PSA-recurrent Prostate Cancer Research Articles

Primary analysis of STARTAR: A phase 2 salvage trial of androgen receptor (AR) inhibition with androgen deprivation therapy (ADT) and apalutamide with radiation therapy (RT) followed by docetaxel in men with PSA recurrent prostate cancer (PC) after radical prostatectomy (RP).

5016 Background: ADT with salvage RT improves survival for men with PSA recurrence after RP. For high risk PSA recurrence, current standard ADT duration is up to 2 years with RT; shortening but intensifying systemic therapy may improve outcomes. The STREAM trial showed 6 mo enzalutamide with ADT/RT had 3-year progression free survival (PFS) of 53% in a high risk population, including lymph node (LN) positive. Given docetaxel (doce) improves survival in mHSPC, we evaluated the combination of salvage RT, ADT/apalutamide (apa) and doce in this setting. Methods: STARTAR is a multicenter investigator initiated phase 2 trial for salvage treatment of PSA recurrent PC post-RP, conducted in the DOD Prostate Cancer Clinical Trials Consortium. Key inclusion criteria included Gleason 7 with T3/positive margin/N1 or Gleason 8-10 PC, PSA relapse <4 years post-RP (inclusion PSA 0.2-4 ng/mL), and <4 positive LNs, standard imaging negative. Patients (pts) received ADT with apa for 9 months, RT (66-74 Gy to the prostate bed +/- pelvic LNs over 6-8 wks) starting wk 8, and then completed 6 cycles of concurrent doce 75mg/m2 q3 wks. The primary endpoint was 36 month PFS, defined as composite of freedom from PSA>0.2 + post-RT nadir with subsequent rise, clinical progression, other therapy start, or death, among pts with testosterone (T) recovery (>100ng/dL). Kaplan-Meier estimates for PFS were used to determine landmark 24 mo and 36 mo rates and compared to PFS rates from prior trials using a binomial test. Results: From 3/2018 to 2/2020, 39 pts were enrolled. As of 12/2022 data cutoff, median follow up was 36 months. Baseline characteristics: Gleason 7 in 54%; Gleason 8-10 in 46%; 23% LN positive; median PSA 0.58 ng/mL (range 0.21-3.40), and median time from RP 7.6 mo (range 2-98). 37 pts (95%) and 23 pts (62%) completed at least 1 and all 6 cycles doce, respectively. All pts achieved undetectable PSA nadirs. At 24mo and 36mo, PFS rates were 84% and 72%, respectively, with 95% pts recovering T at 36 mo. Compared to 40% historical PFS and 53% STREAM PFS rates, the 72% 36-mo PFS rate was statistically significantly improved (p<0.001 and p=0.013, respectively). Common any-grade adverse events (AEs) included 98% hot flashes, 88% fatigue, 77% alopecia, 57% dysgeusia, and 53% rash (28% grade 1; 15% grade 2, 10% grade 3), with 5% febrile neutropenia. Conclusions: In this first phase 2 trial of ADT, apa, salvage RT, and 6 cycles of doce for high risk PSA recurrence, the primary endpoint 3-year PFS rate improved to 72%, indicating durable remissions beyond historic controls. Intensifying systemic treatments in the non-metastatic hormone sensitive but high risk salvage setting may be feasible and efficacious, with fewer pts experiencing cancer progression over time. Clinical trial information: NCT03311555 .

Phase II Randomized Study of Salvage Radiation Therapy (SRT) plus Enzalutamide or Blinded Placebo for High-Risk PSA-Recurrent Prostate Cancer after Radical Prostatectomy: The SALV-ENZA Trial

<h3>Purpose/Objective(s)</h3> We sought to investigate whether enzalutamide (ENZA) treatment, without androgen deprivation therapy, increases freedom‐from‐PSA‐progression (FFPP) when combined with salvage radiation therapy (SRT) in men with recurrent prostate cancer post-radical prostatectomy (RP). <h3>Materials/Methods</h3> Men with biochemically recurrent prostate cancer after RP were enrolled into a randomized, double‐blind, phase II, placebo-controlled, multicenter study of SRT + placebo vs SRT + ENZA. The randomization (1:1) was stratified by center, surgical margin status (R0 vs R1), PSA prior to salvage treatment (PSA ≥0.5 vs <0.5 ng/mL), and pathologic Gleason sum (7 vs 8‐10) using a minimization algorithm. Following randomization, patients received either placebo or ENZA 160 mg PO once daily for 6 months. Following 2 months of study drug therapy, external beam radiotherapy to 66.6‐70.2 Gy was administered to the prostate bed (no pelvic nodes). The primary endpoint was FFPP. The trial design was powered for a HR 0.44 FFPP benefit with intended enrollment of 96 subjects and was closed as planned to enrollment on March 2020 short of that goal. Secondary endpoints were time to local recurrence (LR) within the radiation field, metastasis‐free survival (MFS), and safety as determined by frequency and severity of adverse events (AEs). <h3>Results</h3> A total of 86 patients were randomized with a median follow-up of 34 (range 0-52) months. The median pre-SRT PSA was 0.3 (range 0.06-4.6) ng/mL, 56/86 (65%) had extra-prostatic disease (pT3), 39/86 (45%) had Gleason Grade Group 4 or higher and 43/96 (50%) had positive surgical margins. Trial arms were well balanced. FFPP was significantly improved with ENZA vs placebo, for example 2-year FFPP was 87.1% vs 68.1%, respectively, and overall, with a HR 0.40 [95% confidence interval (CI), 0.17-0.92, p-value =0.026]. Subgroup analyses demonstrate differential benefit (p-value of interaction=0.031) of ENZA in men with pT3 (HR 0.19, 95%CI 0.05-0.67) vs pT2 disease (HR 1.29, 95%CI 0.34-4.81). There were insufficient secondary endpoint events for analysis. The most common adverse events were grade 1-2 fatigue (13% ENZA vs 9%) and urinary frequency (6 % ENZA vs 8%). <h3>Conclusion</h3> SRT plus ENZA monotherapy for men with PSA recurrent high-risk prostate cancer following RP is safe and delays PSA progression relative to SRT alone. The impact of ENZA on distant metastasis or survival is unknown at this time. Additional molecular biomarker analyses are being pursued.

