Effectiveness of the internet-based Unified Protocol transdiagnostic intervention for the treatment of depression, anxiety and related disorders in a primary care setting: a randomized controlled trial

Background

Research has shown that internet-based cognitive behavioural therapy (iCBT) can be a very promising solution to increase access to and the dissemination of evidence-based treatments to all of the population in need. However, iCBT is still underutilized in clinical contexts, such as primary care. In order to achieve the effective implementation of these protocols, more studies in ecological settings are needed. The Unified Protocol (UP) is a transdiagnostic CBT protocol for the treatment of emotional disorders, which includes depression, anxiety and related disorders, that has shown its efficacy across different contexts and populations. An internet-based UP (iUP) programme has recently been developed as an emerging internet-based treatment for emotional disorders. However, the internet-delivered version of the UP (iUP) has not yet been examined empirically. The current project seeks to analyse the effectiveness of the iUP as a treatment for depression, anxiety and related emotional disorders in a primary care public health setting.

Methods

The current study will employ a parallel-group, randomized controlled trial design. Participants will be randomly assigned to (a) the internet-based Unified Protocol (iUP), or (b) enhanced waiting list control (eWLC). Randomization will follow a 2:1 allocation ratio, with sample size calculations suggesting a required sample of 120 (iUP=80; eWLC=40). The Mini-International Neuropsychiatric Interview (M.I.N.I.) will be used for assessing potential participants. The Overall Anxiety Severity and Impairment Scale (OASIS) and the Overall Depression Severity and Impairment Scale (ODSIS) as well as other standardized questionnaires will be used for assessments at baseline, 4 weeks, 8 weeks and 12 weeks from baseline and for the iUP condition during the follow-up.

Discussion

Combining the advantages of a transdiagnostic treatment with an online delivery format may have the potential to significantly lower the burden of emotional disorders in public health primary care setting. Anxiety and depression, often comorbid, are the most prevalent psychological disorders in primary care. Because the iUP allows for the treatment of different disorders and comorbidity, this treatment could represent an adequate choice for patients that demand mental health care in a primary care setting.

Trial registration

ISRCTN18056450 10.1186/ISRCTN18056450.

Reproducibility of outcomes in sequential trials using CMV-targeted dendritic cell vaccination for glioblastoma

2005

Background: Vaccination with dendritic cells (DCs) fares poorly in primary and recurrent glioblastoma (GBM). Moreover, GBM vaccine trials are often underpowered due to limited sample size. Methods: To address these limitations, we conducted three sequential clinical trials utilizing Cytomegalovirus (CMV)-specific DC vaccines in patients with newly diagnosed GBM eligible to receive standard of care resection and adjuvant radiation therapy and temozolomide chemotherapy. Autologous DCs were generated and electroporated with mRNA encoding for the CMV protein pp65. Serial vaccination was given throughout adjuvant temozolomide cycles, and 111Indium radiolabeling was implemented to assess migration efficiency of DC vaccines. Patients were followed for median overall survival (mOS) and OS. Results: Our initial study was the phase II ATTAC study (NCT00639639; total n = 12) with 6 patients randomized to vaccine site preconditioning with tetanus-diphtheria (Td) toxoid. This led to an expanded cohort trial (ATTAC-GM; NCT00639639) of 11 patients receiving CMV DC vaccines containing granulocyte-macrophage colony-stimulating factor (GM-CSF). Follow-up data from ATTAC and ATTAC-GM revealed 5-year OS rates of 33.3% (mOS 38.3 months; CI95 17.5-undefined) and 36.4% (mOS 37.7 months; CI95 18.2-109.1), respectively. ATTAC additionally revealed a significant increase in DC migration to draining lymph nodes following Td preconditioning ( P = 0.049). Increased DC migration was associated with OS (Cox proportional hazards model, HR = 0.820, P = 0.023). Td-mediated increased migration has been recapitulated in our larger confirmatory trial ELEVATE (NCT02366728) of 43 patients randomized to preconditioning (Wilcoxon rank sum, Td n = 24, unpulsed DC n = 19; 24h, P = 0.031 and 48h, P = 0.0195). In ELEVATE, median follow-up of 42.2 months revealed significantly longer OS in patients randomized to Td ( P = 0.026). The 3-year OS for Td-treated patients in ELEVATE was 34% (CI95 19-63%) compared to 6% given unpulsed DCs (CI95 1-42%). Conclusions: We report reproducibility of our findings across three sequential clinical trials using CMV pp65 DCs. Despite their small numbers, these successive trials demonstrate consistent survival outcomes, thus supporting the efficacy of CMV DC vaccine therapy in GBM. Clinical trial information: NCT00639639, NCT02366728.

Innovating in a Crisis: A Qualitative Evaluation of a Hospital and Google Partnership to Implement a COVID-19 Inpatient Video Monitoring Program

Objective

To describe adaptations necessary for effective use of direct-to-consumer (DTC) cameras in an inpatient setting, from the perspective of health care workers.

Methods

Our qualitative study included semi-structured interviews and focus groups with clinicians, information technology (IT) personnel, and health system leaders affiliated with the Mount Sinai Health System. All participants either worked in a coronavirus disease 2019 (COVID-19) unit with DTC cameras or participated in the camera implementation. Three researchers coded the transcripts independently and met weekly to discuss and resolve discrepancies. Abiding by inductive thematic analysis, coders revised the codebook until they reached saturation. All transcripts were coded in Dedoose using the final codebook.

Results

Frontline clinical staff, IT personnel, and health system leaders (N = 39) participated in individual interviews and focus groups in November 2020–April 2021. Our analysis identified 5 areas for effective DTC camera use: technology, patient monitoring, workflows, interpersonal relationships, and infrastructure. Participants described adaptations created to optimize camera use and opportunities for improvement necessary for sustained use. Non-COVID-19 patients tended to decline participation.

Discussion

Deploying DTC cameras on inpatient units required adaptations in many routine processes. Addressing consent, 2-way communication issues, patient privacy, and messaging about video monitoring could help facilitate a nimble rollout. Implementation and dissemination of inpatient video monitoring using DTC cameras requires input from patients and frontline staff.

Conclusions

Given the resources and time it takes to implement a usable camera solution, other health systems might benefit from creating task forces to investigate their use before the next crisis.

Effects of low-dose naltrexone on quality of life in high-grade glioma patients: a placebo-controlled, double-blind randomized trial

PURPOSE

At diagnosis and throughout the disease course, patients with high-grade glioma (HGG) experience a diminished quality of life (QOL) and increased fatigue. Naltrexone, an orally semisynthetic opiate antagonist, is FDA-approved for the treatment of heroin/alcohol addiction, and low-dose naltrexone (LDN) has been observed to improve QOL and lower fatigue in other neurological illnesses, such as multiple sclerosis. LDN is believed to function as a partial agonist and can lead to shifts in neurochemicals that reduce fatigue. Based on this, we sought to study whether LDN has an impact on QOL and fatigue in patients with HGG.

METHODS

In a placebo-controlled, double-blind study, we randomized 110 HGG patients to receive placebo (N = 56) or LDN 4.5 mg orally at night (N = 54). Subjects received LDN or placebo at day 1 of concurrent radiation and temozolomide therapy and continued for 16 weeks. Change from baseline in patient-reported outcomes of QOL (Functional Assessment of Cancer Therapy-Brain) and fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue) was assessed.

RESULTS

Demographics were WHO grade IV (85%), male (56%), KPS 90-100 (51%), grossly resected (55%), and mean age of 56 years. QOL and fatigue changes between baseline and post concurrent chemotherapy and radiation therapy were not significantly different between patients receiving LDN or placebo. The adverse event profiles for LDN and placebo were similar and attributed to concomitant use of temozolomide.

CONCLUSIONS

LDN has no effect on QOL and fatigue in HGG patients during concurrent chemotherapy and radiation therapy.

TRIAL REGISTRATION

United States National Library of Medicine Clinical Trials.gov NCT01303835, Date 2/25/2011.

Phase II Trial of Enzalutamide and Androgen Deprivation Therapy with Salvage Radiation in Men with High-risk Prostate-specific Antigen Recurrent Prostate Cancer: The STREAM Trial

BACKGROUND

Salvage external beam radiotherapy (RT) with androgen deprivation therapy (ADT) improves survival over RT in men with prostate cancer (PC) and rising prostate-specific antigen (PSA) levels after radical prostatectomy (RP).

OBJECTIVE

To investigate the safety and efficacy of enzalutamide concurrent with salvage RT and ADT.

DESIGN, SETTING, AND PARTICIPANTS

This was a three-center prospective phase 2 single-arm trial (NCT02057939) of men with Gleason 7-10 PC and PSA recurrence within 4 yr of RP ranging from 0.2 to 4.0 ng/dl, no prior hormonal therapy, and no radiographic evidence of metastases. We enrolled 38 men; 37 completed therapy and were evaluable with testosterone recovery at 2 yr.

INTERVENTION

Six months of ADT with 160 mg/d enzalutamide and 66 Gy RT to the prostate bed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was improved 2-yr progression-free survival (PFS) over historical controls. Secondary objectives included 3-yr PFS, safety, and patient-reported quality of life (QOL).

RESULTS AND LIMITATIONS

The primary endpoint of 2-yr PFS was 65% (95% confidence interval [CI]: 47, 78) versus 51% (95% CI: 33, 67) in a trial of men with similar eligibility treated with salvage RT and adjuvant docetaxel. The 3-yr PFS was 53%. Eleven (29%) men experienced G3 toxicities, and there were no G4-5 or unexpected toxicities. QOL data suggest modest worsening of bowel, bladder, and hormonal symptoms at 3 mo, with recovery by 24 mo in most men.

CONCLUSIONS

Salvage RT with enzalutamide and ADT following RP for men with PSA recurrent high-risk PC is safe and demonstrates encouraging efficacy, warranting prospective controlled phase 3 trials of ADT with or without potent androgen receptor inhibition in this curative-intent setting.

PATIENT SUMMARY

Addition of 6 mo of oral daily enzalutamide to standard salvage radiation and hormone therapy is safe and may improve prostate cancer remission rates at 2 and 3 yr.

CTIM-10. REPRODUCIBILITY OF CLINICAL TRIALS USING CMV-TARGETED DENDRITIC CELL VACCINES IN PATIENTS WITH GLIOBLASTOMA

INTRODUCTION

Vaccination with dendritic cells (DCs) fares poorly in primary and recurrent glioblastoma (GBM). Moreover, GBM vaccine trials are often underpowered due to limited sample size.

METHODS

To address these limitations, we conducted three sequential clinical trials utilizing Cytomegalovirus (CMV)-specific DC vaccines in patients with primary GBM. Autologous DCs were generated and electroporated with mRNA encoding for the CMV protein pp65. Serial vaccination was given throughout adjuvant temozolomide cycles, and 111Indium radiolabeling was implemented to assess migration efficiency of DC vaccines. Patients were followed for median overall survival (mOS) and OS.

