Management of advanced prostate cancer in the Asia-Pacific region: Summary of the Asia-Pacific Advanced Prostate Cancer Consensus Conference 2023.

AIM: The aim of the third Asia-Pacific Advanced Prostate Cancer Consensus Conference (APAC APCCC 2023) was to discuss the application in the Asia-Pacific (APAC) region of consensus statements from the 4th Advanced Prostate Cancer Consensus Conference (APCCC 2022). METHODS: The one-day meeting in July 2023 brought together 27 experts from 14 APAC countries. The meeting covered five topics: (1) Intermediate- and high-risk and locally advanced prostate cancer; (2) Management of newly diagnosed metastatic hormone-sensitive prostate cancer; (3) Management of non-metastatic castration-resistant prostate cancer; (4) Homologous recombination repair mutation testing; (5) Management of metastatic castration-resistant prostate cancer. Pre- and post-symposium polling gathered APAC-specific responses to APCCC consensus questions and insights on current practices and challenges in the APAC region. RESULTS: APAC APCCC highlights APAC-specific considerations in an evolving landscape of diagnostic technologies and treatment innovations for advanced prostate cancer. While new technologies are available in the region, cost and reimbursement continue to influence practice significantly. Individual patient considerations, including the impact of chemophobia on Asian patients, also influence decision-making. CONCLUSION: The use of next-generation imaging, genetic testing, and new treatment combinations is increasing the complexity and duration of prostate cancer management. Familiarity with new diagnostic and treatment options is growing in the APAC region. Insights highlight the continued importance of a multidisciplinary approach that includes nuclear medicine, genetic counseling, and quality-of-life expertise. The APAC APCCC meeting provides an important opportunity to share practice and identify APAC-specific issues and considerations in areas of low evidence where clinical experience is growing.

Comparing outcomes of transperineal to transrectal prostate biopsies performed under local anaesthesia.

Objectives: To compare and review the outcomes of transperineal (TP) prostate biopsies with transrectal (TR) biopsies performed under local anaesthesia (LA). A review of the relevant published literature is presented. Patients and methods: We prospectively analysed 212 consecutive patients who underwent TP prostate biopsy using the PrecisionPoint™ access system under LA, at our institution from October 2018 to March 2020. We compared the morbidity and cancer detection rates using this approach with our historical cohort of 178 patients who underwent the TR biopsy method under LA. Results: The mean age of the TP biopsy group was 69 years, and median prostate specific antigen (PSA) was 13.17 ng/ml. Mean prostate volume was 45.1 ml with a median of 12 cores taken per patient. Patient demographics were similar to our TR biopsy cohort, with mean age of 68 years, median PSA of 10.76, mean prostate volume of 49.6 ml and a median of 12 cores taken per patient. The TP biopsy group had 0% sepsis rate compared with 2.2% in the TR group. Haematuria in the TP versus transrectal ultrasonography (TRUS) cohort was 0.9% versus 1.7%, respectively. The TP biopsy-naïve group had a cancer detection rate of 63.5% (127 of 200 patients), of which 84% were ≥Grade Group 2 (GG2). The TR biopsy-naïve group had cancer detection rate of 50% (86 of 172 patients), of which 87.2% was ≥GG2. Conclusion: TP prostate biopsy had less urinary infectious and septic complications compared with the TR approach. Our data suggest at least comparable diagnostic accuracy between both biopsy approaches.

Health-related quality of life, psychological well-being, and sexual function in patients with benign prostatic hyperplasia after prostatic surgery.

