Michael Krainer’s research while affiliated with Medical University of Vienna and other places

Circulating tumor cells (CTCs) are an established prognostic marker in metastatic prostate cancer (PrC) but have received little attention in localized high-risk disease. Peripheral blood was obtained from patients with early intermediate and high-risk PrC (n = 15) at baseline, after radiotherapy, and during follow-up, as well as from metastatic PrC patients (n = 23). CTCs were enriched using the microfluidic Parsortix® technology. CTC-related marker were quantified with qPCR and RNA in-situ hybridization (ISH). Positivity and associations to clinical parameters were assessed using McNemar test, Fisher Exact test or log-rank test. The overall positivity was high in both cohorts (87.0% metastatic vs. 66.7% early at baseline). A high concordance of qPCR and RNA ISH was achieved. In metastatic PrC, PSA and PSMA were prognostic for shorter overall survival. In early PrC patients, an increase of positive transcripts per blood sample was observed from before to after radiation therapy, while a decrease of positive markers was observed during follow-up. CTC analysis using the investigated qPCR marker panel serves as tool for achieving high detection rates of PrC patient samples even in localized disease. RNA ISH offers the advantage of confirming these markers at the single cell level. Employing the clinically relevant marker PSMA, our CTC approach can be used for diagnostic purposes to screen patients profiting from PSMA-directed PET-CT or PSMA-targeted therapy.

22 Background: In preliminary analyses from the randomized phase 2, open-label CheckMate 650 trial, nivolumab (NIVO) 1 mg/kg (N1) plus ipilimumab (IPI) 3 mg/kg (I3) Q3W × 4 doses showed clinical activity in patients (pts) with post-chemotherapy (post-CT) mCRPC, particularly those with high tumor mutational burden (TMB), but early toxicity contributed to treatment discontinuations. Here, we report results from pts with post-CT mCRPC receiving alternative NIVO+IPI dosing regimens vs IPI alone vs cabazitaxel (CABA) in CheckMate 650. Methods: Newly enrolled pts previously treated with docetaxel for mCRPC were randomized 2:2:1:2 to cohorts D1 (NIVO 3 mg/kg [N3] + IPI 1 mg/kg [I1] Q3W × 4 doses then NIVO 480 mg Q4W), D2 (N1 Q3W × 8 doses + I3 Q6W × 4 doses then NIVO 480 mg Q4W), D3 (I3 Q3W × 4 doses), or D4 (CABA 20 or 25 mg/m ² Q3W + prednisone 10 mg × 10 doses). Crossover from cohorts D3 and D4 to cohort D1 was allowed after radiographic progressive disease. Outcomes included safety, objective response rate (ORR), prostate-specific antigen response rate (PSA-RR; confirmed PSA decline ≥ 50% from baseline), radiographic progression-free survival (rPFS) per blinded independent central review (BICR), and overall survival (OS). Associations between efficacy and TMB were assessed. Results: Overall, 259 pts were randomized (D1, n = 73; D2, n = 74; D3, n = 38; D4, n = 74). Median (range) follow-up for OS was 23.3 (6.0–31.5) months. In the NIVO+IPI cohorts (D1 and D2), median duration of therapy was 2.8 and 2.4 months; the median number of IPI doses received was 4 and 2, and 15% and 26% of pts discontinued due to study drug toxicity, respectively. Two pts died due to study drug toxicity (1 each in cohorts D1 and D2). Key safety and efficacy data are shown. Several pts in cohorts D1 and D2 showed notable reductions (75-100%) in tumor size and PSA. Approximately one-third of pts in cohorts D3 and D4 crossed over to D1. Based on preliminary analyses in small numbers of evaluable pts, there was no clear and consistent association between efficacy and tissue or blood TMB in the NIVO+IPI cohorts (D1 and D2). Conclusions: These results further support the clinical activity of NIVO+IPI in select pts with post-CT mCRPC. Detailed evaluations of the characteristics of responders to NIVO+IPI, including more expansive biomarker analyses, are warranted. Clinical trial information: NCT02985957 . [Table: see text]