RESULTS

Our initial study was the phase II ATTAC study (NCT00639639; total n=12) with 6 patients randomized to vaccine site preconditioning with tetanus-diphtheria (Td) toxoid. This led to an expanded cohort trial (ATTAC-GM; NCT00639639) of 11 patients receiving CMV DC vaccines containing granulocyte-macrophage colony-stimulating factor (GM-CSF). Follow-up data from ATTAC and ATTAC-GM revealed 5-year OS rates of 33.3% (mOS 38.3 months; CI95 17.5-undefined) and 36.4% (mOS 37.7 months; CI95 18.2-109.1), respectively. ATTAC additionally revealed a significant increase in DC migration to draining lymph nodes following Td preconditioning (P=0.049). Increased DC migration was associated with OS (Cox proportional hazards model, HR=0.820, P=0.023). Td-mediated increased migration has been recapitulated in our larger confirmatory trial ELEVATE (NCT02366728) of 43 patients randomized to preconditioning (Wilcoxon rank sum, Td n=24, unpulsed DC n=19; 24h, P=0.031 and 48h, P=0.0195). In ELEVATE, median follow-up of 42.2 months revealed significantly longer OS in patients randomized to Td (P=0.026). The 3-year OS for Td-treated patients in ELEVATE was 34% (CI95 19-63%) compared to 6% given unpulsed DCs (CI95 1-42%).

CONCLUSION

We report reproducibility of our findings across three sequential clinical trials using CMV pp65 DCs. Despite their small numbers, these successive trials demonstrate consistent survival outcomes, thus supporting the efficacy of CMV DC vaccine therapy in GBM.

A prospective trial of abiraterone acetate plus prednisone in Black and White men with metastatic castrate-resistant prostate cancer

BACKGROUND

Retrospective analyses of randomized trials suggest that Black men with metastatic castration-resistant prostate cancer (mCRPC) have longer survival than White men. The authors conducted a prospective study of abiraterone acetate plus prednisone to explore outcomes by race.

METHODS

This race-stratified, multicenter study estimated radiographic progression-free survival (rPFS) in Black and White men with mCRPC. Secondary end points included prostate-specific antigen (PSA) kinetics, overall survival (OS), and safety. Exploratory analysis included genome-wide genotyping to identify single nucleotide polymorphisms associated with progression in a model incorporating genetic ancestry. One hundred patients self-identified as White (n = 50) or Black (n = 50) were enrolled. Eligibility criteria were modified to facilitate the enrollment of individual Black patients.

RESULTS

The median rPFS for Black and White patients was 16.6 and 16.8 months, respectively; their times to PSA progression (TTP) were 16.6 and 11.5 months, respectively; and their OS was 35.9 and 35.7 months, respectively. Estimated rates of PSA decline by ≥50% in Black and White patients were 74% and 66%, respectively; and PSA declines to <0.2 ng/mL were 26% and 10%, respectively. Rates of grade 3 and 4 hypertension, hypokalemia, and hyperglycemia were higher in Black men.

CONCLUSIONS

Multicenter prospective studies by race are feasible in men with mCRPC but require less restrictive eligibility. Despite higher comorbidity rates, Black patients demonstrated rPFS and OS similar to those of White patients and trended toward greater TTP and PSA declines, consistent with retrospective reports. Importantly, Black men may have higher side-effect rates than White men. This exploratory genome-wide analysis of TTP identified a possible candidate marker of ancestry-dependent treatment outcomes.

Circulating Tumor Cell Chromosomal Instability and Neuroendocrine Phenotype by Immunomorphology and Poor Outcomes in Men with mCRPC Treated with Abiraterone or Enzalutamide

PURPOSE

While the detection of AR-V7 in circulating tumor cells (CTC) is associated with resistance to abiraterone or enzalutamide in men with metastatic castration-resistant prostate cancer (mCRPC), it only accounts for a minority of this resistance. Neuroendocrine (NE) differentiation or chromosomal instability (CIN) may be additional mechanisms that mediate resistance.

EXPERIMENTAL DESIGN

PROPHECY was a multicenter prospective study of men with high-risk mCRPC starting abiraterone or enzalutamide. A secondary objective was to assess Epic CTC CIN and NE phenotypes before abiraterone or enzalutamide and at progression. The proportional hazards (PH) model was used to investigate the prognostic importance of CIN and NE in predicting progression-free survival and overall survival (OS) adjusting for CTC number (CellSearch), AR-V7, prior therapy, and clinical risk score. The PH model was utilized to validate this association of NE with OS in an external dataset of patients treated similarly at Memorial Sloan Kettering Cancer Center (MSKCC; New York, NY).

RESULTS

We enrolled 118 men with mCRPC starting on abiraterone or enzalutamide; 107 were evaluable on the Epic platform. Of these, 36.4% and 8.4% were CIN positive and NE positive, respectively. CIN and NE were independently associated with worse OS [HR, 2.2; 95% confidence interval (CI), 1.2-4.0 and HR 3.8; 95% CI, 1.2-12.3, respectively] when treated with abiraterone/enzalutamide. The prognostic significance of NE positivity for worse OS was confirmed in the MSKCC dataset (n = 173; HR, 5.7; 95% CI, 2.6-12.7).

CONCLUSIONS

A high CIN and NE CTC phenotype is independently associated with worse survival in men with mCRPC treated with abiraterone/enzalutamide, warranting further prospective controlled predictive studies to inform treatment decisions.

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.

Expression of immune checkpoints on circulating tumor cells in men with metastatic prostate cancer

BACKGROUND

A subset of men with metastatic prostate cancer (mPC) responds to immune checkpoint inhibitors, and there is an unmet need to predict those most likely to benefit. We characterized circulating tumor cells (CTCs) for expression of immune checkpoint ligands in men with mPC as a non-invasive biomarker of immune evasion and immunotherapy benefit.

METHODS

Three cohorts of patients were enrolled: 1) men with mCRPC starting abiraterone acetate/prednisone or enzalutamide (pre-ARSI), 2) men with mCRPC who were progressing on enzalutamide or abiraterone acetate/prednisone (post-ARSI), and 3) men with newly diagnosed metastatic hormone sensitive prostate cancer (mHSPC) starting androgen deprivation therapy. CTCs were captured using the CellSearch® system and stained for PD-L1, PD-L2, B7-H3, and CTLA-4 at baseline, on treatment, and disease progression. Summary statistics on mean CTCs per cohort, as well as rates of ligand positivity were used to analyze CTCs by cohort and by timepoint.

RESULTS

Men in all cohorts and timepoints had prevalent CTC B7-H3 expression (> 80%). We found evidence for CTC PD-L1 expression across disease states, in which > 1 positive CTC or > 50% of CTCs were positive for PD-L1 in 40 and 30% of men with mHSPC, respectively, 60 and 20% of men with mCRPC pre-ARSI, and 70 and 30% of men with mCRPC post-ARSI. CTC PD-L2 expression was present in 20-40% of men in each disease state, while CTC CTLA-4 expression was rare, present in 20% of men with mCRPC pre-ARSI and 10% of men with mCRPC post-ARSI or with mHSPC. CTC immune checkpoint expression was heterogeneous within/between men and across disease states.

CONCLUSIONS

We have identified that CTCs from men with mPC heterogeneously express immune checkpoints B7-H3, PD-L1, PD-L2, and CTLA-4, and the detection of these immune checkpoints may enable monitoring on immunotherapy.

Spiritual well-being and its association with health-related quality of life in primary brain tumor patients

Background

Spirituality can impact patients' attitudes and decisions about treatment and end-of-life care when coping with cancer. Previous studies documented health-related quality of life (HRQoL) and spiritual well-being (SWB) as positively correlated within a general cancer patient population, but little is known about their association in the primary brain tumor population. We sought to measure SWB in primary brain tumor patients and evaluate whether it was associated with HRQoL.

Methods

Six-hundred and six patients treated at The Preston Robert Tisch Brain Tumor Center at Duke between December 16, 2013 and February 28, 2014 with data in the PRoGREss registry are included in this retrospective analysis. Each patient completed the Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being 12 (FACIT-Sp-12) and -Fatigue (FACIT-F), and the Functional Assessment of Cancer Therapy-General and -Brain (FACT-G and FACT-Br).

Results

Mean age was 49.1 years (SD = 13.5 years), male (N = 328, 54.1%), married (N = 404, 66.7%), at least college-educated (N = 381, 62.9%), and diagnosed with a high-grade glioma (N = 412, 68.0%). Multiple regression analyses were performed on both the FACT-G and the FACT-Br using the FACIT-Sp-12 sub-scales of Meaning/Peace and Faith, FACIT-F, belief in God or a higher power, prayer, gender, tumor grade, and Karnofsky Performance Status (KPS) as predictors. We found that greater SWB (measured by FACIT-Sp-12) was associated with better HRQoL (measured by FACT-G and FACT-Br; p < .0001).

Conclusion

The association between reported SWB and reported improved HRQoL emphasizes the importance of spirituality in primary brain tumor patients, suggesting SWB must be considered in strategies to improve HRQoL.

EPCT-13. CMV PP65 RNA-PULSED DENDRITIC CELL VACCINES FOR PEDIATRIC GLIOBLASTOMA AND MEDULLOBLASTOMA: PHASE I TRIAL RESULTS

BACKGROUND

Recurrent medulloblastoma and malignant glioma are lethal tumors that are virtually incurable. The cytomegalovirus (CMV) antigen pp65 is ubiquitously expressed on medulloblastoma and malignant glioma but not on healthy brain. We evaluated autologous CMV pp65 RNA-pulsed dendritic cell (DC) vaccines in children and young adults in a phase I trial.

METHODS

Circulating monocytes were harvested using leukapheresis, differentiated into DCs, matured, and pulsed with pp65 RNA using electroporation. DCs were packaged into vaccines (2x10⁷DC/vaccine) and administered intradermally following tetanus-diphtheria toxoid site preconditioning every 2 weeks x3, then monthly. The primary objectives of the study were to establish the feasibility of generating at least 3 vaccines and safety. An exploratory objective was to evaluate the ability of vaccination to create and enhance patient pp65-specific T cell responses.

RESULTS

Eleven patients were enrolled with medulloblastoma (n=3) or glioblastoma (n=8). Ages ranged from 9–30 years old (mean 15.5y). Ten of 11 patients (91%) generated at least 3 vaccines (mean 6.2). Eight patients received at least 3 vaccines. To date, 4 patients have received all generated vaccines without progression, 4 patients have progressed, and 2 patients are still receiving vaccines. There have not been any severe adverse events probably or definitely related to vaccines. More mature data will be presented at ISPNO.

CONCLUSIONS

Leukapheresis and monocyte differentiation is a feasible strategy for generating adequate DCs for active immunization in children with malignant brain tumors. CMV pp65 RNA-pulsed DCs are well-tolerated and immunogenic. Efficacy endpoints will be evaluated in a subsequent phase II trial.

Abstract PO-100: Ancestry-related variation in Sphingosine Kinase Type 1-Interacting Protein (SKIP) and Sphingosine Kinase 1 (SPHK1) and response to secondary hormonal therapy in metastatic castration-resistant prostate cancer

The number of cases and deaths from prostate cancer (PCa) is highest for African American (AA) men compared with men of other racial and ethnic groups, and AA men more frequently have more aggressive disease. However, recent studies have shown that AA PCa patients have a better response to certain therapeutic regimens than white PCa patients. We conducted a DoD Prostate Cancer Clinical Trials Consortium (PCCTC) prospective study of secondary hormonal therapy (HT) in metastatic castration-resistant PCa (mCRPC) patients stratified by race, Abi-Race.

