Bipolar androgen therapy plus nivolumab for patients with metastatic castration-resistant prostate cancer: the COMBAT phase II trial.

Cyclic high-dose testosterone administration, known as bipolar androgen therapy (BAT), is a treatment strategy for patients with metastatic castration-resistant prostate cancer (mCRPC). Here, we report the results of a multicenter, single arm Phase 2 study (NCT03554317) enrolling 45 patients with heavily pretreated mCRPC who received BAT (testosterone cypionate, 400 mg intramuscularly every 28 days) with the addition of nivolumab (480 mg intravenously every 28 days) following three cycles of BAT monotherapy. The primary endpoint of a confirmed PSA50 response rate was met and estimated at 40% (N = 18/45, 95% CI: 25.7-55.7%, P = 0.02 one-sided against the 25% null hypothesis). Sixteen of the PSA50 responses were achieved before the addition of nivolumab. Secondary endpoints included objective response rate (ORR), median PSA progression-free survival, radiographic progression-free survival (rPFS), overall survival (OS), and safety/tolerability. The ORR was 24% (N = 10/42). Three of the objective responses occurred following the addition of nivolumab. After a median follow-up of 17.9 months, the median rPFS was 5.6 (95% CI: 5.4-6.8) months, and median OS was 24.4 (95% CI: 17.6-31.1) months. BAT/nivolumab was well tolerated, resulting in only five (11%) drug related, grade-3 adverse events. In a predefined exploratory analysis, clinical response rates correlated with increased baseline levels of intratumoral PD-1 + T cells. In paired metastatic tumor biopsies, BAT induced pro-inflammatory gene expression changes that were restricted to patients achieving a clinical response. These data suggest that BAT may augment antitumor immune responses that are further potentiated by immune checkpoint blockade.

Test-retest repeatability of organ uptake on PSMA-targeted 18 F-DCFPyL PET/CT in patients with prostate cancer.

OBJECTIVES: We evaluated 18 F-DCFPyL test-retest repeatability of uptake in normal organs. METHODS: Twenty-two prostate cancer (PC) patients underwent two 18 F-DCFPyL PET scans within 7 days within a prospective clinical trial (NCT03793543). In both PET scans, uptake in normal organs (kidneys, spleen, liver, and salivary and lacrimal glands) was quantified. Repeatability was determined by using within-subject coefficient of variation (wCOV), with lower values indicating improved repeatability. RESULTS: For SUVmean , repeatability was high for kidneys, spleen, liver, and parotid glands (wCOV, range: 9.0%-14.3%) and lower for lacrimal (23.9%) and submandibular glands (12.4%). For SUVmax , however, the lacrimal (14.4%) and submandibular glands (6.9%) achieved higher repeatability, while for large organs (kidneys, liver, spleen, and parotid glands), repeatability was low (range: 14.1%-45.2%). CONCLUSION: We found acceptable repeatability of uptake on 18 F-DCFPyL PET for normal organs, in particular for SUVmean in the liver or parotid glands. This may have implications for both PSMA-targeted imaging and treatment, as patient selection for radioligand therapy and standardized frameworks for scan interpretation (PROMISE, E-PSMA) rely on uptake in those reference organs.

Multi-timepoint imaging with PSMA-targeted [18F]F-Florastamin PET/CT: lesion detection and comparison to conventional imaging.

OBJECTIVE: The aims of this study were to investigate the utility of [18F]F-Florastamin, a novel prostate-specific membrane antigen (PSMA)-targeted PET radiotracer with facile radiochemistry, relative to the conventional imaging for the detection of sties of disease and evaluate the effect of multi-timepoint imaging with [18F]F-Florastamin PET on lesion detectability. METHODS: Eight prostate cancer patients with known or suspected recurrence who underwent [18F]F-Florastamin PET/CT at 1-h and 2-h imaging time-points were included in this prospective pilot study. [18F]F-Florastamin PET images were interpreted visually and quantitatively at both time points and compared with CIM. RESULTS: [18F]F-Florastamin PET was superior to CT in the detection of active osseous metastases and small-sized metastatic lymph nodes that do not fall under the anatomic imaging size criteria for metastasis. Multi-timepoint imaging showed a significant reduction in the blood pool, bone marrow and muscular uptake, and increase in liver uptake over time. There is a significant improvement in tumor-to-background ratio (TBR) at the 2-h imaging time-point (P = 0.04). The mean percentage change in TBR at 2-h was 21% (SD = 0.31). CONCLUSIONS: [18F]F-Florastamin is a promising new radioligand for PSMA-targeted PET with suitable lesion detectability and high TBR at both time points.

Lack of repeatability of radiomic features derived from PET scans: Results from a 18 F-DCFPyL test-retest cohort.