Phase II, double-blind, randomized study of salvage radiation therapy (SRT) plus enzalutamide or placebo for high-risk PSA-recurrent prostate cancer after radical prostatectomy: The SALV-ENZA Trial.

5012 Background: We sought to investigate whether enzalutamide (ENZA) treatment, without androgen deprivation therapy, increases freedom-from-PSA-progression (FFPP) when combined with salvage radiation therapy (SRT) in men with recurrent prostate cancer post-radical prostatectomy (RP). Methods: Men with biochemically recurrent prostate cancer after RP were enrolled into a randomized, double-blind, phase II, placebo-controlled, multicenter study of SRT + placebo vs SRT + ENZA. The randomization (1:1) was stratified by center, surgical margin status (R0 vs R1), PSA prior to salvage treatment (PSA ≥0.5 vs &lt; 0.5 ng/mL), and pathologic Gleason sum (7 vs 8-10) using a minimization algorithm. Following randomization, patients received either placebo or ENZA 160 mg PO once daily for 6 months. Following 2 months of study drug therapy, external beam radiotherapy to 66.6-70.2 Gy was administered to the prostate bed (no pelvic nodes). The primary endpoint was FFPP. The trial design was powered for a HR 0.44 FFPP benefit with intended enrollment of 96 subjects and was closed as planned to enrollment on March 2020 short of that goal. Secondary endpoints were time to local recurrence (LR) within the radiation field, metastasis‐free survival (MFS), and safety as determined by frequency and severity of adverse events (AEs). Results: A total of 86 patients were randomized with a median follow-up of 34 (range 0-52) months. The median pre-SRT PSA was 0.3 (range 0.06-4.6) ng/mL, 56/86 (65%) had extra-prostatic disease (pT3), 39/86 (45%) had Gleason Grade Group 4 or higher and 43/96 (50%) had positive surgical margins. Trial arms were well balanced. FFPP was significantly improved with ENZA vs placebo, for example 2-year FFPP was 87.1% vs 68.1%, respectively, and overall with a HR 0.40 [95% confidence interval (CI), 0.17-0.92, p-value = 0.026]. Subgroup analyses demonstrate differential benefit (p-value of interaction = 0.031) of ENZA in men with pT3 (HR 0.19, 95%CI 0.05-0.67) vs pT2 disease (HR 1.29, 95%CI 0.34-4.81). There were insufficient secondary endpoint events for analysis. The most common adverse events were grade 1-2 fatigue (13% ENZA vs 9%) and urinary frequency (6 % ENZA vs 8%). Conclusions: SRT plus ENZA monotherapy for men with PSA recurrent high-risk prostate cancer following RP is safe and delays PSA progression relative to SRT alone. The impact of ENZA on distant metastasis or survival is unknown at this time. Additional molecular biomarker analyses are being pursued. Clinical trial information: NCT02203695.

Interim analysis of STARTAR: A phase II salvage trial of androgen receptor (AR) inhibition with androgen deprivation therapy (ADT) and apalutamide with radiation therapy (RT) followed by docetaxel in men with PSA recurrent prostate cancer (PC) after radical prostatectomy (RP).