This study enrolled 50 AA and 50 white patients with mCRPC and received abiraterone and prednisone daily until disease progression or adverse event. AA men had higher rates of Prostate Specific Antigen (PSA) response and time to PSA progression. Herein we focus on correlative science in the context of Abi-Race to determine novel relationships between ancestry-related genetic variation and response and time to progression on secondary HT in mCRPC. An exploratory genome-wide analysis assessing the role of genotypic and local ancestry variation with respect to time to progression identified a missense variant in Sphingosine Kinase Type 1-Interacting Protein (SKIP) with predicted pathogenicity and potentially high ancestral variation. SKIP plays a role in modulating the conversion of sphingosine to sphingosine-1-phosphate (S1P) by regulating Sphingosine Kinase 1 (SPHK1) activity within the cytosol. S1P is a potent lipid mediator that plays a role in multiple cancer-promoting biofunctions. SKIP directly binds and inhibits SPHK1 activity, resulting in the decreased production of S1P and S1P-associated cell signaling. The relationship between SKIP and SPHK1 and response to secondary HT in mCRPC was investigated. We knocked down SKIP or SPHK1 in LN95 prostate cancer cells and assessed resulting alterations in proliferation with or without abiraterone. Knockdown of SKIP increased proliferation in untreated cells and knockdown cells were more resistant to treatment with abiraterone compared with the control group. Conversely, knockdown of SPHK1 decreased proliferation in untreated cells and knockdown cells were more sensitive to treatment with abiraterone compared with the control group. In addition, we are measuring changes in sphingosine and S1P in serum samples we collected from fasting Abi-Race patients at baseline and cycle 4 of treatment to investigate ancestry-related sphingosine and S1P variations and associated outcomes. Lastly, we are further investigating the potential function of the variant in SKIP associated with time to progression on secondary HT in mCRPC.

These findings will further the understanding of ancestry-related biological factors that influence response to secondary HT in mCRPC and could have direct implications for the timing and selection of AA patients for secondary HT and those needing additional therapy. Ultimately, such strategies have the potential to mitigate prostate cancer disparities.

Citation Format: Sean A. Piwarski, Tyler A. Allen, Dadong Zhang, Alexander B. Sibley, Patrick Healy, Brendon M. Patierno, Bonnie L. LaCroix, Rick A. Kittles, Kouros Owzar, Terry Hyslop, Steven R. Patierno, Daniel J. George, Jennifer A. Freedman. Ancestry-related variation in Sphingosine Kinase Type 1-Interacting Protein (SKIP) and Sphingosine Kinase 1 (SPHK1) and response to secondary hormonal therapy in metastatic castration-resistant prostate cancer [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-100.

Combination of Radiation Therapy and Short-Term Androgen Blockade With Abiraterone Acetate Plus Prednisone for Men With High- and Intermediate-Risk Localized Prostate Cancer

PURPOSE

Long-term androgen-deprivation therapy (ADT) is the standard of care in combination with radiation therapy (RT) in high-risk prostate cancer (PC), despite substantial toxicity from the resulting hypogonadism. We hypothesized that a combination of more potent but shorter-term androgen inhibition in men with intermediate- or high-risk localized PC would synergize with definitive RT to provide short-term testosterone recovery and improve disease control.

METHODS AND MATERIALS

This prospective phase 2 single-arm trial enrolled men with low-volume unfavorable intermediate or high-risk localized PC. Treatment included 6 months of ADT concurrent with abiraterone acetate plus prednisone (AAP) once daily and RT to prostate and seminal vesicles. The primary endpoint was the proportion of men with an undetectable prostate-specific antigen (PSA) at 12-months; secondary objectives included biochemical progression-free survival (PFS), testosterone recovery, toxicity, and sexual and hormonal quality of life.

RESULTS

We enrolled 37 men between January 2014 and August 2016, 45% of whom were high risk. All patients had T1-2 disease and PSA < 20 ng/mL. Median follow-up is 37 months (95% confidence interval [CI], 35.7-39.1). Treatment noted 32% grade 3 toxicities related to AAP, predominantly hypertension, with no toxicities ≥G4. The rate of undetectable PSA at 12 months was 55% (95% CI, 36%-72%). With 46 months of median follow-up, 2 of 37 patients developed PSA progression (36-month PFS = 96%; 95% CI, 76%-99%), and 81% of patients recovered testosterone with a median time to recovery of 9.2 months. Hormonal or sexual function declined at 6 months with subsequent improvement by 24 months.

CONCLUSIONS

The combination of RT and 6 months of ADT and AAP demonstrated acceptable toxicity and a high rate of testosterone recovery with restoration of quality of life and excellent disease control in men with low-volume, intermediate- or high-risk localized prostate cancer. Prospective comparative studies are justified.

Prospective Multicenter Study of Circulating Tumor Cell AR-V7 and Taxane Versus Hormonal Treatment Outcomes in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Androgen receptor splice variant 7 (AR-V7) detection in circulating tumor cells (CTCs) is associated with a low probability of response and short progression-free (PFS) and overall survival (OS) in men with metastatic castration-resistant prostate cancer (mCRPC) treated with enzalutamide or abiraterone. However, it is unclear whether such men benefit from taxane chemotherapy.

PATIENTS AND METHODS

PROPHECY is a multicenter prospective blinded study of patients with poor-risk mCRPC starting abiraterone or enzalutamide and observed through subsequent progression and taxane chemotherapy. We assessed AR-V7 status using the Johns Hopkins modified AdnaTest CTC AR-V7 messenger RNA assay and the Epic Sciences CTC nuclear-localized AR-V7 protein assay before treatment. The primary objective was to validate the independent prognostic value of CTC AR-V7 status based on radiographic/clinical PFS. OS, confirmed prostate-specific antigen (PSA), and objective radiologic responses were secondary end points.

RESULTS

We enrolled 118 men with mCRPC treated with abiraterone or enzalutamide, 51 of whom received subsequent docetaxel or cabazitaxel. Pretreatment CTC AR-V7 status by the Johns Hopkins and Epic Sciences assays was independently associated with worse PFS (hazard ratio [HR], 1.7; 95% CI, 1.0 to 2.9 and HR, 2.1; 95% CI, 1.0 to 4.4, respectively) and OS (HR, 3.3; 95% CI, 1.7 to 6.3 and HR, 3.0; 95% CI, 1.4 to 6.3, respectively) and a low probability of confirmed PSA responses, ranging from 0% to 11%, during treatment with abiraterone or enzalutamide. At progression, subsequent CTC AR-V7 detection was not associated with an inferior PSA or radiographic response or worse PFS or OS with subsequent taxane chemotherapy after adjusting for CellSearch CTC enumeration and clinical prognostic factors.

CONCLUSION

Detection of AR-V7 in CTCs by two different blood-based assays is independently associated with shorter PFS and OS with abiraterone or enzalutamide, but such men with AR-V7-positive disease still experience clinical benefits from taxane chemotherapy.

Once, Twice, Three Times a Finding: Reproducibility of Dendritic Cell Vaccine Trials Targeting Cytomegalovirus in Glioblastoma

Despite standard of care for glioblastoma, including gross total resection, high-dose radiation, and dose-limited chemotherapy, this tumor remains one of the most aggressive and therapeutically challenging. The relatively small number of patients with this diagnosis compared with more common solid tumors in clinical trials commits new glioblastoma therapies to testing in small, underpowered, nonrandomized settings. Among approximately 200 registered glioblastoma trials identified between 2005 and 2015, nearly half were single-arm studies with sample sizes not exceeding 50 patients. These constraints have made demonstrating efficacy for novel therapies difficult in glioblastoma and other rare and aggressive cancers. Novel immunotherapies for glioblastoma such as vaccination with dendritic cells (DC) have yielded mixed results in clinical trials. To address limited numbers, we sequentially conducted three separate clinical trials utilizing cytomegalovirus (CMV)-specific DC vaccines in patients with newly diagnosed glioblastoma whereby each follow-up study had nearly doubled in sample size. Follow-up data from the first blinded, randomized phase II clinical trial (NCT00639639) revealed that nearly one third of this cohort is without tumor recurrence at 5 years from diagnosis. A second clinical trial (NCT00639639) resulted in a 36% survival rate at 5 years from diagnosis. Results of the first two-arm trial (NCT00639639) showed increased migration of the DC vaccine to draining lymph nodes, and this increased migration has been recapitulated in our larger confirmatory clinical study (NCT02366728). We have now observed that nearly one third of the glioblastoma study patient population receiving CMV-specific DC vaccines results in exceptional long-term survivors.

Abstract 3507: Race-related genetic variation and response to secondary hormonal therapy in metastatic castration-resistant prostate cancer

Prostate cancer (PCa) is the second most common cancer diagnosed in men globally, after lung cancer. PCa incidence, aggressiveness and mortality are significantly higher among African Americans (AAs) compared with men of other racial/ethnic groups. Despite the worse prognosis associated with African ancestry, several recent studies have shown that PCa patients of African ancestry have a better response to certain PCa therapeutic regimens than those of European ancestry. The overall objective of our study is to identify ancestry-related genetic variation that associates with outcomes on abiraterone/prednisone therapy in metastatic castration-resistant prostate cancer (mCRPC). Our central hypothesis is that differences in ancestry-related single nucleotide polymorphisms (SNPs), gene expression and polymorphic CAG trinucleotide repeats located in the androgen receptor (AR) gene will associate with prostate-specific antigen (PSA) response and time to progression on secondary hormonal therapy in mCRPC patients. Toward our objective, we collected whole blood at baseline and archival tumor tissue from 50 self-identified AA and 50 self-identified white patients enrolled in the Abi Race study, a Phase II study of abiraterone/prednisone in AA and white men with mCRPC. To perform ancestral and genome-wide genotyping, we isolated DNA from the whole blood samples collected at baseline and interrogated DNA using the Infinium Multi-Ethnic Global BeadChip (Illumina). We identified nine candidate SNPs in genes having previously reported relevance to cancer and/or PCa that were associated with longer time to confirmed PSA progression (TTP) in blacks and shorter TTP in whites. To perform gene expression profiling, we isolated RNA from archival formalin-fixed, paraffin-embedded PCa tissue and interrogated RNA using a NanoString Custom CodeSet (NanoString Technologies). Preliminary analysis revealed significant race-related differential expression of 30 PCa-related genes. To accomplish AR CAG repeat length profiling, we performed PCR using primers flanking the CAG repeat region and utilized a DNA Bioanalyzer to measure the relative nucleotide length. AR CAG repeat lengths varied from 8 to 40 and we are currently investigating the association between length and patient outcomes on abiraterone/prednisone therapy. Future analyses will focus on defining the functional significance of the aforementioned ancestry-related genetic variation using preclinical cancer models and validation of the aforementioned ancestry-related genetic variation in an independent cohort. These findings will further understanding of ancestry-related biological factors that influence response to secondary hormonal therapy in mCRPC and could have direct implications for the timing and selection of AA patients for secondary hormonal therapy and those needing additional therapy. As secondary hormonal therapy use expands to earlier disease settings, these findings could support the need for further studies in AA men in these disease settings. Ultimately, such strategies have the potential to mitigate PCa disparity.

Citation Format: Tyler Allen, Gary Lipton, Alexander B. Sibley, Patrick Healy, Brendon Patierno, Bonnie Lacroix, Steven Patierno, Kouros Owzar, Terry Hyslop, Daniel J. George, Jennifer A. Freedman. Race-related genetic variation and response to secondary hormonal therapy in metastatic castration-resistant prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3507.

