Cabazitaxel in patients aged ≥80 years with castration-resistant prostate cancer: Results of a post-marketing surveillance study in Japan

Efficacy and Feasibility of Cabazitaxel for Very Elderly Patients of ≥ 80 Years of Age With Metastatic Castration-Resistant Prostate Cancer: A Real-World Multi-Intuitional Analysis

BACKGROUND

Cabazitaxel (CBZ) is a key drug used for metastatic castration-resistant prostate cancer (mCRPC). However, clinical trial data on CBZ in very elderly patients are still lacking. This study aimed to investigate the efficacy and feasibility of CBZ for mCRPC patients of ≥ 80 years of age.

METHODS

We retrospectively reviewed 484 patients with mCRPC who started CBZ treatment between September 2019 and March 2024. Therapeutic efficacy (PSA response, progression-free survival, overall survival, and safety profile) was compared between patients of < 80 years of age (< 80 group) and those of ≥ 80 years of age (≥ 80 group). In addition, risk factors associated with grade ≥ 3 neutropenia in the ≥ 80 group were investigated using a logistic regression model.

RESULTS

Seventy-three (15.1%) patients were included in the ≥ 80 group. Although more patients in the ≥ 80 group received a reduced dose relative to the < 80 group, there was no significant difference in therapeutic efficacy between the two groups. The incidence of grade ≥ 3 neutropenia was similar between two groups (< 80: 27.5% vs. ≥ 80: 31.5%). In the ≥ 80 group, BMI < 22 kg/m2 and neutrophil count ≤ 5000 cells/µL were significantly associated with grade ≥ 3 neutropenia, with odds ratios of 5.28 (p = 0.005) and 4.00 (p = 0.023), respectively.

CONCLUSION

In mCRPC patients of ≥ 80 years of age, CBZ showed similar safety and efficacy to younger patients. Our findings suggest that CBZ treatment with appropriate dose modification and prophylactic AE treatments may be still beneficial for elderly mCRPC patients in the current aging population.

Current Evidence on Cabazitaxel for Prostate Cancer Therapy: A Narrative Review

The incidence of prostate cancer (PC) has recently increased in Japan. Androgen deprivation therapy (ADT) has been a key treatment in patients with castration-sensitive PC (CSPC); however, resistance typically emerges through multiple mechanisms, leading to metastatic castration-resistant PC (mCRPC). Taxane-based therapy (i.e., docetaxel, cabazitaxel) has been standard care in patients with mCRPC. New evidence supporting the addition of androgen receptor signaling inhibitors (ARSIs, e.g., enzalutamide, abiraterone) to docetaxel and ADT for patients with metastatic CSPC (mCSPC) raises questions about the role of taxane-based therapies and their optimal sequencing, as well as how to identify patients who may benefit from taxane-based therapy. Here we review the evidence on taxane-based therapy, including cabazitaxel, in the treatment of PC, with a focus on clinical and real-world evidence from Japan. Cabazitaxel has proven effective for patients with mCRPC who have a history of ARSI and docetaxel use, and it is preferable to a second alternative ARSI, as indicated in the CARD study. The safety profile of cabazitaxel (particularly, the incidence of neutropenia) can be managed through prophylactic use of granulocyte colony-stimulating factor, as well as a lower dosage and possibly variation of the dosage interval. However, a certain dose intensity is required because neutropenia has been identified as a potential prognostic indicator for treatment effectiveness. In the ARSI era for mCSPC, evidence on mCRPC treatment sequencing is limited. A better understanding of PC biology and the collection of real-world data is essential for effective treatment and improved safety-benefit outcomes.

Feasibility of cabazitaxel in octogenarian prostate cancer patients

Background

To evaluate the effectiveness and safety of cabazitaxel in castration-resistant prostate cancer patients aged ≥80 years, we performed a retrospective study on a sample of patients from 11 Italian cancer centers.

