (AEs) such as muscle and joint pain, while increased amylase was associated with a lower risk for gastrointestinal AEs. TASQ treatment was associated with anaemia, but did not affect CV risk factors such as hypertension or QTc prolongation, and the rate of composite cardiac events was acceptably low. Clearance of TASQ is decreased with age (1.4 % per year) and patients over 80 often required dose reduction due to increased exposure and toxicities.

Conclusions: TASQ improved PFS in men with metastatic CRPC. Side effects are manageable and seem to correlate with laboratory markers. Individualized dosing based on tolerability is recommended and a phase III placebo-controlled study is being initiated.

[Table: see text]

Effect of angiotenstin system inhibitors (ASIs) on the outcome of sunitinib treatment (tx) in patients (pts) with metastatic renal cell carcinoma (mRCC)

317

Background: The VEGFR inhibitor sunitinib is a standard tx for mRCC. ASIs include angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs). ASIs are used in the tx of hypertension (HTN), kidney disease, and heart failure. Preclinical and clinical studies in several cancer types have shown that they may inhibit tumor growth. Their effect on the outcome of sunitinib in mRCC is poorly defined. Aims: to study the effect of ASIs on the outcome sunitinib tx for mRCC.

Methods: We performed a retrospective study of an unselected cohort of pts with mRCC, who were treated with 50 mg of oral sunitinib in cycles of 4 weeks followed by 2 weeks of rest. Pts were divided into 2 groups: (1) ASIs users and (2) ASIs naive. The effect of ASIs use on objective response, time to progression (TTP), and overall survival (OS), was tested with adjustment of other known confounding risk factors using a chisquare test and partial likelihood test from cox model.

Results: Between 2004–2010, 124 pts with mRCC were treated with sunitinib. There were 44 ASIs users (group 1) and 80 nonusers (group 2). With regard to sunitinib tx initiation time, 39 users started ASIs before, 3 within 1 month, and 2 after 5 months. The groups were balanced regarding the following known clinical prognostic factors: past nephrectomy, RCC histology, time from diagnosis to tx, ≥ 2 metastatic sites, lung/liver/bone metastasis, ECOG performance status, Hb level, corrected ca > 10 mg/dL, platelets count, prior cytokines/ targeted tx, sunitinib induced HTN, % pts that had dose reduction/tx interruption, and mean dose/cycle. Objective response in group 1 vs. 2 was partial response (PR) 48% vs 38% (p=0.24), stable disease (SD) 38% both, and progressive disease (PD) 14% vs. 24% (p=0.19). Median TTP was 12 vs. 6 ms (HR 0.635 in ASIs users, p=0.034). Median OS was 25 vs. 22 ms (p=0.3).

Conclusions: ASIs may improve the outcome of pts with mRCC that are treated with sunitinib. This should be investigated prospectively, and if validated, applied in clinical practice and clinical trials.

No significant financial relationships to disclose.

Association of PTEN loss with outcome of patients (pts) with early high-risk prostate cancer (CaP) treated with adjuvant docetaxel following radical prostatectomy (RP)

43

Background: Loss of the PTEN tumor suppressor and subsequent activation of the PI3K pathway is common and has potential clinical and therapeutic value in CaP. We examined the PTEN status of primary tumors in pts who underwent adjuvant docetaxel tx in a prospective clinical trial.

Methods: Of the 77 pts enrolled in a prospective multi-institutional adjuvant docetaxel trial (TAX 2501, J Urol 2007), we prospectively collected 56 primary tumor pathology specimens suitable for analysis of PTEN status by immunoreactivity (IHC) and/or fluorescence in situ hybridisation (FISH) assay. Protocol defined progression included a PSA of ≥ 0.4 ng/mL, radiological/pathological evidence of recurrent disease or death from any cause. Univariate and multivariable analyses based on the Cox proportional hazards regression model were used to analyze the independent association of PTEN and other known prognostic factors with progression free survival (PFS).

Results: PTEN loss was observed in 37/56 pts (66%). Pts with PTEN loss vs detectable PTEN were balanced regarding clinical stage, combined Gleason score, seminal vesicles and surgical margins involvement, and lymph nodes status. Pts with a detectable PTEN had a significantly higher pre-RP PSA (median 14 vs 8.6 ng/mL, p=0.015). 41/56 (73.2%, median followup of 37.5 months, range 10.4 to 44.5) progressed with an overall median PFS of 13 months (mos) (95% CI 9.8–15.8). Independent prognostic factors of progression by multivariate analysis were: seminal vesicles involvement (HR 2.19, p=0.024), combined Gleason score 9–10 (HR 2.46, p=0.027) and PTEN loss (HR 2.36, p=0.037). PFS on pts without PTEN loss (median not reached at a followup time of 37.5 mos, range 10.4–44.5 mos) was significantly longer (log rank test, p = 0.026) compared to those with undetectable PTEN (median PFS 12.9 mos, 95% CI 9.7–15.3).

