Real-world evaluation of upfront docetaxel in metastatic castration-sensitive prostate cancer

[UPFRONT DOCETAXEL WITH ANDROGEN DEPRIVATION THERAPY IN MALES WITH HIGH-VOLUME METASTATIC CASTRATION-SENSITIVE PROSTATE CANCER: RESULTS OF A SINGLE-INSTITUTION SERIES]

(Objective) This study aimed at evaluating the efficacy and safety of upfront docetaxel (DTX) treatment and androgen deprivation therapy (ADT) in male patients with high-volume metastatic castration-sensitive prostate cancer (HV-mCSPC). (Methods) This retrospective study was conducted using the medical records of 30 patients treated for HV-mCSPC by using upfront DTX treatment along with ADT at Atsugi City Hospital between December 2015 and December 2022. The patient characteristics, demographics, oncological outcomes, adverse events, and sequential therapy were evaluated. (Results) Thirty patients were included in the final analysis. The median patient age and prostate-specific antigen at diagnosis were 73 years (range, 53-83 years) and 250 mg/ml (range, 0.54-3,817 ng/ml), respectively. The completion rate of six cycles of upfront DTX treatment was 86.7%. The median progression-free survival was 24 months; the median overall survival was not reached, and the 5-year survival rate was 71.5%. Alopecia was the most frequent non-hematological adverse event (60%) followed by fatigue (53.3%). Overall, adverse events of grade 3 or higher occurred in 46.7% of the patients, with neutropenia being the most frequent. The incidence of neutropenia of grade 3 or higher was significantly lower in the group receiving primary prophylaxis with long-acting granulocyte colony-stimulating factor (7.7% vs. 75%, P = 0.009). Abiraterone was the most frequently administered sequential treatment in 12 patients (60%). (Conclusion) In the triplet combination treatment era, upfront DTX treatment and ADT for patients with HV-mCSPC was safe as primary prophylaxis for severe neutropenia and effective as an upfront treatment. However, it should be selected if its effectiveness is superior to triplet treatment considering adverse events, cost-effectiveness, and quality of life.

Time trends in systemic treatment for patients with metastatic prostate cancer: a national cohort study

BACKGROUND

Several new systemic treatments for primary metastatic prostate cancer patients (mPCa) were introduced in the last decade for both hormone-sensitive (mHSPC) and castration-resistant prostate cancer (mCRPC). However, little is known about the introduction of these treatments in clinical practice. In this national cohort study, we described users and non-users of systemic treatment beyond androgen deprivation therapy (ADT). We also explored whether there was a shift in treatment patterns after the introduction of Docetaxel for mHSPC patients.

MATERIALS AND METHODS

All patients registered in the Cancer Registry of Norway with mPCa diagnosed in 2010-18 were included. Data on systemic therapy (Docetaxel, Abiraterone, Enzalutamide, Cabazitaxel, and Radium-223) were provided from the Norwegian Prescription Database, the Norwegian Patient Registry, and the Norwegian Control and Payment of Health Reimbursement Database. Descriptive results about patient and disease characteristics were presented using frequencies and proportions, means and standard deviations, or medians and interquartile ranges.

RESULTS

Of the 2770 patients included in this study, 48% received systemic treatment beyond ADT. The proportion of patients receiving systemic treatment increased during the study period. Systemic treatment users were younger, in better general condition, and had more aggressive tumors than non-users. A treatment shift was observed after 2015, with 48% of patients receiving systemic treatment (mainly Docetaxel) in the mHSPC phase compared to 4% of those diagnosed 2010-14. No significant treatment differences were observed across health regions.

CONCLUSIONS

An increasing proportion of patients received systemic treatment during the period 2010-18. However, less than 50% of patients in our study received systemic treatment. In accordance with updated guidelines, Docetaxel was introduced after 2015 with an increasing proportion of patients receiving systemic treatment as mHSPC. Further studies should address the disease course and treatment given to patients who do not receive systemic treatment.

Attainment of early, deep prostate-specific antigen response in metastatic castration-sensitive prostate cancer: A comparison of patients initiated on apalutamide or enzalutamide

BACKGROUND

Deep prostate-specific antigen (PSA) response, defined as a ≥90% decline in PSA (PSA90), is an important early response indicator for achieving radiographic progression-free and overall survival in patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with a next-generation androgen signaling inhibitor (ASI), such as apalutamide or enzalutamide. The objective of this study was to compare deep PSA response among patients with mCSPC newly initiated on apalutamide or enzalutamide.