Abstract B064: Race-related genetic variation and response to secondary hormonal therapy in metastatic castration-resistant prostate cancer

Prostate cancer (PCa) is the most prevalent cancer and third leading cause of cancer death among men in the United States. PCa incidence, aggressiveness and mortality are significantly higher among African Americans (AAs) compared with men of other racial groups. Despite the worse prognosis associated with African ancestry, several recent studies have shown that PCa patients of African ancestry have a better response to certain PCa therapeutic regimens than those of European ancestry. The overall objective of our study is to identify ancestry-related genetic variation that associates with outcomes on abiraterone/prednisone therapy in metastatic castration-resistant prostate cancer (mCRPC). Our central hypothesis is that differences in ancestry-related single nucleotide polymorphisms (SNPs), gene expression and/or metabolites will associate with prostate-specific antigen (PSA) response and time to progression on secondary hormonal therapy in mCRPC patients. Toward our objective, we collected whole blood, archival tumor tissue and serum from 50 self-identified AA and 50 self-identified white patients enrolled in the Abi Race study, a Phase II study of abiraterone/prednisone in AA and white men with mCRPC. To perform ancestral and genome-wide genotyping, we isolated DNA from the whole blood samples collected at baseline and interrogated DNA using the Infinium Multi-Ethnic Global BeadChip (Illumina). Preliminary analysis identified 622 SNPs that associated with PSA progression-free survival on abiraterone or variation in minor allele frequency by ancestry. To perform gene expression profiling, we isolated RNA from archival formalin-fixed, paraffin-embedded PCa tissue and interrogated RNA using a NanoString Custom CodeSet (NanoString Technologies). Preliminary analysis revealed significant race-related differential expression of 30 prostate cancer-related genes. To perform metabolomic profiling, we used fasting serum samples collected at baseline and during treatment and the Biocrates p400 HR Kit (Biocrates Life Sciences AG). From this analysis, we have prioritized four ancestry-related metabolites associated with time to confirmed PSA progression for further study. Future analyses will focus on defining the functional significance of the aforementioned ancestry-related genetic variation using preclinical cancer models and validation of the aforementioned ancestry-related genetic variation in an independent cohort. These findings will further understanding of ancestry-related biological factors that influence response to secondary hormonal therapy in mCRPC and could have direct implications for the timing and selection of AA patients for secondary hormonal therapy and those needing additional therapy. As secondary hormonal therapy use expands to earlier disease settings, these findings could support the need for further studies in AA men in these disease settings. Ultimately, such strategies have the potential to mitigate PCa disparity.

Citation Format: Tyler A Allen, Gary Lipton, Alexander B Sibley, Patrick Healy, Brendon M Patierno, Bonnie Lacroix, Steven R Patierno, Kouros Owzar, Terry Hyslop, Daniel J George, Jennifer A Freedman. Race-related genetic variation and response to secondary hormonal therapy in metastatic castration-resistant prostate cancer [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 B064.

BMX-HGG: Phase II trial of newly diagnosed high-grade glioma treated with concurrent radiation therapy, temozolomide, and BMX-001

TPS2577

Background: Patients diagnosed with malignant high-grade gliomas (WHO grade III-IV) experience significant morbidity and mortality associated with these cancers. While the mainstay of therapy for patients with newly diagnosed high-grade glioma is surgery followed by concurrent chemotherapy and radiation therapy (RT), the outcomes remain very poor. BMX-001 (MnTnBuOE-2-PyP5+) is a metalloporphyrin with differential action in response to radiation therapy and chemotherapy-induced oxidative stress. Early preclinical studies demonstrated BMX-001’s ability to act as a radioprotectant to healthy tissue such as a central nervous white matter and as a radiosensitizer to cancer cells, in particular, human glioblastoma xenografts. We evaluated the safety of BMX-001 in combination with concurrent RT and temozolomide (TMZ) in a phase I study of newly diagnosed high-grade glioma patients, and we found that BMX-001 is safe and well-tolerated in this population. The maximum tolerated dose of BMX-001 during concurrent RT and TMZ was determined to be 28 mg delivered subcutaneously (SC) followed by 16 biweekly SC doses at 14 mg (Peters et al., Neuro-Oncology 2018). Methods: For this multi-site, open-label, phase II study (NCT02655601), we will randomize approximately 160 patients 1:1 to concurrent RT and TMZ with BMX-001 versus concurrent RT and TMZ alone. Key eligibility criteria include newly diagnosed histologically confirmed high-grade glioma (WHO III-IV), 18 ≥ years, and Karnofsky performance status ≥ 70%. The primary endpoint is overall survival. Secondary endpoints include cognitive performance as assessed by standardized cognitive testing, bone marrow protection, safety and tolerability, progression-free survival, overall tumor response rate, and plasma pharmacokinetics. Exploratory endpoints are health-related quality of life (as assessed by Functional Assessment of Cancer Therapy–Brain, Functional Assessment of Cancer Therapy-Cognition, and Functional Assessment of Chronic Illness Therapy-Fatigue), qualitative hair loss, and white matter integrity (as measured by MRI diffusion tensor/susceptibility imaging). Since November 2018, this phase II study has enrolled 64 of 160 high-grade glioma patients at six sites with future sites planned to be implemented. Clinical trial information: NCT02655601 .

Phase I trial of D2C7 immunotoxin (D2C7-IT) administered intratumorally via convection-enhanced delivery (CED) for recurrent malignant glioma (MG)

2566

Background: D2C7-IT is a recombinant immunotoxin comprised of a dual-specific antibody fragment targeting EGFRwt and EGFRvIII and a genetically engineered form of the Pseudomonas exotoxin, PE38-KDEL. We report the results of a phase I trial evaluating D2C7-IT delivered intratumorally by CED. Methods: Eligible patients were adults with recurrent supratentorial WHO grade III or IV MG; solitary tumor; ≥4 weeks after chemotherapy, bevacizumab or study drug; adequate organ function; and KPS>70%. Two patients per dose level (DL) were to enroll in the dose escalation portion (dose range: 40ng/mL to 23,354ng/mL). Results: From May 2015 to May 2018, 43 patients enrolled on study. Observed dose limiting toxicities include: grade 4 seizure (n=1) on DL3, grade 3 confusion and pyramidal tract syndrome (n=1) on DL13, and grade 4 cerebral edema (n=1) and grade 3 dysphasia (n=1) on DL17. Grade 3 or higher adverse events possibly related to D2C7-IT include: seizure (grade 4, n=2; grade 3, n=3), cerebral edema (grade 4, n=1), hydrocephalus (grade 3, n=5), headache (grade 3, n=4), hemiparesis (grade 3, n=4), dysphasia (grade 3, n=3), lymphopenia (grade 3, n=4), thromboembolic event (grade 3, n=3); and one each of grade 3 elevated ALT, urinary tract infection, fall, wound complication, generalized muscle weakness, confusion, encephalopathy, and somnolence. As of February 2020, four patients remain alive, with three patients demonstrating persistent radiographic partial response more than 54, 34 and 28 months after a single infusion of D2C7-IT. Conclusions: Dose level 13 (6,920ng/mL) was selected as the optimal phase II dose. Accrual in a dose expansion phase II trial is ongoing, and we are initiating a combination trial of D2C7-IT with checkpoint inhibitior. Clinical trial information: NCT02303678 .

Randomized open-label phase II trial of 5-day aprepitant plus ondansetron compared to ondansetron alone in the prevention of chemotherapy-induced nausea-vomiting (CINV) in glioma patients receiving adjuvant temozolomide

PURPOSE

CINV remains a distressing side effect experienced by glioma patients receiving multi-day temozolomide therapy, in spite of guideline-based antiemetic therapy with selective serotonin-receptor-antagonists. Antiemetic research with aprepitant has routinely excluded glioma patients. In this randomized open-label phase II study, use of a nonstandard 5-day regimen of aprepitant for glioma patients was investigated.

METHODS

One hundred thirty-six glioma patients receiving their first cycle of adjuvant temozolomide (150-200 mg/m2/day × 5 days every 28 days) were randomized to Arm-A (ondansetron 8 mg days 1-5 with aprepitant day 1: 125 mg, days 2-5: 80 mg) or Arm-B (ondansetron). Randomization was stratified by tumor grade and number of prior chemotherapy regimens. The primary endpoint was the percentage of patients achieving complete control (CC), defined as no emetic episode or antiemetic rescue medication over the 7-day study period. Secondary endpoints included CINV efficacy in the acute phase (≤ 24 h) and delayed phase (days 2-7), as well as safety and quality of life (QoL).

RESULTS

Patients were 61% male, 97% white, 48% with KPS > 90%, 60% non-smokers, mean age 54, 92% with low alcohol use, and 46% with a CINV history. The CC was 58.6% (Arm-A) and 54.5% (Arm-B). Acute-complete response (CR) rates, defined as CC on day 1 in Arm-A and -B, were 97.1% and 87.9%, respectively (p = 0.056). Treatment-related toxicities were mild or moderate in severity.

CONCLUSIONS

Aprepitant plus ondansetron may increase acute-CR, may have benefit regarding CINV's effect on QoL, and is safe for 5-day temozolomide compared to ondansetron. This study provides no evidence that aprepitant increases CC rate over ondansetron alone.

Patterns of relapse after successful completion of initial therapy in primary central nervous system lymphoma: a case series

PURPOSE

Primary central nervous system lymphoma (PCNSL) is a subtype of non-Hodgkin's lymphoma that involves the brain, spinal cord, or leptomeninges, without evidence of systemic disease. This rare disease accounts for ~ 3% of all primary central nervous system (CNS) tumors. Methotrexate-based regimens are the standard of care for this disease with overall survival rates ranging from 14 to 55 months. Relapse after apparent complete remission can occur. We sought to understand the outcomes of patients who relapsed.

METHODS

This is an IRB-approved investigation of patients treated at our institution between 12/31/2004 and 10/12/2016. We retrospectively identified all cases of PCNSL as part of a database registry and evaluated these cases for demographic information, absence or presence of relapse, location of relapse, treatment regimens, and median relapse-free survival.

RESULTS

This analysis identified 44 patients with a pathologically confirmed diagnosis of PCNSL. Mean age at diagnosis was 63.1 years (range 20-86, SD = 13.2 years). Of the 44 patients, 28 patients successfully completed an initial treatment regimen without recurrence or toxicity that required a change in therapy. Relapse occurred in 11 patients with the location of relapse being in the CNS only (n = 5), vitreous fluid only (n = 1), outside CNS only (n = 3), or a combination of CNS and outside of the CNS (n = 2). Sites of relapse outside of the CNS included testes (n = 1), lung (n = 1), adrenal gland (n = 1), kidney/adrenal gland (n = 1), and retroperitoneum (n = 1). Median relapse-free survival after successful completion of therapy was 6.7 years (95% CI 1.1, 12.6).

CONCLUSION

After successful initial treatment, PCNSL has a propensity to relapse, and this relapse can occur both inside and outside of the CNS. Vigilant monitoring of off-treatment patients with a history of PCNSL is necessary to guide early diagnosis of relapse and to initiate aggressive treatment.

