DAYBUE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DAYBUE (DAYBUE).
DAYBUE (trofinetide) is a synthetic analog of the N-terminal tripeptide of insulin-like growth factor 1 (IGF-1). Its exact mechanism is unknown, but it is thought to reduce neuroinflammation and normalize synaptic function.
| Metabolism | Trofinetide is metabolized via hydrolysis to further smaller peptides and amino acids. CYP450 enzymes are not involved in its metabolism. |
| Excretion | Primarily excreted unchanged in urine (~70% in 24 hours) via active renal secretion and glomerular filtration; ~30% metabolized in liver to inactive metabolites and excreted in bile/feces. |
| Half-life | Terminal elimination half-life is 3–4 hours in healthy adults; 4–6 hours in patients with renal impairment (CrCl <30 mL/min). Dose adjustment needed in renal impairment. |
| Protein binding | Minimal protein binding (<10%); primarily bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.6–0.8 L/kg; indicates distribution into total body water and some tissue binding. |
| Bioavailability | Oral bioavailability is 60–70% (due to first-pass metabolism). Food does not significantly affect absorption. |
| Onset of Action | Oral: Clinical effect (improvement in seizures) observed within 2–4 weeks of initiating therapy; peak plasma concentrations at 1–2 hours post-dose. |
| Duration of Action | Duration of clinical effect is 6–8 hours due to short half-life; requires three times daily dosing. Steady-state achieved by day 3–5. |
Initial: 100 mg orally twice daily; titrate by 50 mg twice daily weekly to target maintenance dose of 200 mg twice daily. Maximum 200 mg twice daily.
| Dosage form | SOLUTION |
| Renal impairment | eGFR 30-59 mL/min/1.73m²: 75 mg twice daily for 1 week, then increase to 150 mg twice daily. eGFR 15-29 mL/min/1.73m²: 50 mg twice daily for 1 week, then 100 mg twice daily. eGFR <15 mL/min or dialysis: not recommended. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: 100 mg twice daily for 1 week, then 200 mg twice daily. Child-Pugh Class C: not recommended. |
| Pediatric use | Administer via oral solution (200 mg/5 mL) or tablets. Weight-based dosing not applicable; age-based dosing identical to adult regimen for patients aged 2 years and older. |
| Geriatric use | No specific dose adjustment required; monitor renal function (CrCl) as elderly may have decreased clearance; follow renal adjustment guidelines if applicable. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DAYBUE (DAYBUE).
| Breastfeeding | There are no data on the presence of trofinetide in human milk, its effects on the breastfed infant, or its effects on milk production. The molecular weight (approximately 309 Da) suggests potential excretion into breast milk. Because of the potential for serious adverse reactions in nursing infants, patients should be advised that breastfeeding is not recommended during treatment and for at least 2 weeks after the last dose. M/P ratio is unknown. |
| Teratogenic Risk | Daybue (trofinetide) is a synthetic analog of the N-terminal tripeptide of insulin-like growth factor 1 (IGF-1). There are no adequate and well-controlled studies in pregnant women. In animal reproduction studies, intravenous administration of trofinetide to pregnant rats and rabbits during organogenesis resulted in maternal toxicity and reduced fetal body weights at doses approximately 10 times the maximum recommended human dose (MRHD) based on AUC. No structural malformations were observed. Due to the lack of human data, trofinetide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. The risk in the first trimester is unknown; second and third trimester risks are similarly undefined due to insufficient data. |
■ FDA Black Box Warning
None
| Serious Effects |
None
| Precautions | ["Diarrhea: Can be severe; monitor for dehydration.","Weight loss: Monitor body weight during treatment.","Gastrointestinal adverse reactions: May require dose reduction, interruption, or discontinuation."] |
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| Fetal Monitoring | Recommended monitoring during pregnancy includes routine prenatal care with attention to fetal growth assessment due to reduced fetal body weights observed in animal studies. Maternal monitoring for gastrointestinal adverse effects (e.g., diarrhea, nausea) is advised, as these are the most common adverse reactions with trofinetide. No specific fetal monitoring is required beyond standard obstetric practice. |
| Fertility Effects | There are no human data on the effects of trofinetide on fertility. In animal studies, intravenous administration of trofinetide to male and female rats at doses up to 10 times the MRHD based on AUC showed no adverse effects on fertility or reproductive performance. Therefore, trofinetide is not expected to impair fertility in humans at clinically relevant doses. |