ADT, ARPIs and docetaxel in metastatic hormone-sensitive prostate cancer

Androgen deprivation plus treatment intensification: doublets, triplets, flare and bone health

For clinicians and students · Regimen tutorial · Prostate cancer · 11 min read · last reviewed September 30, 2026

Indications

This tutorial covers metastatic castration-sensitive (hormone-sensitive) prostate cancer (mCSPC/mHSPC). That means newly diagnosed metastatic disease (de novo) or metastatic relapse after local therapy, where testosterone has not yet been suppressed to castrate levels long enough for resistance to develop.

Across ASCO, ESMO, EAU and NCCN guidance, the standard of care for suitable patients is ADT plus intensification. ADT alone is no longer adequate. The options are:

• ADT + ARPI doublet: abiraterone + prednisone, enzalutamide, apalutamide or darolutamide.
• ADT + docetaxel + ARPI triplet: darolutamide (ARASENS) or abiraterone (PEACE-1). Generally used for fit patients with de novo, particularly high-volume, disease.
• ADT + docetaxel doublet: largely superseded by the triplets. It remains in some protocols, for example BC Cancer GUPDOCADT for high-volume disease.

Eligibility (BC Cancer):

• No prior systemic therapy for metastatic disease.
• ADT for mCSPC is permitted if it began less than 6 months before starting, and no adjuvant ADT within the past year.
• Patients may have one of the funded mCSPC ARPI protocols, not sequential ARPIs.

Volume definition (CHAARTED): high volume means visceral metastases, or 4 or more bone metastases with at least one outside the vertebral column and pelvis.

Regimen table

1. ADT backbone (BC Cancer GUPADT)

ADT continues indefinitely alongside every intensification option, unless the patient has had a bilateral orchiectomy.

2. ARPI doublets (continue until progression or unacceptable toxicity)

Abiraterone dosing note: LATITUDE used prednisone 5 mg once daily. BC Cancer's default is 10 mg per day because the lower dose causes more hypokalaemia, oedema and hypertension.

3. Docetaxel-containing regimens (docetaxel every 21 days × 6 cycles)

In the docetaxel protocols, docetaxel is given without daily prednisone. If docetaxel is stopped for intolerance, darolutamide and ADT continue.

Premedication & supportive care

• Docetaxel premedication:
• BC Cancer gives dexamethasone 8 mg PO twice daily for 3 days, starting the day before each docetaxel dose. At least 3 doses must be taken before treatment.
• This reduces fluid retention and hypersensitivity reactions.
• Additional antiemetics are not usually needed, as docetaxel has low emetogenic risk.
• Frozen gloves, worn from 15 minutes before until 15 minutes after the infusion, may prevent nail and hand toxicity.
• Febrile neutropenia: docetaxel carries a meaningful risk in this population. Consider primary G-CSF per local policy and patient risk, since FN rates were notable in the Asian and older subgroups of the mHSPC trials.
• Flare prevention with GnRH agonists:
• The testosterone surge in the first 1–3 weeks can worsen bone pain, urinary obstruction or spinal cord compression.
• Give an antiandrogen for 3–4 weeks, starting 1–2 weeks before the first agonist dose.
• Use an antagonist such as degarelix or relugolix for patients with impending cord compression, obstruction or severe pain.
• Bone health:
• At baseline, assess fracture risk: bone mineral density or FRAX, falls history, vitamin D.
• Advise calcium and vitamin D, weight-bearing and resistance exercise, and stopping smoking.
• Give osteoporosis-dose antiresorptive therapy (denosumab or a bisphosphonate, per bone-health guidelines) when osteoporosis or high fracture risk is present.
• Enzalutamide and apalutamide increase falls and fractures. BC Cancer suggests considering a bone-sparing agent or bone-health referral.
• In castration-sensitive disease, bone-targeted agents at the higher "skeletal-related event" dosing did not improve outcomes. They are indicated for bone health, not for disease control.
• Cardiometabolic health: ADT raises the risk of weight gain, insulin resistance, dyslipidaemia and cardiovascular events.
• Assess cardiovascular risk and manage it per guidelines, in partnership with primary care.
• Correct electrolytes, and review QT-prolonging drugs (ADT, enzalutamide).
• In HERO, relugolix was associated with fewer major adverse cardiovascular events than leuprolide.
• Hot flushes and sexual health: counsel before starting. Offer non-hormonal options (for example venlafaxine or gabapentin) and sexual-health referral.

