Abstract D084: Overall survival (OS) of African-American (AA) and Caucasian (CAU) men who received sipuleucel-T for metastatic castration-resistant prostate cancer (mCRPC)—final PROCEED analysis

BACKGROUND: Prostate cancer risk and mortality are higher in AAs versus CAUs. Post-hoc analyses of pooled Phase 3 data (n = 737) suggested substantial OS benefit for AA men receiving sipuleucel-T (n=33) vs placebo (n = 10) (McLeod 2012). Compared with pooled placebo patients (n = 249), number needed to treat for OS benefit at 3 years was 3 for AAs and 8 for all sipuleucel-T-treated patients (n = 488) (Moses 2017). Herein we analyzed PROCEED (NCT01306890), a large real-world registry, in which all patients received sipuleucel-T. Previously presented at ASCO Annual Meeting 2019 (Sartor 2019).METHODS: In PROCEED, 1902 mCRPC patients received 1 or more sipuleucel-T infusions. OS of all AA (n=221) and CAU (n=1649) men were compared. Baseline prostate-specific antigen (PSA), the most important prognostic variable for OS after sipuleucel-T (Schellhammer 2013), substantially differed by race. Thus, OS for a PSA-matched cohort (n=219 AA; n=438 CAU) was compared and univariable/multivariable analyses were performed. Post-sipuleucel-T use of OS-prolonging anticancer interventions was also assessed. RESULTS: After a median follow-up of 46.6 mo, median OS was 35.2 (all sipuleucel-T-treated AAs) and 29.9 mo (all sipuleucel-T-treated CAUs): HR 0.81, 95% CI 0.68–0.97; P=0.03. In the PSA-matched cohort, median OS was 35.3 and 25.8 mo, respectively (HR 0.70, 95% CI 0.57–0.86; p<0.001). Sipuleucel-T-treated AAs with lower baseline PSA had markedly longer median OS vs sipuleucel-T-treated CAUs. Among those with PSA less than or equal to median baseline PSA (29.48 ng/ml), median OS was 54.3 mo (AA) vs. 33.4 (CAUs); HR 0.52, 95% CI 0.37–0.72; p<0.001. Along with other known prognostic factors, AA race was independently associated with prolonged OS on detailed multivariable analyses (HR 0.60, 95% CI 0.48–0.74; p<0.001) and confirmed on sensitivity analyses. Post-sipuleucel-T life-prolonging anti-cancer therapies were balanced between groups. CONCLUSIONS: Sipuleucel-T-treated AAs had significantly improved OS vs sipuleucel-T-treated CAUs. This analysis marks the largest known racial difference in OS in response to any therapy for mCRPC, a finding with implications for both prostate cancer pathophysiology and cancer immunotherapy. REFERENCES: Sartor 2012 (DOI: 10.1200/JCO.2019.37.15_suppl.5035); McLeod 2012 (DOI: 10.1016/j.juro.2012.02.1051); Moses KA et al 2017 (DOI: 10.1016/j.urology.2016.07.045); Schellhammer 2013 (DOI: 10.1016/j.urology.2013.01.061)

Citation Format: Oliver Sartor, Andrew J Armstrong, Chiledum Ahaghotu, David G McLeod, Matthew R Cooperberg, David F Penson, Philip W Kantoff, Nicholas J Vogelzang, Arif Hussain, Christopher. M Pieczonka, Neal D Shore, David I Quinn, Elisabeth I Heath, Ronald F Tutrone, Paul F Schellhammer, Matthew Harmon, Nancy N Chang, Stephen J Freedland, Celestia S Higano. Overall survival (OS) of African-American (AA) and Caucasian (CAU) men who received sipuleucel-T for metastatic castration-resistant prostate cancer (mCRPC)—final PROCEED analysis [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D084.

Open Label Phase II Study of Enzalutamide With Concurrent Administration of Radium 223 Dichloride in Patients With Castration-Resistant Prostate Cancer

BACKGROUND

Numerous globally approved castration-resistant prostate cancer (CRPC) therapies are available. Enzalutamide and radium 223 (Ra 223) are approved for survival prolongation and ability to delay radiographic progression. Both have markedly different mechanisms of action as well as safety and tolerability profiles. We prospectively investigated their combined safety and tolerability.

PATIENTS AND METHODS

EnzaRadiCate, a phase II investigator-initiated trial, enrolled subjects with metastatic CRPC from 4 United States uro-oncology research sites. Safety assessment included physical examination, Eastern Cooperative Oncology Group status, electrocardiogram results, laboratory values, opioid use, radiographic responses, and adverse events (AEs). Quality of life and pain were assessed using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) and the Brief Pain Inventory Short Form (BPI-SF) questionnaires.

RESULTS

Thirty-nine subjects completed at least 2 cycles of Ra 223, and 34 (87%) completed all 6 cycles through and the EOT visit. Sixty-one treatment-related AEs were reported by 53.8% of subjects. The most frequent AEs were fatigue (25.6%), nausea (17.9%), and anemia (12.8%). Three subjects experienced non-treatment-related serious AEs. One subject was hospitalized for sepsis, and 2 deaths were attributed to disease progression. Fifteen (38.5%) subjects demonstrated radiographic progression, and 24 (61.5%) subjects had no radiographic progression.

CONCLUSIONS

Safety and tolerability of combinatorial use of enzalutamide and Ra 223 were demonstrated. Subjects experienced improvements in quality of life and pain, without unexpected toxicities nor increases in falls, fractures, or deaths. Phase III combination trials of Ra 223 with novel oral hormonal agents are ongoing to further evaluate radiographic progression and overall survival benefit.

Survival of African-American and Caucasian men after sipuleucel-T immunotherapy: outcomes from the PROCEED registry

Purpose

African Americans experience greater prostate cancer risk and mortality than do Caucasians. An analysis of pooled phase III data suggested differences in overall survival (OS) between African American and Caucasian men receiving sipuleucel-T. We explored this in PROCEED (NCT01306890), an FDA-requested registry in over 1900 patients with metastatic castration-resistant prostate cancer (mCRPC) treated with sipuleucel-T.

Patients and methods

OS for patients who received ≥1 sipuleucel-T infusion was compared between African American and Caucasian men using an all patient set and a baseline prostate-specific antigen (PSA)-matched set (two Caucasians to every one African American with baseline PSAs within 10% of each other). Univariable and multivariable analyses were conducted. Survival data were examined using Kaplan–Meier and Cox proportional hazard methodologies.