Materials and methods

Fifty-seven patients aged ≥80 years were treated with cabazitaxel after previous failure with docetaxel; 39 completed a comprehensive geriatric assessment questionnaire (34 fit and 5 vulnerable) and 8 patients (14%) had an Eastern Cooperative Oncology Group performance status (PS) ≥2, while most had a PS of 0-1 (86%). Cabazitaxel was administered at a dose of 25 mg/m2 in 30 (52%) patients and 20 mg/m2 or adapted schedules in 27 (48%) patients. These schedules were adopted mainly in patients ≥85 years (75%), with a PS ≥2 (87.5%), and those classified as vulnerable (100%).

Results

The duration of treatment was 4.8 months and was comparable in all subgroups; disease control rate was reported in 36 patients (63%); prostate-specific antigen response was recorded in 18 patients (31.5%). Median overall survival was 13.1 months regardless of age (<85/≥85 years), but overall survival was reduced in vulnerable (7.2 months) and PS ≥ 2 patients (6.8 months). The most frequently documented grade 3-4 toxicities were neutropenia (14%) and diarrhea (10.5%). Six patients (10.5%) dropped out due to severe toxicity.

Conclusions

Octogenarian patients can be treated with cabazitaxel with reduced doses or alternative schedules that are associated with less toxicity and fewer treatment interruptions. Comprehensive geriatric assessment could facilitate more appropriate patient selection.

A national questionnaire survey of Japanese urologists on treatment perspectives for elderly prostate cancer patients

OBJECTIVE

This study conducted a national questionnaire survey of Japanese urologists from a treatment perspective for older patients with prostate cancer.

METHODS

A questionnaire was distributed to 922 teaching hospitals of the Japanese Urological Association. Questionnaire items included years of urologist experience, gender, workplace, treatment equipment owned, daily specialty practice area, urological cancer specialty, treatment reference items for older adults, upper age limit for radical treatment, medication, and two hypothetical cases of Gleason grade group 2 prostate cancer with or without oligometastasis.

RESULTS

In total, 1732 questionnaires were analyzed, with responses evenly distributed across all age groups. Workplaces included general hospitals (49.4%), university hospitals (40.3%), and cancer centers (4.2%). Performance status was the most frequently mentioned treatment-related item, followed by comorbidities and cognitive function. In addition, geriatric assessment was used by only 13.3% of respondents. No upper age limit was found for total prostatectomy, brachytherapy, and external beam radiation. Anti-androgens, androgen receptor-axis-targeted agents, chemotherapy, poly ADP ribose polymerase inhibitors, and immune-checkpoint inhibitors were selected by 6.8%, 35.6%, 47.3%, 89%, 62.8%, 24.7%, 41.9%, and 41.7% of the respondents, respectively. Response rates for administration of hormone therapy for hypothetical cases of Gleason grade group 2 prostate cancer with or without oligometastases were 96.8% and 61.2%, respectively.

CONCLUSIONS

Less than 15% of urologists used geriatric assessments. Several responded that they would set age limits for highly invasive radical and systemic therapies.

Comprehensive analysis of the associations between clinical factors and outcomes by machine learning, using post marketing surveillance data of cabazitaxel in patients with castration-resistant prostate cancer

BACKGROUND

We aimed to evaluate relationships between clinical outcomes and explanatory variables by network clustering analysis using data from a post marketing surveillance (PMS) study of castration-resistant prostate cancer (CRPC) patients.

METHODS

The PMS was a prospective, multicenter, observational study of patients with metastatic, docetaxel-refractory CRPC treated with cabazitaxel in Japan after its launch in 2014. Graphical Markov (GM) model-based simulations and network clustering in 'R' package were conducted to identify correlations between clinical factors and outcomes. Factors shown to be associated with overall survival (OS) in the machine learning analysis were confirmed according to the clinical outcomes observed in the PMS.