Conclusions: PTEN loss may be an independent prognostic factor associated with poorer outcome of pts with early high-risk CaP treated with adjuvant docetaxel following RP. These findings may have important prognostic and therapeutic implications in CaP.

No significant financial relationships to disclose.

Phase II study of single-agent volasertib (BI 6727) for second-line treatment of urothelial cancer (UC)

253

Background: Polo-like kinase 1 (Plk1) controls multiple essential steps of mitosis. Volasertib (BI 6727) is a first-in-class, selective inhibitor of Plk1. In vitro, Plk1 depletion in cancer cells leads to activation of the mitotic checkpoint, prolonged mitotic arrest, and eventually apoptosis. No standard therapy exists for metastatic urothelial cancer (UC) progressing after initial chemotherapy. Thus, there is an urgent need for novel treatment options. Interim efficacy and tolerability results are presented from an open-label, single-arm, multi-center phase II trial of volasertib in patients (pts) with previously treated advanced UC.

Methods: Pts progressing after one prior systemic chemotherapy for locally advanced or metastatic UC or relapsing within 2 years of adjuvant/ neoadjuvant treatment received 300 mg volasertib (2-hour intravenous infusion) on day 1 every 21 days. If well tolerated, dose escalation to 350 mg in cycle 2 was encouraged. Primary endpoint was objective tumor response, defined by RECIST. The trial follows a modified Gehan-two-stage design with an early stopping rule based on the observed response rate of the first 20 pts receiving up to 4 courses of treatment. A minimum response rate of 10% (2/20) was required to recommend additional study.

Results: This trial is ongoing: 31 pts (median age 67) were treated between December 2009 and August 2010. All pts were eligible for interim safety/efficacy analysis. As of August 2010, 6 pts (19%) demonstrated a partial response, 7 pts (23%) had stable disease and 16 (52%) progressed between 3-6 weeks after study initiation. Thirteen (42%) pts remain on trial between 13-41 weeks (median time on trial 5 months) without disease progression. Major grade 3 or 4 adverse events (irrespective of drug relatedness) were neutropenia (10 pts, 32%), thrombocytopenia (7 pts, 23%), anemia (5 pts, 16%), hyponatremia (3 pts, 10%), dehydration (2 pts, 7%), and urinary tract infection (2 pts, 7%).

Conclusions: Single-agent volasertib was well tolerated and demonstrates clinical activity in the second-line treatment of pts with advanced UC. The early signs of clinical benefit allows proceeding per protocol to the second stage of the trial.

[Table: see text]

Safety and efficacy of ketoconazole (K) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): Contemporary experience and prognostic indicators

145

Background: Intracrine conversion of adrenal androgens to testosterone play an important role in CRPC progression. Treatments (tx) that block adrenal steroid synthesis have shown significant clinical benefits in mCRPC. Aims: To evaluate contemporary data on safety and efficacy associated with K in mCRPC.

Methods: All/unselected mCRPC pts progressing on GnRH-a and antiandrogens (AA) treated with K were retrospectively analyzed. Pts were maintained on gonadal suppression, discontinued AA, and received and K 200-400 mg t.i.d. until disease progression or dose-limiting toxicity (DLT). Initial 600mg/d dose was escalated to 1,200mg/d if a PSA decrease was not seen at 3 months (mos) or if a response/subsequent progression to 600/mg/d was observed (optional). Follow up included hematological/chemical profile q 3 mos, scans upon clinical (physical exam/symptoms) or at biochemical progression (PSA increase ≥ 25% and ≥2ng/mL from nadir). A multivariate cox regression model was used to identify variables significantly associated with disease progression.

Results: From 1999-2010 (mean follow up 40 mos, range 5-129), 114 m-CRPR pts were treated with K 200mg (n=82, 72%) or 400mg (n=32, 28%) tid. Most common grade 3/4 tox events (n=23) were fatigue, abdominal discomfort, nausea, and dizziness. 9 pts (8%) had DLT (fatigue n=7, hepatotoxicity/thrombocytopenia n=1). 55/114 (48%) had ≥ 50% PSA decline. Overall median time to progression (TTP) was 8 mos (range 1-129). 14 pts remain progression free > 7 mos (range 7-129). Significant prognostic factors (table) were response to prior AA (≥6 vs <6 mos), pre-tx PSADT (≥3 vs <3 mos) and extent of disease (limited-axial skeleton and/or nodal vs extensive- appendicular skeleton and/or visceral).

Conclusions: K is effective and safe in m-CRPC. Prior response to AA, PSADT ≥ 3mos and limited metastatic disease is associated with TTP and further supports a therapeutic role for suppressing adrenal androgens in m-CRPC.

[Table: see text]

No significant financial relationships to disclose.

Tolerance of full-dose sorafenib (S) combined with irinotecan (I; weekly, two on, one off) and cetuximab (C) in previously treated patients with advanced colorectal cancer (CRC)

522

Background: The epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) pathways are qualified targets in CRC, and are both inhibited by S. Preclinical evidence suggests S may also overcome cetuximab resistance. We previously reported (2008 GI Symposium, abstr#435) excessive toxicity of this combination with I 120 mg/m2 days (d) 1,8,15,22 every 42 d; the study was amended with an alternative I dose/schedule and the phase I results are presented.