Results

Median follow-up was 46.6 months. Overall survival differed between African American and Caucasian men with hazard ratios (HR) of 0.81 (95% confidence interval [CI]: 0.68–0.97, P = 0.03) in the all patient set and 0.70 (95% CI: 0.57–0.86, P < 0.001) in the PSA-matched set. Median OS was longer in African Americans than in Caucasian men for both analysis sets, e.g., 35.3 and 25.8 months, respectively, in the PSA-matched set. Similar results were observed in the all patient set. Differences were larger when treatment began at lower baseline PSA; curves were more similar among patients with higher baseline PSA. In patients with baseline PSA below the median, the HR was 0.52 (95% CI: 0.37–0.72, P < 0.001), with median OS of 54.3 versus 33.4 months. Known prognostic factors and African American race (multivariable analyses; HR: 0.60, 95% CI: 0.48–0.74, P < 0.001) were independently associated with OS. Use of post-sipuleucel-T anticancer interventions was balanced between races.

Conclusion

In this exploratory analysis of a registry including nearly 12% African American men with mCRPC, OS was significantly different between African Americans and Caucasians, indicating further research is warranted.

Overall survival (OS) of African-American (AA) and Caucasian (CAU) men who received sipuleucel-T for metastatic castration-resistant prostate cancer (mCRPC): Final PROCEED analysis

5035

Background: Prostate cancer risk and mortality are higher in AAs versus CAUs. Post-hoc analyses of pooled Phase 3 data (n = 737) suggested substantial OS benefit for AA men receiving sipuleucel-T (n = 33) vs placebo (n = 10) (McLeod 2012). Compared with pooled placebo patients (n = 249), number needed to treat for OS benefit at 3 years was 3 for AAs and 8 for all sipuleucel-T-treated patients (n = 488) (Moses 2019). Herein we analyzed PROCEED (NCT01306890), a large real-world registry, in which all patients received sipuleucel-T. Methods: In PROCEED, 1902 mCRPC patients received ≥1 sipuleucel-T infusion. OS of all AA (n = 221) and CAU (n = 1649) men were compared. Baseline prostate-specific antigen (PSA), the most important prognostic variable for OS after sipuleucel-T (Schellhammer 2013), substantially differed by race. Thus, OS for a PSA-matched cohort (n = 219 AA; n = 438 CAU) was compared and univariable/multivariable analyses were performed. Post-sipuleucel-T use of OS-prolonging anticancer interventions was also assessed. Results: After a median follow-up of 46.6 mo, median OS was 35.2 (all sipuleucel-T-treated AAs) and 29.9 mo (all sipuleucel-T-treated CAUs): HR 0.81, 95% CI 0.68–0.97; P = 0.03. In the PSA-matched cohort, median OS was 35.3 and 25.8 mo, respectively (HR 0.70, 95% CI 0.57–0.86; P < 0.001). Sipuleucel-T-treated AAs with lower baseline PSA had markedly longer median OS vs sipuleucel-T-treated CAUs. Among those with ≤ median baseline PSA (29.48 ng/ml), median OS was 54.3 mo (AA) vs. 33.4 (CAUs); HR 0.52, 95% CI 0.37–0.72; p < 0.001. Along with other known prognostic factors, AA race was independently associated with prolonged OS on detailed multivariable analyses (HR 0.60, 95% CI 0.48–0.74; p < 0.001) and confirmed on sensitivity analyses. Post-sipuleucel-T life-prolonging anti-cancer therapies were balanced between groups. Conclusions: Sipuleucel-T-treated AAs had significantly improved OS vs sipuleucel-T-treated CAUs. This analysis marks the largest known racial difference in OS in response to any therapy for mCRPC, a finding with implications for both prostate cancer pathophysiology and cancer immunotherapy. Clinical trial information: NCT01306890.

Androgen Receptor Targeted Treatments of Prostate Cancer: 35 Years of Progress with Antiandrogens

PURPOSE

Antiandrogens inhibit the androgen receptor and have an important role in the treatment of prostate cancer. This review provides a historical perspective on the development and clinical benefit of antiandrogens in the treatment of prostate cancer.

MATERIALS AND METHODS

We searched PubMed® for clinical trials with the search terms antiandrogens and prostate cancer combined with drug names for antiandrogens. This article represents a collaboration of clinical investigators who have made critical scientific contributions leading to the approval of antiandrogens for treating patients with prostate cancer.

RESULTS

Antiandrogens differ in chemical structure and exert varying efficacy and safety profiles. The unfavorable therapeutic index of steroidal antiandrogens led to replacement by safer nonsteroidal agents. Flutamide, nilutamide and bicalutamide, which were designed to target the androgen receptor, were developed primarily for use in combination with castration to provide combined androgen blockade. Modest clinical benefits were observed with the combination of first generation antiandrogens and castration vs castration alone. With increased knowledge of androgen receptor structure and its biological functions a new generation of antiandrogens without agonist activity was designed to provide more potent inhibition of the androgen receptor. Randomized clinical trials in patients with metastatic, castration resistant prostate cancer showed significant survival benefits, which led to the approval of enzalutamide in August 2012. Apalutamide was recently approved while darolutamide is not yet approved in the United States. These next generation antiandrogens are being actively tested in earlier disease states such as nonmetastatic prostate cancer. Evolving knowledge of resistance mechanisms to androgen receptor targeted treatments will stimulate research and drug discovery for additional compounds. Further testing in nonmetastatic castration resistant prostate cancer as well as castration sensitive disease states will hopefully augment our ability to treat a broader spectrum of patients with prostate cancer.

CONCLUSIONS

Antiandrogens have already provided important benefits for prostate cancer treatment. Greater knowledge about the structural and functional biology of the androgen receptor in prostate cancer will facilitate further discovery and development of further improved antiandrogens with enhanced clinical activity in patients with advanced metastatic disease. Testing these new agents earlier in the course of prostate cancer may further improve the survival and quality of life of patients with current local and/or systemic treatment modalities.

A Urologist's Personal View of Prostate Cancer

A urologist's personal experience with multiple surgical, hormonal, and radio/immunotherapeutic options for the treatment of advanced prostate cancer and thoughts on the role of old and new therapies.

Might men diagnosed with metastatic prostate cancer benefit from definitive treatment of the primary tumor? A SEER-based study

BACKGROUND

Few data exist regarding the impact on survival of definitive treatment of the prostate in men diagnosed with metastatic prostate cancer (mPCa).

OBJECTIVE

To evaluate the survival of men diagnosed with mPCa based on definitive treatment of the prostate.