Simple Summary Circulating tumor cells are precursors of distant metastasis in many cancer types. These cells circulate in the peripheral blood, which can be analyzed in a non-invasive procedure to identify patients at risk to develop metastases. In order to improve non-invasive diagnostic procedures for breast cancer, we aimed at investigating gene transcripts as liquid biopsy markers in the blood employing density gradient centrifugation as a cost- and time-saving method for the isolation of the target cells. We were able to detect the selected biomarkers in 86.1% of metastatic and 31.1% of early breast cancer patients. The presence of some markers were significantly related with shorter survival of the patients. Our data suggest that these transcripts have the potential to identify patients with poor prognosis who might benefit from further clinical intervention. Abstract Liquid biopsy is a promising tool for therapy monitoring of cancer patients, but a need for further research in this field exists in order to improve sensitivity, specificity, standardization and minimize costs. In our present study, we evaluated two panels of transcripts related with the presence of circulating tumor cells (CTCs) (Panel 1: CK19, EpCAM, SCGB2A2 and Panel 2: EMP2, SLC6A8, HJURP, MAL2, PPIC and CCNE2) in two cohorts of breast cancer patients (metastatic and early). A blood cell fraction possibly containing CTCs was isolated with density gradient centrifugation, followed by RNA isolation and qPCR using TaqMan® or RT-qPCR using hybridization probes. The positivity rates of the investigated panels were similar, albeit higher in metastatic (69.4% Panel 1, 75.0% Panel 2; total 86.1%) compared to early (18.9% Panel 1, 23.3% Panel 2; total 31.1%) breast cancer patients. CK19, SCGB2A2, EMP2, HJURP, MAL2, and CCNE2 individually correlated with shorter overall survival in the metastatic patient cohort. The findings highlight the additional value of Panel 2 markers, which are in contrast to CK19 and EpCAM not solely linked to an epithelial phenotype.

Recently, the development of immunotherapies such as cellular therapy, monoclonal antibodies, vaccines and immunomodulators has revolutionized the treatment of various cancer entities. In order to close the existing gaps in knowledge about cellular immunotherapy, specifically focusing on the chimeric antigen receptors (CAR) T-cells, their benefits and application in clinical settings, we conducted a comprehensive systematic review. Two co-authors independently searched the literature and characterized the results. Out of 183 records, 26 were considered eligible. This review provides an overview of the cellular immunotherapy landscape in treating prostate cancer, honing in on the challenges of employing CAR T-cell therapy. CAR T-cell therapy is a promising avenue for research due to the presence of an array of different tumor specific antigens. In prostate cancer, the complex microenvironment of the tumor vastly contributes to the success or failure of immunotherapies.

Purpose Circulating tumor cells (CTCs) hold promise to be a non-invasive measurable biomarker in all cancer stages. Because the analysis of CTCs is still a technical challenge, we compared different types of microfluidic enrichment protocols to isolate these rare cells from the blood. Methods Blood samples from patients with early and metastatic breast cancer (BC) were processed using the microfluidic Parsortix® technology employing (i) a single-step cell separation using the standard GEN3D6.5 microfluidic cassette, (ii) a two-step separation with an upfront pre-enrichment, and (iii) a two-step separation with a different type of cassette. In the enriched cells, the gene expression levels of CTC-related transcripts were assessed using quantitative real-time PCR (qPCR) by Taqman® and Lightcycler (LC) technology. Results 23/60 (38.3%) BC samples were assigned as positive due to the presence of at least one gene marker beyond the threshold level. The prevalence of epithelial markers was significantly higher in metastatic compared to early BC ( EpCAM : 31.3% vs. 7.3%; CK19 : 21.1% vs. 2.4%). A high level of concordance was observed between CK19 assessed by Taqman® and LC technology, and for detection of the BC-specific gene SCGB2A2 . An upfront pre-enrichment resulted in lower leukocyte contamination, at the cost of fewer tumor cells captured. Conclusion The Parsortix® system offers both reasonable recovery of tumor cells and depletion of contaminating leukocytes when the single-step separation using the GEN3D6.5 cassette is employed. Careful selection of suitable markers and cut-off thresholds is an essential point for the subsequent molecular analysis of the enriched cells.