Methods: Patients (pts) with advanced, pretreated CRC irrespective of KRAS mutation status with ECOG PS 0-2 and good organ function were eligible. The original dose/schedule of I was combined with C 400 mg/m2 IV d1 and 250 mg/m2 weekly; and S PO daily with dose level (DL) 1 = 200mg QD, DL2=200 mg BID and DL 3=400 mg BID. 2/4 pts had DLTs: grade (g) 3 fatigue and febrile neutropenia. The dose/schedule were amended to I 100 mg/m2 d1, 8 of 21d cycles (c) without changing S or C. As with the original design, there was a C/S lead-in for 2 weeks in c1, thus c1 (DLT window) was 5 weeks (w).

Results: In the original design, 5 subjects were recruited; after the study amendment, 13 additional pts were recruited (3, 3 and 7 pts respectively at amended DL1, DL2 and DL3). Overall, median age was 56.5 yrs, M: F 12:6 and colon: rectal cancer 16:2. All patients are evaluable and 3 are still on treatment (10+ - 20+ w). At the amended I dose/schedule, there were no further DLTs. Any c g3 toxicities included constitutional (fatigue:2, dehydration:1), gastrointestinal (nausea:1, vomiting:2, diarrhea:1), metabolic (hypomagnesemia:2 including one with tetany; hypokalemia:3), elevated ALT:1 and neutropenia:1. G 4 toxicities included neutropenia:1, thrombocytopenia:1. Two pts (one KRAS MT) had partial response with one pt (KRAS WT) on treatment for >44 w. 10 pts had stable disease (5–20+ w). PK/PD analysis is ongoing.

Conclusions: The recommended phase II dose is I 100 mg/m2d1,8; C 400 mg/m2 IV d1 and 250 mg/m2 weekly; and S 400 mg PO BID. The regimen is tolerable in advanced, pretreated CRC. Due to the limited responses and current phase III studies with S in CRC, there are no plans to open the phase II portion at this time.

No significant financial relationships to disclose.

A randomized, double-blind, placebo-controlled phase III trial comparing docetaxel, prednisone, and placebo with docetaxel, prednisone, and bevacizumab in men with metastatic castration-resistant prostate cancer (mCRPC): Survival results of CALGB 90401

LBA4511

Background: The preclinical activity of vascular endothelial growth factor (VEGF) blockade, the inverse relationship of plasma and urine VEGF levels and survival in mCRPC patients (pts), and encouraging phase II data testing estramustine and docetaxel with bevacizumab suggested that VEGF blockade was an appropriate potential strategy in mCRPC. A phase III study testing the effect of adding bevacizumab to standard docetaxel and prednisone therapy administered every 3 weeks in pts with mCRPC was conducted.

Methods: 1050 pts with chemotherapy naïve, mCRPC with evidence of progressive disease despite castrate testosterone levels and anti-androgen withdrawal, ECOG performance status ≤ 2, and adequate bone marrow, hepatic and renal function were eligible. Pts were prospectively randomized with equal probability to receive docetaxel (D:75 mg/m2 IV over 1 hour q 21 days), plus prednisone (P) 5 mg po BID with either bevacizumab (B:15 mg/kg given intravenously q 3 weeks following D) or placebo. All patients received dexamethasone 8 mg PO 12, 3 and 1 hour prior to D. Randomization was stratified by predicted 24 mo survival probability, age and history of prior arterial thrombotic event. The primary endpoint was overall survival (OS). The trial was designed with 86% power to detect a 21% decrease in the hazard rate of death (equivalent to an increase in median OS from 19 months to 24 months) assuming a two-sided significance level of 0.05. The primary analysis was based on the stratified log-rank statistic adjusted for the stratification factors following observation of 748 deaths.

Results: See Table .

Conclusions: Despite an improvement in PFS, measurable disease response and post-therapy PSA decline, the addition of bevacizumab to docetaxel and prednisone did not improve OS in men with mCRPC, and was associated with greater morbidity and mortality. The median OS of pts treated with standard DP (21.5 m) was longer than previously reported (19 m).

[Table: see text]

[Table: see text]

A randomized phase III trial of denosumab versus zoledronic acid in patients with bone metastases from castration-resistant prostate cancer

LBA4507

Background: Bone metastases from hormone-refractory (castration-resistant) prostate cancer (CRPC) are associated with RANKL-mediated osteoclast activation resulting in bone destruction and skeletal-related events (SRE). Denosumab is a fully human monoclonal antibody against RANKL. This phase III, randomized, double-blind, active-controlled trial compared the efficacy and safety of denosumab vs. zoledronic acid (ZA) in patients with metastatic CRPC.