Association of circulating tumor cell chromosomal instability with worse outcomes in men with mCRPC treated with abiraterone or enzalutamide

183

Background: While AR-V7 is a known driver of hormonal resistance, most men with mCRPC lack AR-V7 detection and commonly experience cross-resistance to abiraterone and enzalutamide (abi/enza). Loss of AR dependence through neuroendocrine (NE) differentiation or chromosomal instability (CIN) may explain AR therapy cross-resistance in additional men. Methods: PROPHECY was a multicenter prospective study of men with poor risk mCRPC starting abi/enza. We assessed Epic CTC AR-V7, CIN and NE phenotypes before abi/enza and at progression. Radiographic/clinical progression free survival (PFS) and overall survival (OS) were associated with CIN (>3 CTCs) and NE (>3 CTCs) CTC phenotypes using the proportional hazards model adjusting for Cellsearch CTC, AR-V7, and clinical risk score. Results: 118 men with mCRPC starting on abi/enza were enrolled; 106 had evaluable CTCs for AR-V7, CIN, and NE on the Epic platform. Of these, 22.6% and 9.4% of men exhibited high CTC CIN and NE scores, respectively. High pre-treatment CIN and NE phenotypic scores were observed in 63 and 27% of AR-V7 (+) and in 17 and 7% of AR-V7 (-) men. CTC CIN phenotype but not NE phenotype was associated with a lower confirmed PSA response rate and OS (TABLE) with abi/enza, adjusting for CTC number, AR-V7 and risk score. Conclusions: A high chromosomal instability CTC phenotype is associated with worse outcomes in men with mCRPC treated with abi/enza and warrants further study as a prognostic or predictive biomarker. Clinical trial information: NCT02269982. [Table: see text]

AR-V7 and prediction of benefit with taxane therapy: Final analysis of PROPHECY

184

Background: We previously found that men with AR-V7 (+) poor risk mCRPC have a low chance of benefit with abiraterone or enzalutamide. The benefits of subsequent taxane chemotherapy based on AR-V7 status may help inform treatment decisions. Methods: We conducted a multicenter prospective study of men with poor risk mCRPC (PROPHECY, NCT02269982) starting Abi or Enza and subsequent taxane chemotherapy. AR-V7 status from CTCs was assessed before abi/enza and again before taxane chemotherapy using the Epic nuclear protein assay or the Johns Hopkins Adnatest assay. The primary endpoint was to test the association of AR-V7 with radiographic/ clinical progression free survival (PFS) and OS with taxane chemotherapy, using the proportional hazards model, adjusting for Cell Search enumeration and clinical risk score. Results: We enrolled 118 men with mCRPC starting Abi/Enza; of these, 51 were evaluable with CTC AR-V7 testing and received subsequent taxane chemotherapy. With 50 PFS events, see table for final results. While AR-V7 positivity was associated with worse outcomes overall, AR-V7 (+) patients had similar PFS, OS, and confirmed >50% PSA declines adjusting for CTC enumeration and clinical prognostic factors. Concordance between the two AR-V7 assays pre-taxane was 0.78 (kappa 0.46). AR-V7 positivity increased at progression on abi/enza, but not following taxane chemotherapy. Conclusions: Men with AR-V7 positive mCRPC have poor outcomes, but may benefit from taxane chemotherapy after progression on abi/enza. AR-V7 may provide a helpful predictive biomarker to guide treatment with a second AR inhibitor or a taxane. Clinical trial information: NCT02269982. [Table: see text]

Disulfiram (DSF) pharmacokinetics (PK) and copper PET imaging in a phase Ib study of intravenous (IV) copper loading with oral DSF for patients with metastatic castration-resistant prostate cancer (mCRPC)

96

Background: In preclinical models of prostate cancer (PC), DSF reduced tumor growth when co-administered with copper (Cu). Further, intracellular Cu uptake is partially regulated by androgen-receptor signaling. Given these data, we conducted a phase Ib clinical trial of mCRPC patients (pts) receiving Cu with DSF. Methods: Pts with mCRPC were assigned to 1 of 3 cohorts: neuroendocrine PC (NEPC) (A), adenocarcinoma (adenoCA) mCRPC with non-liver/peritoneal metastases (B), and adenoCA mCRPC with liver and/or peritoneal metastases (C). IV CuCl2 was given weekly for 3 doses with oral daily DSF. After CuCl2 dosing, daily oral Cu gluconate was started and DSF continued until disease progression as defined by Prostate Cancer Working Group Three (PCWG3). DSF and metabolite MeDDC levels in plasma were sampled at 0, 2, 4, 6 and 8 hours after the first dose and on Cycle 2 Day 1, and measured by HPLC. DSF and MeDDC were evaluated for cytotoxicity in 3 PC cell lines (22Rv1, LnCAP, and PC3) and a prostate epithelial cell line (PWR-1E). mCRPC Cu avidity was measured by 64Cu PET scan at baseline for all pts. Results: We treated 9 pts with mCRPC, 6 on cohort B and 3 on cohort C. No confirmed PSA declines or radiographic responses were observed in either cohort. Common adverse events included fatigue and psychomotor depression; no grade 4/5 AEs were observed. PK analysis: No DSF was detected in plasma (LOQ = 0.032 ng/mL, LOD = 0.01 ng/mL), whereas MeDDC was measurable in all study samples (LOQ = 0.512 ng/mL). MeDDC exhibited no cytotoxicity activity in PC cell lines. On 64Cu PET scans, bone metastases showed differential and heterogeneous Cu uptake. Lymph node and pulmonary metastases were evaluable, but not liver metastases due to significant Cu uptake in the liver. Conclusions: Oral DSF is not an effective treatment for mCRPC because it is quickly metabolized into the non-cytotoxic inactive metabolite, MeDDC. As such, this trial has stopped enrollment. Further work is needed to identify a stable DSF formulation so that the conditional lethality of Cu and DSF may be evaluated for treatment of mCRPC. Clinical trial information: NCT02963051.

Multicenter retrospective analysis of patients with metastatic renal cell carcinoma (mRCC) and bone metastases treated with ipilimumab and nivolumab

648

Background: Ipilimumab & nivolumab (I+N) followed by nivolumab maintenance is approved as front-line therapy for intermediate and poor-risk metastatic renal cell carcinoma (mRCC). Bone metastases (BM) are present in up to 30% of mRCC patients (pts) and remain a clinical challenge. We present a multicenter experience of mRCC pts with BMs treated with I+N. Methods: Patients with mRCC and bone metastases treated with (I+N) at Duke Cancer Network and Cleveland Clinic were retrospectively reviewed. Patient demographics, tumor histology, IMDC risk stratification, RECIST-defined ORR and adverse events were collected. Fisher’s exact test was used to determine predictors of response (alpha 0.05). Results: Forty-eight pts with mRCC and radiographically confirmed BMs were included in the analysis: 81% male; median age 54 (range: 41-81); 77% clear cell histology; IMDC risk 17%/52%/31% favorable/intermediate/poor, respectively. I+N was used as first-line medical therapy in 63% of pts and ≥ second-line in remaining pts. Best response on I+N per RECIST criteria: objective response rate (ORR) 23% (0% CR); 23% stable disease (SD); 44% progressive disease (PD). Median duration of treatment was 64 days with 27% of pts still on I+N. PD was the most common reason for discontinuation (38%) followed by adverse events (19%). Nearly half of pts (48%) experienced at least one irAE attributed to I+N therapy. None of the factors examined above was significantly associated with response to treatment. Conclusions: I+N has clinical activity and is well tolerated in mRCC pts with bone metastases; however ORR in this population is lower than expected and 44% pts had PD as best response. Therefore, identifying prognostic factors & improving novel therapies for this cohort of patients are priorities, given overall poorer outcomes in this population.

A multicenter retrospective study to evaluate real-world clinical outcomes in patients with metastatic renal cell carcinoma (mRCC) and brain metastasis treated with ipilimumab and nivolumab

637

Background: The combination of ipilimumab & nivolumab (I+N) followed by maintenance nivolumab has improved outcomes in patients (pts) with mRCC. Little is known about the outcomes in mRCC pts with brain metastasis. In this multicenter retrospective analysis, we present a real-world experience in pts with brain metastasis treated with I+N. Methods: Pts with mRCC and brain metastases treated with I+N at the Duke Cancer Institute and Cleveland Clinic were identified. Pt characteristics were summarized with descriptive statistics. Fisher’s exact test was used to determine predictors of response (alpha 0.05). Results: From 10/2017 to 2/2019, 17 pts received I+N for mRCC with brain metastases. Median age was 60; 29% were female. IMDC risk was 18%/59%/24% favorable/intermediate/poor, and 77% were clear cell histology. Pts received I+N as either first-line (65%) or ≥ second-line (35%) therapy. Of the pts evaluable for response: objective response rate (ORR) was 42% [0% CR]; with 29% achieving stable disease and 18% progressive disease as their best response. Median duration on therapy was 13 weeks. 59% of pts developed an immune-related adverse event (AE). The most common reason for treatment discontinuation was disease progression (47%) followed by AEs (18%). There were no significant predictors of any radiographic response category (PR, SD, or PD) among variables assessed (gender, IMDC risk, histology, presence of bone metastasis, line of therapy, or presence of irAE). Of note, 50% (3/6) patients treated in the second-line or greater setting experienced a PR. Conclusions: In our real-world cohort of mRCC patients with brain metastasis, I+N is clinically effective. Further investigation is warranted in this population given exclusion from prior clinical trials.

Targeting PD-L1 Initiates Effective Antitumor Immunity in a Murine Model of Cushing Disease

PURPOSE

Although pituitary adenoma is classified as benign, Cushing disease is associated with significant morbidity due to the numerous sequelae of elevated cortisol levels. Successful therapy for Cushing disease remains elusive due to high rates of treatment-refractory recurrence. The frequent emergence of lymphocytic hypophysitis following checkpoint blockade for other cancers, as well as the expression of PD-L1 on pituitary adenomas, suggest a role for immunotherapy.

EXPERIMENTAL DESIGN

This study confirms PD-L1 expression on functioning pituitary adenomas and is the first to evaluate the efficacy of checkpoint blockade (anti-PD-L1) therapy in a preclinical model of Cushing disease.

RESULTS

Herein, treatment with anti-PD-L1 was successful in reducing adrenocorticotropic hormone plasma levels, decreasing tumor growth, and increasing survival in our model. Furthermore, tumor-infiltrating T cells demonstrated a pattern of checkpoint expression similar to other checkpoint blockade-susceptible tumors.

CONCLUSIONS

This suggests that immunotherapy, particularly blockade of the PD1/PD-L1 axis, may be a novel therapeutic option for refractory Cushing disease. Clinical investigation is encouraged.

HOUT-21. CHARACTERISTICS OF SHORT-TERM SURVIVAL IN PATIENTS WITH GLIOBLASTOMA: A RETROSPECTIVE ANALYSIS

We sought to identify characteristics of glioblastoma (GBM) patients with short survival (< 10 months) in order to identify prognostic factors useful for guiding treatment management. This is an IRB-approved retrospective analysis of adult newly diagnosed GBM patients from 2008–2016 who survived < 10 months from diagnosis. We extracted demographics, tumor characteristics, and treatment details. We calculated survival from surgical diagnosis to date of death. The cohort includes 197 subjects (61% male) with a median age of 68 years (range 19–94). The majority (93%) are non-Hispanic white. The cohort has a median survival of 144 days (95% CI: 130–160). We focused on traditional prognostic indicators, including extent of surgical resection and KPS. A majority had biopsy only (n=92, 46.7%) rather than gross total (n=59, 29.9%) or subtotal (n=46, 23.4%) resection. Moreover, 160 out of 197 patients had a documented KPS with a majority being below 90 (KPS=70–80 (n=96); KPS < 70 (n=31)). Of 179 patients with data on RT course, 18% (n=32) received no RT or opted for hospice after diagnosis, 3% (n=6) received only RT, 54% (n=97) received RT+temozolomide (TMZ), and 24% (n=43) received RT+TMZ+bevacizumab. Of the 147 subjects receiving RT, 79% completed their RT course as prescribed. Most commonly, RT was prescribed as a 6- to 6-1/2-week course (85%), typically 59.4 Gy (45Gy primary, 14.4Gy boost) over 33 fractions or 60 Gy over 30 fractions. In contrast, 15% received a 3-week RT course, typically scheduled as 15 fractions of 2.667 Gy. We concluded that GBM patients with survival < 10 months were more likely to have biopsy only and a KPS < 90, notably associated with poorer prognosis. We continue to explore this dataset for further prognostic factors, particularly inability to complete planned RT course, and are comparing these traits to a larger cohort.