METHODS

Clinical data from 69 community urology practices in the United States were evaluated. Patients with mCSPC were classified into cohorts based on their first dispensation (index date) for apalutamide or enzalutamide and were followed until the earliest of treatment discontinuation, initiation of a new next-generation androgen receptor signaling inhibitor, end of clinical activity (including death), or end of data availability (03/05/2021). Inverse probability of treatment weights (IPTW) were used to reduce baseline confounding. PSA90 was defined as the earliest ≥90% PSA decline relative to baseline PSA. The proportion of patients achieving PSA90 and time to PSA90 were reported using weighted Kaplan-Meier analysis and weighted Cox proportional hazards models, respectively.

RESULTS

The apalutamide and enzalutamide cohorts comprised 186 and 165 patients, respectively. Patient characteristics were generally well balanced after IPTW. By 6 months, patients initiated on apalutamide had a 56% greater likelihood of attaining PSA90 than those initiated on enzalutamide (P = 0.014). This result remained significant through the end of the observation period. The median time to achieving PSA90 was 3.1 months with apalutamide and 5.2 months with enzalutamide.

CONCLUSIONS

This real-world study demonstrated that apalutamide initiation is associated with a significantly higher likelihood of achieving ≥90% reduction in PSA as compared to initiation of enzalutamide. Moreover, this deep PSA response was observed to occur earlier with apalutamide treatment than with enzalutamide.

Comparison of prostate-specific antigen response in patients with metastatic castration-sensitive prostate cancer initiated on apalutamide or abiraterone acetate: A retrospective cohort study

BACKGROUND

Deep prostate-specific antigen (PSA) response (≥90% reduction in PSA [PSA90]) is an important early response indicator of radiographic progression-free survival and overall survival in patients with metastatic castration-sensitive prostate cancer (mCSPC). This study compared PSA90 responses by 6 months between patients with mCSPC at first use of apalutamide or abiraterone acetate, both androgen receptor signaling inhibitors.

METHODS

Clinical data from 77 community urology practices in the United States were analyzed. Patients with mCSPC were classified into treatment cohorts based on their first filled prescription (index date) for apalutamide or abiraterone acetate on or after September 17, 2019 (approval date of apalutamide for mCSPC). Patients were followed from the index date until the earliest of index treatment discontinuation, treatment switch, end of clinical activity, or end of data availability (September 17, 2021). Inverse probability of treatment weighting (IPTW) was used to ensure similarity in distribution of baseline characteristics between cohorts. PSA90 was defined as the earliest attainment of ≥90% reduction in PSA relative to baseline (most recent value within 13 weeks pre-index). Time to PSA90 between cohorts was compared by weighted Kaplan-Meier analysis and with Cox proportional hazards models.

RESULTS

A total of 364 patients treated with apalutamide and 147 treated with abiraterone acetate met the study criteria. Patient characteristics were well balanced after IPTW. By 6 months post-index, patients initiated on apalutamide were 53% more likely to achieve PSA90 than those initiated on abiraterone acetate (P = 0.016). Similar results were observed by 9 and 12 months post-index (both P ≤ 0.019). The median time to PSA90 was 3.5 months for the apalutamide cohort and not reached for the abiraterone acetate cohort.

CONCLUSIONS

In real-world patients with mCSPC, significantly more patients achieved PSA90 with apalutamide than with abiraterone acetate, and this response was achieved earlier with apalutamide.

Real-world outcomes and risk stratification in patients with metastatic castration-sensitive prostate cancer treated with upfront abiraterone acetate and docetaxel

PURPOSE

We assessed clinical outcomes in patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with two upfront therapies.

METHODS

The medical records of 301 patients with mCSPC treated with androgen deprivation therapy plus upfront abiraterone acetate (ABI) or docetaxel (DOC) between 2014 and 2021 were retrospectively reviewed. Propensity score matching (PSM) was performed to compare survival outcomes. Subgroup analyses of risk factors for second progression were conducted.

RESULTS

A total of 95 patients received upfront DOC, whereas 206 received upfront ABI. After PSM, the ABI group had a significantly better castration-resistant prostate cancer (CRPC)-free survival than the DOC group [hazard ratio (HR), 0.53; 95% confidence interval (CI), 0.34-0.82]. Second progression-free survival (PFS2) tended to be longer in the ABI group than in the DOC group, but the difference was not statistically significant (HR, 0.64; 95% CI, 0.33-1.22). No significant difference in overall survival (OS) was found between the two groups (HR, 0.92; 95% CI, 0.42-2.03). In the subgroup analysis, upfront ABI had significantly favorable PFS2 in patients aged ≥ 75 years compared with upfront DOC (p = 0.038). Four risk factors for second progression (primary Gleason 5, liver metastasis, high serum alkaline phosphatase level, and high serum lactate dehydrogenase level) successfully stratified patients into three risk groups.

CONCLUSIONS

Upfront ABI provided better CRPC-free survival than upfront DOC; however, no significant differences in PFS2 or OS were observed between the two groups. Personalized management based on prognostic risk factors may benefit patients with mCSPC treated with upfront intensified therapies.