Methods: Patients (n = 1,901) with CRPC and at least 1 bone metastasis, but no prior IV bisphosphonate use, received either SC denosumab 120 mg and IV placebo (n = 950), or SC placebo and IV ZA 4 mg (n = 951) adjusted for creatinine clearance every 4 weeks. All patients were instructed to take supplemental calcium and vitamin D. The primary endpoint was time to first on-study SRE, defined as pathologic fracture, radiation or surgery to bone, or spinal cord compression.

Results: Denosumab significantly delayed the time to first on-study SRE compared with ZA, (HR 0.82 ; 95% CI: 0.71, 0.95 ; p = 0.008.) The median time to first on-study SRE was 20.7 mo denosumab vs. 17.1 mo ZA, a difference of 3.6 months. Denosumab also significantly delayed the time to first and subsequent on-study SRE (multiple event analysis) (HR 0.82 ; 95% CI: 0.71, 0.94 ; p = 0.004). Greater suppression of the bone turnover markers uNTx and BSAP occurred in denosumab patients compared with ZA (p < 0.0001 for both). Overall, adverse event (AE) rates (97% each) and serious AEs (63% denosumab, 60% ZA) were similar, irrespective of potential relationship to study drugs. AEs of hypocalcemia were reported in 13% and 6% of denosumab and ZA patients. Osteonecrosis of the jaw occurred in 22 (2.3%) denosumab compared with 12 (1.3%) ZA patients (p = 0.09). Overall survival (HR 1.03 ; 95% CI: 0.91, 1.17 ; p = 0.65) and time to cancer progression (HR 1.06; 95% CI: 0.95, 1.18; p = 0.30) were similar between treatment arms.

Conclusions: Denosumab demonstrated superiority over ZA in delaying or preventing SREs in patients with bone metastases from CRPC. Adverse events were consistent in both treatment groups with those previously reported in advanced cancer populations.

[Table: see text]

HIF-1alpha and calcium signaling as targets for treatment of prostate cancer by cardiac glycosides

Prostate cancer possesses its unique feature of low proliferation rate and slow growth. Ca(2+)-induced apoptosis is not dependent on cell cycle progression and targeting this pathway could circumvent the problems encountered using current cytotoxic chemotherapies for prostate cancer. Hypoxia-inducible factor 1alpha (HIF-1alpha) is another novel cancer drug target and inhibitors of hypoxia-response pathway are being developed. Digoxin and other cardiac glycosides, known inhibitors of the alpha-subunit of sarcolemmal Na(+)K(+)-ATPase, were recently found to block tumor growth via the inhibition of HIF-1alpha synthesis. Thus, cardiac glycosides disrupt two important cellular pathways and, therefore, may be useful as an anticancer therapy. This review will focus on HIF-1alpha and calcium signaling as novel cancer drug targets in prostate cancer. The possible application of digoxin and other cardiac glycosides in cancer therapeutics especially in prostate cancer is discussed.

Does pre-existing diabetes affect prostate cancer prognosis? A systematic review

To summarize the influence of pre-existing diabetes on mortality and morbidity in men with prostate cancer. We searched MEDLINE and EMBASE from inception through 1 October 2008. Search terms were related to diabetes, cancer and prognosis. Studies were included if they reported an original data analysis of prostate cancer prognosis, compared outcomes between men with and without diabetes and were in English. Titles, abstracts and articles were reviewed independently by two authors. Conflicts were settled by consensus or third review. We abstracted data on study design, analytic methods, outcomes and quality. We summarized mortality and morbidity outcomes qualitatively and conducted a preliminary meta-analysis to quantify the risk of long-term (>3 months), overall mortality. In total, 11 articles were included in the review. Overall, one of four studies found increased prostate cancer mortality, one of two studies found increased nonprostate cancer mortality and one study found increased 30-day mortality. Data from four studies could be included in a preliminary meta-analysis for long-term, overall mortality and produced a pooled hazard ratio of 1.57 (95% CI: 1.12-2.20). Diabetes was also associated with receiving radiation therapy, complication rates, recurrence and treatment failure. Our analysis suggests that pre-existing diabetes affects the treatment and outcomes of men with prostate cancer.

A phase II study of once-daily dasatinib for patients with castration-resistant prostate cancer (CRPC) (CA180085)