ATIM-24. DOSE FINDING AND DOSE EXPANSION TRIAL OF D2C7 IMMUNOTOXIN (D2C7-IT) ADMINISTERED INTRATUMORALLY VIA CONVECTION-ENHANCED DELIVERY (CED) FOR RECURRENT MALIGNANT GLIOMA (MG)

BACKGROUND

D2C7-IT is a recombinant immunotoxin comprised of a dual-specific antibody fragment targeting EGFRwt and EGFRvIII and a genetically engineered form of the Pseudomonas exotoxin, PE38-KDEL. We report results of a phase 1 trial, with dose expansion at the selected phase 2 dose, evaluating D2C7-IT delivered intratumorally by CED.

METHODS

Eligible patients are adults with recurrent supratentorial WHO grade III or IV MG; solitary tumor; ≥4 weeks after chemotherapy, bevacizumab or study drug; adequate organ function; and KPS >70%. Two patients per dose level (DL) were to be enrolled in the dose escalation portion (dose range: 40ng/mL to 23,354ng/mL), followed by dose expansion at the selected phase 2 dose (DL13).

RESULTS

As of 6/07/2019, 51 patients have been treated; 10 patients on the phase 2 dose. Observed dose limiting toxicities include: grade 4 seizure (n=1) on DL3, grade 3 confusion and pyramidal tract syndrome (n=1) on DL13, and grade 4 cerebral edema (n=1) and grade 3 dysphasia (n=1) on DL17. Grade 3 or higher adverse events possibly related to D2C7-IT include: seizure (grade 4, n=2, grade 3, n=3), cerebral edema (grade 4, n=1), hydrocephalus (grade 3, n=5), headache (grade 3, n=4), hemiparesis (grade 3, n=4), dysphasia (grade 3, n=4), lymphopenia (grade 3, n=3), thromboembolic event (grade 3, n=3); and one each of grade 3 elevated ALT, urinary tract infection, fall, wound complication, generalized muscle weakness, confusion, encephalopathy, and somnolence. Fourteen patients are alive. Three patients have partial radiographic response and remain alive without additional therapy more than 46, 27 and 21 months after D2C7-IT infusion.

CONCLUSION

Dose level 13 was selected as the optimal phase 2 dose and patient accrual is ongoing on the dose expansion arm. Encouraging efficacy results have been observed. A trial of D2C7-IT with checkpoint inhibitor is planned to start in the near future.

ATIM-31. SAFETY OF TUMOR-SPECIFIC PEPTIDE VACCINE TARGETING ISOCITRATE DEHYDROGENASE 1 MUTATION IN RECURRENT RESECTABLE LOW GRADE GLIOMA PATIENTS

BACKGROUND

Low grade gliomas (LGGs) represent 10–15% of glial tumors in adults and while LGG patients have a better prognosis over high-grade gliomas, these cancers ultimately recur and transform to more aggressive tumors. Isocitrate dehydrogenase 1 (IDH1) is commonly mutated in LGG, and when mutated, it is the oncogenic driver by leading to the production of oncometabolite 2-hydroxyglutarate (2-HG). We developed a phase 1 study for recurrent resectable IDH1 mutant LGG utilizing a tumor-specific peptide vaccine targeting IDH1 mutant protein that spans the mutated region of IDHR132H (PEPIDH1M vaccine).

METHODS

We performed a phase 1, single-center, clinical trial in recurrent resectable IDH1 mutant WHO grade II glioma patients. Subjects received three PEPIDH1M vaccine q2wks and then proceeded to surgical resection. If subject’s tumor retained grade II status, then the subject proceeded with 12 cycles of daily TMZ (50 mg/m2 X 28 days) and PEPIDH1M vaccine (12 injections q4wks). If subject’s tumor transformed to grade III, then subject proceeded to radiation therapy (RT) with concurrent TMZ followed by 12 cycles of daily TMZ (50 mg/m2 X 28 days) and PEPIDH1M vaccine (12 injections q4wks). Primary endpoint was safety of PEPIDH1M vaccine in combination with adjuvant TMZ and/or XRT/TMZ and evaluable subjects needed to receive ≥6 PEPIDH1M vaccines. We assessed safety using CTCAE 4.03.

RESULTS

We enrolled 24 recurrent LGG subjects with mean age of 43.8 yrs (sd=11.4 yrs). Twenty subjects completed ≥6 PEPIDH1M vaccines. Most common related toxicity was grade 1 injection site reaction (N=20) and skin induration (n=17) with no grade 3–4 related toxicities.

CONCLUSIONS

PEPIDH1M vaccine in combination with surgical resection, daily TMZ and/or RT + TMZ with daily TMZ was safe and well tolerated in recurrent IDH1 mutant LGG. We are currently exploring secondary/correlative endpoints including immunogenicity of PEPIDH1M vaccine and magnetic resonance spectroscopy for 2-HG.

Phase 1b trial of docetaxel, prednisone, and pazopanib in men with metastatic castration-resistant prostate cancer

BACKGROUND

Docetaxel prednisone is a standard of care for men with metastatic castration-resistant prostate cancer (mCRPC), and plasma vascular endothelial growth factor (VEGF) levels are a poor prognostic factor in this population; therefore, we evaluated the combination of docetaxel prednisone with pazopanib, an oral VEGF receptor inhibitor, for safety and preliminary efficacy.

METHODS

This is a two-site phase 1b Department of Defense Prostate Cancer Clinical Trials Consortium trial of docetaxel, prednisone, and pazopanib once daily and ongoing androgen deprivation therapy and prophylactic pegfilgrastim in men with mCRPC. The primary endpoint was safety and the determination of a maximum tolerated dose (MTD) through a dose-escalation and expansion design; secondary endpoints included progression-free and overall survival (OS), prostate specific antigen (PSA) declines, radiographic responses, and pharmacokinetic and plasma angiokine biomarker analyses.

RESULTS

Twenty-five men were treated over six dose levels. Pegfilgrastim was added to the regimen after myelosuppression limited dose escalation. With pegfilgrastim, our target MTD of docetaxel 75 mg/m² q3 weeks; prednisone 10 mg daily; and pazopanib 800 mg daily was reached. Eleven additional patients were accrued at this dose level for a total of 36 patients. Dose-limiting toxicities included neutropenia, syncope, and hypertension. Three deaths attributed to study treatment occurred. The objective response rate was 31%; median PFS was 14.1 months (95% confidence interval [CI]: 7.1 and 22.2); and OS was 18.6 months (95% CI: 11.8 and 22.2).

CONCLUSIONS

The combination of docetaxel, prednisone, and pazopanib (with pegfilgrastim) was tolerable at full doses and demonstrated promising efficacy in a relatively poor risk patients with mCRPC. Further development of predictive biomarkers may enrich for patients who receive clinical benefit from this regimen.

Pembrolizumab in men with heavily treated metastatic castrate-resistant prostate cancer

BACKGROUND

Pembrolizumab is approved for patients with metastatic, microsatellite instability (MSI)-high or mismatch repair-deficient (dMMR) solid tumors. However, very few men with prostate cancer were included in these initial studies.

METHODS

We performed a single institution retrospective review of men with metastatic castrate-resistant prostate cancer (mCRPC) who were treated with pembrolizumab. The primary objective was to describe the clinical efficacy of pembrolizumab associated with patient and genomic characteristics.

RESULTS

We identified 48 men who received ≥1 cycle of pembrolizumab for mCRPC. Of these, 94% (45/48) had ≥3 prior lines of therapy for mCRPC. Somatic tumor sequencing was available in 18/48 men (38%). We found that 17% (8/48) had a ≥50% confirmed PSA decline with pembrolizumab, and 8% (4/48) had a ≥90% PSA decline with durations of response ranging from 3.1 to 16.3 months. Two of these four men had mutations in LRP1b, one of whom also had MSH2 loss and was MSI-H and TMB-high. Despite prior progression on enzalutamide, 48% (23/48) of men were treated with concurrent enzalutamide. The median PSA progression-free-survival was 1.8 months (range 0.4-13.7 months), with 31% of patients remaining on pembrolizumab therapy and 54% of men remain alive with a median follow-up of 7.1 months.

CONCLUSIONS

In a heavily pretreated population of men with mCRPC, pembrolizumab was associated with a ≥50% PSA decline in 17% (8/48) of men, including a dramatic ≥90% PSA response in 8% (4/48), two of whom harbored pathogenic LRP1b mutations suggesting that LRP1b mutations may enrich for PD-1 inhibitor responsiveness in prostate cancer.

Improved efficacy against malignant brain tumors with EGFRwt/EGFRvIII targeting immunotoxin and checkpoint inhibitor combinations

BACKGROUND

D2C7-IT is a novel immunotoxin (IT) targeting wild-type epidermal growth factor receptor (EGFRwt) and mutant EGFR variant III (EGFRvIII) proteins in glioblastoma. In addition to inherent tumoricidal activity, immunotoxins induce secondary immune responses through the activation of T cells. However, glioblastoma-induced immune suppression is a major obstacle to an effective and durable immunotoxin-mediated antitumor response. We hypothesized that D2C7-IT-induced immune response could be effectively augmented in combination with αCTLA-4/αPD-1/αPD-L1 therapies in murine models of glioma.

METHODS

To study this, we overexpressed the D2C7-IT antigen, murine EGFRvIII (dmEGFRvIII), in established glioma lines, CT-2A and SMA560. The reactivity and therapeutic efficacy of D2C7-IT against CT-2A-dmEGFRvIII and SMA560-dmEGFRvIII cells was determined by flow cytometry and in vitro cytotoxicity assays, respectively. Antitumor efficacy of D2C7-IT was examined in immunocompetent, intracranial murine glioma models and the role of T cells was assessed by CD4+ and CD8+ T cell depletion. In vivo efficacy of D2C7-IT/αCTLA-4/αPD-1 monotherapy or D2C7-IT+αCTLA-4/αPD-1 combination therapy was evaluated in subcutaneous unilateral and bilateral CT-2A-dmEGFRvIII glioma-bearing immunocompetent mice. Further, antitumor efficacy of D2C7-IT+αCTLA-4/αPD-1/αPD-L1/αTim-3/αLag-3/αCD73 combination therapy was evaluated in intracranial CT-2A-dmEGFRvIII and SMA560-dmEGFRvIII glioma-bearing mice. Pairwise differences in survival curves were assessed using the generalized Wilcoxon test.