AIMS AND BACKGROUND: Patients with benign prostatic hyperplasia (BPH) may receive prostatic surgery due to severe lower urinary tract symptoms (LUTS). This study aimed to investigate the health-related quality of life (HRQoL), psychological well-being, and sexual function of patients with BPH after prostatic surgery and identify the predictors of HRQoL among this group of patients. METHODS: This was a cross-sectional, descriptive, correlational study. A convenience sample of 94 participants was recruited from a urology center in a tertiary public hospital in Singapore. The 12-item Short Form Health Survey version 2 (SF-12v2), International Prostate Symptom Score (IPSS), Hospital Anxiety and Depression Scale (HADS), and 5-item International Index of Erectile Function (IIEF-5) were used to measure the study variables. RESULTS: Compared to the general population norms and the findings of similar studies conducted in western countries, this group of patients reported poorer physical health but better mental health as assessed by SF-12v2. Despite the prostatic surgery, over a quarter of the patients experienced moderate LUTS, and 13.8% experienced severe erectile dysfunction. Multiple linear regression analysis identified that LUTS (B=-0.51, p=0.02) and maximum flow rate (B=-0.23, p=0.02) predicted poor physical health, accounting for 45.9% of variance, while HADS-Anxiety (B=-1.07, p<0.01) and LUTS (B=-0.32, p=0.03) predicted poor mental health, accounting for 57.2% of variance. CONCLUSION: The physical health of BPH patients with prostatic surgery was poor, with many suffering moderate LUTS and sexual dysfunction. Special attention should be given to those patients with severe LUTS who have a low maximum flow rate or have anxiety symptoms.

Health-related quality of life and psychological well-being in patients with benign prostatic hyperplasia.

AIMS AND OBJECTIVES: To examine the health-related quality of life and psychological well-being of patients with benign prostatic hyperplasia and identify the predictive factors of health-related quality of life. BACKGROUND: Benign prostatic hyperplasia is highly prevalent in ageing men and causes bothersome lower urinary tract symptoms, which has a negative impact on their health-related quality of life. The current practice of managing benign prostatic hyperplasia focuses on relieving physical symptoms. However, the impact of benign prostatic hyperplasia on the patients' health-related quality of life and psychological well-being remains understudied, especially in the Asian population. DESIGN: A descriptive correlational survey study. METHODS: A convenience sample of 97 patients with benign prostatic hyperplasia was recruited at an outpatient urology clinic of a tertiary hospital in Singapore. The health-related quality of life, lower urinary tract symptoms and psychological well-being of the participants were assessed using the 12-item Short-Form Health Survey, International Prostate Symptom Score and the Hospital Anxiety and Depression Scale, respectively. RESULTS: The health-related quality of life scores were low with physical and mental health component scores of 47·0 and 48·9, respectively, as assessed by the 12-item Short-Form Health Survey. There was a high prevalence of anxiety (10·3%) and depression (21·6%). Correlation analysis revealed significantly negative relationships between lower urinary tract symptoms, anxiety, depression and physical and mental health dimensions of the 12-item Short-Form Health Survey. Multiple linear regression analysis further identified that postvoid residual urine and lower urinary tract symptoms were predictive factors of the physical health dimension, whereas anxiety and depression were predictive factors of the mental health dimension of the 12-item Short-Form Health Survey. CONCLUSIONS: The health-related quality of life of patients with benign prostatic hyperplasia was poor, and their psychological well-being was severely affected. Postvoid residual urine, lower urinary tract symptoms, anxiety and depression were identified to be significant predictive factors of the health-related quality of life of patients with benign prostatic hyperplasia. RELEVANCE TO CLINICAL PRACTICE: Findings from this study provide useful evidence-based information for healthcare professionals in the development and implementation of effective and culturally sensitive interventions to improve the health-related quality of life and psychological well-being of patients with benign prostatic hyperplasia.

Automated dynamic fed-batch process and media optimization for high productivity cell culture process development.