5147

Background: Dasatinib is a potent oral SRC family kinase inhibitor that also inhibits c-KIT and PDGFR in vitro. The anti-proliferative/anti-metastatic activity as well as osteoclast inhibitory function of dasatinib in pre-clinical models supports its potential as a targeted therapy for prostate cancer. Previously we presented results on BID dosing of dasatinib in the treatment of CRPC (ASCO. 2008 Abstract 5156). A second group of patients (pts) was enrolled to investigate the activity, safety and bone effects of 100 mg once daily dosing. Methods: Male pts with progressive metastatic CRPC, rising PSA, castrate levels of testosterone (< 50 ng/dL) and no prior chemotherapy were enrolled. Dasatinib dose was 100 mg QD. Continuation of bisphosphonates was permitted. Primary endpoint was a composite of: PSA responses, bone scans and disease control by RECIST. Urinary N-telopeptide (uNTX) and bone alkaline phosphatase (BAP) were determined Q 4-weeks as indicators of bone metabolism. Results: 47 pts were treated (median treatment duration was 2.3 months). 11 patients were evaluable by RECIST; of these 64% achieved SD. The composite response rate was (8/47) 17%. Of 22 pts with bone scans, 50% were stable at 12 weeks and 3/9 (33%) were stable at 24 weeks. A prolonged PSA doubling time was observed in 32 of 39 pts (82%), including one pt with a PSA response. Of the pts with evaluable bone markers, including those who continued on bisphosphonate therapy, 20/41 (49%) had a ≥ 35% decrease in uNTX and 21/42 (50%) had a decrease from baseline in BAP. Grade 3/4 adverse events (AEs) were experienced by 13% of pts (diarrhea, asthenia, and pleural effusion [n=1]). Grade 1/2 AEs (≥ 15% of pts) were diarrhea, nausea, headache, fatigue, asthenia, anorexia and dyspnea. Conclusions: Fewer and less severe AEs were observed in all categories for the QD dosing group compared to the previously reported BID dosing cohort. In addition, preliminary clinical activity (tumor and PSA response; decreasing bone turnover [uNTX, BAP]), is now confirmed to be similar in pts treated with 100mg QD and BID dosing. These data support the relevance of further studies of dasatinib in metastatic CRPC.

[Table: see text]

A randomized double blind phase I-II study to determine the tolerability/efficacy of two different doses of lenalidomide (L), CC- 5013, in biochemically relapsed (BR) prostate cancer (PC) patients (pts) (M0) after local treatment (LT)

5130

Background: BR following LT is common in PC with no defined standard treatment. Lenalidomide (L) is an immunomodulatory agent with anti-angiogenic and direct antitumor effects. Methods: This trial was designed to evaluate a dose-effect relationship of L in BR PC. Pts were randomized to either 5 or 25 mg/day(d), PO, d 1–21 (28-d cycles); then stratified by PSADT (< 3, 3–8.9, ≥ 9 mos), LT and prior ADT. Eligible pts had: rising PSA (≥1 ng/mL), M0 disease, testosterone > 150 ng/mL, adequate bone marrow, renal, and hepatic function. Baseline and Q 2 mos PSA's were processed after Q 6 mos of L, along with CT and bone scan. Toxicity exams were Q mo. Primary endpoints are safety and progression after 6 mo of L (defined by a confirmed ↑ in PSA > 25% over the baseline value or mets). Secondary endpoints are changes of slopes in PSA related to pharmacokinetics (pk). A sample size of 30 pts/arm provides an 85% power to detect a PSA progression rate of 40% (compared to 80% predicted ) with a Type I error = 0.05 (Fishers exact test). Results: 59 pts were entered July 20, 2006-December 31, 2008. Pooled data from the 2 arms: median: age 64 (50–81), ECOG PS 0, baseline PSA 9.3 ng/ml (1.3–92.8 ng/ml). 16 pts had PSADT <3 mos, 26 from 3–8.9 mos, and 17 ≥ 9 mos. Median: F/U on all 59 pts is 351 + d (9 +-887+d); # cycles = 6 (1–30). Thus far, 44/59 pts completed 6 cycles of L (1 had PD, 6 stopped L due to toxicity, 8 too early). 22 /44 who completed 6 mos of L remained on L > 6 mos ( 7+-30+ mos); including 7 pts ≥ 24 mos. Of 44 pts, blinded evaluation of PSA's at 6 mos: 4 pts had ≥ 50% ↓, 22 had stable PSA,17 had PD, 1 too early . Rash was DLT. Other Gr toxicities: appendicitis, abd pain, neck pain, venous thrombolic disease, fatigue, pruritus. Conclusions: Preliminary data prior to unblinding the study treatment arms, from pooled data, suggest that L may be administered > 6 mos with acceptable toxicity, and is associated with PSA declines and long term stabilization in pts with BR. Supported by a grant from Celgene Corporation. Data coordination infrastructure is supported by the Prostate Cancer Foundation and The James Stine research fund.

[Table: see text]

Phase I study of enzastaurin (ENZ) and bevacizumab (BV) in patients with advanced cancer: Safety, pharmacokinetics (PK), and response assessment