RESULTS

D2C7-IT effectively killed CT-2A-dmEGFRvIII (IC₅₀ = 0.47 ng/mL) and SMA560-dmEGFRvIII (IC₅₀ = 1.05 ng/mL) cells in vitro. Treatment of intracranial CT-2A-dmEGFRvIII and SMA560-dmEGFRvIII tumors with D2C7-IT prolonged survival (P = 0.0188 and P = 0.0057, respectively), which was significantly reduced by the depletion of CD4+ and CD8+ T cells. To augment antitumor immune responses, we combined D2C7-IT with αCTLA-4/αPD-1 in an in vivo subcutaneous CT-2A-dmEGFRvIII model. Tumor-bearing mice exhibited complete tumor regressions (4/10 in D2C7-IT+αCTLA-4 and 5/10 in D2C7-IT+αPD-1 treatment groups), and combination therapy-induced systemic antitumor response was effective against both dmEGFRvIII-positive and dmEGFRvIII-negative CT-2A tumors. In a subcutaneous bilateral CT-2A-dmEGFRvIII model, D2C7-IT+αCTLA-4/αPD-1 combination therapies showed dramatic regression of the treated tumors and measurable regression of untreated tumors. Notably, in CT-2A-dmEGFRvIII and SMA560-dmEGFRvIII intracranial glioma models, D2C7-IT+αPD-1/αPD-L1 combinations improved survival, and in selected cases generated cures and protection against tumor re-challenge.

CONCLUSIONS

These data support the development of D2C7-IT and immune checkpoint blockade combinations for patients with malignant glioma.

Pharmacodynamic study of radium-223 in men with bone metastatic castration resistant prostate cancer

BACKGROUND

Radium-223 is a targeted alpha-particle therapy that improves survival in men with metastatic castration resistant prostate cancer (mCRPC), particularly in men with elevated serum levels of bone alkaline phosphatase (B-ALP). We hypothesized that osteomimicry, a form of epithelial plasticity leading to an osteoblastic phenotype, may contribute to intralesional deposition of radium-223 and subsequent irradiation of the tumor microenvironment.

METHODS

We conducted a pharmacodynamic study (NCT02204943) of radium-223 in men with bone mCRPC. Prior to and three and six months after radium-223 treatment initiation, we collected CTCs and metastatic biopsies for phenotypic characterization and CTC genomic analysis. The primary objective was to describe the impact of radium-223 on the prevalence of CTC B-ALP over time. We measured radium-223 decay products in tumor and surrounding normal bone during treatment. We validated genomic findings in a separate independent study of men with bone metastatic mCRPC (n = 45) and publicly accessible data of metastatic CRPC tissues.

RESULTS

We enrolled 20 men with symptomatic bone predominant mCRPC and treated with radium-223. We observed greater radium-223 radioactivity levels in metastatic bone tumor containing biopsies compared with adjacent normal bone. We found evidence of persistent Cellsearch CTCs and B-ALP (+) CTCs in the majority of men over time during radium-223 therapy despite serum B-ALP normalization. We identified genomic gains in osteoblast mimicry genes including gains of ALPL, osteopontin, SPARC, OB-cadherin and loss of RUNX2, and validated genomic alterations or increased expression at the DNA and RNA level in an independent cohort of 45 men with bone-metastatic CRPC and in 150 metastatic biopsies from men with mCRPC.

CONCLUSIONS

Osteomimicry may contribute in part to the uptake of radium-223 within bone metastases and may thereby enhance the therapeutic benefit of this bone targeting radiotherapy.

Immune checkpoint inhibitor response in tumors with LRP1B variants

e14291

Background: Low-density lipoprotein receptor-related protein 1B (LRP1B) is a putative tumor suppressor gene spanning > 500 kb on chromosome 2. A melanoma study previously reported enrichment of LRP1B mutations in responders (34%) to immune checkpoint inhibitors (ICIs) compared with non-responders (3%). Deep deletions in LRP1B are frequently observed in non-small cell lung cancer (NSCLC, 12%), head and neck (11%), cervical (9%), bladder (8%), and prostate cancers (8%). This study examines the clinical response to ICIs in a diverse group of tumor types with LRP1B alterations. Methods: We conducted a single center retrospective study inclusive of all patients (pts) with tumors containing any LRP1B variant who were treated with an ICI between 01/2015 and 11/2018. The primary outcome of the study was to describe the clinical outcomes of patients with LRP1B alterations, with respect to radiographic response to therapy, time on therapy, duration of response, and overall survival. Results: 44 pts with an LRP1B variant were treated with an ICI at Duke between 01/2015 and 11/2018. The most common ICIs were pembrolizumab (29/44, 66%) and nivolumab (12/44, 27%). Tumor types included NSCLC (24/44, 55%), renal cell carcinoma (RCC, 5/44, 11%), and prostate cancer (5/44, 11%). 14 (32%) pts had pathogenic variants (PVs) and 30 pts (68%) had variants of uncertain significance (VUS). Among pts with LRP1b PVs, 36% (95%CI 14%-64%) had radiographic responses (5/14, 2 lung, 1 prostate, 1 RCC, 1 endometrial carcinoma), two of whom were MSI high. As a control, the radiographic response rate among patients with a LRP1b VUS was 10% (95%CI 3%-28%). Of those with PVs, 3 pts had stable disease, one of whom has been on CPI therapy for > 22 months and 5 (36%) remain on therapy, with 2 (14%) pts discontinued due to immune toxicities, and 7 (50%) pts discontinued due to disease progression. The median TMB among responders was 12 (2-150.05 mut/Mb) and the median TMB amongst non-responders was 9.5 (6-18 mut/Mb). Conclusions: In a tumor agnostic population of pts harboring LRP1B PVs, 36% of pts have responses to ICI. The majority of responders were MSS and TMB low, which may suggest that PV in LRP1B may independently predict for response to ICI. Prospective and multicenter validation is now needed.

Safety of nivolumab in combination with dendritic cell vaccines in recurrent high-grade glioma

e13526

Background: Recurrence of high-grade glioma (HGG) (WHO grade III-IV) is a nearly universal phenomenon and necessitates the development of new therapeutic modalities. Two possible immunotherapeutic modalities are checkpoint blockade with agents such as nivolumab, a blocking antibody against the inhibitory checkpoint programmed cell death-1 (PD-1), and dendritic cell (DC) vaccination. We have shown in phase 1 and 2 trials that DC vaccination against the glioblastoma (GBM)-associated antigen human cytomegalovirus pp65-lysosomal-associated membrane protein (CMVpp65) is safe and possesses potential benefit. We hypothesized that nivolumab-induced immune checkpoint blockade could enhance efficacy of DC vaccination. Therefore, we undertook a phase 1 study to evaluate safety of nivolumab in combination with CMVpp65 mRNA pulsed DC vaccination in subjects with first or second recurrence of resectable HGG. Methods: We performed a phase 1, single-center, randomized study of nivolumab alone versus nivolumab + DC vaccination prior to planned surgical resection for both groups. We administered nivolumab 3 mg/kg IV q2weeks for 8 weeks followed by surgery and planned continuation of nivolumab. For the group receiving nivolumab + DC vaccination, we administered 3 vaccines before surgical resection with both groups receiving 5 planned post-resection DC vaccines. Primary endpoint was safety assessment using NCI-CTCAE 4.03. Results: We enrolled 6 subjects (4: GBM, 1: anaplastic astrocytoma, 1: anaplastic oligodendroglioma) with 3 receiving nivolumab alone and 3 receiving nivolumab + DC vaccination. Age range was 45-63 years subjects. We documented similar adverse events in both groups with most common grade 1-2 toxicities being fatigue (2 subjects, nivolumab alone) and thrombocytopenia (2 subjects, nivolumab + DC vaccine). Grade 4 toxicities included wound infection (2 subjects, nivolumab + DC vaccine) and meningitis (1 subject, nivolumab + DC vaccine). While we designed the study to enroll 66 subjects, we terminated the study early in light of CheckMate 143 phase III data showing nivolumab did not improve overall survival in recurrent GBM. Conclusions: Safety of nivolumab + DC vaccination in recurrent HGG is similar to nivolumab alone. Continued evaluation of new therapeutics including immunotherapy is underway for this patient population. Clinical trial information: NCT02529072.

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.

Variation in outcome reporting in randomized controlled trials of interventions for prevention and treatment of fetal growth restriction

OBJECTIVE

Although fetal growth restriction (FGR) is well known to be associated with adverse outcomes for the mother and offspring, effective interventions for the management of FGR are yet to be established. Trials reporting interventions for the prevention and treatment of FGR may be limited by heterogeneity in the underlying pathophysiology. The aim of this study was to conduct a systematic review of outcomes reported in randomized controlled trials (RCTs) assessing interventions for the prevention or treatment of FGR, in order to identify and categorize the variation in outcome reporting.

METHODS

MEDLINE, EMBASE and The Cochrane Library were searched from inception until August 2018 for RCTs investigating therapies for the prevention and treatment of FGR. Studies were assessed systematically and data on outcomes that were reported in the included studies were extracted and categorized. The methodological quality of the included studies was assessed using the Jadad score.

RESULTS

The search identified 2609 citations, of which 153 were selected for full-text review and 72 studies (68 trials) were included in the final analysis. There were 44 trials relating to the prevention of FGR and 24 trials investigating interventions for the treatment of FGR. The mean Jadad score of all studies was 3.07, and only nine of them received a score of 5. We identified 238 outcomes across the included studies. The most commonly reported were birth weight (88.2%), gestational age at birth (72.1%) and small-for-gestational age (67.6%). Few studies reported on any measure of neonatal morbidity (27.9%), while adverse effects of the interventions were reported in only 17.6% of trials.

CONCLUSIONS

There is significant variation in outcome reporting across RCTs of therapies for the prevention and treatment of FGR. The clinical applicability of future research would be enhanced by the development of a core outcome set for use in future trials. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

MTAP Loss Promotes Stemness in Glioblastoma and Confers Unique Susceptibility to Purine Starvation

Homozygous deletion of methylthioadenosine phosphorylase (MTAP) is one of the most frequent genetic alterations in glioblastoma (GBM), but its pathologic consequences remain unclear. In this study, we report that loss of MTAP results in profound epigenetic reprogramming characterized by hypomethylation of PROM1/CD133-associated stem cell regulatory pathways. MTAP deficiency promotes glioma stem-like cell (GSC) formation with increased expression of PROM1/CD133 and enhanced tumorigenicity of GBM cells and is associated with poor prognosis in patients with GBM. As a combined consequence of purine production deficiency in MTAP-null GBM and the critical dependence of GSCs on purines, the enriched subset of CD133⁺ cells in MTAP-null GBM can be effectively depleted by inhibition of de novo purine synthesis. These findings suggest that MTAP loss promotes the pathogenesis of GBM by shaping the epigenetic landscape and stemness of GBM cells while simultaneously providing a unique opportunity for GBM therapeutics. SIGNIFICANCE: This study links the frequently mutated metabolic enzyme MTAP to dysregulated epigenetics and cancer cell stemness and establishes MTAP status as a factor for consideration in characterizing GBM and developing therapeutic strategies.

Health economic analysis of a cluster-randomised trial (OptiBIRTH) designed to increase rates of vaginal birth after caesarean section

OBJECTIVE

To perform a health economic analysis of an intervention designed to increase rates of vaginal birth after caesarean, compared with usual care.

DESIGN

Economic analysis alongside the cluster-randomised OptiBIRTH trial (Optimising childbirth by increasing vaginal birth after caesarean section (VBAC) through enhanced women-centred care).

SETTING

Fifteen maternity units in three European countries - Germany (five), Ireland (five), and Italy (five) - with relatively low VBAC rates.

POPULATION

Pregnant women with a history of one previous lower-segment caesarean section; sites were randomised (3:2) to intervention or control.

METHODS

A cost-utility analysis from both societal and health-services perspectives, using a decision tree.