Importance: DCVAC/PCa is an active cellular immunotherapy designed to initiate an immune response against prostate cancer. Objective: To evaluate the efficacy and safety of DCVAC/PCa plus chemotherapy followed by DCVAC/PCa maintenance treatment in patients with metastatic castration-resistant prostate cancer (mCRPC). Design, setting, and participants: The VIABLE double-blind, parallel-group, placebo-controlled, phase 3 randomized clinical trial enrolled patients with mCRPC among 177 hospital clinics in the US and Europe between June 2014 and November 2017. Data analyses were performed from December 2019 to July 2020. Interventions: Eligible patients were randomized (2:1) to receive DCVAC/PCa (add-on and maintenance) or placebo, both in combination with chemotherapy (docetaxel plus prednisone). The stratification was applied according to geographical region (US or non-US), prior therapy (abiraterone, enzalutamide, or neither), and Eastern Cooperative Oncology Group performance status (0-1 or 2). DCVAC/PCa or placebo was administered subcutaneously every 3 to 4 weeks (up to 15 doses). Main outcomes and measures: The primary outcome was overall survival (OS), defined as the time from randomization until death due to any cause, in all randomized patients. Survival was compared using 2-sided log-rank test stratified by geographical region, prior therapy with abiraterone and/or enzalutamide, and Eastern Cooperative Oncology Group performance status. Results: A total of 1182 men with mCRPC (median [range] age, 68 [46-89] years) were randomized to receive DCVAC/PCa (n = 787) or placebo (n = 395). Of these, 610 (81.8%) started DCVAC/PCa, and 376 (98.4%) started placebo. There was no difference in OS between the DCVAC/PCa and placebo groups in all randomized patients (median OS, 23.9 months [95% CI, 21.6-25.3] vs 24.3 months [95% CI, 22.6-26.0]; hazard ratio, 1.04; 95% CI, 0.90-1.21; P = .60). No differences in the secondary efficacy end points (radiological progression-free survival, time to prostate-specific antigen progression, or skeletal-related events) were observed. Treatment-emergent adverse events related to DCVAC/PCa or placebo occurred in 69 of 749 (9.2%) and 48 of 379 (12.7%) patients, respectively. The most common treatment-emergent adverse events (DCVAC/PCa [n = 749] vs placebo [n = 379]) were fatigue (271 [36.2%] vs 152 [40.1%]), alopecia (222 [29.6%] vs 130 [34.3%]), and diarrhea (206 [27.5%] vs 117 [30.9%]). Conclusions and relevance: In this phase 3 randomized clinical trial, DCVAC/PCa combined with docetaxel plus prednisone and continued as maintenance treatment did not extend OS in patients with mCRPC and was well tolerated. Trial registration: ClinicalTrials.gov Identifier: NCT02111577.

Simple Summary We deeply characterized a frequently used mouse model of prostate cancer and found cellular and molecular regulators of resistance against antihormonal treatment, such as basal cell function and MALAT1 gene fusions. As these mechanisms also occur in human disease, our findings highlight the importance of this model for human cancer and may be helpful for future research focusing on overcoming antihormonal treatment resistance. Abstract Targeting testosterone signaling through androgen deprivation therapy (ADT) or antiandrogen treatment is the standard of care for advanced prostate cancer (PCa). Although the large majority of patients initially respond to ADT and/or androgen receptor (AR) blockade, most patients suffering from advanced PCa will experience disease progression. We sought to investigate drivers of primary resistance against antiandrogen treatment in the TRAMP mouse model, an SV-40 t-antigen driven model exhibiting aggressive variants of prostate cancer, castration resistance, and neuroendocrine differentiation upon antihormonal treatment. We isolated primary tumor cell suspensions from adult male TRAMP mice and subjected them to organoid culture. Basal and non-basal cell populations were characterized by RNA sequencing, Western blotting, and quantitative real-time PCR. Furthermore, effects of androgen withdrawal and enzalutamide treatment were studied. Basal and luminal TRAMP cells exhibited distinct molecular signatures and gave rise to organoids with distinct phenotypes. TRAMP cells exhibited primary resistance against antiandrogen treatment. This was more pronounced in basal cell-derived TRAMP organoids when compared to luminal cell-derived organoids. Furthermore, we found MALAT1 gene fusions to be drivers of antiandrogen resistance in TRAMP mice through regulation of AR. Summarizing, TRAMP tumor cells exhibited primary resistance towards androgen inhibition enhanced through basal cell function and MALAT1 gene fusions.

Prostate cancer (PCa) is the most common non-cutaneous cancer in men in Europe and is predicted to exhibit declining mortality in the European Union (EU) due to various recent improvements in treatment. The goal of this short review is to give insight into the European treatment landscape of PCa, while focusing on improvements in care.