3517

Background: ENZ, an oral kinase inhibitor, suppresses tumor growth through PKC and PI-3 kinase/AKT. BV binds VEGF and inhibits angiogenesis. Since ENZ and BV are complementary in inhibiting angiogenesis, we conducted a Phase I study of ENZ / BV. Methods: Eligible patients (pts) had advanced cancer, adequate organ function and no co-morbidities for increased risk of drug-related toxicities. Six pts were enrolled per cohort; if ≤1 DLT the next cohort opened. A loading dose of ENZ 1125 mg was given on Day 1, C1. After 1 cohort combining ENZ 500 mg/QD and BV at 5mg/kg IV q 2 wks, subsequent cohorts alternated pts between BV 10 mg/kg IV q 2 wks and BV 15 mg/kg IV q 3wks with escalating doses of ENZ (500 mg/QD, 250 mg/BID, and 375 mg/BID) for a total of 7 cohorts. DLT was defined as C1: Grade (G)4 neutropenia ≥7 days, febrile neutropenia, G3 thrombocytopenia with bleeding or G4 thrombocytopenia; G3/G4 non-hematological toxicities, and toxicities associated with BV. ENZ PK was performed at steady-state on Day 1, C2. Results: 43 pts (21 with ovarian cancer) are evaluable for toxicity. Two DLTs (G3 elevated aminotransferase and intraparenchymal hemorrhage) occurred at different dose levels. No apparent increase in ENZ or BV toxicity was seen. Two SAEs (DVT and myocardial ischemia) in two pts occurred at DL 3 after 3 cycles and 13 cycles, respectively. Common toxicities included fatigue, chromaturia, dry/sore mouth, nausea and diarrhea. Nine of 43 pts (21%) had a response (CR, PR), 6 responses were in the ovarian subset (29%). Median time to progression was 3.9 mos (range 0–19.2 mos) and 7.7 mos for ovarian pts (range 0.3–19.2 mos). Overall, 43% remained on study without disease progression for >6 mos (51% of ovarian pts remained on study for >6 mos). Mean steady-state ENZ concentrations (%CV) at 500 mg/QD, 250mg/BID and 375mg/BID were 1080 nmol/L (82.8 %), 516 nmol/L (102%) and 1120 nmol/L (93.3%), respectively. Conclusions: The addition of ENZ to BV in any of the currently approved BV dosing schedules is well tolerated and clinically active in advanced cancer pts. ENZ exposures are highly variable and comparable across the three dose groups. The combination of ENZ / BV demonstrates encouraging activity, specifically in our population of ovarian cancer pts.

[Table: see text]

Pain and analgesic use in men with metastatic prostate cancer

e20515

Background: Pain is an important endpoint in metastatic prostate cancer and was the basis for the 1996 FDA approval of mitoxantrone. Standards for pain assessment have evolved, and a 2006 draft FDA guidance provides new recommendations for patient- reported outcomes. Contemporary palliation models generally require pain reduction starting from baseline worst pain scores of ≥4/10, and progression models require a sufficient proportion of patients’ pain scores to worsen in order to assure an adequate effect size. The prevalence and distribution of pain severity at specific points in the prostate cancer disease continuum are not well defined. Consequently, it is unclear if sufficient numbers of patients are available to conduct prospective studies using pain palliation or prevention as primary endpoints. Methods: A questionnaire that includes the Brief Pain Inventory and additional pain/analgesia items was developed as a collaboration between the DOD/PCF-supported Prostate Cancer Clinical Trials Consortium (PCCTC) and FDA Study Endpoints and Labeling Design (SEALD) team. IRB waivers were obtained for anonymous administration at 5 PCCTC institutions (Sloan-Kettering, Duke, Johns Hopkins, Anderson, OHSU). Administration is ongoing. Results: Between August-December 2008, 325 men with prostate cancers representing different disease states being seen in outpatient clinics of participating centers were each queried once. Median age was 70 (range 49–87). More than half (n=175) self-reported metastatic disease, including 129 with bone metastases. Among those with bone metastases, 76 (59%) reported experiencing any level of pain in the last week; 49 (38%) reported a worst pain score ≥4/10 of which 38 (78%) used analgesics over the past week and 31 (63%) used daily analgesia. In addition, 70 of the 76 (92%) noted that their pain interfered with work, sleep, or enjoyment of life, with 25 (33%) noting severe interference. Among the 49 patients with pain scores ≥4/10, current or past docetaxel use was reported by 32 (65%), androgen deprivation therapy by 47 (96%), and 28 (57%) had been or were currently enrolled in a clinical trial. Conclusions: Pain is sufficiently prevalent in men with metastatic prostate cancer to enable prospective assessment of palliation endpoints in clinical trials.

No significant financial relationships to disclose.

Prostate cancer clinical trials consortium: A multicenter mechanism for the rapid design, development, and implementation of early phase clinical trials