OBJECTIVES: PET-based radiomic metrics are increasingly utilized as predictive image biomarkers. However, the repeatability of radiomic features on PET has not been assessed in a test-retest setting. The prostate-specific membrane antigen-targeted compound 18 F-DCFPyL is a high-affinity, high-contrast PET agent that we utilized in a test-retest cohort of men with metastatic prostate cancer (PC). METHODS: Data of 21 patients enrolled in a prospective clinical trial with histologically proven PC underwent two 18 F-DCFPyL PET scans within 7 days, using identical acquisition and reconstruction parameters. Sites of disease were segmented and a set of 29 different radiomic parameters were assessed on both scans. We determined repeatability of quantification by using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland-Altman analysis. RESULTS: In total, 230 lesions (177 bone, 38 lymph nodes, 15 others) were assessed on both scans. For all investigated radiomic features, a broad range of inter-scan correlation was found (r, 0.07-0.95), with acceptable reproducibility for entropy and homogeneity (wCOV, 16.0% and 12.7%, respectively). On Bland-Altman analysis, no systematic increase or decrease between the scans was observed for either parameter (±1.96 SD: 1.07/-1.30, 0.23/-0.18, respectively). The remaining 27 tested radiomic metrics, however, achieved unacceptable high wCOV (≥21.7%). CONCLUSION: Many common radiomic features derived from a test-retest PET study had poor repeatability. Only Entropy and homogeneity achieved good repeatability, supporting the notion that those image biomarkers may be incorporated in future clinical trials. Those radiomic features based on high frequency aspects of images appear to lack the repeatability on PET to justify further study.

Phase II Randomized Study of Salvage Radiation Therapy Plus Enzalutamide or Placebo for High-Risk Prostate-Specific Antigen Recurrent Prostate Cancer After Radical Prostatectomy: The SALV-ENZA Trial.

PURPOSE: We sought to investigate whether enzalutamide (ENZA), without concurrent androgen deprivation therapy, increases freedom from prostate-specific antigen (PSA) progression (FFPP) when combined with salvage radiation therapy (SRT) in men with recurrent prostate cancer after radical prostatectomy (RP). PATIENTS AND METHODS: Men with biochemically recurrent prostate cancer after RP were enrolled into a randomized, double-blind, phase II, placebo-controlled, multicenter study of SRT plus ENZA or placebo (ClinicalTrials.gov identifier: NCT02203695). Random assignment (1:1) was stratified by center, surgical margin status (R0 v R1), PSA before salvage treatment (PSA ≥ 0.5 v < 0.5 ng/mL), and pathologic Gleason sum (7 v 8-10). Patients were assigned to receive either ENZA 160 mg once daily or matching placebo for 6 months. After 2 months of study drug therapy, external-beam radiation (66.6-70.2 Gy) was administered to the prostate bed (no pelvic nodes). The primary end point was FFPP in the intention-to-treat population. Secondary end points were time to local recurrence within the radiation field, metastasis-free survival, and safety as determined by frequency and severity of adverse events. RESULTS: Eighty-six (86) patients were randomly assigned, with a median follow-up of 34 (range, 0-52) months. Trial arms were well balanced. The median pre-SRT PSA was 0.3 (range, 0.06-4.6) ng/mL, 56 of 86 patients (65%) had extraprostatic disease (pT3), 39 of 86 (45%) had a Gleason sum of 8-10, and 43 of 86 (50%) had positive surgical margins (R1). FFPP was significantly improved with ENZA versus placebo (hazard ratio [HR], 0.42; 95% CI, 0.19 to 0.92; P = .031), and 2-year FFPP was 84% versus 66%, respectively. Subgroup analyses demonstrated differential benefit of ENZA in men with pT3 (HR, 0.22; 95% CI, 0.07 to 0.69) versus pT2 disease (HR, 1.54; 95% CI, 0.43 to 5.47; Pinteraction = .019) and R1 (HR, 0.14; 95% CI, 0.03 to 0.64) versus R0 disease (HR, 1.00; 95% CI, 0.36 to 2.76; Pinteraction = .023). There were insufficient secondary end point events for analysis. The most common adverse events were grade 1-2 fatigue (65% ENZA v 53% placebo) and urinary frequency (40% ENZA v 49% placebo). CONCLUSION: SRT plus ENZA monotherapy for 6 months in men with PSA-recurrent high-risk prostate cancer after 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.

Neutropenia, neutrophilia, and neutrophil-lymphocyte ratio as prognostic markers in patients with metastatic castration-resistant prostate cancer.

Background and purpose: Chemotherapy-induced neutropenia and neutrophil-to-lymphocyte ratio (NLR) are potentially useful prognostic markers in patients with metastatic castration-resistant prostate cancer (mCRPC). This post hoc analysis investigated whether these markers can be utilized for dose considerations and evaluated the prognostic impact of leukocyte subtypes. Patients and methods: PROSELICA assessed the non-inferiority of cabazitaxel 20 mg/m2 (C20; n = 598) versus 25 mg/m2 (C25; n = 602) for overall survival (OS) in patients with mCRPC previously treated with docetaxel. The association of grade ⩾ 3 neutropenia, NLR, baseline neutrophilia and lymphopenia with OS, progression-free survival (PFS), and prostate-specific antigen response rate (PSArr) was investigated by an unplanned uni- and multivariate analyses. Results: PROSELICA confirmed the negative prognostic value of increased baseline NLR [⩾3, hazard ratio (HR) 1.40; p < 0.0001], but did not identify a subgroup of patients benefiting more from C20 or C25. In this post hoc analysis, patients who developed grade ⩾3 neutropenia (n = 673) had a significantly improved OS [∆OS = 2.7 months, HR = 0.78 (95% CI 0.68-0.89)] with the greatest advantage observed in patients with baseline neutrophilia [n = 85; 5.3 months, 0.60 (0.42-0.84)]. After adjustment for the Halabi criteria, neutropenia grade ⩾ 3 was the only biomarker that remained significantly associated with OS [ (HR 0.86 (0.75-0.98)], PFS [HR 0.78 (0.68-0.88)], and PSArr [odds ratio (OR) 1.82 (1.37-2.41)] while neutrophilia showed the strongest association with OS [1.53 (1.29-1.81)]. Conclusions: Grade ⩾ 3 neutropenia was the only leukocyte-based biomarker associated with all key outcome parameters in mCRPC patients receiving cabazitaxel and might be able to overcome the negative prognostic effect of baseline neutrophilia. NCT number: NCT01308580.