DESIGN, SETTING, AND PARTICIPANTS

Men with documented stage IV (M1a-c) PCa at diagnosis identified using Surveillance Epidemiology and End Results (SEER) (2004-2010) and divided based on definitive treatment of the prostate (radical prostatectomy [RP] or brachytherapy [BT]) or no surgery or radiation therapy (NSR).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Kaplan-Meier methods were used to calculate overall survival (OS). Multivariable competing risks regression analysis was used to calculate disease-specific survival (DSS) probability and identify factors associated with cause-specific mortality (CSM).

RESULTS AND LIMITATIONS

A total of 8185 patients were identified: NSR (n=7811), RP (n=245), and BT (n=129). The 5-yr OS and predicted DSS were each significantly higher in patients undergoing RP (67.4% and 75.8%, respectively) or BT (52.6 and 61.3%, respectively) compared with NSR patients (22.5% and 48.7%, respectively) (p<0.001). Undergoing RP or BT was each independently associated with decreased CSM (p<0.01). Similar results were noted regardless of the American Joint Committee on Cancer (AJCC) M stage. Factors associated with increased CSM in patients undergoing local therapy included AJCC T4 stage, high-grade disease, prostate-specific antigen ≥20 ng/ml, age ≥70 yr, and pelvic lymphadenopathy (p<0.05). The major limitation of this study was the lack of variables from SEER known to influence survival of patients with mPCa, including treatment with systemic therapy.

CONCLUSIONS

Definitive treatment of the prostate in men diagnosed with mPCa suggests a survival benefit in this large population-based study. These results should serve as a foundation for future prospective trials.

PATIENT SUMMARY

We used a large population-based cancer database to examine survival in men diagnosed with metastatic prostate cancer (mPCa) undergoing definitive therapy for the prostate. Local therapy (LT) appeared to confer a survival benefit. Therefore, we conclude that prospective trials are needed to further evaluate the role of LT in mPCa.

Quality of life after sipuleucel-T therapy: results from a randomized, double-blind study in patients with androgen-dependent prostate cancer

OBJECTIVE

To collect and analyze quality-of-life (QOL) data from PROvenge Treatment and Early Cancer Treatment trial (PROTECT, NCT00779402), a phase III, randomized controlled trial of sipuleucel-T in patients with asymptomatic androgen-dependent prostate cancer.

METHODS

Patients experiencing prostate-specific antigen relapse after radical prostatectomy entered a 3- to 4-month run-in phase of androgen-deprivation therapy (ADT), followed by 2:1 randomization to sipuleucel-T or control. QOL was assessed throughout the run-in and 26-week post-randomization phases using the Brief Fatigue Inventory (BFI), Linear Analog Self-Assessment (LASA) scale, Global Rating of Change (GRoC) scale, and an elicited symptoms list.

RESULTS

One hundred seventy-six patients were randomized into 2 groups, the sipuleucel-T group (n = 117) or the control group (n = 59). The sample provided 80% power to detect a difference in fatigue interference score between treatment arms of 0.9 points. QOL declined predictably during ADT. At week 26, 26.2% of sipuleucel-T-treated patients and 21.6% of control-treated patients (P = .68) reported fatigue in the previous week, and the mean score for fatigue interference in the past 24 hours was 0.9 for both arms (P = .88). Results were comparable for usual fatigue (P = .91) and worst fatigue (P >.99). Mean LASA scores decreased in both groups (P = .26). The proportion of patients reporting better overall QOL on GRoC was similar (P = .62).

CONCLUSION

There is no clinically significant negative impact on QOL after sipuleucel-T treatment compared with control after a period of ADT in patients with asymptomatic androgen-dependent prostate cancer.

Lower baseline prostate-specific antigen is associated with a greater overall survival benefit from sipuleucel-T in the Immunotherapy for Prostate Adenocarcinoma Treatment (IMPACT) trial

OBJECTIVE

To explore the prognostic and predictive value of baseline variables in 512 patients with metastatic castration-resistant prostate cancer from the phase III Immunotherapy for Prostate Adenocarcinoma Treatment (IMPACT) trial who were randomized to receive sipuleucel-T or control.

METHODS

The most powerful of these prognostic factors, baseline prostate-specific antigen (PSA), was subdivided into quartiles to evaluate treatment effect patterns. Cox regression analyses were used to assess predictors of overall survival (OS) and sipuleucel-T treatment effect within PSA quartiles. Median OS was estimated by the Kaplan-Meier method.

RESULTS

PSA was the strongest baseline prognostic factor (P <.0001). Furthermore, the sipuleucel-T treatment effect appeared greater with decreasing baseline PSA. The OS hazard ratio for patients in the lowest baseline PSA quartile (≤22.1 ng/mL) was 0.51 (95% confidence interval, 0.31-0.85) compared with 0.84 (95% confidence interval, 0.55-1.29) for patients in the highest PSA quartile (>134 ng/mL). Estimated improvement in median survival varied from 13.0 months in the lowest baseline PSA quartile to 2.8 months in the highest quartile. Estimated 3-year survival in the lowest PSA quartile was 62.6% for sipuleucel-T patients and 41.6% for control patients, representing a 50% relative increase.

CONCLUSION

The greatest magnitude of benefit with sipuleucel-T treatment in this exploratory analysis was observed among patients with better baseline prognostic factors, particularly those with lower baseline PSA values. These findings suggest that patients with less advanced disease may benefit the most from sipuleucel-T treatment and provide a rationale for immunotherapy as an early treatment strategy in sequencing algorithms for metastatic castration-resistant prostate cancer.

Intermittent versus continuous androgen deprivation in prostate cancer

BACKGROUND

Castration resistance occurs in most patients with metastatic hormone-sensitive prostate cancer who are receiving androgen-deprivation therapy. Replacing androgens before progression of the disease is hypothesized to prolong androgen dependence.

METHODS

Men with newly diagnosed, metastatic, hormone-sensitive prostate cancer, a performance status of 0 to 2, and a prostate-specific antigen (PSA) level of 5 ng per milliliter or higher received a luteinizing hormone-releasing hormone analogue and an antiandrogen agent for 7 months. We then randomly assigned patients in whom the PSA level fell to 4 ng per milliliter or lower to continuous or intermittent androgen deprivation, with patients stratified according to prior or no prior hormonal therapy, performance status, and extent of disease (minimal or extensive). The coprimary objectives were to assess whether intermittent therapy was noninferior to continuous therapy with respect to survival, with a one-sided test with an upper boundary of the hazard ratio of 1.20, and whether quality of life differed between the groups 3 months after randomization.

RESULTS

A total of 3040 patients were enrolled, of whom 1535 were included in the analysis: 765 randomly assigned to continuous androgen deprivation and 770 assigned to intermittent androgen deprivation. The median follow-up period was 9.8 years. Median survival was 5.8 years in the continuous-therapy group and 5.1 years in the intermittent-therapy group (hazard ratio for death with intermittent therapy, 1.10; 90% confidence interval, 0.99 to 1.23). Intermittent therapy was associated with better erectile function and mental health (P<0.001 and P=0.003, respectively) at month 3 but not thereafter. There were no significant differences between the groups in the number of treatment-related high-grade adverse events.

