MYQORZO
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYQORZO (MYQORZO).
Myqorzo (selinexor) is a selective inhibitor of nuclear exportin 1 (XPO1). It binds to and inhibits XPO1, leading to nuclear retention and activation of tumor suppressor proteins, reduction in oncoprotein levels, and cell cycle arrest and apoptosis in cancer cells.
| Metabolism | Selinexor is primarily metabolized by CYP3A4 and, to a lesser extent, by CYP1A2, CYP2C19, CYP2D6, and CYP3A5. UDP-glucuronosyltransferases (UGTs) and glutathione-S-transferases (GSTs) also contribute to metabolism. |
| Excretion | Primarily renal excretion as unchanged drug (approx. 70-80%), with about 10-15% eliminated in feces via biliary excretion. Less than 5% is metabolized. |
| Half-life | Terminal elimination half-life is approximately 18-24 hours in patients with normal renal function. This supports once-daily dosing and allows for trough concentration monitoring. |
| Protein binding | Approximately 90-95% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is about 0.3-0.5 L/kg, indicating distribution mainly into extracellular fluid and limited tissue penetration. |
| Bioavailability | Intravenous administration yields complete (100%) bioavailability. Oral bioavailability is negligible (<1%) due to extensive first-pass metabolism, thus only administered intravenously. |
| Onset of Action | Intravenous administration: Onset of action occurs within 1-2 hours after infusion initiation, with peak effect observed by the end of infusion. |
| Duration of Action | Duration of action is approximately 24 hours, consistent with the dosing interval. Clinical effect may persist for 12-24 hours after the last dose, depending on renal function. |
100 mg intravenous every 28 days
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (eGFR >=30 mL/min). Not recommended in severe renal impairment (eGFR <30 mL/min) or dialysis due to lack of data. |
| Liver impairment | No dose adjustment required for Child-Pugh A or B. Not recommended in Child-Pugh C due to lack of data. |
| Pediatric use | Not established in patients <18 years of age. |
| Geriatric use | No specific dose adjustments; monitor for increased susceptibility to infections. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MYQORZO (MYQORZO).
| Breastfeeding | No data on human milk excretion. Based on molecular weight (584.7 Da) and high protein binding (>99%), excretion likely minimal. However, due to potential adverse effects in infant, breastfeeding not recommended during therapy and for at least 2 weeks after last dose. |
| Teratogenic Risk | Pregnancy Category X. Contraindicated in pregnancy. Risk of fetal harm based on animal studies (teratogenicity, embryolethality at subtherapeutic doses). Avoid in women of childbearing potential without effective contraception. If exposure occurs, report to pregnancy registry. |
■ FDA Black Box Warning
WARNING: THROMBOCYTOPENIA, NEUTROPENIA, and RISK OF INFECTION. Selinexor can cause severe thrombocytopenia and neutropenia leading to hemorrhage and infection. Monitor blood counts throughout treatment. Supportive care including platelet and growth factor transfusions may be required. Selinexor can cause severe infection including sepsis and death.
| Serious Effects |
["Concomitant use with strong CYP3A4 inhibitors or inducers (due to risk of increased toxicity or reduced efficacy).","Patients with known hypersensitivity to selinexor or any excipients."]
| Precautions | ["Thrombocytopenia: Monitor platelet count; manage with dose reduction or transfusion per guidelines.","Neutropenia: Monitor neutrophil count; manage with growth factors or dose modification.","Gastrointestinal toxicity: Nausea, vomiting, diarrhea, and anorexia are common; use antiemetics and supportive care.","Hyponatremia: Monitor serum sodium; manage with dose adjustment and appropriate fluid management.","Serious infection: Monitor for signs of infection; treat promptly.","Fetal harm: Can cause fetal harm; advise contraception in females and males.","Cataracts: Perform ophthalmologic exams as clinically indicated."] |
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| Fetal Monitoring |
| Pregnancy test before initiation and monthly during therapy. Monitor for fetal heart rate abnormalities and growth via ultrasound if exposure occurs. Monitor maternal liver function tests, renal function, and electrolytes due to potential hepatotoxicity and fluid retention. |
| Fertility Effects | Animal studies show impaired fertility in females (decreased implantation sites, embryo-fetal loss). Effects on male fertility unknown. Advise patients on fertility preservation options prior to treatment. |