Association between baseline body mass index and survival in men with metastatic hormone-sensitive prostate cancer: ECOG-ACRIN CHAARTED E3805.

BACKGROUND: E3805 (CHAARTED) is a phase 3 trial demonstrating improved survival for men with metastatic hormone-sensitive prostate cancer (mHSPC) randomized to treatment with docetaxel (D) and androgen-deprivation therapy (ADT) versus ADT alone. We assessed the association of baseline body mass index (BMI) and metformin exposure with quality of life (QOL) and prostate cancer outcomes including survival in patients enrolled in the CHAARTED study. METHODS: We performed a posthoc exploratory analysis of the CHAARTED trial of men with mHSPC randomized to treatment with ADT with or without D between 2006 and 2012. Cox proportional hazards models and Kruskal-Wallis test were used to evaluate the association between BMI with QOL and prostate cancer outcomes and between metformin exposure and survival. RESULTS: In 788 of 790 enrolled patients with prospectively recorded baseline BMI and metformin exposure status, lower BMI was not associated with survival, but was associated with high volume disease (p < 0.0001) and poorer baseline QOL on functional assessment of cancer therapy-prostate (p = 0.008). Only 68 patients had prevalent metformin exposure at baseline in the CHAARTED trial. Four groups were identified: ADT + D + metformin (n = 39); ADT + D (n = 357); ADT + metformin (n = 29); and ADT alone (n = 363). Baseline clinicopathologic characteristics were similar between groups. In this small exploratory multivariable analysis, metformin exposure was not associated with survival (hazard ratio: 1.15; 95% confidence interval: 0.81-1.63, p = 0.44). CONCLUSIONS: There was no link between baseline BMI and survival, but lower baseline BMI was associated with features of greater cancer burden and poorer QOL.

A Phase Ib/II Study of Sabizabulin, a Novel Oral Cytoskeleton Disruptor, in Men with Metastatic Castration-resistant Prostate Cancer with Progression on an Androgen Receptor-targeting Agent.

PURPOSE: Sabizabulin, an oral cytoskeleton disruptor, was tested in a phase Ib/II clinical study in men with metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: The phase Ib portion utilized a 3+3 design with escalating daily oral doses of 4.5-81 mg and increasing schedule in 39 patients with mCRPC treated with one or more androgen receptor-targeting agents. Prior taxane chemotherapy was allowed. The phase II portion tested a daily dose of 63 mg in 41 patients with no prior chemotherapy. Efficacy was assessed using PCWG3 and RECIST 1.1 criteria. RESULTS: The MTD was not defined in the phase Ib and the recommended phase II dose was set at 63 mg/day. The most common adverse events (>10% frequency) at the 63 mg oral daily dosing (combined phase Ib/II data) were predominantly grade 1-2 events. Grade ≥3 events included diarrhea (7.4%), fatigue (5.6%), and alanine aminotransferase/aspartate aminotransferase elevations (5.6% and 3.7%, respectively). Neurotoxicity and neutropenia were not observed. Preliminary efficacy data in patients treated with ≥1 continuous cycle of 63 mg or higher included objective response rate in 6 of 29 (20.7%) patients with measurable disease (1 complete, 5 partial) and 14 of 48 (29.2%) patients had PSA declines. The Kaplan-Meier median radiographic progression-free survival was estimated to be 11.4 months (n = 55). Durable responses lasting >2.75 years were observed. CONCLUSIONS: This clinical trial demonstrated that chronic oral daily dosing of sabizabulin has a favorable safety profile with preliminary antitumor activity. These data support the ongoing phase III VERACITY trial of sabizabulin in men with mCRPC.

High SUVs Have More Robust Repeatability in Patients with Metastatic Prostate Cancer: Results from a Prospective Test-Retest Cohort Imaged with 18F-DCFPyL.