CONCLUSIONS

Our findings were statistically inconclusive. In patients with metastatic hormone-sensitive prostate cancer, the confidence interval for survival exceeded the upper boundary for noninferiority, suggesting that we cannot rule out a 20% greater risk of death with intermittent therapy than with continuous therapy, but too few events occurred to rule out significant inferiority of intermittent therapy. Intermittent therapy resulted in small improvements in quality of life. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00002651.).

Expression of prostate-specific membrane antigen in normal, benign, and malignant prostate tissues

Prostate-specific membrane antigen (PSMA) is a trans-membrane glycoprotein recognized by the murine monoclonal antibody (MAb) 7EII-C5.3 both in its native (CYT-351) and immunoconjugate form (CYT-356). Previous studies have shown that tissue expression of PSMA is highly restricted to prostate tissues. In this study, a definitive immunohistochemistry evaluation was performed to assess PSMA expression in prostate tissues. A stain index was established by multiplying the percentage of stained cells by the intensity of the stained cells to provide a quantitative measurement of PSMA expression in the various tissue types. The cellular location of PSMA, its correlation with clinical status, and its comparison with the expression of prostate-specific antigen (PSA) were evaluated. Prostate-specific membrane antigen was found to be highly expressed in most of the normal intraepithelial neoplasia, and the primary and metastatic prostate tumor specimens evaluated. In contrast to PSA, PSMA expression was often heterogeneous with variable staining patterns, ranging from a low-level diffuse cytoplasmic staining in normal prostate epithelium to very intense cytoplasmic and focal membrane staining in high-grade primary carcinomas and metastatic tissues. The predominant cytoplasmic staining was expected because the antigenic epitope of the PSMA transmembrane glycoprotein recognized by MAb 7EII-C5.3 is located in the cytoplasmic domain. Benign prostate tumors, ie, hypertrophy, showed the lowest expression of PSMA with a stain index of 52, compared with stain indexes of 146 and 258 for normal prostate and bone metastatic tissues, respectively. The reason for the apparent down-regulation of PSMA in benign prostate tissue is unknown but may be related to a splicing variant or post-translational modification of PSMA. Expression of PSMA was observed to increase with increasing pathologic grade, but not with clinical stage. Although PSMA was overexpressed in poorly differentiated and metastatic prostate tumors, expression in the primary tumor did not correlate with nodal status, extracapsular penetration, or seminal vesicle invasion. These results suggest that PSMA is not a useful biomarker of disease progression; however, high expression does appear to be associated with the more aggressive prostate carcinoma phenotype. The restricted specificity, differential prostate tissue expression, and overexpression of PSMA in metastatic tissues support the continued study of this unique prostate tumor-associated biomarker for developing new strategies for diagnostic and therapy of prostate cancer.

Intermittent androgen suppression for rising PSA level after radiotherapy

BACKGROUND

Intermittent androgen deprivation for prostate-specific antigen (PSA) elevation after radiotherapy may improve quality of life and delay hormone resistance. We assessed overall survival with intermittent versus continuous androgen deprivation in a noninferiority randomized trial.

METHODS

We enrolled patients with a PSA level greater than 3 ng per milliliter more than 1 year after primary or salvage radiotherapy for localized prostate cancer. Intermittent treatment was provided in 8-month cycles, with nontreatment periods determined according to the PSA level. The primary end point was overall survival. Secondary end points included quality of life, time to castration-resistant disease, and duration of nontreatment intervals.

RESULTS

Of 1386 enrolled patients, 690 were randomly assigned to intermittent therapy and 696 to continuous therapy. Median follow-up was 6.9 years. There were no significant between-group differences in adverse events. In the intermittent-therapy group, full testosterone recovery occurred in 35% of patients, and testosterone recovery to the trial-entry threshold occurred in 79%. Intermittent therapy provided potential benefits with respect to physical function, fatigue, urinary problems, hot flashes, libido, and erectile function. There were 268 deaths in the intermittent-therapy group and 256 in the continuous-therapy group. Median overall survival was 8.8 years in the intermittent-therapy group versus 9.1 years in the continuous-therapy group (hazard ratio for death, 1.02; 95% confidence interval, 0.86 to 1.21). The estimated 7-year cumulative rates of disease-related death were 18% and 15% in the two groups, respectively (P=0.24).

CONCLUSIONS

Intermittent androgen deprivation was noninferior to continuous therapy with respect to overall survival. Some quality-of-life factors improved with intermittent therapy. (Funded by the Canadian Cancer Society Research Institute and others; ClinicalTrials.gov number, NCT00003653.).

Intermittent (IAD) versus continuous androgen deprivation (CAD) in hormone sensitive metastatic prostate cancer (HSM1PC) patients (pts): Results of S9346 (INT-0162), an international phase III trial

4

Background: Castration resistance occurs in the vast majority of HSM1PC pts treated with AD, with a median survival of 2.5 years (y). It is in part an adaptive process with activation of genes resulting in the production of autocrine/paracrine growth factors that contribute to maintaining the viability of PC cells. Replacing androgens before castration resistance is hypothesized to maintain PC androgen-dependence. Preclinically IAD prolonged time to castration resistance and early clinical data indicated feasibility and potential for better quality of life. Methods: HSM1PC pts with performance status (PS) 0-2, PSA ≥ 5 ng/ml were treated with 7 months (m) of goserelin + bicalutamide. Pts achieving PSA ≤4 ng/ml on m 6 and 7 were stratified by prior neoadjuvant AD/finasteride, PS and disease extent (minimal, extensive) and randomized to CAD or IAD. Primary objective: To assess if overall survival (OS) with IAD is noninferior to CAD using a one-sided test with an upper bound hazard ratio=1.20, adjusting for stratification factors. Sample size: 756 pts/arm, type I and II error rates of 0.05 and 0.10. Results: 3,040 pts were accrued by SWOG, CALGB, ECOG, NCIC, and EORTC (5/95- 9/08). After 7 m of CAD, 1535 eligible pts achieved PSA ≤4.0 (median age 70 yrs, 4% PS 2, 48% extensive disease, 12% prior neoadjuvant AD) and were randomized to CAD (759 pts) or IAD (770 pts). Grade 3/4 related adverse events: IAD 30.3%, CAD 32.6%. Median follow-up was 9.2 yrs. Median and 10 yr OS: All eligible pts from study entry: 3.6 yrs, 17%; from randomization CAD: 5.8 yrs, 29%; IAD: 5.1 yrs, 23%, HR (IAD/CAD) = 1.09 (95% CI 0.95, 1.24). No interaction with therapy was significant (p>0.25) except suggestion with disease extent (p=0.08): extensive disease HR=0.96 (95% CI 0.79, 1.15, p=0.64); minimal disease: HR=1.23 (95% CI 1.02, 1.48, p=0.035). PC was cause of death in 56% of CAD and 64% IAD pts. OSby race was not different (p=0.44). Conclusions: In HSM1PC, IAD is not proven to be noninferior to CAD. For extensive disease pts IAD was noninferior; however, IAD was statistically inferior in minimal disease pts suggesting that CAD is the preferred treatment in this group.

