Apalutamide

Introduction Overview

Generic Name

apalutamide

Brand Name

Erleada

Dosage Form

oral tablet (240 mg; 60 mg)

Drug Class

Antiandrogens; Hormones / antineoplastics

Pharmacokinetics

Absorption:
Apalutamide is administered orally, and it is well absorbed from the gastrointestinal tract following tablet ingestion. The drug’s bioavailability is high, allowing for effective plasma concentrations to be reached with once-daily dosing. Absorption is not significantly affected by food, which permits administration with or without meals, providing flexibility and convenience for patients. Peak plasma concentrations are generally achieved within hours post-dose, supporting its suitability for daily dosing schedules.

Distribution:
Apalutamide exhibits extensive tissue distribution due to its lipophilic nature and moderate protein binding characteristics. It binds primarily to plasma proteins such as albumin, which aids in maintaining sustained systemic exposure. The drug penetrates target tissues, including prostate cancer cells and androgen-sensitive tissues, to exert its therapeutic effect. Distribution volume indicates adequate dispersion beyond the vascular compartment, which contributes to its efficacy in metastatic and non-metastatic prostate cancer settings.

Metabolism:
The drug undergoes hepatic metabolism primarily through the cytochrome P450 enzyme system, mainly CYP2C8 and CYP3A4 isoenzymes. This metabolic pathway results in the formation of an active metabolite, which contributes to the overall pharmacological activity of apalutamide. Metabolism also involves biotransformation through oxidation and other phase I reactions. Interindividual variability in CYP450 activity can influence the metabolism rates and plasma levels, necessitating consideration in patients with hepatic impairment or concomitant CYP modulators.

Elimination:
Apalutamide and its metabolites are eliminated via a combination of renal and fecal routes, with the fecal route being predominant. The elimination half-life of apalutamide supports once-daily dosing, typically allowing for steady-state concentrations within a week of continuous administration. Renal clearance plays a minor role, but patients with significant renal dysfunction should still be monitored due to overall exposure. The drug’s elimination profile underpins its sustained pharmacologic effect in suppressing androgen receptor signaling.

Dosage Forms

Available Dosage Forms:
Erleada is available in oral film-coated tablets in two strengths: 60 mg and 240 mg. These tablets are designed to be taken orally and should be swallowed whole without crushing, chewing, or breaking. The 240 mg dosage is typically administered as four 60 mg tablets once daily to achieve the standard therapeutic dose.

Dosages for Adults and Adolescents:
The standard adult dose for the treatment of prostate cancer, including metastatic castration-sensitive prostate cancer (mCSPC) and non-metastatic castration-resistant prostate cancer (nmCRPC), is 240 mg taken orally once daily. This regimen is often combined with androgen deprivation therapy, such as concomitant use of a gonadotropin-releasing hormone (GnRH) analog or following bilateral orchiectomy. Dosing should be consistent daily, and missed doses should be taken on the day remembered without doubling doses.

Specific Patient Populations:
Erleada is not approved for use in women or children. In males with prostate cancer, concurrent androgen deprivation therapy is critical to ensure efficacy. Use in patients with hepatic or renal impairment should be cautious due to the drug’s metabolism and elimination pathways, although no specific dosage adjustments are formally recommended. Older adults should be monitored for increased risk of falls and fractures. Patients with a history of seizures, stroke, or cardiovascular disease require careful evaluation before therapy initiation. Counseling regarding contraception is essential due to the drug’s teratogenic potential via exposure from male patients to female partners.

Mechanism Of Action

Apalutamide, the active ingredient in Erleada, is a selective androgen receptor inhibitor that binds competitively to androgen receptors (AR) on prostate cancer cells. By antagonizing the AR, apalutamide prevents the natural male hormones, chiefly testosterone and dihydrotestosterone, from activating these receptors. Since androgens drive the growth and proliferation of prostate cancer cells, their inhibition results in decreased cell growth and potential tumor regression.

At the molecular level, apalutamide blocks androgen receptor nuclear translocation, a necessary step for androgen-induced gene transcription that promotes tumor cell survival and proliferation. By inhibiting this translocation, apalutamide disrupts AR-mediated transcriptional activity, leading to reduced expression of genes that support cancer proliferation and survival.

Furthermore, apalutamide has demonstrated potency in inhibiting testosterone-driven DNA binding by ARs and downstream signaling pathways that contribute to tumor progression. Unlike earlier generation antiandrogens, apalutamide exhibits higher binding affinity and improved ability to prevent AR nuclear translocation, increasing its efficacy in resistant prostate cancer populations.