Current industry practices for large-scale mammalian cell cultures typically employ a standard platform fed-batch process with fixed volume bolus feeding. Although widely used, these processes are unable to respond to actual nutrient consumption demands from the culture, which can result in accumulation of by-products and depletion of certain nutrients. This work demonstrates the application of a fully automated cell culture control, monitoring, and data processing system to achieve significant productivity improvement via dynamic feeding and media optimization. Two distinct feeding algorithms were used to dynamically alter feed rates. The first method is based upon on-line capacitance measurements where cultures were fed based on growth and nutrient consumption rates estimated from integrated capacitance. The second method is based upon automated glucose measurements obtained from the Nova Bioprofile FLEX® autosampler where cultures were fed to maintain a target glucose level which in turn maintained other nutrients based on a stoichiometric ratio. All of the calculations were done automatically through in-house integration with a Delta V process control system. Through both media and feed strategy optimization, a titer increase from the original platform titer of 5 to 6.3 g/L was achieved for cell line A, and a substantial titer increase of 4 to over 9 g/L was achieved for cell line B with comparable product quality. Glucose was found to be the best feed indicator, but not all cell lines benefited from dynamic feeding and optimized feed media was critical to process improvement. Our work demonstrated that dynamic feeding has the ability to automatically adjust feed rates according to culture behavior, and that the advantage can be best realized during early and rapid process development stages where different cell lines or large changes in culture conditions might lead to dramatically different nutrient demands.

Two-dimensional difference fluorescence gel electrophoresis to verify the scale-up of a non-affinity-based downstream process for isolation of a therapeutic recombinant antibody.

For therapeutic antibody production Protein A chromatography is often replaced by non-affinity-based purification sequences, which are considered as more economical. 2-D DIGE was applied for evaluation of scale-up of non-affinity based process of a humanized monoclonal antibody, anti-Rh(D) IgG(1), in comparison with other conventional analytical methods, like SDS-PAGE, Western blot, or SEC. Due to a high sensitivity of this technique (125 pg protein/spot) and high dynamic range of five orders of magnitude, low molecular weight impurities were detected in purified samples. Cation exchange chromatography was efficient capture step for IgG(1) purification in laboratory and pilot scale. The differences between samples after first purification step in laboratory and pilot scale were compensated with second purification step where almost the same protein pattern was observed. 2-D DIGE is a helpful tool for monitoring of purification effects and for scale-up verification of downstream processes.

Regulation of XBP-1 signaling during transient and stable recombinant protein production in CHO cells.

X-box binding protein 1 (XBP-1) is a key regulator of cellular unfolded protein response (UPR). The spliced isoform of XBP-1, XBP-1S, is a transcription activator, which is expressed only when UPR is induced. However, the impact of recombinant protein production on the regulation of XBP-1 signaling in CHO cells is not well understood. In this report, we cloned the Chinese hamster XBP-1 homolog to aid the investigation of the interplay between protein productivity, culture conditions, and endogenous XBP-1 signaling in CHO cells. Interestingly, expression of XBP-1S is detected in the non-producing and unstressed CHO-K1 cells. Transient expression of recombinant erythropoietin reveals a positive correlation between XBP-1 mRNA abundance and protein production level. However, such a correlation is not observed in batch cultivation of stable producing cell lines. The increased XBP-1 splicing is detected in late-phase cultures, suggesting that induction of XBP-1S may be a result of nutrient limitations or other environmental stresses rather than that of increased intracellular accumulation of recombinant proteins. Our data suggest that XBP-1 is a key determinant for the secretory capacity of CHO cells. Understanding its dynamic regulation hence provides a rational basis for cellular engineering strategies to improve recombinant protein secretion.

Overexpression of heat shock proteins (HSPs) in CHO cells for extended culture viability and improved recombinant protein production.

It has been widely reported that CHO cells undergo apoptosis in culture, despite supplementation of nutrients through fed-batch strategies. Improvement of cell viability in culture can effectively improve recombinant protein yield through extension of the culture's production lifespan, especially at high cell densities. Heat shock proteins (HSPs) have been reported to demonstrate anti-apoptotic effects against a wide range of physical and chemical stimuli through their ability to bind and act as antagonists to critical apoptotic molecules. CHO-IFN-gamma cells, expressing recombinant human interferon-gamma (IFN-gamma), were engineered to overexpress two HSPs (HSP27 and HSP70) either individually or in combination. In fed-batch bioreactor cultures, the engineered cell lines exhibited a more gradual viability loss and extension of culture times of 36-72h, with corresponding delays in escalation of caspases 2, 3, 8 and 9 activities, compared to the control cultures utilizing cells transfected with the vector backbone. The extension in culture times translated to a 2.5-fold improvement in IFN-gamma production over controls in fed-batch cultures. These results suggest that overexpression of HSPs represents a promising generic strategy for the development of robust CHO cell lines resistant to apoptotic insults and possessing improved culture characteristics to enhance recombinant glycoprotein yields.