Objectives: In patients with prostate cancer (PC) receiving prostate-specific membrane antigen- (PSMA-) targeted radioligand therapy (RLT), higher baseline standardized uptake values (SUVs) are linked to improved outcome. Thus, readers deciding on RLT must have certainty on the repeatability of PSMA uptake metrics. As such, we aimed to evaluate the test-retest repeatability of lesion uptake in a large cohort of patients imaged with 18F-DCFPyL. Methods: In this prospective, IRB-approved trial (NCT03793543), 21 patients with history of histologically proven PC underwent two 18F-DCFPyL PET/CTs within 7 days (mean 3.7, range 1 to 7 days). Lesions in the bone, lymph nodes (LN), and other organs were manually segmented on both scans, and uptake parameters were assessed (maximum (SUVmax) and mean (SUVmean) SUVs), PSMA-tumor volume (PSMA-TV), and total lesion PSMA (TL-PSMA, defined as PSMA - TV × SUVmean)). Repeatability was determined using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland-Altman analysis. Results: In total, 230 pairs of lesions (177 bone, 38 LN, and 15 other) were delineated, demonstrating a wide range of SUVmax (1.5-80.5) and SUVmean (1.4-24.8). Including all sites of suspected disease, SUVs had a strong interscan correlation (R 2 ≥ 0.99), with high repeatability for SUVmean and SUVmax (wCOV, 7.3% and 12.1%, respectively). High SUVs showed significantly improved wCOV relative to lower SUVs (P < 0.0001), indicating that high SUVs are more repeatable, relative to the magnitude of the underlying SUV. Repeatability for PSMA-TV and TL-PSMA, however, was low (wCOV ≥ 23.5%). Across all metrics for LN and bone lesions, interscan correlation was again strong (R 2 ≥ 0.98). Moreover, LN-based SUVmean also achieved the best wCOV (3.8%), which was significantly reduced when compared to osseous lesions (7.8%, P < 0.0001). This was also noted for SUVmax (wCOV, LN 8.8% vs. bone 12.0%, P < 0.03). On a compartment-based level, wCOVs for volumetric features were ≥22.8%, demonstrating no significant differences between LN and bone lesions (PSMA-TV, P =0.63; TL-PSMA, P =0.9). Findings on an entire tumor burden level were also corroborated in a hottest lesion analysis investigating the SUVmax of the most intense lesion per patient (R 2, 0.99; wCOV, 11.2%). Conclusion: In this prospective test-retest setting, SUV parameters demonstrated high repeatability, in particular in LNs, while volumetric parameters demonstrated low repeatability. Further, the large number of lesions and wide distribution of SUVs included in this analysis allowed for the demonstration of a dependence of repeatability on SUV, with higher SUVs having more robust repeatability.

Combined Longitudinal Clinical and Autopsy Phenomic Assessment in Lethal Metastatic Prostate Cancer: Recommendations for Advancing Precision Medicine.

BACKGROUND: Systematic identification of data essential for outcome prediction in metastatic prostate cancer (mPC) would accelerate development of precision oncology. OBJECTIVE: To identify novel phenotypes and features associated with mPC outcome, and to identify biomarker and data requirements to be tested in future precision oncology trials. DESIGN SETTING AND PARTICIPANTS: We analyzed deep longitudinal clinical, neuroendocrine expression, and autopsy data of 33 men who died from mPC between 1995 and 2004 (PELICAN33), and related findings to mPC biomarkers reported in the literature. INTERVENTION: Thirty-three men prospectively consented to participate in an integrated clinical-molecular rapid autopsy study of mPC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Data exploration with correction for multiple testing and survival analysis from the time of diagnosis to time to death and time to first occurrence of severe pain as outcomes were carried out. The effect of seven complications on the modeled probability of dying within 2 yr after presenting with the complication was evaluated using logistic regression. RESULTS AND LIMITATIONS: Feature exploration revealed novel phenotypes related to mPC outcome. Four complications (pleural effusion, severe anemia, severe or controlled pain, and bone fracture) predict the likelihood of death within 2 yr. Men with Gleason grade group 5 cancers developed severe pain sooner than those with lower-grade tumors. Surprisingly, neuroendocrine (NE) differentiation was frequently observed in the setting of high serum prostate-specific antigen (PSA) levels (≥30 ng/ml). In 4/33 patients, no controlled (requiring analgesics) or severe pain was detected, and strikingly, 14/15 metastatic sites studied in these men did not express NE markers, suggesting an inverse relationship between NE differentiation and pain in mPC. Intracranial subdural metastasis is common (36%) and is usually clinically undetected. Categorization of "skeletal-related events" complications used in recent studies likely obscures the understanding of spinal cord compression and fracture. Early death from prostate cancer was identified in a subgroup of men with a low longitudinal PSA bandwidth. Cachexia is common (body mass index <0.89 in 24/31 patients) but limited to the last year of life. Biomarker review identified 30 categories of mPC biomarkers in need of winnowing in future trials. All findings require validation in larger cohorts, preferably alongside data from this study. CONCLUSIONS: The study identified novel outcome subgroups for future validation and provides "vision for mPC precision oncology 2020-2050" draft recommendations for future data collection and biomarker studies. PATIENT SUMMARY: To better understand variation in metastatic prostate cancer behavior, we assembled and analyzed longitudinal clinical and autopsy records in 33 men. We identified novel outcomes, phenotypes, and aspects of disease burden to be tested and refined in future trials.

Elucidating Prostate Cancer Behaviour During Treatment via Low-pass Whole-genome Sequencing of Circulating Tumour DNA.

