A real-world comparison of docetaxel versus abiraterone acetate for metastatic hormone-sensitive prostate cancer

Androgen receptor pathway inhibitors vs. docetaxel chemotherapy for metastatic hormone-sensitive and first-line castration resistant prostate cancer

PURPOSE

No currently available phase III trial compared docetaxel vs. androgen receptor pathway inhibitors (ARPI) regarding cancer-control outcomes in metastatic hormone-sensitive prostate cancer (mHSPC). Moreover, few is known about the effect of sequential therapies in mHSPC and subsequent metastatic castration resistant prostate cancer (mCRPC).

METHODS

We relied on the FRAMCAP database and compared docetaxel vs. ARPI in mHSPC patients regarding time to mCRPC (ttCRPC) and overall survival (OS). Sensitivity analyses addressed high volume mHSPC patients. Finally, sequential therapies were compared regarding progression-free survival (PFS) and OS in first-line mCRPC.

RESULTS

Of 419 included mHSPC patients, 25% received docetaxel vs. 75% ARPI. ARPI patients were significantly older (71 vs. 66 years), and harbored lower baseline PSA (38 vs. 183 ng/ml, both p ≤ 0.002). Median ttCRPC was significantly longer for ARPI than for docetaxel-treated patients (30 vs. 17 months, hazard ratio [HR]: 0.49, p < 0.001). In OS analyses, ARPI patients also exhibited significantly longer OS, relative to docetaxel patients (96 vs. 50 months, HR: 0.67, p = 0.03). After multivariable adjustment in Cox regression models, no difference between both treatments remained in both analyses (all p > 0.05). In sensitivity analyses of high volume mHSPC patients only, also no ttCRPC or OS differences were observed for ARPI vs. docetaxel (all p > 0.05). Regarding sequential therapies, no PFS and OS differences were observed for all and specifically high volume mHSPC patients, when ARPI-ARPI vs. ARPI-docetaxel vs. docetaxel-ARPI treatments were compared (all p > 0.05).

CONCLUSION

In real-world setting, ARPI treatment performs comparable to docetaxel chemotherapy in mHSPC. Therefore, docetaxel should only be used in triplet therapy. Moreover, no differences for sequential therapies of ARPI/docetaxel combinations in first-line mCRPC were observed.

Comparison of Short-Term Outcomes and Safety Profiles between Androgen Deprivation Therapy+Abiraterone/Prednisone and Androgen Deprivation Therapy+Docetaxel in Patients with De Novo Metastatic Hormone-Sensitive Prostate Cancer

PURPOSE

This study aimed to compare the short-term outcomes and safety profiles of androgen-deprivation therapy (ADT)+abiraterone/prednisone with those of ADT+docetaxel in patients with de novo metastatic hormone-sensitive prostate cancer (mHSPC).

MATERIALS AND METHODS

A web-based database system was established to collect prospective cohort data for patients with mHSPC in Korea. From May 2019 to November 2022, 928 patients with mHSPC from 15 institutions were enrolled. Among these patients, data from 122 patients who received ADT+abiraterone/prednisone or ADT+docetaxel as the primary systemic treatment for mHSPC were collected. The patients were divided into two groups: ADT+abiraterone/prednisone group (n=102) and ADT+docetaxel group (n=20). We compared the demographic characteristics, medical histories, baseline cancer status, initial laboratory tests, metastatic burden, oncological outcomes for mHSPC, progression after mHSPC treatment, adverse effects, follow-up, and survival data between the two groups.

RESULTS

No significant differences in the demographic characteristics, medical histories, metastatic burden, and baseline cancer status were observed between the two groups. The ADT+abiraterone/prednisone group had a lower prostate-specific antigen (PSA) progression rate (7.8% vs. 30.0%; p=0.011) and lower systemic treatment discontinuation rate (22.5% vs. 45.0%; p=0.037). No significant differences in adverse effects, oncological outcomes, and total follow-up period were observed between the two groups.

CONCLUSIONS

ADT+abiraterone/prednisone had lower PSA progression and systemic treatment discontinuation rates than ADT+docetaxel. In conclusion, further studies involving larger, double-blinded randomized trials with extended follow-up periods are necessary.

