Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
KADCYLA vs AGRYLIN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
KADCYLA (ado-trastuzumab emtansine) is an antibody-drug conjugate composed of trastuzumab, a humanized anti-HER2 antibody, linked to the microtubule inhibitor DM1 (maytansinoid). It binds to HER2 receptors on tumor cells, internalized via receptor-mediated endocytosis, and releases DM1 intracellularly, causing 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.
Adjuvant treatment of patients with HER2-positive early breast cancer who have residual invasive disease after neoadjuvant taxane and trastuzumab-based treatment,Treatment of patients with HER2-positive metastatic breast cancer who previously received trastuzumab and a taxane, separately or in combination,Off-label: Use in HER2-positive advanced gastric cancer (limited data)
Essential thrombocythemia (ET) to reduce elevated platelet counts and the risk of thrombotic complications
3.6 mg/kg intravenously every 3 weeks until disease progression or unacceptable toxicity.
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 half-life approximately 4 days (range 2.8-5.6 days), supporting every-3-week dosing.
Terminal elimination half-life: 1.3–1.5 days (31–36 hours) in patients with ET; allows twice-daily dosing.
DM1 is primarily metabolized by CYP3A4 and to a lesser extent by CYP3A5.
Primarily metabolized by CYP1A2 to the active metabolite 3-hydroxyanagrelide, and to a lesser extent by CYP2C19 and CYP2D6.
Primarily hepatic metabolism with biliary excretion; minimal renal elimination (<10% unchanged).
Renal: 80% (primarily unchanged drug), Biliary/Fecal: 5%
93% bound to plasma proteins (trastuzumab component).
82–88% bound to plasma proteins (primarily albumin).
Approximately 2.58 L/m² (central Vd), indicating limited extravascular distribution.
30–36 L (approximately 0.45–0.5 L/kg for a 70 kg adult); indicates extensive tissue distribution.
100% (intravenous administration only).
Oral: 65–80% (median 73%)
No dose adjustment required for mild to moderate renal impairment (Cr Cl ≥30 m L/min). Safety and efficacy not established in severe renal impairment (Cr Cl <30 m L/min).
No specific GFR-based recommendations; use with caution in renal impairment (Cr Cl <50 m L/min) and monitor closely.
No dose adjustment for mild hepatic impairment (Child-Pugh A). Not recommended for moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment due to lack of data.
Child-Pugh A: No adjustment. Child-Pugh B or C: Reduce initial dose by 50% and titrate cautiously.
Safety and efficacy in pediatric patients have not been established.
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 for elderly patients. Clinical studies included patients aged ≥65 years, but no overall differences in safety or efficacy were observed.
No specific adjustment; start at lower end of dosing range (0.5 mg twice daily) and monitor renal function and platelet counts closely.
WARNING: HEPATOTOXICITY, CARDIAC TOXICITY, EMBRYO-FETAL TOXICITY Hepatotoxicity: Severe hepatotoxicity has been observed, including liver failure and death. Monitor liver function tests prior to each dose and as clinically indicated. Cardiac Toxicity: Left ventricular ejection fraction (LVEF) should be assessed prior to initiation and at regular intervals during treatment. Discontinue for clinically significant decline. Embryo-Fetal Toxicity: Exposure during pregnancy can cause embryo-fetal harm. Advise patients of these risks and need for effective contraception.
None
Hepatotoxicity: Monitor liver function tests; dose reduction or discontinuation may be required for elevated liver enzymes or bilirubin.,Cardiac toxicity: Assess LVEF before and during treatment; discontinue if symptomatic heart failure or significant asymptomatic decline.,Pulmonary toxicity: Interstitial lung disease (ILD) including pneumonitis has been reported; monitor for signs/symptoms and discontinue if confirmed.,Extravasation: Administer as IV infusion; extravasation may cause tissue necrosis. Ensure proper IV access.,Thrombocytopenia: Monitor platelet counts; dose modifications required for grade 3 or 4 thrombocytopenia.,Neuropathy: Peripheral neuropathy may occur; monitor and manage accordingly.,Embryo-fetal toxicity: Advise of risk and use effective contraception during and 7 months after treatment.,Increased intracranial pressure: Cases of reversible posterior leukoencephalopathy syndrome (RPLS) reported; monitor and discontinue if occurs.