90 Background: ADT with salvage RT improves survival for men with PSA recurrence after RP. Current standard duration of ADT for high risk PSA recurrence is up to 2 years with RT; therefore shortening but intensifying systemic therapy may improve outcomes. The STREAM trial showed 6 mo of enzalutamide added to ADT/RT had a 3-year progression free survival (PFS) of 53% in high risk patients including lymph node (LN) positive. Given that docetaxel improves survival in men with mHSPC, we evaluated the combination of salvage RT, ADT/apalutamide and docetaxel in this setting. Methods: STARTAR is a multicenter phase 2 trial for salvage treatment of PSA recurrent PC following RP conducted within the US Dept. of Defense Prostate Cancer Clinical Trials Consortium (DOD PCCTC). Key inclusion criteria included PC with Gleason 7 with T3/positive margin/1-4 positive LNs or Gleason 8-10 disease and PSA relapse within 4 years of RP (min PSA 0.2 ng/mL to max PSA 4 ng/mL). Men with up to 4 positive resected LNs were eligible. Men started ADT with apalutamide, continued with RT (66-74 Gy to the prostate bed +/- pelvic LNs over 6-8 weeks), and finally completed docetaxel 75mg/m2 IV q3 weeks for 6 cycles. Men were treated with ADT and apalutamide for approximately 9 months. The primary endpoint was PSA PFS at 36 months. This interim analysis evaluated secondary endpoints of 1-year PSA recurrence, testosterone recovery, and safety of this treatment sequence. Results: From 3/2018 to 12/2019, 39 men were enrolled at Duke, Wake Forest, Cornell, and the GU Research Network. With a data cutoff in 9/2020, median follow up from enrollment was 14 months. Baseline patient characteristics included Gleason 4+3 = 7 in 54% and Gleason 8-10 in 46%, and 23% LN positive; median PSA at the time of enrollment was 0.58 ng/mL (range 0.21-3.40) and the median time from RP to enrollment was 7 mo (range 2-98). At 1 year, there have been no progression events with 38% (12/31) of men with post-treatment testosterone recovery into normal range (recovery time median 10 mos [1-17 mos]). Common adverse events (AEs) of any-grade at least possibly related to the regimen were 98% hot flashes, 88% fatigue, 77% alopecia, 57% dysgeusia, and 53% rash (28% grade 1; 15% grade 2, 10% grade 3), with neutropenia as the most common grade 3/4 AE (27/39 men, 70%) with two grade 3 febrile neutropenia. Conclusions: In this first phase 2 trial of ADT, apalutamide, radiation, and 6 cycles docetaxel in the salvage setting for high risk PSA recurrence, short term outcomes are excellent with no recurrences at 12 months of follow-up. This salvage treatment was well tolerated in the majority of men with the exception of a high rate of drug rashes and neutropenia related to the course of treatment, in line with known safety profiles of the study agents. Clinical trial information: NCT03311555.

Phase II trial of a DNA vaccine encoding prostatic acid phosphatase (pTVG-HP) and nivolumab (Nivo) in patients (pts) with nonmetastatic, PSA-recurrent prostate cancer (PCa).

TPS273 Background: Radical prostatectomy (RP) and radiation therapy (RT) are the gold standard, curative intent treatment for pts with presumed organ-confined PCa. However, about one third of these pts will have progressive or metastatic disease at 10 years (yr). Pts with PSA recurrence without radiographic evidence of metastatic (m) PCa (stage M0) will ultimately develop radiographically apparent mPCa within a median of 8 yr. Pts with rapid PSA doubling time (DT) have a markedly shorter time to mPCa and death. Utilizing an immunotherapeutic approach could utilize the sensitivity and specificity of the immune system to treat microscopic disease and potentially avoid or postpone androgen deprivation therapy (ADT) and its unwanted side effects. Methods: In this single arm, two-stage phase II trial, a total of 21-41 PCa pts with PSA only progression (4 rising PSA with final PSA ≥ 2 ng/mL) after initial RP for presumed organ-confined disease who have no radiographic evidence of mPCa in conventional imaging (CT and bone scan) will be enrolled. Pts with small cell or other variant PCa, or history of ADT other than concurrent with RT are excluded. All pts will be treated with pTVG-HP 100 μg intradermally (id) and Nivo 240 mg IV every (Q) 2 weeks (w) x6, and then pTVG-HP 100 μg id and Nivo 480 mg IV Q4w x9 beginning w12 on study. Pts with PSA on w4 &gt; PSA on day 1 will additionally receive rhGM-CSF 208 μg id, as a vaccine adjuvant, Q2w x4 beginning w4 on study. Pts will be treated until progression or up to a total of 1 yr. Response will be monitored by CT and bone scan Q6 months or as clinically indicated. Primary endpoints are safety and tolerability of this combination and PSA complete response rate (PSA &lt; 0.2 ng/mL). Key secondary endpoints are 2-yr metastasis-free survival, median radiographic progression-free survival, PSA response rate (≤50% of baseline), and changes in PSA DT. Elicited antigen-specific T-cell and/or IgG response and its correlation with PSA response will be explored. Bone mets not detected by conventional imaging and their association with response will be evaluated by Quantitative Total Bone Imaging (QTBI) by NaF PET/CT. Updated enrollment will be presented. Clinical trial information: NCT03600350.

A phase II randomized placebo-controlled double-blind study of salvage radiation therapy plus placebo versus SRT plus enzalutamide with high-risk PSA-recurrent prostate cancer after radical prostatectomy (SALV-ENZA)

BackgroundIn men with a rising PSA following radical prostatectomy, salvage radiation therapy (SRT) offers a second chance for cure. Hormonal therapy can be combined with SRT in order to increase prostate tumor control, albeit with associated higher rates of treatment side effects. This trial studies the effectiveness of SRT combined with hormonal therapy using a more potent anti-androgen with a favorable side effect profile. Enzalutamide, a next generation selective androgen receptor antagonist, is approved by the Food and Drug Administration for the treatment of metastatic castrate-resistant prostate cancer (CRPC) where it has been shown to improve overall survival in combination with androgen deprivation therapy. The primary objective of this study is to evaluate the efficacy of combination SRT and enzalutamide for freedom-from-PSA-progression. Secondary objectives include time to local recurrence within the radiation field, metastasis-free survival and safety as determined by frequency and severity of adverse events.Methods/designThis is a randomized, double-blind, phase II, prospective, multicenter study in adult males with biochemically recurrent prostate cancer following radical prostatectomy. Following registration, enzalutamide 160 mg or placebo by mouth (PO) once daily will be administered for 6 months. Following two months of study drug, external beam radiotherapy to 66.6–70.2 Gray (Gy) will be administered to the prostate bed over 7–8 weeks while continuing daily placebo/enzalutamide. This is followed by two additional months of placebo/enzalutamide.DiscussionThe SALV-ENZA trial is the first phase II placebo-controlled double-blinded randomized study to test SRT in combination with a next generation androgen receptor antagonist in men with high-risk recurrent prostate cancer after radical prostatectomy. The primary hypothesis of this study is that clinical outcomes will be improved by the addition of enzalutamide compared to standard-of-care SRT alone and pave the path for phase III evaluation of this combination.Trial registrationsClinicaltTrials.gov Identifier: NCT02203695 Date of Registration: 06/16/2014. Date of First Participant Enrollment: 04/16/2015.