Clinically, these molecular actions translate to slowed or halted progression of prostate cancer, particularly in metastatic and castration-resistant settings where cancer cells continue to rely on androgen receptor signaling despite reduction of circulating testosterone levels. Comparative clinical studies highlight apalutamide’s advantage in improving metastasis-free survival and overall patient outcomes relative to placebo and other treatments. The drug’s mechanism, including its interference with androgen receptor signaling at multiple steps, constitutes the basis for its therapeutic role in managing advanced prostate cancer.

Pharmacological Actions

Selective inhibition of androgen receptor signaling by competitive binding.
Prevention of androgen receptor nuclear translocation, impairing gene transcription.
Inhibition of androgen-driven prostate cancer cell proliferation and survival.
Reduction of tumor growth and metastasis in androgen-sensitive prostate cancer.
Active metabolite formation contributing to sustained pharmacological effect.
Synergistic effect with androgen deprivation therapies in castration-sensitive settings.
Modulation of downstream androgen receptor-regulated oncogenic pathways.
Delayed progression of non-metastatic castration-resistant prostate cancer.
Reduction of androgen receptor activity in resistant prostate cancer clones.
Minimal activity on other nuclear hormone receptors, enhancing specificity.

Therapeutic Or Clinical Uses

Treatment of metastatic castration-sensitive prostate cancer (mCSPC).
Management of non-metastatic castration-resistant prostate cancer (nmCRPC).
Used in combination with gonadotropin-releasing hormone (GnRH) analog or post-orchiectomy.
Therapeutic option after failure of surgery or other treatments in non-metastatic cases.
Helps delay disease progression and metastasis in advanced prostate cancer.
Improves metastasis-free survival in patients with nmCRPC.
Used in patients still responsive to androgen deprivation therapy.
Provides an oral systemic antiandrogen therapy alternative to injectable agents.
Reduces tumor burden and prolongs progression-free survival.
Effective in prostate cancer types that rely on androgen receptor signaling.
Used in clinical protocols as a first-line treatment for certain prostate cancers.
Part of combination therapy regimens targeting androgen axis.
Suitable for long-term maintenance therapy to delay castrate resistance.
Treatment associated with improvements in patient-reported outcomes relating to disease symptoms.

Side Or Adverse Effects

Hot flashes (vasomotor symptoms commonly reported).
Diarrhea and gastrointestinal disturbances.
Loss of appetite leading to weight loss in some patients.
Generalized fatigue and tiredness.
Increased risk of falls, particularly in older adults.
Rash and various skin reactions, including severe dermatologic events.
Joint pain (arthralgia) affecting quality of life.
Hypertension (elevated blood pressure) requiring monitoring and management.
Increased incidence of bone fractures due to bone weakening effects.
Risk of seizure occurring in susceptible individuals.
Potential for cardiovascular side effects including chest pain and shortness of breath.
Neurologic adverse events such as dizziness and balance issues.
Serious hypersensitivity reactions including anaphylaxis and severe skin reactions.
Laboratory abnormalities like liver enzyme elevations and altered lipid profiles.
Occasional reports of stroke or thromboembolic events.

Precautions

Use caution in patients with a history of seizures or risk factors for seizure.
Monitor blood pressure regularly due to hypertension risk.
Evaluate fall risk and implement preventive measures in elderly patients.
Assess bone health and consider bone-strengthening agents to prevent fractures.
Avoid exposure during pregnancy; male patients should use effective contraception.
Do not donate sperm during treatment and for 3 months after the last dose.
Careful monitoring in patients with cardiovascular disease or previous stroke.
Frequent liver function tests recommended given the potential for hepatotoxicity.
Use with caution in patients with pre-existing skin disorders.
Inform patients about possible rash and instruct to report severe skin symptoms immediately.
Adjust treatment if serious adverse effects such as seizures or severe allergic reactions occur.
Regular evaluation of electrolyte and metabolic parameters to detect early abnormalities.
Avoid abrupt discontinuation to prevent disease progression.
Healthcare providers should evaluate for drug interactions before starting therapy.
Ensure patients understand proper dosing to minimize missed doses and overdosing.