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.
Known hypersensitivity to ado-trastuzumab emtansine or any of its components,Pregnancy (can cause embryo-fetal harm)
Severe hepatic impairment,Known hypersensitivity to anagrelide or any component of the formulation
No specific food interactions are known for Kadcyla. However, avoid grapefruit and grapefruit juice as they may inhibit CYP3A4 and potentially increase exposure. Maintain a healthy diet to manage nausea and support overall health.
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.
Kadcyla (ado-trastuzumab emtansine) is an antibody-drug conjugate. Trastuzumab component can cause oligohydramnios, fetal renal impairment, and pulmonary hypoplasia when administered during the second and third trimesters. The DM1 component (emtansine) is a microtubule inhibitor with potential embryofetal toxicity. Based on its mechanism and animal studies, there is risk for teratogenicity in the first trimester, including structural anomalies. Avoid use during pregnancy unless benefit outweighs risk; advise effective contraception.
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 Kadcyla is excreted in human milk. Due to the potential for serious adverse reactions in nursing infants, including tumorigenicity and developmental toxicity, advise women not to breastfeed during treatment and for at least 7 months after the last dose. M/P ratio is unknown.
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 dose adjustment recommendations specific to pregnancy; however, pharmacokinetics may be altered due to increased plasma volume and renal clearance. Use only if clearly needed. Consider therapeutic drug monitoring if available, but no established target levels. Close maternal-fetal monitoring recommended.
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.
Monitor left ventricular ejection fraction (LVEF) before and during treatment due to risk of cardiotoxicity. Infusion reactions are common; premedicate with antihistamines and corticosteroids. Do not substitute trastuzumab emtansine for trastuzumab or ado-trastuzumab emtansine. Avoid concomitant use with strong CYP3A4 inhibitors or inducers. Monitor for hepatotoxicity and pulmonary toxicity. Dose reduction required for thrombocytopenia or elevated transaminases.
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 is given as an IV infusion every 3 weeks. It may cause infusion reactions during or shortly after administration; tell your doctor immediately if you experience chills, fever, difficulty breathing, or chest pain.,Kadcyla can cause heart problems; you will have regular heart function tests (echocardiograms) before and during treatment. Report any new shortness of breath, cough, or swelling of ankles/legs.,This medication can cause liver damage; blood tests will be done to monitor liver function. Notify your doctor if you develop yellowing of skin/eyes, dark urine, or abdominal pain.,Kadcyla may lower platelet counts, increasing bleeding risk. Avoid activities that may cause injury or bruising. Report unusual bleeding or bruising.,This drug can cause severe birth defects; use effective contraception during treatment and for at least 7 months after the last dose. Do not breastfeed while taking Kadcyla.,You may experience fatigue, nausea, muscle/joint pain, or headache. Report persistent or severe symptoms to your healthcare provider.
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 KADCYLA vs AGRYLIN, answered by our medical review team.
KADCYLA is a Antineoplastic Agent that works by KADCYLA (ado-trastuzumab emtansine) is an antibody-drug conjugate composed of trastuzumab, a humanized anti-HER2 antibody, linked to the microtubule inhibitor DM1 (maytansinoid). It binds to HER2 receptors on tumor cells, internalized via receptor-mediated endocytosis, and releases DM1 intracellularly, causing 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 KADCYLA 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 KADCYLA is: 3.6 mg/kg intravenously every 3 weeks until disease progression or unacceptable toxicity.. 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 KADCYLA 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. KADCYLA is classified as Category C. Kadcyla (ado-trastuzumab emtansine) is an antibody-drug conjugate. Trastuzumab component can cause oligohydramnios, fetal renal impairment, and pulmonary hypoplasia when administer. 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.