A phase II Salvage Trial of AR Inhibition with ADT and Apalutamide with Radiation therapy followed by docetaxel in men with PSA recurrent prostate cancer (PC) after radical prostatectomy (STARTAR).

TPS5097 Background: Androgen deprivation combined with salvage external beam radiation therapy (RT) have improved survival for patients (pts) with non-metastatic hormone naïve PC and PSA recurrence after radical prostatectomy (RP). Our recent STREAM trial showed addition of enzalutamide to RT and ADT had a 3-year progression free survival (PFS) of 53%. Adding effective PC treatments in this setting may further improve 3-year PFS. Methods: STARTAR is an investigator-initiated phase 2 trial for salvage treatment of biochemically recurrent PC following prostatectomy. Key inclusion criteria include histologic prostate adenocarcinoma, either Gleason 7 with T3/positive margin/1-4 positive lymph nodes or Gleason 8-10 disease, PSA relapse within 4 years of prostatectomy (minimum PSA 0.2 ng/mL to maximum PSA 4 ng/mL). Treatment involves ADT with apalutamide for 9 months, continue with with prostate bed +/- nodal RT at month 3, followed by 6 cycles of docetaxel 75mg/m2 IV every 3 weeks for 6 cycles. The primary endpoint of the study is 3-year PFS. With a one-sided alpha of 0.05 to improve 3-year PFS from 50% to 75%, we will have 92% power by enrolling 42 pts (including 10% dropout rate) based on the binomial test. Key secondary endpoints include 1, 2, and 3-year PSA recurrence rates with testosterone recovery, PSA PFS, PSA nadir, time to testosterone recovery, and safety of combination therapy. Quality of life will be assessed by EPIC questionnaire. As of February 2019, we have enrolled and treated 12 pts in this PCCTC trial. Accrual to the STARTAR trial is ongoing (NCT03311555). Clinical trial information: NCT03311555.

Randomized phase II trial of a DNA vaccine encoding prostatic acid phosphatase (pTVG-HP) versus GM-CSF adjuvant in patients with PSA-recurrent prostate cancer.

5037 Background: Phase I/II studies of pTVG-HP showed safety and increases in prostatic acid phosphatase (PAP)-specific T cells. Based on these, we conducted a multi-center, randomized phase II trial using pTVG-HP with GM-CSF adjuvant vs GM-CSF alone in patients with PSA-recurrent, non-metastatic, non-castrate, prostate cancer (stage M0). Methods: 99 patients with M0 prostate cancer (negative CT and bone scan) with PSA doubling time (DT) of &lt; 12m were randomly assigned to pTVG-HP + GM-CSF vs GM-CSF. Treatments were every 2 wk x 6, and then quarterly for up to 24m. Primary endpoint was 2-year MFS. Secondary endpoints included median MFS, changes in PSA DT, and immune response to PAP antigen. Additional analysis included quantitative changes in bone lesion activity by NaF PET/CT. Results: Few grade 3/4 events were observed and were not statistically different between arms. 2-year MFS between control and pTVG-HP was 42.3% and 41.8% (p = 0.97). Median MFS was not different (18.3m control versus 18.9m pTVG-HP, HR = 1.6, p = 0.13). Changes in PSA DT, and immunity to the PAP target, were not different between study arms. A pre-planned subset analysis showed median MFS was significantly longer in patients with rapid PSA DT ( &lt; 3m) treated with pTVG-HP (6.1m versus 12.0m, n = 21, HR = 4.4, p = 0.03). In patients with baseline metastases detected on NaF PET/CT, total activity (SUVtotal) increased 17% with GM-CSF alone, but decreased 29% with pTVG-HP from baseline to month 6 (n = 27, p = 0.07). Conclusions: This trial did not demonstrate an overall increase in 2-year MFS following treatment with pTVG-HP, but suggested a modest effect in patients with rapidly progressive disease. NaF PET/CT imaging suggests that pTVG-HP has a detectable effect on decreasing metastatic activity in bone. A separate trial suggests that pTVG-HP is an immune activating agent that improves activity of PD-1 blockade. A trial using pTVG-HP in combination with nivolumab in patients with M0 prostate cancer is currently underway. Clinical trial information: NCT01341652.

Phase II trial enzalutamide and androgen deprivation therapy (ADT) with salvage radiation in men with high-risk PSA recurrent prostate cancer (PC): The STREAM trial.