Preliminary quality-of-life outcomes for SWOG-9346: Intermittent androgen deprivation in patients with hormone-sensitive metastatic prostate cancer (HSM1PC)—Phase III

4571

Background: The relative quality of life (QOL) for patients with newly diagnosed, metastatic prostate cancer, treated with intermittent androgen deprivation (IAD) has been assumed and hypothesized, yet never compared in a well-powered randomized trial (RT) to continuous androgen deprivation (CAD). SWOG-9346 provided such a RT in which to test QOL differences between CAD and IAD in men with metastatic prostate cancer. Methods: Patients were randomized to CAD or IAD. Patients completed the SWOG QOL Questionnaire (SF-20/SF-36, Symptom Distress Scale, treatment-specific symptoms, global QOL) at randomization and months (mo) 3, 9, and 15 post-randomization. Five QOL change scores at one time point (mo 3) were designated as primary for the QOL endpoint and are reported in this abstract: impotence, libido, energy/vitality (E/V), physical function (PF), and emotional function (EF). Significance level was adjusted for 5 comparisons (used p=0.01). Results: 615 patients in the CAD arm and 633 in the IAD arm completed the QOL questionnaire at baseline. Change between baseline and 3 months differed for the two arms with CAD reporting statistically significantly more impotence and less libido than IAD. EF was also slightly better for the IAD arm. Conclusions: These results indicate better sexual function in men receiving IAD versus CAD through post-randomization month 3. Additional benefits for IAD may include better PF, E/V and EF. Ongoing analyses will address the role of missing data, additional follow-up assessments, and resumption of therapy in the IAD arm. [Table: see text]

Overall survival (OS) benefit with sipuleucel-T by baseline PSA: An exploratory analysis from the phase III IMPACT trial

4648

Background: Sipuleucel-T is an autologous cellular immunotherapy approved for asymptomatic or minimally symptomatic metastatic castrate-resistant prostate cancer. In the IMPACT trial, sipuleucel-T showed a 22.5% reduction in risk of death vs the control group (hazard ratio [HR]=0.775 [95% CI 0.614, 0.979]; P=0.032). A pre-specified subgroup analysis for baseline prognostic variables showed homogeneous treatment effects consistently favoring sipuleucel-T. In patients (pts) with baseline PSA below vs above the median, there was a trend toward greater treatment effect (HR=0.685 vs. 0.865). In this exploratory analysis, we further sub-divide baseline PSA into quartiles to evaluate potential treatment effect patterns. Methods: The analysis included all randomized pts from IMPACT (n=512). Pts were categorized by baseline PSA quartile (Table), ECOG PS and by median for other baseline prognostic variables (i.e., LDH, PAP, ALP in bone-only disease, and Hgb). Median OS and HR were estimated using Kaplan-Meier and Cox models, respectively. Results: Increasing baseline PSA quartile was associated with markers of advanced disease. HRs suggest a consistent treatment effect in all subsets, although there is inadequate power to show significant results within each quartile. There was a trend toward an increased magnitude of treatment benefit in pts with a lower baseline PSA (Table). Results for other baseline prognostic variables also suggest a trend toward greater benefit in subjects with better prognostic features. However, results for baseline Hgb indicated an opposite trend. Conclusions: Although not adequately powered for significance, the results of this analysis support a consistent OS benefit with sipuleucel-T across PSA quartiles. The greater magnitude of benefit in pts with lower baseline PSA suggests that pts with less advanced disease may benefit more from treatment with sipuleucel-T. [Table: see text]

Intermittent (IAD) versus continuous androgen deprivation (CAD) in hormone sensitive metastatic prostate cancer (HSM1PC) patients (pts): Results of S9346 (INT-0162), an international phase III trial

4

The full, final text of this abstract will be available at abstract.asco.org at 12:01 AM (EDT) on Sunday, June 3, 2012, and in the Annual Meeting Proceedings online supplement to the June 20, 2012, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Sunday edition of ASCO Daily News.

Treatment options for localized prostate cancer

In the United States, more than 90 percent of prostate cancers are detected by serum prostate-specific antigen testing. Most patients are found to have localized prostate cancer, and most of these patients undergo surgery or radiotherapy. However, many patients have low-risk cancer and can follow an active surveillance protocol instead of undergoing invasive treatments. Active surveillance is a new concept in which low-risk patients are closely followed and proceed to intervention only if their cancer progresses. Clinical guidelines can help in selecting between treatment or active surveillance based on the cancer's stage and grade, the patient's prostate-specific antigen level, and the comorbidity-adjusted life expectancy. Radical prostatectomy or external beam radiation therapy is recommended for higher-risk patients. These treatments are almost equivalent in effectiveness, but have different adverse effect profiles. Brachytherapy is an option for low- and moderate-risk patients. Evidence is insufficient to determine whether laparoscopic or robotic surgery or cryotherapy is superior to open radical prostatectomy.

Randomized trial of autologous cellular immunotherapy with sipuleucel-T in androgen-dependent prostate cancer

PURPOSE

Sipuleucel-T, an autologous cellular immunotherapy, was investigated in a randomized, double-blind, controlled trial to determine its biologic activity in androgen-dependent prostate cancer (ADPC).

EXPERIMENTAL DESIGN

Patients with prostate cancer detectable by serum prostate-specific antigen (PSA) following radical prostatectomy received 3 to 4 months of androgen suppression therapy, and were then randomized (2:1) to receive sipuleucel-T (n = 117) or control (n = 59). The primary endpoint was time to biochemical failure (BF) defined as serum PSA ≥ 3.0 ng/mL. PSA doubling time (PSADT), time to distant failure, immune response, and safety were also evaluated.