e16065

Background: Leading investigators in prostate cancer have hypothesized that clinical trials (CT) are optimally conducted as multicenter studies. To test this, the Prostate Cancer Clinical Trials Consortium (PCCTC) was formed with support from the Prostate Cancer Foundation (PCF) and the Department of Defense Clinical Consortium Award (DOD). Since the PCCTC's inception in 2006, members have cooperatively designed, carried out, and evaluated phase 1 and 2 multicenter studies in prostate cancer. Methods: PCF and DOD awards support a consortium of 13 cancer research centers. Memorial Sloan-Kettering Cancer Center serves as the coordinating center and is charged with creating an infrastructure to conduct early phase, multicenter trials. Annually, each participating center is required to introduce at least one CT for consideration by the PCCTC and accrue at least 35 patients to PCCTC studies. Investigators meet face-to-face twice per year to discuss the PCCTC's progress, and hold monthly conference calls to discuss scientific objectives, trial design, and ongoing studies. Results: Since inception, the PCCTC has expanded from 8 to 13 leading research centers. Through September 2008, it has opened 47 trials and accrued 1,282 patients at member sites. Members utilize a CT management system for protocol tracking, electronic data capture, and data storage. A legal framework has been instituted, and standard operating procedures, administrative structure, editorial support, centralized budgeting, and mechanisms for scientific review have been established. Each year, the number of trials presented and patients accrued increases, and three concepts have progressed to the next phase of clinical testing. Conclusions: The PCCTC fulfills a congressional directive to create a CT instrument dedicated to rapid accrual to early-phase, multicenter studies in prostate cancer. The member institutions have built a shared administrative, informatics, legal, financial, statistical, and scientific infrastructure to support this endeavor. As the PCCTC has expanded and taken an increasingly active role in designing and evaluating protocols, clinical trials continue to open and accrue in excess of federally mandated goals.

No significant financial relationships to disclose.

Pharmacodynamic (PD) study of pre-prostatectomy rapamycin in men with advanced localized prostate cancer (PC): A DOD Prostate Cancer Clinical Trials Consortium Trial

5001

Background: Rapamycin is an orally bioavailable and generic mTOR inhibitor with an MTD of 6 mg daily and anticancer activity in solid tumors. We sought to determine the optimal biologic dose (OBD) in the pre-operative setting in men with PC. Methods: We explored the safety and PD activity of 3 and 6 mg of daily oral rapamycin for 14 days prior to radical prostatectomy (RP) in cohorts of 21 men with intermediate risk localized PC. Ten untreated control subjects were included using identical inclusion criteria. Men had Gleason >6 PC involving multiple cores. PD markers in pre-treatment prostate biopsies and RP specimens included p-S6 and p-Akt, 4EBP-1, PTEN, p27, Ki-67, and cleaved caspase-3. Tissue and whole blood sirolimus levels were measured. A Simon 2-stage design using PD efficacy (tumor S6 inhibition > 60%) was utilized. Results: 32 subjects were accrued to this 2 stage pharmacodynamic trial, including 10 control subjects. Median pre-treatment PSA was 6.4 ng/dl, age 60y, Gleason 7 in 85%. 20 accrued to the 3 mg cohort without DLT. However, 2/2 men enrolled at the 6 mg dose level experienced DLT consisting of thrombocytopenia leading to a delay in surgery (<100K) and fever with grade 3 stomatitis. AEs observed in the 3 mg cohort included stomatitis (2), rash (1), post-operative ileus (2), and mild neutropenia (2). One post-operative ileus was observed among control patients. PD studies demonstrated tumor S6 inhibition in >50% of subjects (median 60% decline, p=0.026 vs. baseline) with no negative effect on the state of Akt phosphorylation (p=0.82) or p27 levels (p=0.10). Prostate sirolimus levels (range 7.1–47.2 ng/g) were two-fold higher than whole blood concentrations (range 3.2–19.2 ng/ml). There was no effect of rapamycin on rates of post-operative wound healing or bleeding. PBMC S6 activity inhibition did not correlate with tumor S6 inhibition. Conclusions: The MTD/OBD of daily rapamycin in the pre-operative or prevention setting is 3 mg. This dose demonstrated downstream mTOR inhibition in tumor tissue and achieved adequate prostate tissue levels. Additional PD and genomic studies will be presented. Conducted through the DOD PCCTC and registered at clinicaltrials.gov as NCT00311623 .

[Table: see text]

The natural history of metastatic progression in men with PSA-recurrent prostate cancer after radical prostatectomy: 25-year follow-up

5008

Background: In men with prostate specific antigen (PSA) recurrence following radical prostatectomy (RP) and no other therapy, the natural history of metastatic progression was previously described in 1999. We now report data reflecting up to 25 years of follow-up. Methods: We performed a retrospective analysis of 774 men treated with RP between 4/1982 and 7/2008 who developed PSA recurrence (>0.2 ng/ml) and never received adjuvant or salvage therapy. We investigated factors influencing the development of metastases. Results: Mean follow-up after RP was 8.5 y (median 8 y). Of 774 men with PSA recurrence, 295 (38%) developed metastases, and 433 had data on PSA doubling time (PSADT), forming our cohort. The mean time from RP to PSA recurrence in the entire cohort was 4.2 y (median 3 y). In those who developed metastases, the mean time from PSA recurrence to metastasis was 3.1 y (median 2 y). The mean PSA at the time of metastasis was 90.3 ng/ml (median 31.4 ng/ml). In Cox regression analysis: PSADT, Gleason score, and time to PSA progression were predictive of the development of metastases ( Table ). In Kaplan-Meier survival analysis, the median actuarial time from PSA recurrence to metastasis was 10 y (95% CI 9 - 15 y). Median actuarial metastasis-free survival from PSA recurrence for men with PSADT <3 mo, 3 - 8.9 mo, 9 - 14.9 mo, and >15 mo was 1 y (95% CI 0 - 1 y), 4 y (95% CI 2 - 6 y), 9 y (95% CI 7 - 13 y), and 15 y (95% CI 12 - 20 y), respectively. Conclusions: PSADT, Gleason score, and time to PSA progression are strong independent predictors of metastasis-free survival in men with PSA-recurrent prostate cancer. These data facilitate patient counseling and logical risk-based treatment planning. They also provide the background for appropriate selection of patients, treatments, and endpoints for clinical trials.