29 Background: Salvage external beam radiotherapy (RT) and hormonal therapy improves survival over RT alone in men with non-metastatic hormone naïve PC and PSA recurrence after radical prostatectomy (RP). We investigated the safety/efficacy of enzalutamide with salvage RT and ADT in this setting. Methods: This was a 3 center prospective phase 2 single arm clinical trial in the Dept of Defense Prostate Cancer Clinical Trials Consortium. Eligibility: Gleason 7-10 PC and PSA recurrence within 4 years (yrs) of RP, PSA 0.2-4.0, no prior hormonal therapy, and no metastases on CT/Bone Scan imaging. Men received 6 months (mos) of ADT with 160 mg/d enzalutamide and 66 Gy RT to the prostate bed. Primary endpoint was 2 yr PFS with testosterone (T) recovery to &gt;100 ng/dl. Secondary objectives included PSA nadir, 3 yr PFS, safety and patient reported quality-of-life over time. This trial was designed with 84% power to detect a 20% improvement in 2 yr PFS vs historic data and a 1-sided alpha of 0.05. Results: We enrolled 38 men (90% white, 8% black, 2% Asian); 37 (97%) completed therapy and were evaluable with T recovery at 2 yrs. Median age was 64 yrs; 47% Gleason 8-10, 79% T3/T4 disease, 21% had resected N+ PC; median PSA was 0.4 (0.19-4.19). Median follow-up is 29.5 mo. Treatment was well tolerated with 11 patients (29%) experiencing G3 toxicities (including 4 HTN, 2 urinary retention, 2 CV events); no G4-5 or unexpected toxicities were observed. T recovery occurred in 35 (95%) at 12 mos. The primary endpoint of 2 yr PFS was 65% (95% CI: 47%-78% vs. historic controls with 51% 2 yr PFS rate) among the 37 patients with T recovery. PSA remained at undetectable levels in 69% at 2 yrs. The 3 yr PFS was 53% (95% CI: 36%, 68%). QOL data over time suggest short term reductions in urinary and sexual function with recovery by 12-24 mo in most men. Conclusions: Salvage enzalutamide and ADT for 6 months with RT following RP for men with PSA recurrent high risk PC is safe, and demonstrates encouraging efficacy at 2 and 3 years. Most men have testosterone recovery at 1 year. These data warrant prospective controlled phase 3 trials to assess the impact of potent AR inhibition in this curative intent setting. Clinical trial information: NCT02057939.

Prime-boost vaccination targeting prostatic acid phosphatase (PAP) in patients with metastatic castration-resistant prostate cancer (mCRPC) using Sipuleucel-T and a DNA vaccine

BackgroundProstatic acid phosphatase (PAP) is a prostate tumor antigen, and the target of the only FDA-approved anti-tumor vaccine, sipuleucel-T. We have previously reported in two clinical trials that a DNA vaccine encoding PAP (pTVG-HP) could elicit PAP-specific, Th1-biased T cells in patients with PSA-recurrent prostate cancer. In the current pilot trial we sought to evaluate whether this vaccine could augment PAP-specific immunity when used as a booster to immunization with sipuleucel-T in patients with metastatic, castration-resistant prostate cancer (mCRPC).MethodsEigthteen patients with mCRPC were randomized to receive sipuleucel-T alone or followed by intradermal immunization with pTVG-HP DNA vaccine. Patients were followed for time to progression, and immune monitoring was conducted at defined intervals.ResultsOverall, patients were followed for a median of 24 months. 11/18 patients completed treatments as per protocol. No treatment-associated events > grade 2 were observed. Th1-biased PAP-specific T-cell responses were detected in 11/18 individuals, and were not statistically different between study arms. Higher titer antibody responses to PAP were detectable in patients who received pTVG-HP booster immunizations. Median time to progression was less than 6 months and not statistically different between study arms. The median overall survival for all patients was 28 months.ConclusionsThese findings suggest that prime-boost vaccination can augment and diversify the type of immunity elicited with anti-tumor vaccination in terms of T-cell and humoral immunity. Future studies will explore DNA as priming immunization rather than a booster immunization.Trial registrationNCT01706458.

SM88 in non-metastatic rising PSA-recurrent prostate cancer.

e16567 Background: SM88 is a novel combination of substituted amino acid ( AA) and repurposed agents with non-toxic activity in a variety of cancers including prostate (PC). Non-metastatic biochemically recurrent PC (nmPC) is ideal for such a well-tolerated, non-androgen based treatment. We present biomarker activity including CTCs (circulating tumor cells) after completion of the Ib dose escalating pharmacokinetic portion of the SM88 development plan. Methods: Planned analysis of an ongoing prospective Phase Ib/II open label study of nmPC (PCWG3 definition). Subject 1 received the 1stdose level of AA, and others received 2x dose. All subjects also received a combination of low dose re-purposed CYP3a4 inducer, oxidative stress catalyst, and mTOR inhibitor. Results: Four subjects completed at least 1 cycle (28d) with all PK sampling as prespecified. Median age was 73(70-80); all had prior ADT that was discontinued 3-6 yrs earlier, and either had curative intent prostatectomy (n = 2) or RT (n = 2); Testosterone level was castrate in one after prior RT. CTCs fell (p &lt; 0.01) to undetectable (n = 1) or by &gt; 25% (n = 3) (see table) while PSA remained stable (PCWG3 criteria). Preliminary LDH, neutrophil/lymphocyte ratio (N:L), urinary NTx, bone specific AlkPhos (bAP) trends are in the table below. There were no drug related serious adverse events (2 grade: 1- pigmentation, 1- vasomotor). EORTC-QLQ30 and PR25 scores were either improved or stable. Conclusions: Treatment with SM88 in patients with nmPC in the completed phase Ib cohort was associated with CTC reduction, and stable biomarker trends including PSA and LDH. There was no significant toxicity or adverse patient reported outcomes. Based on these results, the dose escalation was stopped at the second level and a cohort expansion phase II initiated. A phase III RCT is planned for confirmation of these results. Clinical trial information: NCT02796898. [Table: see text]

