Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
HALAVEN vs AGRYLIN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Halaven (eribulin mesylate) is a microtubule dynamics inhibitor. It binds to tubulin, suppressing microtubule growth and sequestering tubulin into nonfunctional aggregates, leading to G2/M cell cycle arrest and apoptosis.
Agrylin (anagrelide) inhibits cyclic nucleotide phosphodiesterase III (PDE3) and reduces platelet production by interfering with megakaryocyte maturation and proliferation, likely via inhibition of cyclic AMP phosphodiesterase and modulation of intracellular calcium levels.
Metastatic breast cancer in patients who have received at least two prior chemotherapy regimens including an anthracycline and a taxane,Unresectable or metastatic liposarcoma in patients who have received a prior anthracycline-containing regimen
Essential thrombocythemia (ET) to reduce elevated platelet counts and the risk of thrombotic complications
1.4 mg/m2 intravenously over 2-5 minutes on days 1 and 8 of a 21-day cycle.
Adults: 0.5 mg orally once or twice daily, increased by 0.5 mg every 2 weeks to maintain platelet count <600,000/µL. Maximum dose: 10 mg/day.
Terminal elimination half-life approximately 30-50 hours (mean 40 hours). Clinically, this supports weekly dosing schedule.
Terminal elimination half-life: 1.3–1.5 days (31–36 hours) in patients with ET; allows twice-daily dosing.
Eribulin is primarily metabolized by CYP3A4 with minor contributions from other CYP isoforms. It undergoes minimal hepatic metabolism and is predominantly excreted unchanged in bile and feces.
Primarily metabolized by CYP1A2 to the active metabolite 3-hydroxyanagrelide, and to a lesser extent by CYP2C19 and CYP2D6.
Primarily biliary/fecal: ~70-80% as unchanged drug and metabolites in feces; renal excretion accounts for <10% (mostly metabolites).
Renal: 80% (primarily unchanged drug), Biliary/Fecal: 5%
Approximately 87-95% bound primarily to albumin and alpha-1-acid glycoprotein.
82–88% bound to plasma proteins (primarily albumin).
Vd approximately 32-48 L/m² (approx. 0.9-1.4 L/kg, assuming 70 kg). Large Vd indicates extensive tissue distribution.
30–36 L (approximately 0.45–0.5 L/kg for a 70 kg adult); indicates extensive tissue distribution.
Only intravenous route available; no oral bioavailability data as it is not administered orally.
Oral: 65–80% (median 73%)
For creatinine clearance 30-50 m L/min: 1.1 mg/m2 on days 1 and 8 of a 21-day cycle. For creatinine clearance <30 m L/min: not recommended.
No specific GFR-based recommendations; use with caution in renal impairment (Cr Cl <50 m L/min) and monitor closely.
Child-Pugh A: 1.1 mg/m2 on days 1 and 8 of a 21-day cycle. Child-Pugh B: 0.7 mg/m2 on days 1 and 8 of a 21-day cycle. Child-Pugh C: not recommended.
Child-Pugh A: No adjustment. Child-Pugh B or C: Reduce initial dose by 50% and titrate cautiously.
Safety and efficacy not established in pediatric patients.
Children ≥7 years: 0.5 mg orally once or twice daily; adjust based on platelet response. Maximum: 10 mg/day. Not established for <7 years.
No specific dose adjustment recommended; monitor for toxicity.
No specific adjustment; start at lower end of dosing range (0.5 mg twice daily) and monitor renal function and platelet counts closely.
No FDA boxed warning.
None
Neutropenia: monitor complete blood counts prior to each dose; dose reduce or delay as needed,Peripheral neuropathy: monitor for neuropathy, dose reduce or discontinue if severe,QT prolongation: monitor ECG in patients with heart failure, bradyarrhythmias, or electrolyte abnormalities,Embryo-fetal toxicity: can cause fetal harm, advise effective contraception
Cardiovascular risks: increased risk of ventricular tachycardia, QTc prolongation, and heart failure; use caution in patients with known cardiac disease.,Hematologic effects: monitor complete blood counts regularly due to risk of anemia, leukopenia, or thrombocytopenia.,Hepatic impairment: reduce dose in patients with moderate to severe hepatic impairment.,Renal impairment: use with caution in severe renal impairment.
Hypersensitivity to eribulin or any components of the formulation
Severe hepatic impairment,Known hypersensitivity to anagrelide or any component of the formulation
Avoid grapefruit and grapefruit juice as they may increase eribulin levels.
Grapefruit and grapefruit juice should be avoided as they may increase anagrelide plasma concentrations. No other specific dietary restrictions; however, maintain adequate hydration to reduce risk of crystalluria.
FDA Pregnancy Category D. Based on its mechanism of action (microtubule inhibitor) and animal studies, HALAVEN can cause fetal harm when administered to a pregnant woman. In animal reproduction studies, eribulin was embryotoxic and fetotoxic at doses below the recommended human dose. There are no adequate and well-controlled studies in pregnant women. If used during pregnancy or if the patient becomes pregnant while receiving this drug, apprise the patient of the potential hazard to the fetus. Avoid use during the first trimester due to high risk of teratogenicity; use during second and third trimesters may cause fetal growth restriction and oligohydramnios.
