The New England Journal of Medicine March 24, 2022

Darolutamide and Survival in Metastatic, Hormone-Sensitive Prostate Cancer

Matthew R. Smith, Maha Hussain, Fred Saad, Karim Fizazi, Cora N. Sternberg et al.

Bottom Line

The phase 3 ARASENS trial demonstrated that the addition of darolutamide to androgen-deprivation therapy and docetaxel significantly improved overall survival in patients with metastatic, hormone-sensitive prostate cancer compared to ADT and docetaxel alone.

Key Findings

1. At data cutoff, the risk of death was significantly lower by 32.5% in the darolutamide group compared to the placebo group (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.57 to 0.80; P<0.001).
2. Darolutamide significantly prolonged the time to castration-resistant prostate cancer (CRPC) and delayed the time to pain progression compared to placebo.
3. The incidence of grade 3 or 4 adverse events was similar between the two groups (66.1% in the darolutamide group vs. 63.5% in the placebo group).
4. Neutropenia was the most common grade 3 or 4 adverse event, occurring in 33.7% of the darolutamide group and 34.2% of the placebo group, with most severe events overlapping with the docetaxel treatment period.

Study Design

Design
RCT
Double-Blind
Sample
1,306
Patients
Duration
43.7 mo
Median
Setting
Multicenter, global
Population Patients with metastatic, hormone-sensitive prostate cancer (mHSPC) who were candidates for concurrent androgen-deprivation therapy and docetaxel.
Intervention Darolutamide (600 mg twice daily) + ADT + docetaxel (75 mg/m2 every 3 weeks for 6 cycles)
Comparator Placebo + ADT + docetaxel (75 mg/m2 every 3 weeks for 6 cycles)
Outcome Overall survival (OS)

Study Limitations

The trial design required all patients to receive docetaxel, limiting the applicability of these findings to patients who are ineligible for or decline chemotherapy.
The study did not directly compare triplet therapy (ADT + docetaxel + darolutamide) to a doublet non-chemotherapy regimen (ADT + darolutamide), leaving questions about the optimal patient selection for chemotherapy versus ARPI alone.
A smaller proportion of enrolled patients had low-volume metastatic disease, which slightly limits the statistical power of subgroup analyses in that specific population.

Clinical Significance

ARASENS established triplet therapy with darolutamide, ADT, and docetaxel as a new standard of care for patients with metastatic hormone-sensitive prostate cancer (mHSPC) who are candidates for chemotherapy. The addition of darolutamide resulted in a pronounced and statistically significant overall survival benefit without substantially compounding the toxicity of docetaxel, revolutionizing the treatment paradigm for early-stage metastatic prostate cancer.

Historical Context

Historically, the backbone of treatment for metastatic hormone-sensitive prostate cancer was androgen deprivation therapy (ADT) alone. In 2015, the CHAARTED and STAMPEDE trials demonstrated that adding docetaxel to ADT prolonged survival in mHSPC, creating the ADT+docetaxel doublet standard. Later, the addition of androgen receptor pathway inhibitors (ARPIs) like abiraterone, enzalutamide, or apalutamide to ADT also became doublet standards. ARASENS (alongside the PEACE-1 trial for abiraterone) tested the logical next step: 'triplet' therapy. By successfully proving that adding a second-generation ARPI (darolutamide) to the ADT+docetaxel backbone further decreased mortality, ARASENS helped establish early, intensified multi-agent therapy as the standard for mHSPC.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

What is the mechanism of action of darolutamide, and how do its structural differences from other androgen receptor inhibitors like enzalutamide or apalutamide translate into its specific side effect profile as seen in the ARASENS trial?

Key Response

Darolutamide is a structurally distinct second-generation nonsteroidal androgen receptor antagonist. Unlike enzalutamide or apalutamide, it is characterized by low blood-brain barrier penetration. This foundational pharmacological concept is crucial because it translates clinically into a significant reduction in CNS-related adverse effects, such as fatigue, falls, cognitive impairment, and seizures, which is vital for maintaining quality of life in patients receiving intensive triplet therapy.

Resident
Resident

Based on the ARASENS data, how should clinicians weigh the decision between initiating triplet therapy (ADT plus docetaxel plus darolutamide) versus doublet therapy (ADT plus an androgen receptor pathway inhibitor) for a newly diagnosed patient with metastatic hormone-sensitive prostate cancer?

Key Response

The ARASENS trial establishes triplet therapy as a new standard of care for mHSPC, particularly for those fit for chemotherapy. However, residents must recognize that doublet therapy (ADT plus an AR pathway inhibitor) remains highly appropriate for patients who are frail, have significant comorbidities, or are ineligible for docetaxel. The clinical challenge lies in balancing the robust overall survival benefit of triplet therapy against the added toxicity of chemotherapy, tailoring the choice to the patient's performance status and disease burden.

Fellow
Fellow

In the ARASENS trial, over 80 percent of patients presented with de novo metastatic disease. How does this baseline demographic, in the context of the CHAARTED high-volume versus low-volume criteria, influence the nuanced application of triplet therapy for patients with metachronous, low-volume mHSPC?

