Expanding armamentarium in advanced prostate cancer management: are all novel antiandrogens the same?

Visceral Metastasis Predicts Response to New Hormonal Agents in Metastatic Castration-Sensitive Prostate Cancer

Visceral metastasis (VM) and a higher number of bone metastasis generally define high volume/risk in patients with metastatic castration-sensitive prostate cancer (mCSPC). Subgroup analysis of pivotal trials did not show a clear benefit of second-generation non-steroidal anti-androgens (NSAAs) in patients with VM. However, subgroup analysis of the trial assessing abiraterone acetate, a CYP 17 inhibitor, plus prednisone (AAP) showed an improved overall survival (OS) in patients with mCSPC with VM. We searched MEDLINE, Web of Science, and congress abstracts for the phase III randomized controlled trials of second-generation NSAAs and AAP in patients with mCSPC. In this pooled analysis, we included 6485 patients from the 6 phase III trials. The rate of patients with VM was 15.2%. Interestingly, in contrast to NSAAs, AAP seems to be effective in improving OS among patients with VM (hazard ratio, HR: 0.89, 95% CI, 0.72-1.11, P = .30 for second-generation NSAAs; HR: 0.58, 95% CI, 0.40-0.84, P = .004 for AAP). In contrast, both second-generation NSAAs (HR: 0.63, 95% CI, 0.57-0.70, P < .001) and AAP (HR: 0.68, 95% CI, 0.57-0.81, P < .001) improved OS in patients without VM. In this pooled analysis, we demonstrate that while AAP provided an OS improvement in patients with VM, second-generation NSAAs did not demonstrate a similar OS benefit in this population.

Revision of CHAARTED and LATITUDE criteria among Japanese de novo metastatic prostate cancer patients

BACKGROUND

To identify the real high-risk group among Japanese de novo metastatic prostate cancer patients who fit CHAARTED or LATITUDE criteria.

METHODS

We retrospectively studied patients who fitted CHAARTED (292 patients) and LATITUDE (294 patients) criteria from Japanese multi-institutions. All patients received androgen deprivation therapy with bicalutamide as an initial treatment. Factors related to overall survival (OS) and progression-free survival were statistically analyzed.

RESULTS

The median OS was 55.5 months and 60.0 months in patients who met the CHAARTED and the LATITUDE criteria, respectively. In patients who met CHAARTED criteria, lactate dehydrogenase (LDH) (hazard ratio (HR) 2.63, P < 0.0001) and C-reactive protein (CRP) (HR 1.65, P = 0.042) were independent risk factors for OS. In patients who met the LATITUDE criteria, Gleason score (GS) ≥9 (HR 1.77, P = 0.0326) and LDH (HR 2.62, P < 0.0001) were independent risk factors for OS. Modified CHAARTED criteria by adding LDH and CRP showed a significant difference in OS (HR 2.55, P < 0.0001) with a comparative median OS (31.8 months) to placebo of CHAARTED trial (32.2 months). Modified LATITUDE criteria by adding GS ≥9 and LDH showed a significant difference in OS (HR 2.66, P < 0.0001) with a comparative median OS (32.7 months) to placebo of LATITUDE trial (34.7 months).

CONCLUSION

Modified criteria may potentially elucidate the true "high volume" and "high risk" patients in the Japanese cohort who require early intensive therapy.

Prognostic impact of dose reduction in androgen receptor pathway inhibitors for castration-resistant prostate cancer

Background

Androgen receptor pathway inhibitors (ARPIs) such as abiraterone and enzalutamide have been shown to prolong survival in patients with advanced prostate cancer. However, there is limited evidence on the anticancer effect of a reduced dose of ARPIs. This study compared the prognosis in patients with chemotherapy-naïve castration-resistant prostate cancer (CRPC) between ARPI treatment with standard dose and treatment with reduced dose.

Methods

Japanese patients who were treated with ARPI as first-line treatment for CRPC between 2014 and 2018 were included. The associations between dose reduction and clinicopathological factors, progression-free survival, and overall survival were investigated.

Results

Of the 162 patients included, 33 (20.4%) patients had their dose reduced during ARPI treatment. In the multivariate analysis, higher PSA, abiraterone treatment, and dose reduction were significant prognostic factors for progression-free survival (PFS); however, dose reduction was not associated with overall survival. In the enzalutamide-treated group, the median PFS was 12.1 months (95% CI, 8.5–21.4 months) in the standard-dose group and 7.2 months (95% CI, 5.0–11.5 months) in the reduced-dose group (P = 0.038).

Conclusion

This study suggests inferior oncological outcome when treated with reduced-dose ARPI for CRPC. Full-dose administration of ARPI for CRPC may be appropriate if feasible.