New England Journal of Medicine FEBRUARY 17, 2022

Darolutamide and Survival in Metastatic, Hormone-Sensitive Prostate Cancer

Smith MR, Hussain M, Saad F, Fizazi K, Shore N, et al.

Bottom Line

In patients with metastatic, hormone-sensitive prostate cancer, the addition of darolutamide to androgen-deprivation therapy and docetaxel significantly improved overall survival compared to placebo plus ADT and docetaxel.

Key Findings

1. The addition of darolutamide significantly reduced the risk of death by 32.5% (hazard ratio 0.68; 95% confidence interval 0.57-0.80; P<0.001) compared to the placebo group.

2. The treatment significantly delayed the development of castration-resistant prostate cancer, reducing the risk by 64% (HR 0.36; 95% CI 0.30-0.42; P<0.001).

3. Benefits were consistently observed across prespecified subgroups, including disease volume and risk categories, with hazard ratios for overall survival ranging from 0.62 to 0.71.

4. The incidence of grade 3 or 4 treatment-emergent adverse events was similar between the darolutamide group (66.1%) and the placebo group (63.5%), indicating that adding darolutamide did not significantly increase toxicity despite the longer treatment duration.

Study Design

Design

RCT

Double-Blind

Sample

1,306

Patients

Duration

41 mo (median)

Median

Setting

Multicenter, International

Population Men with metastatic, hormone-sensitive prostate cancer who were candidates for androgen-deprivation therapy and docetaxel.

Intervention Darolutamide (600 mg twice daily) plus androgen-deprivation therapy and docetaxel.

Comparator Matching placebo plus androgen-deprivation therapy and docetaxel.

Outcome Overall survival

Study Limitations

• The study was conducted in a population where patients were fit enough to undergo chemotherapy (docetaxel), potentially limiting generalizability to patients with poorer performance status.

• The trial was designed prior to the widespread adoption of newer androgen receptor pathway inhibitors as first-line therapy for metastatic hormone-sensitive prostate cancer, though this is a common context for trials of this era.

• Long-term outcomes beyond the primary endpoint median follow-up continue to be refined in follow-up analyses.

Clinical Significance

The ARASENS trial establishes the triplet combination of darolutamide, androgen-deprivation therapy (ADT), and docetaxel as a new standard of care for patients with metastatic, hormone-sensitive prostate cancer, offering a statistically significant survival benefit with a manageable toxicity profile.

Historical Context

The treatment landscape for metastatic hormone-sensitive prostate cancer evolved rapidly from ADT alone to the combination of ADT and docetaxel (CHAARTED/STAMPEDE trials) and later to the inclusion of androgen receptor pathway inhibitors. ARASENS was designed to test whether further intensification by adding a potent AR inhibitor like darolutamide to the existing standard of ADT plus docetaxel could improve outcomes.

Guided Discussion

High-yield insights from every perspective

Med Student

Medical Student

What is the specific mechanism of action of darolutamide, and how does its unique chemical structure contribute to a more favorable side-effect profile compared to other second-generation antiandrogens like enzalutamide?

Key Response

Darolutamide is a non-steroidal androgen receptor (AR) antagonist that competitively inhibits androgen binding, AR nuclear translocation, and AR-mediated transcription. Unlike enzalutamide or apalutamide, darolutamide has a distinct polar structure that results in very low penetration across the blood-brain barrier. This significantly reduces the risk of central nervous system-related adverse effects such as seizures and cognitive impairment.

Resident

In a patient newly diagnosed with metastatic hormone-sensitive prostate cancer (mHSPC) who is fit for chemotherapy, how does the ARASENS trial impact the decision to use 'triplet therapy' versus a 'doublet' of ADT and docetaxel?

Key Response

The ARASENS trial demonstrated that the addition of darolutamide to ADT and docetaxel (triplet therapy) led to a 32.5% lower risk of death compared to ADT and docetaxel alone (the previous standard for many). This survival benefit was observed despite a high percentage of patients in the control group receiving subsequent life-prolonging therapies, establishing triplet therapy as a preferred standard of care for patients starting docetaxel.

Fellow

The ARASENS trial showed a survival benefit across both high-volume and low-volume disease according to CHAARTED criteria. Given the lack of a direct comparison to ADT + darolutamide (without docetaxel), how should we interpret the necessity of docetaxel in 'low-volume' mHSPC patients?