DNA vaccine with pembrolizumab to elicit antitumor responses in patients with metastatic, castration-resistant prostate cancer (mCRPC).

168 Background: We have previously investigated a DNA vaccine encoding prostatic acid phosphatase (PAP, pTVG-HP) in patients with PSA-recurrent prostate cancer, and have demonstrated that this can be safely administered over many months and can elicit PAP-specific T cells. A phase 2 trial is currently underway. In preclinical models, we have found that blockade of regulatory receptors, including PD-1, at the time of T cell activation with vaccination produced anti-tumor responses in vivo. Similarly, we have recently found that patients with prostate cancer previously immunized with a DNA vaccine develop PD-1-regulated T cells. These findings suggested that combined PD-1 blockade with vaccination should elicit superior anti-tumor responses in patients with prostate cancer. Methods: A clinical trial was designed to evaluate the immunological and clinical efficacy of pTVG-HP when delivered in combination or in sequence with pembrolizumab, in patients with mCRPC. Serial biopsies, blood draws, and exploratory FLT PET/CT imaging are being conducted for correlative analyses. Results: While trial accrual continues, 1 of 14 subjects has experienced a grade 3 adverse event. There have been no grade 4 events. Several patients treated with the combination have experienced serum PSA declines, and several have experienced decreases in tumor volume by radiographic imaging at 12 weeks, including one partial response. Expansion of PAP-specific Th1-biased T cells has been detected in peripheral blood samples. Exploratory FLT PET/CT imaging has demonstrated proliferative responses in metastatic lesions and in vaccine-draining lymph nodes. Evaluation of biopsy specimens for recruitment of antigen-specific T cells is currently underway. Conclusions: PD-1 pathway inhibitors have demonstrated little clinical activity to date when used as single agents for treating prostate cancer. Our findings suggest that combining this blockade with tumor-targeted T-cell activation by a DNA vaccine is safe and can augment tumor-specific T cells, detectable within the peripheral blood and by imaging, and result in objective anti-tumor changes. Clinical trial information: NCT02499835.

Is there an additional benefit of Tc-99m-PSMA-guided gamma probe use for salvage lymph node dissection in recurrent prostate cancer.

e591 Background: PSMA-PET/CT is the most sensitive diagnostic tool in biochemical recurrent prostate cancer to detect minimal metastatic disease. However, it may be difficult to localize small PSMA-positive lymph nodes intraoperatively. Therefore, it was the aim to investigate whether preoperative Tc-99m-PSMA targeting may improve intraoperative tumor localization by use of a gamma probe. Methods: In 13 Patients Ga-68-PSMA-PET/CT identified iliac lymph nodes in patients suitable for salvage lymph node dissection. On the day before operation a mean activity of 480 MBq Tc-99m-PSMA was injected and gamma camera scintigraphy + SPECT was performed 4-5 hours after tracer application. About 24 hours after tracer application a salvage lymph node dissection was performed on the side of initial suspicious lymph node metastases. Sensitivity, specifity, pos and neg. predictive values were calulated for PSMA-PET/CT and gamma probe use to analyse the additional use. Results: In 9 / 13 patients PSMA-positive metastatic lymph nodes were identified in Ga-68 PSMA-PET/CT. A total of 156 lymph nodes were removed with 14 lymph nodes in 9 patients being positive in histopathologic examination. Sensitivity, specifity, pos and neg. predictive values for PSMA PET/CT and gamma probe were 85% and 79%, 99% and 100%, 85% and 100% and 99% and 98% respectively. In one patient only gamma probe use identified a pathologic lymph node. Conclusions: Gamma probe guided salvage lymph node dissection in PSA recurrent prostate cancer is feasible and had a high concordance with PSMA-PET/CT. However, the additional diagnostic benefit is limited compared to PSMA-PET/CT because in only one patient (7%) a positive lymph node could be identified with the use of the gamma probe outside the standard operative area in salvage lymph node dissection.

