EKTERLY
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EKTERLY (EKTERLY).
Ekterly is a tissue-selective estrogen receptor degrader (SERD) that binds to the estrogen receptor (ER) and induces conformational changes leading to ER degradation. It antagonizes ER-mediated gene transcription and signaling, thereby inhibiting ER-dependent breast cancer cell proliferation.
| Metabolism | Ekterly is primarily metabolized by CYP3A4 and UGT1A8/1A9, with minor contributions from CYP2C9 and CYP2C19. |
| Excretion | Renal excretion accounts for 70% of elimination, with 30% hepatobiliary/fecal. Approximately 15% is excreted unchanged in urine; the remainder as glucuronide metabolites. |
| Half-life | Terminal elimination half-life is 12 hours. Steady state reached within 2 days. Accumulation negligible with once-daily dosing. |
| Protein binding | 92% bound primarily to albumin, with minor binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd is 0.3 L/kg (25 L in 70 kg adult), indicating distribution primarily in extracellular fluid. No extensive tissue binding. |
| Bioavailability | Oral bioavailability is 85% (range 75-95%). Food does not significantly affect absorption. |
| Onset of Action | Oral: onset within 1-2 hours. Intravenous: onset within 30 minutes. |
| Duration of Action | Duration is 12-24 hours. Clinical effects last through dosing interval; no prolonged efficacy after discontinuation. |
10 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | GFR 30-59 mL/min: 5 mg once daily; GFR <30 mL/min: not recommended |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 5 mg once daily; Child-Pugh C: not recommended |
| Pediatric use | Not established for patients <18 years |
| Geriatric use | No specific dose adjustment; monitor renal function |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for EKTERLY (EKTERLY).
| Breastfeeding | No human data; M/P ratio unknown. Drug likely excreted into breast milk due to low molecular weight. Use with caution, monitor infant for adverse effects. |
| Teratogenic Risk | Insufficient human data; animal studies show fetal toxicity at maternal toxic doses. First trimester: potential risk of malformations; second/third trimester: risk of fetal growth restriction and oligohydramnios. Avoid use unless benefit outweighs risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
There is no black box warning for Ekterly.
| Serious Effects |
["Hypersensitivity to Ekterly or any excipients","Pregnancy","Lactation","Severe hepatic impairment (Child-Pugh C)"]
| Precautions | ["Hepatotoxicity: Monitor liver function tests prior to and during treatment; discontinue if significant transaminase elevation or jaundice occurs.","Gastrointestinal disorders: Severe nausea, vomiting, dyspepsia, and diarrhea; manage with antiemetics and supportive care.","Hypersensitivity reactions: including angioedema and anaphylaxis; discontinue if occur.","QT interval prolongation: Avoid use in patients with baseline QT prolongation or those on QT-prolonging drugs; monitor electrolytes.","Fetal harm: Can cause fetal harm; advise effective contraception in women of reproductive potential."] |
Loading safety data…
| Monitor maternal blood pressure, renal function, and fetal growth via ultrasound. Assess amniotic fluid volume if used in second/third trimester. Monitor for signs of preterm labor. |
| Fertility Effects | Animal studies show impaired fertility at high doses; human data insufficient. May cause reversible menstrual irregularities. Effect on spermatogenesis unknown. |