[Table: see text]

No significant financial relationships to disclose.

Phase I trial with a combination of docetaxel and 153Sm- EDTMP in patients (pts) with castration-resistant metastatic prostate cancer (mCRPC)

5155

Background: Bone targeted therapy holds great promise for improving outcomes in mCRPC. Preclinical data strongly supported biological synergism of docetaxel (Tax) and 153Sm-EDTMP (Sm) in mCRPC. Concurrent Tax and Sm regimens were reported feasible and tolerable in phase I studies. This study was designed to evaluate toxicity and preliminary efficacy of 2 cycles (12 wks/cycle, C) of concomitant standard dose/schedule of Sm plus Q3 wks schedule of Tax in mCRPC. Methods: mCRPC pts with progressive bone metastases were treated in 4 cohorts ( CH). Previous Tax and palliative RT to bone was admissible. Dose escalation of Tax was implemented if no DLT was observed in the preceding CH. Tax doses (on days 1, 22, per 12 wk cycle) were given as follows: CH 1- 50mg/m2 (C1 and 2); CH 2–75mg/m2 (C1) and 50mg/m2 (C2); CH3 - 75mg/m2 (C1 and 2) and CH4 ( Tax day 1, 22, 43 per 12 wk C) 75mg/m2 (C1 and 2). Sm was administered on days 2 (Q12 wks X 2) at dose of 1 mCi/kg/cycle (max. of 2 cycles). Disease status was assessed (with bone /CT scans and PSA) after every cycle. Results: Thirteen pts with progressive bone metastases were enrolled. Three had prior Tax and 3 had prior palliative radiation. Thirteen pts received total 20 cycles in 4 cohorts. Toxicity was primarily hematological. There were total 34 episodes Grade 3/4 neutropenia with a median 7 (range 7 -14) days to recovery to ≤ grade1. Tax dose was reduced to 50% in 2 CH4 pts at C2. Only 1 DLT G3 thrombocytopenia occurred on cohort 4 with duration of 9 wks. Median baseline PSA was 100.4 ng/ml (range 8.6 - 1064), 9/13 (69%) pts had PSA>50% decrease. Median time to disease progression was 147 days (range 72 days - 10 months+); 6/13 (46%) pts had stable/improved bone scans at 6 months and 8/8 (100%) symptomatic pts had improvement in pain. Conclusions: Concurrent 6-month administration of 2 and possibly 3 full dose /standard schedule of Tax with 2 full doses of Sm is feasible with reversible bone marrow suppression. The combination may provide additional clinical benefits for mCRPC pts with extensive bone metastasis.

No significant financial relationships to disclose.

Costs of treatments for local/regional prostate cancer

6527

Background: Men with prostate cancer have a variety of treatment options, including surgery, radiation, hormonal therapy, combinations thereof, or active surveillance. Treatment choice may have important cost implications. Methods: Using the SEER-Medicare database, we examined the Inpatient, Outpatient, Emergency, and Other costs of men diagnosed with local/regional prostate cancer in the year 2000 who were 66+ years old and enrolled in the fee-for-service Medicare program. Based on the treatments received in the first 9 months from diagnosis, men were assigned to these treatment groups: active surveillance, radiation, hormonal, hormonal+radiation, surgery (might also include radiation and hormonal therapy). We matched the prostate cancer cases to noncancer controls on age, race, sex, SEER region, comorbidity, and survival. We estimated the costs of prostate cancer care from 1 month pre- to 12 months post-diagnosis by calculating the incremental costs of care for cases vs. controls. Costs of care were estimated using Medicare payments. Results: 13,769 prostate cancer cases were matched with 13,769 controls and allocated to these treatment groups: active surveillance (n=2,805), radiation (n=2,582), hormonal (n=2,190), hormonal+radiation (n=3,992), and surgery (n=2,200). The most expensive treatment group was hormonal+radiation, with cases having a total average incremental cost of $17,795 vs. controls, followed by surgery ($15,467), radiation ($12,326), and hormonal therapy ($10,804). Active surveillance was the least expensive ($4,152). Outpatient costs were the major driver of increased costs for the hormonal+radiation group. Increased costs for surgery patients were driven by both Outpatient and Inpatient costs. Emergency Department and Other costs were generally similar between prostate cancer cases and controls. Conclusions: The treatment choice of men with local/regional prostate cancer has important implications for cost in the year following diagnosis. Additional analyses exploring long-term costs are needed.

[Table: see text]

No significant financial relationships to disclose.