RESULTS

Among the 660 patients analyzed, median patient age was 70.0 years, and median OS and time-to-treatment failure (TTF) were 319 and 116 days, respectively. In GM-based simulations, factors associated with OS were liver metastases, performance status (PS), TTF, and neutropenia (threshold 0.05), and liver metastases, PS, and TTF (threshold 0.01). Factors associated with TTF were OS and relative dose intensity (threshold 0.05), and OS (threshold 0.01). In network clustering in 'R' package, factors associated with OS were number of treatment cycles, discontinuation due to disease progression, and TTF (threshold 0.05), and liver and lung metastases, PS, discontinuation due to adverse events, and febrile neutropenia (threshold 0.01). Kaplan-Meier analysis of patient subgroups demonstrated that visceral metastases and poor PS at baseline were associated with worse OS, while neutropenia or febrile neutropenia and higher number of cabazitaxel cycles were associated with better OS.

CONCLUSIONS

Neutropenia may be a predictive factor for treatment efficacy in terms of survival. Poor PS and distant metastases to the liver and lungs were shown to be associated with worse outcomes, while factors related to treatment duration were shown to positively correlate with better OS.

Safety and survival of docetaxel and cabazitaxel in metastatic castration-resistant prostate cancer

OBJECTIVES

To investigate real-world haematological toxicity, overall survival (OS) and the treatment characteristics of docetaxel and cabazitaxel chemotherapy in metastatic castration-resistant prostate cancer (mCRPC).

PATIENTS AND METHODS

This retrospective claims data study followed patients with mCRPC receiving cabazitaxel or docetaxel from their first chemotherapy infusion. Haematological toxicities were measured using treatment codes and inpatient diagnoses. OS was estimated using the Kaplan-Meier method. A multivariable Cox regression analysis was used to identify OS predictors.

RESULTS

Data from 539 patients administered docetaxel and 240 administered cabazitaxel were analysed. Regarding adverse events, within 8 months of treatment initiation, some kind of treatment for haematological toxicity was documented in 31% of patients given docetaxel and in 61% of patients given cabazitaxel. In the same period, hospitalization associated with haematological toxicity was documented in 11% of the patients in the docetaxel cohort and in 15% of the patients in the cabazitaxel cohort. In the docetaxel cohort, 9.9% of patients required reverse isolation and 13% were diagnosed with sepsis during hospitalization. In the cabazitaxel cohort, the cumulative incidence was 7.9% and 15%, respectively. The median OS was reached at 21.9 months in the docetaxel cohort and, because of a later line of therapy, at 11.3 months in the cabazitaxel cohort. A multivariate Cox regression revealed that indicators of locally advanced and metastatic disease, severe comorbidities, and prior hormonal/cytotoxic therapies were independent predictors of early death.

CONCLUSION

Cabazitaxel patients face an increased risk of haematological toxicities during treatment. Together with their short survival time, this calls for a strict indication when using cabazitaxel in patients with mCRPC.

Efficacy and safety of cabazitaxel therapy in elderly (≥75 years) patients with castration-resistant prostate cancer: A multiinstitutional study

Background

There is little data on the outcome of cabazitaxel (CBZ) treatment of elderly patients with castration-resistant prostate cancer (CRPC). This study assessed the efficacy and safety of CBZ chemotherapy in patients with CRPC aged 75 years or older in a multiinstitutional study.

Methods

We retrospectively reviewed the 74 patients with CRPC treated with CBZ enrolled in 10 institutions. Clinicopathological backgrounds, prognosis including prostate-specific antigen decline, time to treatment failure, progression-free survival, overall survival, and safety profiles were compared between younger (<75 years) and elder (≥75 years) patients.

Results

In total, 74 patients were enrolled; 50 patients were younger than 75 years and 24 were ≥75 years. Clinicopathological characteristics were comparable between younger and elder patients, with the exception of serum albumin values at the time of CBZ treatment. The median prostate-specific antigen decline in younger and elder men was −8.8% and −32.3% from baseline, respectively. The median time to treatment failure, progression-free survival, and overall survival for younger and elder men were 0.24 and 0.33 years, 0.23 and 0.43 years, and 0.69 and 1.17 years, respectively. In addition, safety profiles were comparable between younger and elder patients.

Conclusions

This multiinstitutional study suggests that patients with CRPC aged 75 years or older eligible for CBZ treatment can be treated safely and with noninferior efficacy compared with those younger than 75 years.