Key toxicities

• ADT (all patients):
• Hot flushes, loss of libido and erectile function, fatigue.
• Loss of muscle mass with fat gain, anaemia, bone loss and fractures.
• Metabolic syndrome, cardiovascular events, QT prolongation.
• Mood changes, cognitive complaints, gynaecomastia.
• Abiraterone + prednisone:
• Mineralocorticoid excess from ACTH drive: hypertension, hypokalaemia, fluid retention.
• Hepatotoxicity, mostly in the first 3 months.
• Long-term corticosteroid effects.
• Take abiraterone on an empty stomach, because food greatly increases absorption.
• Enzalutamide: fatigue, hypertension, seizures (a higher risk above 160 mg per day), falls and fractures, cognitive impairment and QT prolongation.
• Enzalutamide is a strong CYP3A4 inducer, so check for interactions with anticoagulants, statins and opioids.
• Reduce to 80 mg if a strong CYP2C8 inhibitor such as gemfibrozil is unavoidable.
• Apalutamide:
• Rash in about 25%, usually in the first 3 months.
• Hypothyroidism in up to 22%, with a median onset of 4 months.
• Falls and fractures, rare seizures, hypertension.
• Apalutamide is also a CYP3A4 inducer.
• Darolutamide: generally well tolerated, with low CNS penetration. Rash is mostly grade 1–2. Main issue is CYP3A4 interactions.
• Docetaxel:
• Neutropenia and febrile neutropenia, fatigue, alopecia.
• Peripheral neuropathy, nail changes, fluid retention, hypersensitivity reactions.
• Diarrhoea, mucositis and taste change.

Monitoring

• ADT: PSA and testosterone to confirm castration (below 1.7 nmol/L, or below 50 ng/dL). Also monitor weight, blood pressure, glucose or HbA1c, and lipids. Check BMD at baseline and periodically.
• Abiraterone (BC Cancer GUMCSPABI):
• Cycles 1–3: check potassium, ALT, bilirubin, alkaline phosphatase and blood pressure every 2 weeks, and a full panel with PSA every 4 weeks.
• From Cycle 4: check at each visit.
• Keep potassium above 3.5 mmol/L (4.0 or higher recommended).
• Enzalutamide: blood pressure every 2 weeks for the first 3 months (BC Cancer), plus PSA and blood pressure at each visit.
• Apalutamide: TSH at baseline and during treatment, plus skin checks.
• Darolutamide: baseline liver panel and INR.
• Docetaxel:
• CBC before each cycle.
• Liver tests at baseline and before Cycle 4, or every cycle if they are abnormal or liver metastases are present.
• PSA every 3 weeks.

Dose-modification principles

Summarized from the BC Cancer protocols. Defer to your local protocol.