Clinical Outcomes of Patients with High-risk Metastatic Hormone-naïve Prostate Cancer: A 3-year Interim Analysis of the Observational J-ROCK Study

BACKGROUND

Androgen deprivation therapy (ADT), administered alone, as combined androgen blockade (CAB) or as ADT plus androgen receptor signalling inhibitors (ARSIs) or ADT plus docetaxel, is the standard treatment for metastatic hormone-naïve prostate cancer (mHNPC) in Japanese real-world practice.

OBJECTIVE

To investigate treatment patterns and clinical outcomes in LATITUDE criteria high-risk mHNPC.

DESIGN, SETTING, AND PARTICIPANTS

The longitudinal, multicentre, J-ROCK registry study enrolled patients initiating ADT in Japan after May 2019, and categorised them as cohort 1 (ADT or CAB) or cohort 2 (ADT plus ARSIs or docetaxel).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate-specific antigen (PSA) response, progression-free survival (PFS), time to castrate-resistant prostate cancer (CRPC), overall survival (OS), and safety were evaluated. PFS, time to CRPC, and OS were estimated via the Kaplan-Meier method and between-cohort comparisons via multivariate Cox regression models.

RESULTS AND LIMITATIONS

In total, 974 patients were included (cohort 1: 38.1%, cohort 2: 61.9%). CAB was preferred (67.4%) to ADT alone in cohort 1, and abiraterone acetate plus prednisolone was used most frequently in cohort 2 (59.4%). The proportion of patients with ≥50%/≥90% PSA decline or who achieved PSA ≤0.2/≤0.1 ng/ml tended to be higher in cohort 2. PFS (adjusted hazard ratio 0.42; 95% confidence interval [CI] 0.31-0.55), time to CRPC (0.28; 95% CI 0.23-0.36), and OS (0.54; 95% CI 0.35-0.82) were longer in cohort 2. In cohorts 1 and 2, adverse drug reactions of special interest (ADRSIs) occurred in 1.3% and 15.1%, and fatal adverse events occurred in 1.9% and 1.7%, respectively. Limitations included nonrandomised design, varying time since marketing authorisation for ARSIs, and limited safety assessments.

CONCLUSIONS

ADT plus ARSIs or docetaxel was used more frequently to treat high-risk mHNPC than standard ADT/CAB and was associated with more favourable clinical outcomes. Although ADRSIs were reported more in cohort 2, the safety profile was considered tolerable.

PATIENT SUMMARY

Although many treatment options are available for high-risk metastatic prostate cancer, there are limited reports on real-world clinical experience with different therapies outside of the clinical trial setting. In this study, we compared clinical and safety outcomes with different treatment regimens, using a large series of patients with high-risk metastatic hormone-naïve prostate cancer across Japan. We found that androgen deprivation therapy in combination with newer androgen receptor signalling inhibitors resulted in improved response compared with androgen deprivation therapy alone or in combination with a first-generation antiandrogen.

A territory-wide real-world efficacy and toxicity analysis of abiraterone acetate versus docetaxel in 574 Asian patients with metastatic hormone-sensitive prostate cancer

INTRODUCTION

Abiraterone acetate (ABI) or docetaxel (DOC), in addition to androgen-deprivation therapy (ADT), are current treatment options for metastatic hormone-sensitive prostate cancer (mHSPC). No randomized head-to-head trial has compared these 2 mHSPC treatments, and real-world data regarding their outcomes in Asian patients are lacking.

PATIENTS AND METHODS

The medical records of mHSPC patients who began upfront ABI or DOC treatment in addition to ADT at seven public oncology centers in Hong Kong between 2015 and 2021 were reviewed. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), prostate-specific antigen (PSA) response, and toxicities. Kaplan-Meier and multivariate Cox regression analyses were performed.

RESULTS

A total of 574 patients were included, of whom 419 received DOC and 155 received ABI. The median follow-up duration was 22.4 (DOC group: 23.8; ABI group: 17.3) months. The ABI group demonstrated significantly better PFS than the DOC group (not reached vs. 15.1 months: hazard ratio = 0.37; 95% confidence interval = 0.28-0.50; P < .001). No significant OS difference was observed (P = .58). Failure to achieve a ≥ 90% decline in PSA level at 3 months and failure to achieve an undetectable PSA nadir were each associated with unfavorable PFS and OS. Patients who received DOC had a higher rate of febrile neutropenia, whereas those who received ABI had higher rates of grade ≥ 3 hypokalemia and elevated alanine transaminase. Treatment discontinuation due to toxicities was more common in the DOC (3.6%) than the ABI (0.6%) group.