RESULTS

Median time to BF was 18.0 months for sipuleucel-T and 15.4 months for control (HR = 0.936, P = 0.737). Sipuleucel-T patients had a 48% increase in PSADT following testosterone recovery (155 vs. 105 days, P = 0.038). With only 16% of patients having developed distant failure, the treatment effect favored sipuleucel-T (HR = 0.728, P = 0.421). The most frequent adverse events in sipuleucel-T patients were fatigue, chills, and pyrexia. Immune responses to the immunizing antigen were greater in sipuleucel-T patients at Weeks 4 and 13 (P < 0.001, all) and were sustained prior to boosting as measured in a subset of patients a median of 22.6 months (range: 14.3-67.3 months) following randomization.

CONCLUSIONS

No significant difference in time to BF could be shown. The finding of increased PSADT in the sipuleucel-T arm is consistent with its biologic activity in ADPC. Long-term follow-up will be necessary to determine if clinically important events, such as distant failure, are affected by therapy. Treatment was generally well tolerated.

Sipuleucel-T immunotherapy for castration-resistant prostate cancer

BACKGROUND

Sipuleucel-T, an autologous active cellular immunotherapy, has shown evidence of efficacy in reducing the risk of death among men with metastatic castration-resistant prostate cancer.

METHODS

In this double-blind, placebo-controlled, multicenter phase 3 trial, we randomly assigned 512 patients in a 2:1 ratio to receive either sipuleucel-T (341 patients) or placebo (171 patients) administered intravenously every 2 weeks, for a total of three infusions. The primary end point was overall survival, analyzed by means of a stratified Cox regression model adjusted for baseline levels of serum prostate-specific antigen (PSA) and lactate dehydrogenase.

RESULTS

In the sipuleucel-T group, there was a relative reduction of 22% in the risk of death as compared with the placebo group (hazard ratio, 0.78; 95% confidence interval [CI], 0.61 to 0.98; P=0.03). This reduction represented a 4.1-month improvement in median survival (25.8 months in the sipuleucel-T group vs. 21.7 months in the placebo group). The 36-month survival probability was 31.7% in the sipuleucel-T group versus 23.0% in the placebo group. The treatment effect was also observed with the use of an unadjusted Cox model and a log-rank test (hazard ratio, 0.77; 95% CI, 0.61 to 0.97; P=0.02) and after adjustment for use of docetaxel after the study therapy (hazard ratio, 0.78; 95% CI, 0.62 to 0.98; P=0.03). The time to objective disease progression was similar in the two study groups. Immune responses to the immunizing antigen were observed in patients who received sipuleucel-T. Adverse events that were more frequently reported in the sipuleucel-T group than in the placebo group included chills, fever, and headache.

CONCLUSIONS

The use of sipuleucel-T prolonged overall survival among men with metastatic castration-resistant prostate cancer. No effect on the time to disease progression was observed. (Funded by Dendreon; ClinicalTrials.gov number, NCT00065442.)

Integrated data from 2 randomized, double-blind, placebo-controlled, phase 3 trials of active cellular immunotherapy with sipuleucel-T in advanced prostate cancer

BACKGROUND

Sipuleucel-T is an investigational active cellular immunotherapy product designed to stimulate an immune response against prostate cancer. The safety and efficacy of sipuleucel-T was evaluated in 2 identically designed, randomized, double-blind, placebo-controlled trials (D9901 and D9902A) conducted in men with advanced prostate cancer.

METHODS

A total of 225 patients were randomized in D9901 or D9902A to sipuleucel-T (n = 147) or placebo (n = 78), given as 3 intravenous infusions approximately 2 weeks apart. Patients were followed for survival until death or a prespecified cutoff of 36 months after randomization.

RESULTS

In the integrated analysis of D9901 and D9902A, patients randomized to sipuleucel-T demonstrated a 33% reduction in the risk of death (hazard ratio, 1.50; 95% confidence interval, 1.10-2.05; P = .011; log-rank). The treatment effect remained strong after performing adjustments for imbalances in baseline prognostic factors, poststudy treatment chemotherapy use, and non-prostate cancer-related deaths. Additional support for the activity of sipuleucel-T is provided by the correlation between a measure of the product's potency, CD54 up-regulation, and overall survival. The most common adverse events associated with treatment were chills, pyrexia, headache, asthenia, dyspnea, vomiting, and tremor. These events were primarily grade 1 and 2, with durations of 1 to 2 days.

CONCLUSIONS

The integrated results of D9901 and D9902A demonstrate a survival benefit for patients treated with sipuleucel-T compared with those treated with placebo. The generally modest toxicity profile, coupled with the survival benefit, suggests a favorable risk-benefit ratio for sipuleucel-T in patients with advanced prostate cancer.

Glycomic characterization of prostate-specific antigen and prostatic acid phosphatase in prostate cancer and benign disease seminal plasma fluids

Prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) are glycoproteins secreted by prostate epithelial cells, and have a long clinical history of use as serum biomarkers of prostate cancers. These two proteins are present at significantly higher concentrations in seminal plasma, making this proximal fluid of the prostate a good source for purifying enough protein for characterization of prostate disease associated changes in glycan structures. With the use of seminal fluid samples representative of normal control, benign prostatic disease and prostate cancers, PAP and PSA were enriched by thiophilic absorption chromatography. Released N-linked glycan constituents from both proteins were analyzed by a combination of normal phase HPLC and MALDI-TOF spectrometry. For PSA, 40 putative glycoforms were determined, and 21 glycoforms were determined for PAP. PAP glycans were further analyzed with a hybrid triple quadrupole/linear ion trap mass spectrometer to assign specific glycoform classes to each of the three N-linked sites. The glycans identified in these studies will allow for more defined targeting of prostate disease-specific changes for PAP, PSA and other secreted prostatic glycoproteins.

Single center experience with third-generation cryosurgery for management of organ-confined prostate cancer: critical evaluation of short-term outcomes, complications, and patient quality of life

BACKGROUND AND PURPOSE

Technical refinements such as improved ultrasonographic localization and the routine use of urethral warmers and small-gauge needle delivery systems have renewed interest in cryosurgical treatment as a minimally invasive option for selected patients with localized prostate cancer. Only three reports of quality of life (QoL) in prostate cryoablation exist, and none report on patients treated with third-generation cryoablative technology. We critically examine our initial series of consecutive patients at a single institution undergoing primary third-generation cryosurgical treatment of localized prostate cancer with respect to treatment outcome, morbidity profile, and QoL parameters. To our knowledge, this is the first QoL report on third-generation cryoablation of the prostate.