Two-dimensional fluorescence difference gel electrophoresis for comparison of affinity and non-affinity based downstream processing of recombinant monoclonal antibody.

Although Staphylococcus Protein A (SpA) affinity chromatography is the state of the art capture step for antibody purification, non-affinity methods are more economical. We used two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) to evaluate the purification of a recombinant IgG(1) antibody from cultured cells, with two different processes: (1) SpA capture followed by cation-exchange chromatography (CEX); and (2) CEX capture, followed by anion exchanger, then hydrophobic interaction chromatography. Efficiencies were similar in sodium dodecylsulphate polyacrylamide gel electrophoresis and size-exclusion chromatography; however, 2-D DIGE revealed higher efficiency with SpA than with CEX capture. Thus, 2-D DIGE is a valuable tool for downstream process development.

2-D DIGE to expedite downstream process development for human monoclonal antibody purification.

Two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) is an established method for assessing protein expression strategies, understanding pathogenesis mechanisms, characterizing biomarkers, and controlling therapeutic processes. We applied 2-D DIGE to facilitate the development of a purification process for a recombinant IgG1 antibody against Rhesus D antigen expressed by Chinese hamster ovary cells. The variability of two expression clones as well as the influence of cell viability on the host-cell protein pattern was assessed quantitatively. Up to 800 different spots were identified. 2-D DIGE showed that differences in cell viability had more influence on the protein expression pattern than did the expression clone itself. After purification of the IgG from different culture supernatants, the protein patterns on 2-D DIGE were identical, indicating the validity of purification scheme.

A study of monoclonal antibody-producing CHO cell lines: what makes a stable high producer?

Generating stable, high-producing cell lines for recombinant protein production requires an understanding of the potential limitations in the cellular machinery for protein expression. In order to increase our understanding of what makes a stable high producer, we have generated a panel of 17 recombinant monoclonal antibody expressing Chinese hamster ovary subclones (CHO-mAb) with specific productivities ranging between 3 and 75 pg cell(-1) day(-1) using the dihydrofolate reductase (dhfr) expression system and compared the molecular features of these high- and low-producer clones. The relative heavy chain (HC) and light chain (LC) transgene copy numbers and mRNA levels were determined using real-time quantitative PCR (RT qPCR). We observed that not only higher transgene copy numbers and mRNA levels of both HC and LC were characteristic for the high-producer clones as compared to the low-producer clones but also a more favorable HC to LC transgene copy numbers ratio. By studying the long-term stability of the CHO-mAb subclones in the absence of methotrexate (MTX) selective pressure over 36 passages we observed a 35-92% decrease in volumetric productivity, primarily caused by a significant decrease in HC and LC mRNA levels with little change in the transgene copy numbers. Using Southern blot hybridization we analyzed the HC and LC transgene integration patterns in the host chromosome and their changes in course of gene amplification and long-term culturing. We observed that MTX-induced gene amplification caused chromosomal rearrangements resulting in clonal variability in regards to growth, productivity, and stability. No further obvious DNA rearrangements occurred during long-term culturing in the absence of MTX, indicating that other mechanisms were responsible for the decreased transcription efficiency. Our results implicate that the amplified transgene sequences were arranged in tandem repeats potentially triggering repeat-induced gene silencing. We hypothesize that the decline in transgene mRNA levels upon long-term culturing without MTX was mainly caused by transgene silencing consequently leading to a loss in mAb productivity. The exact molecular mechanisms causing production instability are not yet fully understood. The herein described extensive characterization studies could help understand the limitations to high-level, stable recombinant protein production and find ways to improving and accelerating the process for high-producer cell line generation and selection.