CONCLUSION

In Asian mHSPC patients, upfront ABI + ADT was associated with better PFS than DOC + ADT, with no significant OS difference. PSA kinetics may help stratify the prognosis for treatment intensification. Toxicity profiles were different, with a higher rate of toxicity-related treatment discontinuation in the DOC group.

Evaluation of Trends in Treatment of Metastatic Hormone Sensitive Prostate Cancer (mHSPC) Across Canada During the COVID-19 Pandemic

BACKGROUND

In metastatic hormone sensitive prostate cancer (mHSPC), treatment intensification with either docetaxel or an androgen-receptor-axis targeted therapy (ARAT), added to androgen deprivation therapy (ADT) is the new standard of care. To better understand patterns of treatment intensification in Canada and specifically how it has been influenced by the COVID-19 pandemic, we conducted a national survey of genitourinary medical oncologists from across Canada.

METHODS

Using SurveyMonkey, we conducted an online survey of 119 medical oncologists in Canada from January 15 to January 27, 2021. The survey consisted of 16 questions, including demographics, and asked specifically about their approach to managing mHSPC before and during the pandemic.

RESULTS

Overall there were 50/119 (42%) respondents. Most were male (65%), from Ontario (35%), practicing in academic centers (71%), with 45% reporting their practices focused primarily on genitourinary malignancies and one other tumor site. The majority were in practice 1 to 5 years (34%). Overall 65% indicated their practice patterns had changed since the pandemic, with 51% offering more ARATs and less docetaxel chemotherapy. In low volume mHSPC, the use of ARATs increased from 73% to 79%, while the use of docetaxel remained unaltered at 2%. In high volume disease, the use of ARATs increased from 63% to 84%, while the use of docetaxel decreased from 37% to 14%. Use of granulocyte colony stimulating factor (G-CSF) with docetaxel chemotherapy increased by 35%. Post-pandemic, 45% reported they intend to maintain these changes. Only 18% reported they had prostate cancer patients test positive for COVID-19, and all patients recovered.

CONCLUSION

Management of patients with mHSPC in Canada has changed during the pandemic, with increased uptake of ARATs and reduced use of docetaxel, a trend expected to continue beyond the pandemic. How this trend will impact uptake of triplet therapy (ADT + ARAT + Docetaxel), downstream treatment choices and overall outcomes remains to be seen.

Advancements in the treatment of metastatic hormone-sensitive prostate cancer

In the last decade, there have been substantial improvements in the outcome of the management of metastatic hormone-sensitive prostate cancer (mHSPC) following the development of several novel agents as well as by combining several therapeutic strategies. Although the overall survival (OS) of mHSPC is shown to improve with intense androgen deprivation therapy (ADT), combined with docetaxel, as well as other novel hormonal therapy agents, or alongside local intervention to the primary neoplasm. Notably, luteinizing hormone-releasing hormone (LHRH) antagonists are known to cause fewer cardiovascular side effects compared with LHRH agonists. Thus, in this mini review, we explore the different approaches in the management of mHSPC, with the aim that we may provide useful information for both basic scientists and clinicians when managing relevant clinical situations.

Biotransformation of Abiraterone Into Five Characteristic Metabolites by the Rat Gut Microbiota and Liver Microsomes

It is well known that the role of gut microbiota in drug metabolism, especially in oral difficult absorbable drugs. Understanding the gut microbiota could enable us to understand drugs in new ways. The purpose of the study was to investigate explore the metabolites of the anti-prostate cancer drug Abiraterone by examining gut microbiota metabolism and hepatic metabolism in vitro. In this study, five metabolites (M1, M2, M3, M4 and M5) of Abiraterone were discovered using LC/MSⁿ-IT-TOF. Four isomeric metabolites M1-M4 were found in liver microsome. M5 was found in the intestinal contents of Sprague-Dawley rats with a molecular weight of 388.31. Among them, M4 was found to be Abiraterone N-Oxide by comparison with the standard sample. After further comparing the metabolic behavior of Abiraterone in rat gut microbiota and liver microsomes, we delineated the possible metabolic pathways of Abiraterone. In conclusion, Abiraterone is metabolized specifically in liver microsomes and gut microbiota. This study can provide a theoretical basis for elucidating the metabolic mechanism of Abiraterone and guide its rational application in clinic.