PATIENTS AND METHODS

We retrospectively review the records of 89 consecutive patients with median followup of 11 months (1-32) who have undergone third-generation cryosurgical ablation of the prostate as primary treatment for localized prostate cancer with intention to cure. Patients were risk stratified according to preprocedural parameters of prostate-specific antigen (PSA), clinical stage, and Gleason score. PSA trends were recorded and treatment effectiveness was observed using different definitions of biochemical failure. Charts were reviewed for postprocedure complications. Quality of life was measured prospectively using the University of California, Los Angeles, Prostate Cancer Index as well as American Urological Association symptom scores. We compare a percent of baseline score (%BS) for various domains between our series of patients treated with primary cryoablation with a series of patients undergoing brachytherapy for localized prostate cancer.

RESULTS

Treatment success was defined by achievement of a PSA nadir of < or =0.1 ng/mL and by biochemical disease-free survival (BDFS) assessed with both a PSA threshold of < or =0.4 ng/dL over time and the American Society for Therapeutic Radiology and Oncology (ASTRO) definition of three consecutive rises in PSA. According to risk stratification, 86%, 81.5%, and 78% of low-, intermediate-, and high-risk patients, respectively, achieved a PSA nadir of < or =0.1 ng/mL. Overall, at 12 months follow-up, 94% of patients achieved BDFS using ASTRO criteria while 70% achieved BDFS using a PSA threshold of < or =0.4 ng/mL. With risk stratification, 74%, 70%, and 60% of low-, intermediate-, and high-risk patients, respectively, achieved BDFS defined by PSA threshold of < or =0.4 ng/mL. Complications were rare. The response rate for Health Related Quality of Life (HRQoL) questionnaires was 71% for cryoablation patients and 51% for brachytherapy patients. At 12 months follow-up, patients undergoing cryoablation on average achieved urinary and bowel domain scores comparable to baseline, but sexual domains remained well below baseline. When compared with a brachytherapy series with better baseline sexual function (P = 0.04) and urinary function (P = 0.03), cryotherapy patients experienced more negative impact on sexual function steadily for up to 12 months (P = 0.02). Urinary function was similar between the groups until 18 months, at which time cryoablation patients fared better (P = 0.01); this was sustained up to 24 months (P = 0.04).

CONCLUSIONS

Treatment success with cryosurgery varies with definition; however, our results are comparable to other series with regard to short-term cancer control. Complication rates in this series of third-generation cryosurgical patients are low. QoL characteristics of third-generation cryoablation are similar to those described in second-generation cryoablation series. Compared with brachytherapy, cryotherapy results in less irritative and obstructive voiding symptoms in the early post-treatment period and may improve urinary function up to 24 months after treatment. In a small group of older patients with baseline erectile dysfunction undergoing cryoablation, sexual function returns to 20% of its baseline value with up to 12 months follow-up.

[Comparative study of surgical efficacy in open versus laparoscopic prostatectomy: virtual prostate reconstruction and periprostatic tissue quantification]

INTRODUCTION

The introduction of laparoscopic surgery as a procedure to perform radical prostatectomy needs an objective method to evaluate the suitability of this new surgical procedure. The traditional parameters, including the incidence of positive surgical margins, are useful, but not sufficiently objective. Different authors publish different criteria to define positive surgical margins. In addition, there are some technical problems that may ocur during the processing of the surgical specimen by the pathologist, which can give false positive margins. We have used a computer modeling software in connection to scanned images from serial sections of the whole gland, to determine the percentage of extracapsular tissue that surrounds the prostate glands, removed by both, open retropubic and laparoscopic procedures. This percentage can be considered as an objective parameter which can potentially predict the benefit of surgery in predicting cancer control, as well as the clinical success of the surgical procedure. The correlation with the clinical results in the long term--survival and bioche--mical recurrence--will be useful to validate as a last resort the clinical utility of this parameter in the coming years.

MATERIALS AND METHODS

We had a total of 32 prostate surgical specimens, 15 from patients who underwent open retropubic prostatectomy and 17 from patients who underwent laparoscopic prostatectomy for this study. After surgery and 24 hours formol fixation, serial cuts were taken at 5 mm thickness intervals to make complete sections ("whole mount") of the prostate. An expert uropathologist reviewed all the surgical sections and drew in each tissue cut the prostatic capsule and tumor contours. The serial images of the whole gland and surrounding prostate tissue were scanned to produce digital images, using a computer software to create a file with capsule information and a file with information on the surrounding fibroadipose tissue (extraprostatic). These procedures allowed the reconstruction of a three dimensional tissue model of the prostatic capsule and the surrounding extraprostatic tissue. Two separate point clouds files were generated, with the purpose of representing capsule and extraprostatic tissue models and software algorithms were used to generate differences in point clouds and thereby quantifying the extracapsular tissue coverage dimension, a parameter that we considered indicative of the adequeacy and feasibility of the surgical procedure.

RESULTS

The global percentage of prostate gland surface covered by extracapsular fibroadipose tissue was statistically higher in specimens removed by a laparoscopic procedure when compared to the open retropubic procedure. When a segmental analysis of the gland percentage of coverage was evaluated, it was found this percentage was significantly higher in the apical and inferolateral segments of those glands removed without nerves preservation and in the apical segments of those glands removed with nerves preservation for the laparoscopic prostatectomy.

CONCLUSIONS

In our series. laparoscopic prostatectomy contributed superior extracapsular tissue coverage than retropubic prostatectomy. Similarly laparoscopic prostatectomy produced a superior tissue coverage in inferolateral and apical regions on those glands removed without nerve preservation and in the apical regions of those glands removed with nerve preservation. Therefore, the surgical suitability of this technique, when compared to the retropubic, seems to be higher

Computer modeling technology to assess extracapsular tissue coverage of whole mount sections after retropubic and laparoscopic radical prostatectomy

PURPOSE

The introduction of new surgical approaches to radical prostatectomy requires methodologies that permit valid comparison that are more expedient than long-term outcomes of biochemical local and distant failure and survival. We used a computer modeling program to assess the percent of extracapsular tissue coverage of prostate glands removed by the open retropubic and laparoscopic approaches.

MATERIALS AND METHODS

Specimens were available for 15 and 17 patients who underwent open and laparoscopic radical prostatectomy, respectively. Serial whole mount sections were taken at 5 mm intervals. A genitourinary pathologist drew the contours of the prostate capsule on each tissue section. The whole mount was scanned to produce digital images. A software program was used to create a file with capsule information and a file with extraprostatic fibroadipose tissue information. Two separate point cloud files were generated to represent the capsule and extraprostatic models, and software algorithms were used to generate differences in the point clouds to quantify the extent of extracapsular tissue coverage.

