Clinical Context
A typical patient is an adolescent or adult with Duchenne muscular dystrophy (DMD) who is eligible for targeted exon-skipping therapy with casimersen. The patient presents to an outpatient infusion or specialty injection clinic for administration of J1426 (injection, casimersen, 10 mg). Prior to the visit, the patient’s prescription is verified against the medical record confirming the dystrophin gene mutation amenable to exon 45 skipping. Baseline vitals, height/weight for dose calculation, and recent laboratory tests (liver function tests, renal panel) are reviewed. The medication is prepared by pharmacy and delivered to the clinic in a nursing area certified for specialty biologic handling. A registered nurse performs pre-injection assessment, verifies site of service, confirms informed consent and allergies, and documents any prior adverse reactions to antisense oligonucleotide therapies. The nurse administers the intravenous or subcutaneous injection per manufacturer guidance (site, rate), observes the patient for acute infusion-related or hypersensitivity reactions for a monitored recovery period, and documents lot number, dose, and administration route in the medical record. If an adverse event occurs, the clinic applies appropriate emergency measures and documents the event. Follow-up scheduling is arranged for ongoing regular dosing and laboratory monitoring as specified in the prescribing information.
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|
96365 | Intravenous infusion, for therapy, prophylaxis, or diagnosis; initial, up to 1 hour | Used when casimersen is administered as an IV infusion requiring timed infusion monitoring for the first hour. |
| 96366 | Intravenous infusion, each additional hour (List separately in addition to code for primary IV infusion) | Used if infusion of casimersen requires additional time beyond the initial hour.
| 96372 | Therapeutic, prophylactic, or diagnostic injection; subcutaneous or intramuscular | Used when casimersen is administered as a single subcutaneous or intramuscular injection per route allowed.
| 96413 | Chemotherapy administration, IV infusion technique; up to 1 hour, single or initial substance/drug | Used in some payor policies for biologic or complex IV drug administration when billed under chemotherapy-style infusion codes.
| 99070 | Supplies and materials (except spectacles), noncovered items billed separately by physician | Used to report expendable supplies associated with administration (e.g., IV tubing, syringes) when payor allows separate billing.