BACKGROUND: Better blood tests to elucidate the behaviour of metastatic castration-resistant prostate cancer (mCRPC) are urgently needed to drive therapeutic decisions. Plasma cell-free DNA (cfDNA) comprises normal and circulating tumour DNA (ctDNA). Low-pass whole-genome sequencing (lpWGS) of ctDNA can provide information on mCRPC behaviour. OBJECTIVE: To validate and clinically qualify plasma lpWGS for mCRPC. DESIGN, SETTING, AND PARTICIPANTS: Plasma lpWGS data were obtained for mCRPC patients consenting to optional substudies of two prospective phase 3 trials (FIRSTANA and PROSELICA). In FIRSTANA, chemotherapy-naïve patients were randomised to treatment with docetaxel (75 mg/m2) or cabazitaxel (20 or 25 mg/m2). In PROSELICA, patients previously treated with docetaxel were randomised to 20 or 25 mg/m2 cabazitaxel. lpWGS data were generated from 540 samples from 188 mCRPC patients acquired at four different time points (screening, cycle 1, cycle 4, and end of study). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: lpWGS data for ctDNA were evaluated for prognostic, response, and tumour genomic measures. Associations with response and survival data were determined for tumour fraction. Genomic biomarkers including large-scale transition (LST) scores were explored in the context of prior treatments. RESULTS AND LIMITATIONS: Plasma tumour fraction was prognostic for overall survival in univariable and stratified multivariable analyses (hazard ratio 1.75, 95% confidence interval 1.08-2.85; p = 0.024) and offered added value compared to existing biomarkers (C index 0.722 vs 0.709; p = 0.021). Longitudinal changes were associated with drug response. PROSELICA samples were enriched for LSTs (p = 0.029) indicating genomic instability, and this enrichment was associated with prior abiraterone and enzalutamide treatment but not taxane or radiation therapy. Higher LSTs were correlated with losses of RB1/RNASEH2B, independent of BRCA2 loss. CONCLUSIONS: Plasma lpWGS of ctDNA describes CRPC behaviour, providing prognostic and response data of clinical relevance. The added prognostic value of the ctDNA fraction over established biomarkers should be studied further. PATIENT SUMMARY: We studied tumour DNA in blood samples from patients with prostate cancer. We found that levels of tumour DNA in blood were indicative of disease prognosis, and that changes after treatment could be detected. We also observed a "genetic scar" in the results that was associated with certain previous treatments. This test allows an assessment of tumour activity that can complement existing tests, offer insights into drug response, and detect clinically relevant genetic changes.

Timing of Androgen Deprivation Treatment for Men with Biochemical Recurrent Prostate Cancer in the Context of Novel Therapies.

PURPOSE: There were 3 recent U.S. Food and Drug Administration approvals for drugs to be used in nonmetastatic castration resistant prostate cancer, a state that arises from the unproven start of continuous androgen deprivation therapy (ADT) for biochemical recurrent prostate cancer (BCR), before metastatic disease is evident. This report examines the outcome of men with BCR who defer ADT until time of metastasis. MATERIALS AND METHODS: Retrospective review of men diagnosed with clinically localized prostate cancer who underwent radical prostatectomy at Johns Hopkins Hospital and Walter Reed National Military Medical Center and developed BCR with a prostate specific antigen doubling time of not more than 10 months (806 patients). The primary end points were metastasis-free survival and overall survival from time of local treatment among men who delayed ADT until time of metastasis. RESULTS: The median metastasis-free survival of men with BCR and a prostate specific antigen doubling time <6 months and 10 months who delay ADT until metastasis is 144 months (95% CI 48-not reached) and 192 months (95% CI 72-not reached), respectively, with a median overall survival of 168 months (95% CI 96-276 months) and 204 months (95% CI 120-276), respectively. CONCLUSIONS: Metastasis-free survival and overall survival of men with BCR who delay hormone therapy is long. This underscores the need to reevaluate when to start primary ADT in this patient population.

Pain Progression at Initiation of Cabazitaxel in Metastatic Castration-Resistant Prostate Cancer (mCRPC): A Post Hoc Analysis of the PROSELICA Study.

BACKGROUND: In the PROSELICA phase III trial (NCT01308580), cabazitaxel 20 mg/m2 (CABA20) was non-inferior to cabazitaxel 25 mg/m2 (CABA25) in mCRPC patients previously treated with docetaxel (DOC). The present post hoc analysis evaluates how the type of progression at randomization affected outcomes. METHODS: Progression type at randomization was defined as follows: PSA progression only (PSA-p; no radiological progression (RADIO-p), no pain), RADIO-p (±PSA-p, no pain), or pain progression (PAIN-p, ±PSA-p, ±RADIO-p). Relationships between progression type and overall survival (OS), radiological progression-free survival (rPFS), and PSA response (confirmed PSA decrease ≥ 50%) were analyzed. RESULTS: All randomized patients (n = 1200) had received prior DOC, and 25.7% had received prior abiraterone or enzalutamide. Progression type at randomization was evaluable in 1075 patients (PSA-p = 24.4%, RADIO-p = 20.8%, PAIN-p = 54.8%). Pain progression was associated with clinical and biological features of aggressive disease. Median OS from CABA initiation or date of mCRPC diagnosis, all arms combined, was shorter in the PAIN-p group than in the RADIO-p or the PSA-p groups (12.0 versus 16.8 and 18.4 months, respectively, p < 0.001). In multivariate analysis, all arms combined, PAIN-p was an independent predictor of poor OS (HR = 1.44, p < 0.001). PSA response, rPFS, and OS were numerically higher with CABA25 versus CABA20 in patients with PAIN-p. CONCLUSIONS: This post hoc analysis of the PROSELICA phase III study shows that pain progression at initiation of CABA in mCRPC patients previously treated with DOC is associated with a poor prognosis. Disease progression should be carefully monitored, even in the absence of PSA rise.

Post Hoc Health-Related Quality of Life Analysis According to Response Among Patients with Prostate Cancer in the PROSELICA and FIRSTANA Studies.