Key Response

While the hazard ratio for OS was favorable in the low-volume subgroup in ARASENS, the absolute benefit of docetaxel in low-volume mHSPC remains controversial based on older trials like CHAARTED and STAMPEDE. Because ARASENS compared Triplet to ADT+Docetaxel (not Triplet to ADT+ARSI), it remains unclear if adding docetaxel provides meaningful benefit over a modern doublet (ADT+ARSI) in low-volume patients, leading many to reserve triplet therapy primarily for high-volume or 'de novo' metastatic disease.

Attending

How do the ARASENS results redefine the 'window of opportunity' for treatment intensification in mHSPC, and what are the teaching points regarding the timing of ARSI initiation relative to docetaxel cycles?

Key Response

ARASENS shifts the paradigm from sequential therapy to upfront intensification. A key teaching point is that darolutamide was started within 6 weeks after the first docetaxel dose. This suggests that the maximal benefit is derived from the early concurrent administration of chemotherapy and AR-directed therapy, preventing the emergence of resistant clones rather than waiting for castration resistance to occur.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD

How does the high rate of crossover to subsequent life-prolonging therapies (roughly 75%) in the control arm of ARASENS affect the statistical power and interpretation of the primary endpoint, and what does this imply about the 'treatment sequencing' vs. 'upfront combination' debate?

Key Response

High crossover rates in the control group typically dilute the observed survival benefit (making it harder to reach statistical significance). The fact that darolutamide still achieved a significant OS benefit (HR 0.68) despite the control group receiving subsequent ARSIs strongly suggests that early 'triplet' intervention is biologically superior to the sequential use of the same agents upon progression.

Journal Editor

Critically appraise the choice of the control arm in ARASENS. Does the use of ADT plus docetaxel as the comparator limit the generalizability of the findings in an era where ADT plus an ARSI is the more common doublet standard?

Key Response

As a reviewer, one would flag that the trial lacks an ADT + Darolutamide arm. Since ADT + ARSI is often preferred over ADT + Docetaxel due to lower toxicity, the trial proves that 'Triplet > ADT + Docetaxel' but does not definitively prove 'Triplet > ADT + Darolutamide.' This leaves a gap in evidence regarding whether the docetaxel component of the triplet is truly adding value for all patients or just increasing toxicity relative to modern doublets.

Guideline Committee

How should the ARASENS data be integrated into current NCCN or EAU guidelines for mHSPC, specifically regarding the strength of recommendation for triplet therapy in 'de novo' vs. 'metachronous' metastatic disease?

Key Response

NCCN guidelines (v1.2023) currently list ADT + Docetaxel + Darolutamide as a Category 1 recommendation. However, the committee must note that the majority of ARASENS patients had de novo metastatic disease (86%). Therefore, while the recommendation is broad, the evidence is strongest for de novo high-volume patients. For metachronous (relapsed) or low-volume disease, guidelines must balance the ARASENS OS benefit against the toxicity profile of docetaxel, which was not shown to benefit these specific subgroups in previous studies like CHAARTED.

Clinical Landscape

Noteworthy Related Trials

2015

CHAARTED Trial

n = 790 · NEJM

Tested

Docetaxel plus androgen-deprivation therapy

Population

Metastatic hormone-sensitive prostate cancer patients

Comparator

Androgen-deprivation therapy alone

Endpoint

Overall survival

Key result: The addition of docetaxel to androgen-deprivation therapy significantly prolonged overall survival compared to androgen-deprivation therapy alone.

2017

LATITUDE Trial

n = 1199 · NEJM

Tested

Abiraterone acetate and prednisone plus androgen-deprivation therapy

Population

High-risk metastatic hormone-sensitive prostate cancer

Comparator

Placebo plus androgen-deprivation therapy

Endpoint

Overall survival and radiographic progression-free survival

Key result: Treatment with abiraterone and prednisone significantly improved overall survival and radiographic progression-free survival.

2019

ARCHES Trial

n = 1150 · JCO

Tested

Enzalutamide plus androgen-deprivation therapy

Population

Metastatic hormone-sensitive prostate cancer patients

Comparator

Placebo plus androgen-deprivation therapy

Endpoint

Radiographic progression-free survival

Key result: Enzalutamide significantly reduced the risk of radiographic progression or death in patients with metastatic hormone-sensitive prostate cancer.

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