Key Response

Patients with de novo mHSPC typically have a more aggressive clinical course and derive a well-documented survival benefit from early docetaxel compared to those with metachronous metastases. Fellows must critically assess the trial's subgroup analyses to determine if the substantial survival benefit of triplet therapy is driven primarily by the high-volume, de novo cohort, and whether exposing low-volume or metachronous patients to the toxicities of upfront docetaxel is truly justified based on current evidence.

Attending
Attending

With the paradigm shift toward upfront triplet therapy in mHSPC driven by ARASENS and PEACE-1, what are the profound practice-changing implications for therapeutic sequencing and the management of resistance mechanisms once these patients inevitably progress to metastatic castrate-resistant prostate cancer (mCRPC)?

Key Response

Deploying the most potent systemic agents (chemotherapy and next-generation AR inhibitors) upfront in the hormone-sensitive setting drastically alters tumor biology and clonal evolution by the time of mCRPC progression. Attendings must anticipate that traditional subsequent lines of therapy will be less effective, necessitating a pivot toward precision oncology tools like PSMA-PET imaging, radioligand therapy (e.g., Lu-177-PSMA-617), PARP inhibitors for HRR-mutated tumors, or novel clinical trials, thus completely reshaping the classic prostate cancer treatment algorithm.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The ARASENS trial demonstrated a statistically significant overall survival benefit despite over 75 percent of patients in the placebo group receiving subsequent life-prolonging therapies. Methodologically, what statistical models are best suited to account for this extensive crossover and subsequent treatment confounding, and how does this impact the interpretation of the true treatment effect magnitude?

Key Response

In modern oncology trials, overall survival endpoints are heavily confounded by effective subsequent therapies, which can dilute the apparent benefit of the investigational arm. PhD-level researchers must evaluate the use of methods such as the Rank Preserving Structural Failure Time (RPSFT) model or inverse probability of censoring weighting (IPCW) to adjust for post-progression therapies. Understanding these methods is critical for validating whether the observed OS hazard ratio underestimates the true biological efficacy of concurrent triplet therapy.

Journal Editor
Journal Editor

As a critical reviewer, one major threat to the external validity of the ARASENS trial is the choice of the control arm (ADT plus docetaxel) rather than ADT plus an androgen receptor pathway inhibitor. How does this methodological choice limit the trial's ability to definitively position triplet therapy over the increasingly preferred, non-chemotherapy doublet standards?

Key Response

While ADT plus docetaxel was a valid standard of care during the trial's design phase, ADT plus an AR pathway inhibitor (e.g., abiraterone or enzalutamide) has arguably become the most widely utilized backbone globally due to its favorable toxicity profile compared to chemotherapy. A seasoned editor would highlight that ARASENS proves Darolutamide/ADT/Docetaxel is superior to ADT/Docetaxel, but fails to provide head-to-head evidence that the triplet is superior to an ADT/ARPI doublet, leaving a critical gap in the evidence-based hierarchy of mHSPC management.

Guideline Committee
Guideline Committee

In light of the Level 1 evidence from the ARASENS trial, how should organizations like the NCCN and EAU update their clinical practice guidelines regarding the strength of recommendation for triplet therapy, and what specific clinical criteria should be explicitly defined to prevent the overtreatment of low-risk mHSPC populations?

Key Response

Guideline committees must integrate ARASENS data by elevating triplet therapy (ADT plus docetaxel plus darolutamide) to a Category 1 recommendation for mHSPC patients fit for chemotherapy. However, given the lack of direct comparison against ADT plus ARPI doublets, guidelines must provide precise stratification algorithms utilizing metrics like the CHAARTED volume criteria or LATITUDE risk criteria. This ensures that the intense triplet regimen is directed toward high-risk, high-volume patients who derive the most benefit, while sparing frail or low-volume patients from unnecessary chemotherapy-induced morbidity.

Clinical Landscape

Noteworthy Related Trials

2015

CHAARTED Trial

n = 790 · NEJM

Tested

Docetaxel plus ADT

Population

Metastatic hormone-sensitive prostate cancer patients

Comparator

ADT alone

Endpoint

Overall survival

Key result: Docetaxel combined with ADT significantly extended median overall survival compared to ADT alone, particularly in high-volume disease.
2019

TITAN Trial

n = 1,052 · NEJM

Tested

Apalutamide plus ADT

Population

Metastatic hormone-sensitive prostate cancer patients

Comparator

Placebo plus ADT

Endpoint

Overall survival and radiographic progression-free survival

Key result: Adding apalutamide to ADT resulted in significantly longer overall survival and radiographic progression-free survival than ADT alone.
2022

PEACE-1 Trial

n = 1,173 · Lancet

Tested

Abiraterone plus prednisone with ADT and docetaxel

Population

De novo metastatic hormone-sensitive prostate cancer patients

Comparator

ADT plus docetaxel

Endpoint

Overall survival and radiographic progression-free survival

Key result: The addition of abiraterone to ADT and docetaxel significantly improved overall survival and radiographic progression-free survival.

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