BACKGROUND: The phase III PROSELICA (NCT01308580) and FIRSTANA (NCT01308567) trials investigated taxane chemotherapy among men with postdocetaxel metastatic, castration-resistant prostate cancer (mCRPC) or chemotherapy-naïve mCRPC, respectively. We present a post hoc analysis of patient-reported health-related quality of life (HRQL) among patients with or without a clinical (pain, tumor, or prostate-specific antigen [PSA]) response. MATERIALS AND METHODS: PROSELICA and FIRSTANA HRQL and pain data were collected and analyzed using protocol-defined Functional Assessment of Cancer Therapy-Prostate (FACT-P) and McGill-Melzack (Present Pain Intensity scale) questionnaires. Outcomes included definitive FACT-P Total Score (TS) improvements and longitudinal assessment of FACT-P TS. RESULTS: In PROSELICA and FIRSTANA, the proportion of patients receiving taxane chemotherapy with a definitive FACT-P TS improvement was significantly higher among patients with versus without a pain or PSA response (pain: PROSELICA: 67% vs. 33.5%; p < .001; FIRSTANA: 75.2% vs. 45.8%; p < .001; PSA: PROSELICA: 50.3% vs. 34.2%; p < .001; FIRSTANA: 49.8% vs. 38.9%; p = .001). In PROSELICA, the proportion of patients receiving taxane chemotherapy with a definitive FACT-P TS improvement was significantly higher among patients with versus without a tumor response; the proportion was numerically higher in FIRSTANA (PROSELICA: 54.4% vs. 36.7%; p = .001; FIRSTANA: 50.6% vs. 45.3%). FACT-P TS was significantly improved or maintained for the majority of treatment cycles analyzed. CONCLUSION: In PROSELICA and FIRSTANA, HRQL improvements were significantly higher among patients with a pain, tumor, or PSA response versus those without, with the exception of patients with a tumor response in FIRSTANA. IMPLICATIONS FOR PRACTICE: Using data from the FIRSTANA and PROSELICA phase III clinical trials, this study demonstrated that patients with metastatic, castration-resistant prostate cancer (mCRPC) receiving docetaxel or cabazitaxel who exhibited a response (pain, tumor, prostate-specific antigen), often experienced significantly greater improvements in health-related quality of life (HRQL) compared with patients without a response. For patients with a pain response, significant HRQL improvements occurred early and were maintained. This study provides further insight into the impact of taxane chemotherapy on the HRQL of patients with mCRPC and allows for a better understanding of the relationship between treatment, response, and HRQL, supporting therapeutic decision making.

Prospective, Single-Arm Trial Evaluating Changes in Uptake Patterns on Prostate-Specific Membrane Antigen-Targeted 18F-DCFPyL PET/CT in Patients with Castration-Resistant Prostate Cancer Starting Abiraterone or Enzalutamide.

PET with small molecules targeting prostate-specific membrane antigen (PSMA) is being adopted as a clinical standard for prostate cancer imaging. In this study, we evaluated changes in uptake on PSMA-targeted PET in men starting abiraterone or enzalutamide. Methods: This prospective, single-arm, 2-center, exploratory clinical trial enrolled men with metastatic castration-resistant prostate cancer initiating abiraterone or enzalutamide. Each patient was imaged with 18F-DCFPyL at baseline and within 2-4 mo after starting therapy. Patients were followed for up to 48 mo from enrollment. A central review evaluated baseline and follow-up PET scans, recording change in SUVmax at all disease sites and classifying the pattern of change. Two parameters were derived: the δ-percent SUVmax (DPSM) of all lesions and the δ-absolute SUVmax (DASM) of all lesions. Kaplan-Meier curves were used to estimate time to therapy change (TTTC) and overall survival (OS). Results: Sixteen evaluable patients were accrued to the study. Median TTTC was 9.6 mo (95% CI, 6.9-14.2), and median OS was 28.6 mo (95% CI, 18.3-not available [NA]). Patients with a mixed-but-predominantly-increased pattern of radiotracer uptake had a shorter TTTC and OS. Men with a low DPSM had a median TTTC of 12.2 mo (95% CI, 11.3-NA) and a median OS of 37.2 mo (95% CI, 28.9-NA), whereas those with a high DPSM had a median TTTC of 6.5 mo (95% CI, 4.6-NA, P = 0.0001) and a median OS of 17.8 mo (95% CI, 13.9-NA, P = 0.02). Men with a low DASM had a median TTTC of 12.2 mo (95% CI, 11.3-NA) and a median OS of NA (95% CI, 37.2 mo-NA), whereas those with a high DASM had a median TTTC of 6.9 mo (95% CI, 6.1-NA, P = 0.003) and a median OS of 17.8 mo (95% CI, 13.9-NA, P = 0.002). Conclusion: Findings on PSMA-targeted PET 2-4 mo after initiation of abiraterone or enzalutamide are associated with TTTC and OS. Development of new lesions or increasing intensity of radiotracer uptake at sites of baseline disease are poor prognostic findings suggesting shorter TTTC and OS.

TRANSFORMER: A Randomized Phase II Study Comparing Bipolar Androgen Therapy Versus Enzalutamide in Asymptomatic Men With Castration-Resistant Metastatic Prostate Cancer.