• Abiraterone:
• ALT above 5 × ULN or bilirubin above 3 × ULN: hold, then resume 250 mg lower once liver tests are grade 1 or better.
• Symptomatic or grade 3–4 hypokalaemia: hold until corrected, and check magnesium.
• Severe hypertension (above 200/110): suspend temporarily.
• Enzalutamide: step down 160 → 120 → 80 mg. Permanently discontinue after a seizure.
• Apalutamide: step down 240 → 180 → 120 mg.
• Grade 1 rash: continue, with topical steroid and antihistamine.
• Grade 3 or higher rash: hold and consider a short oral steroid course, then resume at the same dose or one level lower.
• Permanently discontinue after a seizure.
• Darolutamide:
• Grade 3 or higher toxicity: reduce to 300 mg twice daily or hold. Do not reduce below 300 mg twice daily.
• Child-Pugh B: 300 mg twice daily. Child-Pugh C: not recommended.
• CrCl 15–29 mL/min: 300 mg twice daily. CrCl below 15: not recommended.
• Docetaxel:
• Counts: ANC of 1.5 or more and platelets above 90 → 100%. ANC 1.0–1.5 or platelets 70–90 → 75%. Lower than that → delay.
• After neutropenic sepsis: 75%.
• Liver: if bilirubin is above ULN, or ALP or AST/ALT above 5 × ULN, discuss with the treating oncologist.

Key trials & evidence

• CHAARTED (Sweeney, NEJM 2015): ADT + docetaxel × 6 improved overall survival over ADT alone. The benefit was concentrated in high-volume disease. STAMPEDE's docetaxel arm (James, Lancet 2016) supported this.
• LATITUDE (Fizazi, NEJM 2017): abiraterone + prednisone improved overall survival (HR about 0.62 at the first analysis) in de novo high-risk mCSPC. STAMPEDE's abiraterone comparison (James, NEJM 2017) extended the benefit to a broader population.
• TITAN (Chi, NEJM 2019): apalutamide improved radiographic progression-free and overall survival across volume groups.
• ARCHES (Armstrong, JCO 2019) and ENZAMET (Davis, NEJM 2019): enzalutamide improved radiographic progression-free survival (ARCHES) and overall survival (ENZAMET, where some patients also received docetaxel).
• ARANOTE (Saad, JCO 2024): darolutamide + ADT without docetaxel improved radiographic progression-free survival. This is the basis for BC Cancer GUMCSPDAR.
• ARASENS (Smith, NEJM 2022): adding darolutamide to ADT + docetaxel improved overall survival (HR 0.68) without a meaningful increase in adverse events.
• PEACE-1 (Fizazi, Lancet 2022): in de novo mCSPC, adding abiraterone + prednisone to standard of care improved radiographic progression-free survival and overall survival. In the ADT + docetaxel population, the overall survival HR was about 0.75. Hypertension was the main added toxicity.
• HERO (Shore, NEJM 2020): relugolix achieved faster and more sustained castration than leuprolide and did not cause flare.

Choosing between regimens: triplets have not been compared head-to-head with ARPI doublets in a randomised trial. Guidelines generally favour a triplet for fit patients with de novo high-volume disease, and a doublet for low-volume or metachronous disease, or when docetaxel is unsuitable. Consult current ASCO, ESMO and NCCN guidance rather than reproducing their algorithms here.

Clinical pearls

• Choose ADT by clinical risk. Use an antagonist when flare could be dangerous. If an agonist is used, bicalutamide must start 1–2 weeks before the first agonist dose.
• Don't combine bicalutamide with an ARPI. Stop it when starting enzalutamide, apalutamide or darolutamide.
• Take abiraterone fasting. Taken with food, exposure can rise many-fold.
• Check drug interactions early. Enzalutamide and apalutamide induce CYP3A4 and can reduce DOAC, warfarin, statin and some opioid effect. Darolutamide is the least interaction-prone ARPI.
• Monitor the relugolix-apalutamide combination. Apalutamide can lower relugolix levels. BC Cancer advises monitoring testosterone and considering relugolix 240 mg daily if suppression is inadequate.
• Remember sequencing rules. Most funders do not allow a second ARPI at castration-resistant progression after one was used in mCSPC. Plan the whole treatment pathway.
• Order germline and somatic genetic testing (HRR genes such as BRCA2) early. It informs later PARP-inhibitor options and family counselling.

Educational material for health professionals and students. Not a prescribing order; it does not replace your institution's approved protocol, pharmacy verification or clinical judgement.

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