XBRYK
Clinical safety rating: caution
Comprehensive clinical and safety monograph for XBRYK (XBRYK).
XBRYK is a small molecule inhibitor of Bruton's tyrosine kinase (BTK), forming a covalent bond with Cys481 in the BTK active site, thereby inhibiting B-cell receptor signaling and downstream pathways essential for B-cell proliferation and survival.
| Metabolism | Primarily metabolized by CYP3A4; minor contributions from CYP2D6 and CYP2C19. |
| Excretion | Primarily renal (approx. 70% unchanged drug) with biliary/fecal contribution (approx. 30% as metabolites). |
| Half-life | Terminal half-life is 3.5 hours (range 3–4 hours), necessitating multiple daily dosing for sustained effect. |
| Protein binding | Approximately 85% bound to albumin. |
| Volume of Distribution | 0.5 L/kg, indicating distribution into total body water. |
| Bioavailability | Oral: 80–85% (high first-pass metabolism, but extensive absorption). |
| Onset of Action | Oral: 30–60 minutes; IV: immediate (<5 minutes). |
| Duration of Action | Oral: 4–6 hours; IV: 6–8 hours for analgesic effect; shorter for antipyresis. |
| Molecular Weight | 350.45 |
12 mg subcutaneously every 4 weeks.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for GFR ≥30 mL/min; insufficient data for GFR <30 mL/min. |
| Liver impairment | No dose adjustment required for Child-Pugh Class A or B; not studied in Class C. |
| Pediatric use | Safety and efficacy not established in pediatric patients. |
| Geriatric use | No specific dose adjustment; monitor renal function due to age-related decline. |
| 1st trimester | Limited human data; animal studies show risk; avoid unless maternal benefit outweighs fetal risk. |
| 2nd trimester | Potential fetal toxicity; use only if clearly needed. |
| 3rd trimester | May cause fetal harm; avoid near term. |
Clinical note
Comprehensive clinical and safety monograph for XBRYK (XBRYK).
| Placental transfer | Crosses placenta in animal models; likely in humans. |
| Breastfeeding | Excreted into breast milk in small amounts; potential for serious adverse reactions in nursing infant; a decision should be made whether to discontinue nursing or discontinue drug. |
| Lactation Rating |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to XBRYKSevere hepatic impairmentPregnancy
| Precautions | Hemorrhage: Fatal bleeding events have occurred; monitor for signs of bleeding, consider risk-benefit in patients on anticoagulants or antiplatelet agents., Infections: Serious infections (including opportunistic infections) have occurred; monitor for signs and symptoms., Cytopenias: Grade 3/4 neutropenia, thrombocytopenia, and anemia observed; monitor blood counts regularly., Cardiac arrhythmias: Atrial fibrillation and flutter reported; monitor patients with cardiac risk factors., Second primary malignancies: Non-melanoma skin cancer and other malignancies have occurred., Embryo-fetal toxicity: Can cause fetal harm; advise females of reproductive potential of effective contraception. |
| Food/Dietary | No known food interactions. No restrictions on grapefruit or alcohol. |
Loading safety data…
| L4 (Hazardous) |
| Teratogenic Risk | Pregnancy Category X. Contraindicated in pregnancy due to proven teratogenicity in animal studies and human reports. First trimester: high risk of major congenital malformations (neural tube defects, cardiac anomalies). Second and third trimesters: risk of fetal growth restriction, oligohydramnios, and neonatal toxicity. Effective contraception required before, during, and after treatment. |
| Fetal Monitoring | Confirm negative pregnancy test before initiation. Monthly pregnancy tests during therapy. Fetal ultrasound for anomalies at 18-20 weeks gestation if accidental exposure occurs. Monitor for maternal hepatotoxicity, myelosuppression, and electrolyte imbalances. Assess fetal growth in third trimester if exposure late in pregnancy. |
| Fertility Effects | Impairs fertility in both sexes. In males: may cause oligospermia, azoospermia, and testicular atrophy with potential irreversibility. In females: may cause anovulation, menstrual irregularities, and premature ovarian failure. Advise fertility preservation options (sperm or oocyte cryopreservation) before treatment. |
| Clinical Pearls | XBRYK (generic name: xbrykumab) is a monoclonal antibody targeting IL-23. Monitor for injection site reactions. Do not administer live vaccines during treatment. Screen for latent TB before initiation. Consider hepatitis B reactivation risk. |
| Patient Advice | Report any signs of infection (fever, cough, skin redness) immediately. · Avoid live vaccines (e.g., MMR, varicella) during treatment. · Store medication in refrigerator, do not freeze. · Do not shake the vial; let it warm to room temperature before injection. · Dispose of used syringes in a sharps container. |