PURPOSE: Prostate cancer (PCa) becomes resistant to androgen ablation through adaptive upregulation of the androgen receptor in response to the low-testosterone microenvironment. Bipolar androgen therapy (BAT), defined as rapid cycling between high and low serum testosterone, disrupts this adaptive regulation in castration-resistant PCa (CRPC). METHODS: The TRANSFORMER (Testosterone Revival Abolishes Negative Symptoms, Fosters Objective Response and Modulates Enzalutamide Resistance) study is a randomized study comparing monthly BAT (n = 94) with enzalutamide (n = 101). The primary end point was clinical or radiographic progression-free survival (PFS); crossover was permitted at progression. Secondary end points included overall survival (OS), prostate-specific antigen (PSA) and objective response rates, PFS from randomization through crossover (PFS2), safety, and quality of life (QoL). RESULTS: The PFS was 5.7 months for both arms (hazard ratio [HR], 1.14; 95% CI, 0.83 to 1.55; P = .42). For BAT, 50% decline in PSA (PSA50) was 28.2% of patients versus 25.3% for enzalutamide. At crossover, PSA50 response occurred in 77.8% of patients crossing to enzalutamide and 23.4% to BAT. The PSA-PFS for enzalutamide increased from 3.8 months after abiraterone to 10.9 months after BAT. The PFS2 for BAT→enzalutamide was 28.2 versus 19.6 months for enzalutamide→BAT (HR, 0.44; 95% CI, 0.22 to 0.88; P = .02). OS was 32.9 months for BAT versus 29.0 months for enzalutamide (HR, 0.95; 95% CI, 0.66 to 1.39; P = .80). OS was 37.1 months for patients crossing from BAT to enzalutamide versus 30.2 months for the opposite sequence (HR, 0.68; 95% CI, 0.36 to 1.28; P = .225). BAT adverse events were primarily grade 1-2. Patient-reported QoL consistently favored BAT. CONCLUSION: This randomized trial establishes meaningful clinical activity and safety of BAT and supports additional study to determine its optimal clinical integration. BAT can sensitize CRPC to subsequent antiandrogen therapy. Further study is required to confirm whether sequential therapy with BAT and enzalutamide can improve survival in men with CRPC.

Nivolumab plus ipilimumab, with or without enzalutamide, in AR-V7-expressing metastatic castration-resistant prostate cancer: A phase-2 nonrandomized clinical trial.

BACKGROUND: AR-V7-positive metastatic prostate cancer is a lethal phenotype with few treatment options and poor survival. METHODS: The two-cohort nonrandomized Phase 2 study of combined immune checkpoint blockade for AR-V7-expressing metastatic castration-resistant prostate cancer (STARVE-PC) evaluated nivolumab (3 mg/kg) plus ipilimumab (1 mg/kg), without (Cohort 1) or with (Cohort 2) the anti-androgen enzalutamide. Co-primary endpoints were safety and prostate-specific antigen (PSA) response rate. Secondary endpoints included time-to-PSA-progression-free survival (PSA-PFS), time-to-clinical/radiographic-PFS, objective response rate (ORR), PFS lasting greater than 24 weeks, and overall survival (OS). RESULTS: Thirty patients were treated with ipilimumab plus nivolumab (N = 15, Cohort 1, previously reported), or ipilimumab plus nivolumab and enzalutamide (N = 15, Cohort 2) in patients previously progressing on enzalutamide monotherapy. PSA response rate was 2/15 (13%) in cohort 1 and 0/15 in cohort 2, ORR was 2/8 (25%) in Cohort 1 and 0/9 in Cohort 2 in those with measureable disease, median PSA-PFS was 3.0 (95% confidence interval [CI]: 2.1-NR) in cohort 1 and 2.7 (95% CI: 2.1-5.9) months in cohort 2, and median PFS was 3.7 (95% CI: 2.8-7.5) in cohort 1 and 2.9 (95% CI: 1.3-5.8) months in cohort 2. Three of 15 patients in cohort 1 (20%, 95% CI: 7.1%-45.2%) and 4/15 patients (26.7%, 95% CI: 10.5%-52.4%) in cohort 2 achieved a durable PFS lasting greater than 24 weeks. Median OS was 8.2 (95% CI: 5.5-10.4) in cohort 1 and 14.2 (95% CI: 8.5-NA) months in cohort 2. Efficacy results were not statistically different between cohorts. Grade-3/4 adverse events occurred in 7/15 cohort 1 patients (46%) and 8/15 cohort 2 patients (53%). Combined cohort (N = 30) baseline alkaline phosphatase and cytokine analysis suggested improved OS for patients with lower alkaline phosphatase (hazards ratio [HR], 0.30; 95% CI: 0.11-0.82), lower circulating interleukin-7 (IL-7) (HR, 0.24; 95% Cl: 0.06-0.93) and IL-6 (HR, 0.13; 95% Cl: 0.03-0.52) levels, and higher circulating IL-17 (HR, 4.53; 95% CI: 1.47-13.93) levels. There was a trend towards improved outcomes in men with low sPD-L1 serum levels. CONCLUSION: Nivolumab plus ipilimumab demonstrated only modest activity in patients with AR-V7-expressing prostate cancer, and was not sufficient to justify further exploration in unselected patients. Stratification by baseline alkaline phosphatase and cytokines (IL-6, -7, and -17) may be prognostic for outcomes to immunotherapy.

Detection of Early Progression with 18F-DCFPyL PET/CT in Men with Metastatic Castration-Resistant Prostate Cancer Receiving Bipolar Androgen Therapy.