Abstract B147: Randomized phase II trial of a DNA vaccine encoding prostatic acid phosphatase (PAP) in patients with recurrent prostate cancer (NCT01341652)

Abstract Background: Patients with rapidly rising PSA alone after definitive therapy for prostate cancer are at high risk for metastatic progression and ultimately death from prostate cancer. This is a stage of disease for which there are no standard therapies, although androgen deprivation is often used. We have previously reported that a DNA vaccine encoding PAP (pTVG-HP) was safe and could elicit antigen-specific CD4+ and CD8+ T cells in this population (NCT00582140). Patients who developed persistent Th1-type immunity tended to have favorable changes in serum PSA doubling time. The safety, immunological activity, and changes in PSA doubling time were observed in a second pilot clinical trial evaluating different schedules of administration (NCT00849121). Methods: 106 patients with high-risk PSA-recurrent prostate cancer, PSA doubling time &amp;lt; 12 months, and no metastases by standard radiographic imaging, are being randomized to DNA vaccine with GM-CSF adjuvant versus GM-CSF adjuvant alone in this multicenter trial (NCT01341652). The primary endpoint is 2-year radiographic progression-free survival (PFS). Secondary and exploratory endpoints include median PFS, predictive and early response immune biomarkers, association of T-cell immunity with PFS, and change in tumor growth rates as measured by PSA and quantitative bone imaging using NaF PET imaging. Results: To our knowledge, this is the first randomized, phase II trial using an anti-tumor DNA vaccine. Enrollment is ongoing, but expected to be complete in 2015. The clinical and biomarker plan of evaluation will be presented, as well as descriptions of other pilot clinical trials ongoing with this DNA vaccine. Citation Format: Douglas G. McNeel, Lawrence Fong, Emmanuel S. Antonarakis, Glenn Liu. Randomized phase II trial of a DNA vaccine encoding prostatic acid phosphatase (PAP) in patients with recurrent prostate cancer (NCT01341652). [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B147.

A phase 2 multimodality trial of docetaxel/prednisone with sunitinib followed by salvage radiation therapy (RT) in men with PSA recurrent prostate cancer (PC) after radical prostatectomy (RP).

35 Background: In men with high grade PC and rapid PSA progression after RP, failure rates are unacceptably high despite salvage RT. Androgen deprivation therapy (ADT) is not curative in this setting and we thus evaluated a novel multi-modality approach of systemic chemotherapy and anti-angiogenic therapy prior to prostate bed salvage RT in a multicenter trial. Methods: Eligible men had a rising PSA of 0.1-3.0 ng/ml within 4 years of RP, no metastatic disease except resected positive nodes, no prior ADT, and Gleason 7-10. Men received 4 cycles of docetaxel 70 mg/m2 q3w with prednisone 5 mg bid and sunitinib 37.5 mg qd for 14/21 days each cycle. Salvage RT (66Gy/33fx) to the prostate bed started at day 100. The primary endpoint was progression-free survival at 2 years (PFS2), defined as a confirmed PSA rise above the post-RT nadir or baseline if no nadir occurred, clinical/radiographic progression, or death from date of enrollment. Safety and dose-limiting toxicities were evaluated. This was a single arm prospective open-label phase 2 trial. Results: Thirty-four men accrued in this multisite Dept. of Defense Prostate Cancer Clinical Trials Consortium trial (median age 62, 85% Caucasian, 9% African American); 24% were node positive at surgery, 47% had Gleason 8-10. Median PSA at entry was 0.54 (range 0.2-2.8) and median time since RP was 11 months. The trial was terminated prematurely due to excess dose-limiting toxicity (9 DLT events) including grade 3 events of hand-foot syndrome (n=4), neutropenic fever (n=2), AST increase (n=1), fatigue (n=1), and vomiting with diarrhea (n=1). PFS at 2 years was 48.9% (95% CI: 32.8%, 67.2%) with a median PFS of 26.2 mo (95% CI: 12.5, -). Six men (17.6%) had an undetectable PSA at 2 years. Conclusions: Sunitinib and docetaxel/prednisone followed by salvage RT resulted in excess pre-specified DLTs. However, efficacy data suggests that some men achieved durable long-term disease control with this aggressive approach. Longer-term follow-up and comparative data with salvage XRT and ADT is needed to fully understand the risks/benefits of this combined modality approach in high risk PSA-recurrent PC. Clinical trial information: NCT00734851.

A phase 1A/1B, two-stage study of a PSA/IL-2/GM-CSF vaccine for the treatment of PSA-recurrent prostate cancer in hormone-naive and hormone-independent patients.

TPS3131 Background: Prostate cancer vaccines demonstrate clinical benefit in hormone refractory metastatic prostate cancer patients. The broader application to earlier disease stages remains both c...

872 Long-term immunotherapy by dendritic-cells based vaccine in patients with PSA-recurrent prostate cancer

872 Long-term immunotherapy by dendritic-cells based vaccine in patients with PSA-recurrent prostate cancer

Metastasis-free survival is associated with overall survival in men with PSA-recurrent prostate cancer treated with deferred androgen deprivation therapy

BackgroundClinical trials in men with biochemically recurrent prostate cancer (BRPC) have been hampered by long survival times, making overall survival (OS) a difficult end point to reach. Intermediate end points are needed in order to conduct such trials within a more feasible time frame. Patients and methodsThis is a retrospective analysis of 450 men with BRPC following prostatectomy treated at a single institution between 1981 and 2010, of which 140 developed subsequent metastases. Androgen deprivation therapy (ADT) was deferred until after the development of metastases. Cox regression models were developed to investigate factors influencing OS. ResultsMedian metastasis-free survival (MFS) was 10.2 years [95% confidence interval (CI) 7.6–14.0 years]; median OS after metastasis was 6.6 years (95%CI 5.8–8.4 years). Multivariable Cox regressions identified four independently prognostic variables for OS: MFS (HR 0.77; 95% CI 0.63–0.94), number of metastases (≤3 versus ≥4; HR 0.50; 95% CI 0.29–0.85), pain (absent versus present; HR 0.43; 95% CI 0.25–0.72), and bisphosphonate use (yes versus no; HR 0.60; 95% CI 0.37–0.98). ConclusionsMFS emerged as an independent predictor of OS in men with BRPC treated with deferred ADT after the development of metastases. MFS may be a reasonable intermediate end point in future clinical trials. This observation requires prospective validation.