Pregnancy Category C. Anagrelide is not recommended in pregnancy. Animal studies have shown embryotoxicity and teratogenicity (e.g., increased fetal resorptions, skeletal anomalies) at doses less than the human therapeutic dose. There are no adequate and well-controlled studies in pregnant women. Use only if potential benefit justifies potential risk to fetus. First trimester: Avoid due to organogenesis risk. Second and third trimesters: Unknown risks; consider alternative therapy.
It is not known whether eribulin is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from HALAVEN, advise women not to breastfeed during treatment and for at least 2 weeks after the last dose. No M/P ratio available.
It is not known whether anagrelide is excreted in human milk. No M/P ratio is available. Due to potential for serious adverse reactions in breastfed infants (e.g., thrombocytopenia, cardiovascular effects), advise women not to breastfeed during treatment and for at least 7 days after last dose.
No specific dosing adjustments for pregnancy have been established. Physiological changes during pregnancy (e.g., increased plasma volume, renal clearance) may alter eribulin pharmacokinetics, but no data exist. Use the standard dose of 1.4 mg/m2 intravenously over 2-5 minutes on days 1 and 8 of a 21-day cycle, with dose adjustments based on toxicity (e.g., neutropenia, thrombocytopenia, hepatic impairment) rather than pregnancy status.
No specific pharmacokinetic studies in pregnancy. Pregnancy-induced plasma volume expansion may lower drug concentrations, potentially requiring dose adjustment to maintain therapeutic effect. However, due to teratogenicity risks, avoid use in pregnancy. If necessary, start at lowest effective dose (0.5 mg/day) and titrate based on platelet count monitoring, not to exceed 10 mg/day.
Halaven (eribulin) is a nontaxane microtubule inhibitor used in metastatic breast cancer and liposarcoma. Monitor for neutropenia, peripheral neuropathy, and QT prolongation. Dose reduction required for moderate hepatic impairment (Child-Pugh B). Administer intravenously over 2-5 minutes on days 1 and 8 of a 21-day cycle. Antiemetic prophylaxis recommended.
Agrylin (anagrelide) is a phosphodiesterase III inhibitor used to reduce platelet counts in essential thrombocythemia. Monitor platelet count weekly during titration; target <600,000/µL. Avoid in patients with severe hepatic impairment (Child-Pugh C). Use with caution in cardiac disease due to risk of QT prolongation and arrhythmias. Anagrelide may increase bleeding risk, especially when combined with anticoagulants or NSAIDs. Discontinue 4-5 days before elective surgery.
This drug can lower your white blood cell count, increasing infection risk. Report fever or chills immediately.,You may experience numbness, tingling, or weakness in your hands or feet; notify your doctor if these occur.,Halaven can cause fatigue, nausea, and hair loss; supportive care is available.,Avoid grapefruit and grapefruit juice during treatment due to potential interaction.,Use effective contraception during treatment and for at least 2 weeks after the last dose.,Do not breastfeed while taking this medication.
Take exactly as prescribed; do not skip doses or double up.,Report any signs of bleeding (easy bruising, nosebleeds, black/tarry stools) or palpitations immediately.,Avoid NSAIDs like ibuprofen and aspirin unless directed by your doctor.,Do not consume grapefruit or grapefruit juice while taking this medication.,Inform all healthcare providers (including dentists) that you are on anagrelide.,Store at room temperature away from moisture and heat.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about HALAVEN vs AGRYLIN, answered by our medical review team.
HALAVEN is a Antineoplastic Agent that works by Halaven (eribulin mesylate) is a microtubule dynamics inhibitor. It binds to tubulin, suppressing microtubule growth and sequestering tubulin into nonfunctional aggregates, leading to G2/M cell cycle arrest and apoptosis.. AGRYLIN is a Antineoplastic Agent that works by Agrylin (anagrelide) inhibits cyclic nucleotide phosphodiesterase III (PDE3) and reduces platelet production by interfering with megakaryocyte maturation and proliferation, likely via inhibition of cyclic AMP phosphodiesterase and modulation of intracellular calcium levels.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between HALAVEN and AGRYLIN depend on the specific clinical indication. These are both Antineoplastic Agent agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of HALAVEN is: 1.4 mg/m2 intravenously over 2-5 minutes on days 1 and 8 of a 21-day cycle.. The standard adult dose of AGRYLIN is: Adults: 0.5 mg orally once or twice daily, increased by 0.5 mg every 2 weeks to maintain platelet count <600,000/µL. Maximum dose: 10 mg/day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between HALAVEN and AGRYLIN in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. HALAVEN is classified as Category C. FDA Pregnancy Category D. Based on its mechanism of action (microtubule inhibitor) and animal studies, HALAVEN can cause fetal harm when administered to a pregnant woman. In animal. AGRYLIN is classified as Category C. Pregnancy Category C. Anagrelide is not recommended in pregnancy. Animal studies have shown embryotoxicity and teratogenicity (e.g., increased fetal resorptions, skeletal anomalies. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.