MAIN OUTCOME MEASURES

Costs and resource use per woman and infant were compared between the control and intervention group by country, from pregnancy recognition until 3 months postpartum. Based on the caesarean section rates, and maternal and neonatal morbidities and mortality, the incremental cost-utility ratios were calculated per country.

RESULTS

The mean difference in costs per quality-adjusted life years (QALYs) gained from a societal perspective between the intervention and the control group, using a probabilistic sensitivity analysis, was: €263 (95% CI €258-268) and 0.008 QALYs (95% CI 0.008-0.009 QALYs) for Germany, €456 (95% CI €448-464) and 0.052 QALYs (95% CI 0.051-0.053 QALYs) for Ireland, and €1174 (95% CI €1170-1178) and 0.006 QALYs (95% CI 0.005-0.007 QALYs) for Italy. The incremental cost-utility ratios were €33,741/QALY for Germany, €8785/QALY for Ireland, and €214,318/QALY for Italy, with a 51% probability of being cost-effective for Germany, 92% for Ireland, and 15% for Italy.

CONCLUSION

The OptiBIRTH intervention was likely to be cost-effective in Ireland and Germany.

TWEETABLE ABSTRACT

The OptiBIRTH intervention (to increase VBAC rates) is likely to be cost-effective in Germany and Ireland.

Single-institution retrospective review of patients with recurrent glioblastoma treated with bevacizumab in clinical practice

BACKGROUND AND AIMS

This retrospective review of patients with recurrent glioblastoma treated at the Preston Robert Tisch Brain Tumor Center investigated treatment patterns, survival, and safety with bevacizumab in a real-world setting.

METHODS

Adult patients with glioblastoma who initiated bevacizumab at disease progression between January 1, 2009, and May 14, 2012, were included. A Kaplan-Meier estimator was used to describe overall survival (OS), progression-free survival (PFS), and time to greater than or equal to 20% reduction in Karnofsky Performance Status (KPS). The effect of baseline demographic and clinical factors on survival was examined using a Cox proportional hazards model. Adverse event (AE) data were collected.

RESULTS

Seventy-four patients, with a median age of 59 years, were included in this cohort. Between bevacizumab initiation and first failure, defined as the first disease progression after bevacizumab initiation, biweekly bevacizumab and bevacizumab/irinotecan were the most frequently prescribed regimens. Median duration of bevacizumab treatment until failure was 6.4 months (range, 0.5-58.7). Median OS and PFS from bevacizumab initiation were 11.1 months (95% confidence interval [CI], 7.3-13.4) and 6.4 months (95% CI, 3.9-8.5), respectively. Median time to greater than or equal to 20% reduction in KPS was 29.3 months (95% CI, 13.8-∞). Lack of corticosteroid usage at the start of bevacizumab therapy was associated with both longer OS and PFS, with a median OS of 13.2 months (95% CI, 8.6-16.6) in patients who did not initially require corticosteroids versus 7.2 months (95% CI, 4.8-12.5) in those who did (P = 0.0382, log-rank), while median PFS values were 8.6 months (95% CI, 4.6-9.7) and 3.7 months (95% CI, 2.7-6.6), respectively (P = 0.0243, log-rank). Treatment failure occurred in 70 patients; 47 of whom received salvage therapy, and most frequently bevacizumab/carboplatin (7/47; 14.9%). Thirteen patients (18%) experienced a grade 3 AE of special interest for bevacizumab.

CONCLUSIONS

Treatment patterns and outcomes for patients with recurrent glioblastoma receiving bevacizumab in a real-world setting were comparable with those reported in prospective clinical trials.

Prospective Multicenter Validation of Androgen Receptor Splice Variant 7 and Hormone Therapy Resistance in High-Risk Castration-Resistant Prostate Cancer: The PROPHECY Study

PURPOSE

Androgen receptor splice variant 7 (AR-V7) results in a truncated receptor, which leads to ligand-independent constitutive activation that is not inhibited by anti-androgen therapies, including abiraterone or enzalutamide. Given that previous reports suggested that circulating tumor cell (CTC) AR-V7 detection is a poor prognostic indicator for the clinical efficacy of secondary hormone therapies, we conducted a prospective multicenter validation study.

PATIENTS AND METHODS

PROPHECY (ClinicalTrials.gov identifier: NCT02269982) is a multicenter, prospective-blinded study of men with high-risk mCRPC starting abiraterone acetate or enzalutamide treatment. The primary objective was to validate the prognostic significance of baseline CTC AR-V7 on the basis of radiographic or clinical progression free-survival (PFS) by using the Johns Hopkins University modified-AdnaTest CTC AR-V7 mRNA assay and the Epic Sciences CTC nuclear-specific AR-V7 protein assay. Overall survival (OS) and prostate-specific antigen responses were secondary end points.

RESULTS

We enrolled 118 men with mCRPC who were starting abiraterone or enzalutamide treatment. AR-V7 detection by both the Johns Hopkins and Epic AR-V7 assays was independently associated with shorter PFS (hazard ratio, 1.9 [95% CI, 1.1 to 3.3; P = .032] and 2.4 [95% CI, 1.1 to 5.1; P = .020], respectively) and OS (hazard ratio, 4.2 [95% CI, 2.1 to 8.5] and 3.5 [95% CI, 1.6 to 8.1], respectively) after adjusting for CTC number and clinical prognostic factors. Men with AR-V7–positive mCRPC had fewer confirmed prostate-specific antigen responses (0% to 11%) or soft tissue responses (0% to 6%). The observed percentage agreement between the two AR-V7 assays was 82%.

CONCLUSION

Detection of AR-V7 in CTCs by two blood-based assays is independently associated with shorter PFS and OS with abiraterone or enzalutamide, and such men with mCRPC should be offered alternative treatments.

PEAX: Men with metastatic castrate-resistant prostate cancer (mCRPC) treated with either sipuleucel-T (SIP-T), enzalutamide (ENZA) or abiraterone acetate (ABI) undergoing cardiopulmonary exercise testing (CPET)

281

Background: Both ENZA and ABI are associated with significant toxicity to the cardiovascular-musculoskeletal system and physical side effects. However whether they cause a decline in cardiorespiratory fitness (CRF), as conventional ADT does, has not been studied. We hypothesized that men treated with ENZA or ABI would have a significant decline in CRF, whereas those treated with SIP-T would not. Methods: Men starting standard of care (SOC) ENZA or ABI for asymptomatic or minimally symptomatic mCRPC were treated per institutional standards. SIP-T (SOC) is the control arm. Primary endpoint is change in VO2peak from baseline to week 21 by CPET. Secondary endpoints include measurement of functional status by patient reported outcomes (FACT-P, FACIT-Fatigue) and physician reported outcomes (ECOG PS, AEs). Results: In this single-site, prospective, parallel group, observational study, 28 pts completed the baseline and week 21 CPET and secondary assessments. Median age was 68 years; 86% were white. Two-thirds of pts had ECOG PS 0; the rest had PS 1. 93% were nonsmokers. Intention to treat analyses for mean 21-week change from baseline with a 95% confidence interval (CI) for each assessment by arm are presented in the Table. Conclusions: Unexpectedly, there was great heterogeneity in 21-week ΔVO2peak within each therapy group. Reasons for heterogeneity will be explored and correlated with baseline variables, clinical status, and questionnaire data. A low percentage of patients exercised regularly. Larger trials of exercise training interventions in this setting are warranted. Clinical trial information: NCT02353715. [Table: see text]

Pembrolizumab in men with heavily treated metastatic castration-resistant prostate cancer (mCRPC)

172

Background: Pembrolizumab is approved for patients with metastatic, microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) solid tumors who have progressed on prior therapy and have no satisfactory treatment options. However, very few men with PC were included in these initial studies. We evaluated the clinical activity of pembro in a cohort of men with mCRPC and their responses based on molecular genotype. Methods: We performed a retrospective, IRB-approved review of all men with mCRPC in the Duke Cancer Center who were treated with pembro in order to define the duration of therapy, time to PSA-progression, and imaging responses according to prior/concurrent therapy and by molecular subtypes. Results: We identified 51 men who received ≥1 cycle of pembro for mCRPC. Of these, 86% (44/51) had ≥3 prior lines of therapy after ADT, including abiraterone (88%), docetaxel (86%), enzalutamide (enza, 80%), and sipuleucel-T (74%). Somatic tumor sequencing was available in 18/51 men (35%). We found that 16% (8/51) had a ≥50% confirmed PSA decline with pembro, with 8% (4/51) having ≥90% PSA decline. Two of 4 had mutations in LRP1b, one of whom also had MSH2loss and was MSI-H and TMB-high; of the other 2 patients, one had no actionable mutations and the other had no genetic testing available. Fifty-nine percent (30/51) of men were treated with concurrent therapy with pembro (most commonly enza); however, all patients with PSA responses who were concurrently treated with enza had prior documented PSA progression on enza. Overall, the median time to discontinuation of treatment was 5.8 months (mo), median PSA-PFS, defined as a 25% increase in PSA from baseline, was 1.4 mo, and median OS was 6.7 mo. Among patients with ≥50% PSA decline, duration of response ranged from 3.7 to 16.3 mo with 5 patients with ongoing responses. Conclusions: In a heavily pre-treated population of men with mCRPC, pembrolizumab was associated with a ≥50% PSA decline in 16% (8/51) of men, including a dramatic ≥90% PSA response in 8% (4/51), two of whom harbored LRP1b mutations, one also with MSH2loss and a MSI-H tumor. Large prospective studies with genomic testing are needed to identify men with the greatest chance for response to immunotherapy.

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 >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.

Preventing Lck Activation in CAR T Cells Confers Treg Resistance but Requires 4-1BB Signaling for Them to Persist and Treat Solid Tumors in Nonlymphodepleted Hosts

PURPOSE

Chimeric antigen receptor (CAR) T cells have shown promise against solid tumors, but their efficacy has been limited, due in part, to immunosuppression by CD4+FoxP3+ regulatory T cells (Tregs). Although lymphodepletion is commonly used to deplete Tregs, these regimens are nonspecific, toxic, and provide only a narrow window before Tregs repopulate hosts. Importantly, CARs have also been shown to inadvertently potentiate Tregs by providing a source of IL2 for Treg consumption. We explored whether disruption of the IL2 axis would confer efficacy against solid tumors without the need for lymphodepletion.

EXPERIMENTAL DESIGN

We developed second- (CD28z) and third- (CD28-4-1BBz) generation CARs targeting EGFRvIII. To eliminate secretion of IL2, 2 amino acid substitutions were introduced in the PYAP Lck-binding motif of the CD28 domain (ΔCD28). We evaluated CARs against B16 melanomas expressing EGFRvIII.

RESULTS

CD28z CARs failed to engraft in vivo. Although 4-1BB addition improved expansion, CD28-4-1BBz CARs required lymphodepletion to treat solid tumors. CARs deficient in Lck signaling, however, significantly retarded tumor growth without a need for lymphodepletion and this was dependent on inclusion of 4-1BB. To evaluate CAR vulnerability to Tregs, we lymphodepleted mice and transferred CARs alone or with purified Tregs. Cotransfer with Tregs abrogated the efficacy of CD28-4-1BBz CARs, whereas the efficacy of ΔCD28-4-1BBz CARs remained unperturbed.

CONCLUSIONS

In the absence of lymphodepletion, CARs targeting solid tumors are hindered by Treg immunosuppression and poor persistence. Here, CARs were modified to circumvent Treg suppression and to simultaneously improve in vivo engraftment. Modified CARs treated solid tumors without a need for lymphodepletion.