Warnings

Apalutamide can cause birth defects if a woman is exposed during pregnancy.
Not indicated for use in women or children due to lack of safety data.
Increased risk of seizures; activities requiring alertness should be avoided if affected.
May cause serious dermatologic reactions including rash with blistering or peeling.
Potential for cardiovascular events including chest pain, stroke, and hypertension.
Falls and fractures are more frequent, especially in elderly patients.
Permanent discontinuation may be required if severe adverse reactions occur.
Interaction with other drugs affecting CYP2C8 and CYP3A4 may alter apalutamide levels.
Exposure to female partners through seminal fluid necessitates contraception use.
Patients with prior cerebrovascular disease require careful risk-benefit assessment.
Monitoring for allergic reactions and prompt treatment is critical.
Use caution in patients with metabolic disorders such as diabetes and hyperlipidemia.
Treatment-related delays in cancer therapy may occur due to adverse events.
Concomitant androgen deprivation therapy is essential for clinical efficacy.
Patients should remain under close medical supervision during treatment.

Contraindication

Known hypersensitivity to apalutamide or any tablet components.
Women who are or may become pregnant.
Pediatric population due to unknown safety and efficacy.
Patients with previous severe hypersensitivity reactions to antiandrogen drugs.
Concurrent use with medications contraindicated with CYP2C8 or CYP3A4 modulators without proper monitoring.
Patients unable to adhere to contraception recommendations during and post-treatment.
Those with history of seizures uncontrolled by medication.
Patients with active or unstable cardiovascular conditions posing high risk for stroke or myocardial infarction.
Severe hepatic impairment though specific contraindications not formally stated, caution advised.
Uncontrolled hypertension or bleeding disorders until stabilized.
Use in patients where falls or fractures would pose critical risks without mitigation.
Patients with a history of severe dermatological reactions to systemic androgen receptor inhibitors.
Pregnancy due to teratogenic risk.
Patients unwilling or unable to comply with required monitoring and precautionary measures.
Known or suspected drug interactions that cannot be safely managed.

Drug Interactions

Potent inducers or inhibitors of CYP3A4 and CYP2C8 can significantly alter apalutamide plasma concentrations.
Concomitant use with warfarin may modify anticoagulant effects requiring close INR monitoring.
Drugs that lower seizure threshold may increase risk of seizures when used with apalutamide.
Co-administration with certain corticosteroids may require dose adjustments.
Avoid use with strong CYP3A4 inducers like rifampin that may decrease apalutamide efficacy.
CYP2C8 inhibitors such as gemfibrozil may raise apalutamide levels and side effect risks.
Interaction with statins metabolized via CYP pathways may alter lipid-lowering therapy.
Concurrent use with antihypertensive agents necessitates monitoring for blood pressure changes.
Co-administration with drugs affecting QT interval requires caution to avoid arrhythmias.
Herbal supplements like St. John’s Wort may reduce apalutamide effectiveness via enzyme induction.
Possibility of reduced efficacy of hormonal contraceptives necessitates additional precautions.
Concomitant use with other antiandrogens or androgen deprivation therapies should be supervised.
Potential interaction with antiepileptic drugs requiring careful neurological evaluation.
Apalutamide may affect cytochrome P450 metabolism, altering pharmacokinetics of multiple drugs.
Regular review of patient medication list is essential to identify and manage interactions.

Preparations Of The Drug

Active ingredient: apalutamide.
Available as 60 mg and 240 mg oral film-coated tablets.
240 mg tablets contain film coating with glyceryl monocaprylocaprate, iron oxide black, polyvinyl alcohol, talc, titanium dioxide, and vinyl alcohol grafted copolymer.
60 mg tablets have coating including iron oxide black, iron oxide yellow, polyethylene glycol, polyvinyl alcohol, talc, and titanium dioxide.
Inactive ingredients include colloidal anhydrous silica, croscarmellose sodium, hydroxypropyl methylcellulose-acetate succinate, magnesium stearate, microcrystalline cellulose, and silicified microcrystalline cellulose.
Formulated as film-coated tablets to protect drug stability and enhance patient compliance.
Packaged with desiccants to protect against moisture, recommended to be stored at room temperature.
Manufactured with high purity excipients to ensure consistent bioavailability.
Designed for oral administration, tablets should not be crushed or chewed.
Formulations support flexible dosing and ease of daily administration.
Produced under stringent regulatory guidelines by Janssen Products, LP.
Tablet color and markings aid in correct identification to minimize medication errors.
Provision for administration via feeding tube with appropriate instructions if swallowing is impaired.
Includes patient information leaflets detailing usage, precautions, and side effect management.
Prepared and packaged to maintain drug integrity during distribution and storage.