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

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.

HOW TO OPTIMALLY SEQUENCE AVAILABLE THERAPY LINES IN ADVANCED PROSTATE CANCER

Optimal sequencing of available therapy lines in patients with advanced prostate cancer often poses quite a challenge. The guidelines are sometimes equivocal and clinical trial data are not always applicable to a particular patient. There is a difference in availability of therapy options throughout the world. In decision making, a patient as a whole should be taken into consideration, not just the stage and biology of the disease, but also patient's age, performance status, comorbidities, previous therapy lines, drug's safety profile and patient's preferences. This review article will show certain therapeutic options in the treatment of advanced hormone-sensitive prostate cancer and castration resistant prostate cancer: non- metastatic and metastatic. An attempt will be made to clarify the optimal sequencing.

Management of prostate cancer in older patients

The incidence of prostate cancer among older men has increased in many countries, including Asian countries. However, older patients are ineligible for inclusion in large randomized trials, and the existing guidelines for the management of patients with prostate cancer do not provide specific treatment recommendations for older men. Therefore, generation of evidence for older patients with prostate cancer is a key imperative. The International Society of Geriatric Oncology has produced and updated several guidelines for management of prostate cancer in older men since 2010. Regarding localized prostate cancer, both surgery and radiotherapy are considered as feasible treatment options for intermediate- and high-risk prostate cancer even in older men, whereas watchful waiting and active surveillance are useful options for a proportion of these patients. With regard to advanced disease, androgen-receptor axis targets and taxane chemotherapy are standard treatment modalities, although dose modification and prevention of adverse events need to be considered. Management strategy for older patients with prostate cancer should take cognizance of not only the chronological age but also psychological and physical condition, socio-economic status and patient preferences. Geriatric assessment and patient-reported health-related quality of life are important tools for assessing health status of older patients with prostate cancer; however, there is a paucity of evidence of the impact of these tools on the clinical outcomes. Personalized management according to the patient's health status and tumour characteristics as well as socio-economic condition may be necessary for treatment of older patients with prostate cancer.