Bipolar androgen therapy (BAT) is an emerging treatment for metastatic castration-resistant prostate cancer (mCRPC). 18F-DCFPyL is a small-molecule PET radiotracer targeting prostate-specific membrane antigen (PSMA). We analyzed the utility of 18F-DCFPyL PET/CT in determining clinical response to BAT. Methods: Six men with mCRPC receiving BAT were imaged with 18F-DCFPyL PET/CT at baseline and after 3 mo of treatment. Progression by PSMA-targeted PET/CT was defined as the appearance of any new 18F-DCFPyL-avid lesion. Results: Three of 6 (50%) patients had progression on 18F-DCFPyL PET/CT. All 3 had stable disease or better on contemporaneous conventional imaging. Radiographic progression on CT or bone scanning was observed within 3 mo of progression on 18F-DCFPyL PET/CT. For the 3 patients who did not have progression on 18F-DCFPyL PET/CT, radiographic progression was not observed for at least 6 mo. Conclusion: New radiotracer-avid lesions on 18F-DCFPyL PET/CT in men with mCRPC undergoing BAT can indicate early progression.

The Mutational Landscape of Metastatic Castration-sensitive Prostate Cancer: The Spectrum Theory Revisited.

BACKGROUND: Emerging data suggest that metastasis is a spectrum of disease burden rather than a binary state, and local therapies, such as radiation, might improve outcomes in oligometastasis. However, current definitions of oligometastasis are solely numerical. OBJECTIVE: To characterize the somatic mutational landscape across the disease spectrum of metastatic castration-sensitive prostate cancer (mCSPC) to elucidate a biological definition of oligometastatic CSPC. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective study of men with mCSPC who underwent clinical-grade sequencing of their tumors (269 primary tumor, 25 metastatic sites). Patients were classified as having biochemically recurrent (ie, micrometastatic), metachronous oligometastatic (≤5 lesions), metachronous polymetastatic (>5 lesions), or de novo metastatic (metastasis at diagnosis) disease. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We measured the frequency of driver mutations across metastatic classifications and the genomic associations with radiographic progression-free survival (rPFS) and time to castrate-resistant prostate cancer (CRPC). RESULTS AND LIMITATIONS: The frequency of driver mutations in TP53 (p = 0.01), WNT (p = 0.08), and cell cycle (p = 0.04) genes increased across the mCSPC spectrum. TP53 mutation was associated with shorter rPFS (26.7 vs 48.6 mo; p = 0.002), and time to CRPC (95.6 vs 155.8 mo; p = 0.02) in men with oligometastasis, and identified men with polymetastasis with better rPFS (TP53 wild-type, 42.7 mo; TP53 mutated, 18.5 mo; p = 0.01). Mutations in TP53 (incidence rate ratio [IRR] 1.45; p = 0.004) and DNA double-strand break repair (IRR 1.61; p < 0.001) were associated with a higher number of metastases. Mutations in TP53 were also independently associated with shorter rPFS (hazard ratio [HR] 1.59; p = 0.03) and the development of CRPC (HR 1.71; p = 0.01) on multivariable analysis. This study was limited by its retrospective nature, sample size, and the use of commercially available sequencing platforms, resulting in a limited predefined set of genes examined. CONCLUSIONS: Somatic mutational profiles reveal a spectrum of metastatic biology that helps in redefining oligometastasis beyond a simple binary state of lesion enumeration. PATIENT SUMMARY: Oligometastatic prostate cancer is typically defined as less than three to five metastatic lesions and evidence suggests that using radiation or surgery to treat these sites improves clinical outcomes. As of now, treatment decisions for oligometastasis are solely defined according to the number of lesions. However, this study suggests that tumor mutational profiles can provide a biological definition of oligometastasis and complement currently used numerical definitions.

Bipolar androgen therapy sensitizes castration-resistant prostate cancer to subsequent androgen receptor ablative therapy.

BACKGROUND: Cyclical, high-dose testosterone administration, termed bipolar androgen therapy (BAT), can induce clinical responses and restore sensitivity to androgen signalling inhibition in patients with previously treated castration-resistant prostate cancer (PCa) (CRPC). This trial evaluated whether BAT is a safe and effective first-line hormonal therapy for patients with CRPC. PATIENTS AND METHODS: In cohort C of this single-centre, open-label, phase II, multi-cohort trial (RE-sensitizing with Supraphysiologic Testosterone to Overcome REsistance study), 29 patients with CRPC received first-line hormonal therapy with 400 mg of testosterone cypionate intramuscularly every 28 days concurrent with a luteinising hormone-releasing hormone agonist/antagonist. The primary end-point of the study was the PSA50 response rate to BAT treatment. RESULTS: After treatment with BAT, four of 29 patients (14%; 95% confidence interval [CI]: 4-32%) experienced a PSA50 response. The median radiographic progression-free survival to BAT was 8.5 months (95% CI: 6.9-15.1) for patients with metastatic CRPC. After progression on BAT, 17 of 18 patients (94%; 95% CI: 73-100%) achieved a PSA50 response and 15 of 18 patients (83%; 95% CI: 59-96) achieved a PSA90 response on abiraterone or enzalutamide. Twelve of 15 patients (80%; 95% CI: 52-96) with metastatic CRPC remain on abiraterone or enzalutamide with a median duration of follow-up of 11.2 months. CONCLUSION: As first-line hormonal treatment for CRPC, BAT was well tolerated and resulted in prolonged disease stabilisation. After progression on BAT, patients had favourable responses to second-generation androgen receptor-targeted therapy. TRIAL REGISTRATION: ClinicalTrials.gov NCT02090114.