Efficacy and Safety of Non-Steroidal Anti-Androgens in Patients with Metastatic Prostate Cancer: Meta-Analysis of Randomized Controlled Trials

Time to Castration Resistance is Associated With Overall Survival Even After the Achievement of Castration Resistance in Metastatic Prostate Cancer

BACKGROUND

Recent clinical trials have shown that patients with metastatic castration-sensitive prostate cancer in real-world settings have different overall survival (OS) rates after stratifying for tumor burden or visceral metastasis. However, some patients with a low tumor burden and without visceral metastasis still have a poor survival. Androgen receptor signaling is still a main therapeutic target of prostate cancer treatment even after the achievement of castration resistance. In this regard, we hypothesized that time to castration resistance can be a prognostic factor of metastatic castration-sensitive prostate cancer even after achieving castration resistance. The current study aimed to assess the novel prognostic factors, particularly time to castration resistance, of prostate cancer in patients at a real-world single institution.

METHODS

The data of 261 patients who were newly diagnosed with metastatic castration-sensitive prostate cancer from January 2007 to December 2023 were retrospectively analyzed.

RESULTS

The median OS was 60.7 months, and the median time to castration resistance was 13.1 months. Among 261 patients, 158 developed castration-resistant prostate cancer. A shorter time to castration resistance, the presence of distant lymph node metastasis, ISUP grade group 5, and older age were associated with a shorter OS in patients who developed castration-resistant prostate cancer. A shorter time to castration resistance was significantly associated with a shorter OS regardless of the tumor burden. Further, it was associated with a shorter OS even after the achievement of castration resistance.

CONCLUSIONS

The study results support the presence of persistent androgen receptor signaling even after achieving castration resistance in prostate cancer, and time to castration resistance can be a biomarker for the activation of androgen receptor signaling regardless of tumor burden.

Cost-effectiveness of enzalutamide versus apalutamide versus androgen deprivation therapy alone for the treatment of metastatic castration-sensitive prostate cancer in Canada

AIMS

There are no direct comparisons of the relative cost-effectiveness of second-generation anti-androgens (enzalutamide and apalutamide) used in managing metastatic castration-sensitive prostate cancer (mCSPC) in Canada. This study compared the cost-effectiveness of enzalutamide versus apalutamide versus androgen deprivation therapy (ADT) alone (standard of care) in patients with mCSPC from the Canadian public payer perspective using a Markov model with a 15-year time horizon.

MATERIALS AND METHODS

Efficacy data for enzalutamide and ADT alone were informed by the ARCHES and ENZAMET clinical trials, while a Bayesian network meta-analysis enabled comparison with apalutamide and ADT alone.

RESULTS

Over the 15-year period, enzalutamide achieved the highest number of life-years (LY, 7.6) and quality-adjusted life-years (QALY, 5.62) compared with apalutamide (LY, 6.1; QALY, 4.59) and ADTs (LY, 4.9; QALY, 3.61). Enzalutamide incurred the most costs ($349,345) compared with apalutamide ($294,349) and ADT ($162,550). Sequential analysis showed that enzalutamide lies on the cost-effectiveness frontier with ADT alone (incremental cost-effectiveness ratio: $92,868/QALY), with apalutamide extendedly dominated through enzalutamide and ADT alone.

LIMITATIONS

Limitations include the heterogeneity of the studies included in the network meta-analysis and the validations for the treatment sequencing assumptions in the modeling.

CONCLUSIONS

Enzalutamide was the most effective treatment option for mCSPC in the Canadian market, with the greatest LYs and QALYs, and incurred the most costs.

PIM kinase inhibition: co-targeted therapeutic approaches in prostate cancer

PIM kinases have been shown to play a role in prostate cancer development and progression, as well as in some of the hallmarks of cancer, especially proliferation and apoptosis. Their upregulation in prostate cancer has been correlated with decreased patient overall survival and therapy resistance. Initial efforts to inhibit PIM with monotherapies have been hampered by compensatory upregulation of other pathways and drug toxicity, and as such, it has been suggested that co-targeting PIM with other treatment approaches may permit lower doses and be a more viable option in the clinic. Here, we present the rationale and basis for co-targeting PIM with inhibitors of PI3K/mTOR/AKT, JAK/STAT, MYC, stemness, and RNA Polymerase I transcription, along with other therapies, including androgen deprivation, radiotherapy, chemotherapy, and immunotherapy. Such combined approaches could potentially be used as neoadjuvant therapies, limiting the development of resistance to treatments or sensitizing cells to other therapeutics. To determine which drugs should be combined with PIM inhibitors for each patient, it will be key to develop companion diagnostics that predict response to each co-targeted option, hopefully providing a personalized medicine pathway for subsets of prostate cancer patients in the future.