720 SALVAGE PALLADIUM BRACHYTHERAPY FOR LOCAL FAILURE AFTER INITIAL EXTERNAL RADIOTHERAPY FOR PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Advanced (I)1 Apr 2013720 SALVAGE PALLADIUM BRACHYTHERAPY FOR LOCAL FAILURE AFTER INITIAL EXTERNAL RADIOTHERAPY FOR PROSTATE CANCER Douglas Swartz, Carlos Vargas, Mitchell Terk, and Apoorva Vashi Douglas SwartzDouglas Swartz Jacksonville, FL More articles by this author , Carlos VargasCarlos Vargas Jacksonville, FL More articles by this author , Mitchell TerkMitchell Terk Jacksonville, FL More articles by this author , and Apoorva VashiApoorva Vashi Jacksonville, FL More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.279AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Salvage brachytherapy for localized pathologic failure after primary external beam radiation (EBRT) is rarely used. This retrospective study presents the efficacy and safety of Palladium brachytherapy for patients with only a localized recurrence after external radiotherapy with minimum 5 year follow-up. METHODS Sixty-nine consecutive patients treated with a salvage pd-103 implant for local failure of prostate cancer were evaluated at our institution. All patients had a rising PSA and biopsy proven recurrent localized prostate cancer at least 2-years after initial external radiotherapy. All were negative for metastatic disease on imaging studies, including a bone scan and CT or MRI of the abdomen and pelvis. Patients who had a PSA >5.0 ng/ml on androgen suppression were considered castration resistant (CRPC). Patients were stratified into low, intermediate and high risk according to the NCCN guidelines. 100Gy was the prescribed dose with a Palladium (Pd-103) implant. 89.9% of patients received androgen suppression (AS) for at least 6 months starting before the implant as part of their salvage therapy. Failure was defined as current nadir PSA plus 2 ng/ml from start of AS or radiologic evidence of distant failure. The CTCAE version 4.0 was used to assess complications. RESULTS Median follow-up from the time of initial external radiotherapy was 12 years (3.5-23.5) and after salvage therapy 5.0 years (0.6-13.7). 5 year Biochemical control (BC) for low risk patients was 85.6%, intermediate risk patients 74.8%, and high risk patients 66%. Most patients were on AS at the time of salvage. 5-y BC was 73.8% for non-CRPC and 22% for castration resistant prostate cancer patients (<0.001). For non-CRPC patients, early treatment after PSA failure vs. delayed treatment on AS for 6 months or more was associated with significantly worse 5-y BC: 58.9% vs. 77.8% (p=0.05). PSA >10ng/ml was also predictive: 5-y BC 73.9% vs. 51.4% (p=0.02). Stage T2c had a worse outcome: 76.3% vs. 50%, although this was not statistically significant. No statistical differences were seen by comparing Gleason Score. Grade 3 genitourinary complications including incontinence occurred in 8.7% and there were no grade 4 complications. There were no GI grades 3, 4 or 5 complications. CONCLUSIONS Excellent biochemical control can be achieved with salvage palladium brachytherapy after a local recurrence of prostate cancer after initial external radiotherapy. Side effects are limited and comparable to salvage surgery therefore offering an alternative option. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e296 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Douglas Swartz Jacksonville, FL More articles by this author Carlos Vargas Jacksonville, FL More articles by this author Mitchell Terk Jacksonville, FL More articles by this author Apoorva Vashi Jacksonville, FL More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Association of metastasis-free survival (MFS) with overall survival (OS) in men with PSA-recurrent prostate cancer treated with deferred androgen-deprivation therapy.

109 Background: To support the hypothesis that metastases are a significant clinical event, we aimed to explore the association between MFS with OS in men with biochemically-recurrent prostate cancer. Methods: This is a retrospective analysis of 450 men treated at a single institution between July 1981 and July 2010 with biochemical recurrence following prostatectomy, of which 140 (31%) developed subsequent metastases. In all patients, androgen deprivation therapy was deferred until after the development of radiographic metastases. Univariate and multivariable Cox regression models were developed to investigate factors influencing OS. Results: The median time from biochemical recurrence to metastasis (i.e. MFS) was 10.2 y (95% CI, 7.6–14.0 y), and the median time from first metastasis to death (i.e. OS) was 6.6 y (95% CI, 5.8–8.4 y). Using multivariable Cox regressions, we identified 4 variables that were independently prognostic for OS (Table): MFS (≤3 vs &gt;3 y; P=0.009), number of metastases (≤3 vs ≥4; P=0.001), painful metastases (present vs absent; P&lt;0.001), and ECOG performance status (0 vs ≥1; P=0.001). The concordance index reflecting the association between MFS and OS was 0.67. Conclusions: After adjusting for other prognostic variables, MFS was independently associated with OS in men with biochemically-recurrent prostate cancer. While this observation requires prospective validation, it suggests that MFS may be a reasonable endpoint in future clinical trials. [Table: see text]