Docetaxel rechallenge in metastatic castration-resistant prostate cancer: A retrospective, single-center study

Efficacy of Enzalutamide Rechallenge for Metastatic Castration-Resistant Prostate Cancer

OBJECTIVE

There have been several reports on rechallenge with docetaxel, cabazitaxel, abiraterone acetate, or ethinylestradiol for metastatic castration-resistant prostate cancer (mCRPC). However, the efficacy of enzalutamide rechallenge for mCRPC has not been evaluated.

METHODS

We retrospectively reviewed 63 consecutive patients who received enzalutamide for mCRPC at our institution between 2014 and 2022. Eight of these patients underwent rechallenge with enzalutamide after disease progression on prior enzalutamide and other therapy and were the focus of this study. The prostate-specific antigen (PSA) response (PSA decrease >50%), PSA progression-free survival, treatment duration, overall survival (OS) after CRPC, and treatment-related adverse events were evaluated.

RESULTS

PSA decline to enzalutamide rechallenge was observed in 6 patients (75%), of which 2 patients had a PSA response. The median treatment duration was 4 months (range 1-12) and median PSA progression-free survival was 3 months (range 1-7). Median OS after CRPC was 41 months. OS after CRPC was not increased in patients with a PSA response. No toxicities were worse than grade ≥3.

CONCLUSION

Enzalutamide rechallenge achieved a PSA response in a quarter of our patients with mCRPC after disease progression on prior enzalutamide. However, no improvement of OS was identified in these patients.

The second docetaxel rechallenge for metastatic castration-resistant prostate cancer: a case report

Background

Docetaxel combined with prednisone plus androgen deprivation therapy (ADT) is the preferred treatment option for metastatic hormone-sensitive prostate cancer (mHSPC) or metastatic castration-resistant prostate cancer (mCRPC). With the development of next-generation hormonal agents (NHAs) and poly (ADP-ribose) polymerase (PARP) inhibitors, more aggressive first-line or later-line treatment strategies have been added to the treatment of mHSPC and mCRPC. However, docetaxel rechallenge (DR) has special clinical significance in patients with "docetaxel-sensitive" prostate cancer. There are no reports on the efficacy and safety of the second DR in mCRPC patients.

Case presentation

We report one patient diagnosed with mCRPC who showed progression-free survival (PFS) and overall survival (OS) benefits and safety and good lower urinary tract function after the second DR.

Conclusion

The second DR as a potential alternative later-line treatment strategy should be considered for patients with mCRPC who worry about the high economic burden of multigene molecular testing and PARP inhibitors as well as repeated prostate needle biopsy.

Treatment landscape and burden of disease in metastatic castration-resistant prostate cancer: systematic and structured literature reviews

Purpose

Metastatic castration-resistant prostate cancer (mCRPC) is a lethal disease that imposes a major burden on patients and healthcare systems. Three structured literature reviews (treatment guidelines, treatment landscape, and human/clinical/patient burden) and one systematic literature review (economic burden) were conducted to better understand the disease burden and unmet needs for patients with late-stage mCRPC, for whom optimal treatment options are unclear.

Methods

Embase®, MEDLINE®, MEDLINE® In-Process, the CENTRAL database (structured and systematic reviews), and the Centre for Reviews and Dissemination database (systematic review only) were searched for English-language records from 2009 to 2021 to identify mCRPC treatment guidelines and studies related to the treatment landscape and the humanistic/economic burden of mCRPC in adult men (aged ≥18 years) of any ethnicity.

Results

In total, six records were included for the treatment patterns review, 14 records for humanistic burden, nine records for economic burden, three records (two studies) for efficacy, and eight records for safety. Real-world treatment patterns were broadly aligned with treatment guidelines and provided no optimal treatment sequencing beyond second line other than palliative care. Current post-docetaxel treatments in mCRPC are associated with adverse events that cause relatively high rates of treatment discontinuation or disruption. The humanistic and economic burdens associated with mCRPC are high.

Conclusion

The findings highlight a lack of treatment options with novel mechanisms of action and more tolerable safety profiles that satisfy a risk-to-benefit ratio aligned with patient needs and preferences for patients with late-stage mCRPC. Treatment approaches that improve survival and health-related quality of life are needed, ideally while simultaneously reducing costs and healthcare resource utilization.

UnCHAARTED territory: The role of docetaxel rechallenge following chemohormonal therapy for metastatic castration-sensitive prostate cancer

OBJECTIVE

To assess the effectiveness of docetaxel rechallenge (DR) for metastatic castration-resistant prostate cancer (mCRPC) following chemohormonal therapy for metastatic castrate-sensitive prostate cancer (mCSPC). Additionally, we sought to define clinical factors predicting treatment response.

PATIENTS AND METHODS

Retrospective analysis of men treated with docetaxel for mCSPC and then rechallenged in the mCRPC setting from four cancer centers in Ontario, Canada. Prostate specific antigen (PSA) response, progression-free survival (PFS), and overall survival (OS) following DR were evaluated.

RESULTS

Fifty five patients were identified between 2015 and 2020. Prior to DR, 94.5% of patients received androgen-receptor axis targeted therapy, 20% received radium-223, and 1.8% received cabazitaxel. Among 54 evaluable patients, 27.8% had a PSA decline ≥50%. Median PFS was 4.1 months (95% CI, 2.1-4.8) and median OS from androgen deprivation therapy initiation was 38.3 months (95% CI, 32.9-41.0). A Gleason Score of ≥8 was an independent predictor of prolonged PFS (HR 0.32, 95% CI, 0.12-0.81; P=0.02).

CONCLUSIONS

DR following chemohormonal therapy for mCSPC produced a meaningful PSA response in approximately one-quarter of patients, with relatively short PFS. The impact of Gleason Score on docetaxel response warrants further investigation.

Appropriate Patient Status for Ra-223 Treatment in the Treatment Sequence for Castration-resistant Prostate Cancer

BACKGROUND/AIM

Radium (Ra)-223 is widely used for treating castration-resistant prostate cancer (CRPC) with bone metastasis based on evidence of increased survival and decreased skeletal-related events. However, the timing of Ra-223 use in the treatment sequence of CRPC remains controversial. Therefore, this study aimed to explore the appropriate patient status for Ra-223 use in the CRPC treatment sequence by examining patients treated with Ra-223 from the time of CRPC diagnosis until death.

PATIENTS AND METHODS

The medical records of 67 CRPC patients with bone metastasis who were treated with Ra-223 at two institutes were retrospectively analysed. The impact of 13 factors from the time of CRPC diagnosis until death was analysed using univariate and multivariate Cox hazard ratio models to evaluate the appropriate patient status for Ra-223 treatment.

RESULTS

The median survival time following CRPC diagnosis for all the patient groups was 3.82 years. Univariate analysis identified a higher-than-normal alkaline phosphatase (ALP) level, bone scan indexes ≥2, and prostate-specific antigen (PSA) doubling time <3 months before Ra-223 treatment as predominant adverse prognostic factors. Ra-223 therapy discontinuation was not a significant factor. The survival of CRPC patients with these factors was significantly worse than that of patients without these factors. In the multivariate analysis, a higher-than-normal ALP level at the start of treatment was identified as a poor prognostic factor for mortality.

CONCLUSION

The appropriate patient status for Ra-223 use includes low bone metastasis burden and well-controlled PSA levels.