RESULTS

When separated into sides dissected by a nerve or nonnerve sparing technique, the overall percent of gland surface coverage by extracapsular fibroadipose tissue was statistically greater with laparoscopic dissection than with the open approach. When a segmental analysis of gland coverage was evaluated, a statistically greater percent of fibroadipose coverage was associated with laparoscopic dissection in the apical and inferolateral segments with nonnerve sparing, and in the apical segment with nerve sparing.

CONCLUSIONS

This small radical prostatectomy series, analyzed by computer reconstruction as described, provides information suggesting that overall extracapsular tissue coverage is at least equal if not superior using the laparoscopic vs the open approach. This was specifically the case in areas of inferolateral and apical dissection with nonnerve sparing procedures and in areas of the apical dissection with nerve sparing procedures.

Prospective longitudinal comparative study of early health-related quality-of-life outcomes in patients undergoing surgical treatment for localized prostate cancer: a short-term evaluation of five approaches from a single institution

BACKGROUND AND PURPOSE

Quality of life (QoL) issues are a vital concern for the majority of patients seeking therapeutic intervention once they are found to have prostate cancer. A prospective longitudinal comparison using validated QoL instruments is a valuable technique to evaluate outcome differences. We evaluated the short-term QoL changes from baseline of five surgical approaches for localized prostate carcinoma delivered at a single institution.

PATIENTS AND METHODS

A prospective longitudinal survey of 719 patients with newly diagnosed prostate cancer was initiated in 2001. The surgical procedures performed during this time period were open radical prostatectomy (ORP), laparoscopic radical prostatectomy (LRP), da Vinci robotic prostatectomy (dVP), (103)Pd brachytherapy ((103)Pd), and prostate cryoablation (PCryo). An Institutional Review Board-approved questionnaire comprised of validated QoL instruments (UCLA Prostate Cancer Index and American Urological Association Symptom Index [SI]) was mailed to enrolled patients prior to their selected surgery and again at 1, 3, 6, 9, 12, 18, 24, and 36 months after therapy. A percent of baseline score calculation including data from all five treatment cohorts for follow-up months 1, 3, and 6 was compared within groups. Group I consisted of patients undergoing ORP, LRP, or dVP. Group II consisted of patients undergoing (103)Pd or PCryo.

RESULTS

Between January 2000 and April 2005, 498 patients (69%) were enrolled who completed the baseline questionnaire and at least one follow-up survey at 1, 3, or 6 months. The mean patient age at ORP, LRP, dVP, (103)Pd, and PCryo was 59, 61, 60, 67, and 72 years, respectively. Within Group I, early recovery of sexual function (at 3 months) appeared to occur sooner after dVP (35% return to baseline [RTB]) than ORP (24% RTB) and LRP (21% RTB) (P = 0.03). No other significant differences were noted, and trends toward improvement were seen in all groups. Within Group II, PCryo (18% RTB) had a more negative impact on sexual function at 3 months than did 103Pd (63% RTB) (P = 0.007), although a significant difference in baseline sexual function was also noted (P = 0.001). Early urinary function (at 1 month) was better after (103)Pd (82% RTB) than PCryo (72%) (P = 0.05), but this difference was lost at 6 months. In addition, the irritative and obstructive symptoms evaluated by the AUA SI were significantly worse (P = 0.003) at 3 months after (103)Pd than after PCryo.

CONCLUSIONS

Different surgical approaches for the treatment of localized prostate cancer affect the shortterm QoL results in different ways. Urinary, sexual, and bowel function and bother are affected to a similar degree by ORP, LRP, and dVP. In an older population, the tissue destruction resulting from PCryo appears to relieve obstructive and irritative urinary symptoms but at the sacrifice of sexual function compared with (103)Pd.

Overexpression of alpha-defensin is associated with bladder cancer invasiveness

Alpha-defensin (alpha-defensin) has been identified as a potential marker for bladder cancer in urine by surface enhanced laser desorption ionization studies, and confirmed using both immunoabsorption and immunodepletion studies. The objective of this study was to investigate the role of alpha-defensin in bladder cancer. Immunohistochemical analysis of tissue sections showed that alpha-defensin peptides are frequently expressed in bladder cancer cells. It is noteworthy that expression of alpha-defensins increased with tumor invasiveness. Surface enhanced laser desorption ionization analysis showed the presence of alpha-defensin in the T24 and A498 cancer cell lines. These cell lines show higher classically aggressive in vitro characteristics compared with the J82 cells that did not express alpha-defensin. Exogenously added alpha-defensin increased the proliferation and motility/invasiveness of these cell lines using respective assays. It is interesting that alpha-defensin peptides increased intracellular calcium ions (Ca2+). These data are consistent with a role for alpha-defensin in bladder cancer via modulation of cell motility and invasiveness using common intracellular signals, such as Ca2+. We propose that autocrine tumor expression of alpha-defensins may play an important role in facilitating the invasive phenotype of bladder cancer in patients.

Placebo-controlled phase III trial of immunologic therapy with sipuleucel-T (APC8015) in patients with metastatic, asymptomatic hormone refractory prostate cancer

PURPOSE

Sipuleucel-T (APC8015) is an investigational immunotherapy product designed to stimulate T-cell immunity against prostatic acid phosphatase. A phase III study was undertaken to evaluate the safety and efficacy of sipuleucel-T in a placebo-controlled study.

PATIENTS AND METHODS

A total of 127 patients with asymptomatic metastatic hormone refractory prostate cancer (HRPC) were randomly assigned in a 2:1 ratio to receive three infusions of sipuleucel-T (n = 82) or placebo (n = 45) every 2 weeks. On disease progression, placebo patients could receive APC8015F, a product made with frozen leukapheresis cells.

RESULTS

Of the 127 patients, 115 patients had progressive disease at the time of data analysis, and all patients were followed for survival for 36 months. The median for time to disease progression (TTP) for sipuleucel-T was 11.7 weeks compared with 10.0 weeks for placebo (P = .052, log-rank; hazard ratio [HR], 1.45; 95%CI, 0.99 to 2.11). Median survival was 25.9 months for sipuleucel-T and 21.4 months for placebo (P = .01, log-rank; HR, 1.70; 95%CI, 1.13 to 2.56). Treatment remained a strong independent predictor of overall survival after adjusting for prognostic factors using a Cox multivariable regression model (P = .002, Wald test; HR, 2.12; 95%CI, 1.31 to 3.44). The median ratio of T-cell stimulation at 8 weeks to pretreatment was eight-fold higher in sipuleucel-T-treated patients (16.9 v 1.99; P < .001). Sipuleucel-T therapy was well tolerated.

CONCLUSION

While the improvement in the primary end point TTP did not achieve statistical significance, this study suggests that sipuleucel-T may provide a survival advantage to asymptomatic HRPC patients. Supportive studies are underway.