Sunlenca (Lenacapavir) Dosing
Sunlenca requires a loading regimen on Days 1-2 followed by subcutaneous maintenance injections every 6 months (26 weeks ±2 weeks). 1, 2
Loading Regimen (Initiation)
The CDC and FDA provide two initiation options 1, 2:
Option 1 (Preferred for PrEP):
- Day 1: 927 mg subcutaneous injection (two 1.5-mL injections at least 4 inches apart in the abdomen) PLUS 600 mg orally (two 300-mg tablets)
- Day 2: 600 mg orally (two 300-mg tablets)
Option 2 (Alternative):
- Day 1: 600 mg orally (two 300-mg tablets)
- Day 2: 600 mg orally (two 300-mg tablets)
- Day 8: 300 mg orally (one 300-mg tablet)
- Day 15: 927 mg subcutaneous injection (two 1.5-mL injections)
Maintenance Dosing
927 mg subcutaneous injection (two 1.5-mL injections at least 4 inches apart) every 6 months (26 weeks) ±2 weeks from the date of the last injection. 1, 2
- Injection sites: abdomen or anterior thigh (abdomen preferred per FDA label) 1, 2
- Injections must be administered at a 90-degree angle to avoid intradermal injection, which increases risk of injection site reactions 1
Time to Protection
Protective drug levels are achieved approximately 2 hours after the Day 2 oral dose if both loading doses are taken. 1 If both oral loading doses are missed, time to protection extends to 21-28 days 1.
Missed Dose Management
Planned Missed Injections (>14 days late):
- Start oral bridging: 300 mg orally once weekly for up to 6 months
- First oral dose should be taken 6 months (26 weeks) after the last injection
- Resume maintenance injection within 7 days after the last oral dose 1, 2
Unplanned Missed Injections (>28 weeks since last injection):
- Reinitiate with full loading regimen (Option 1 or 2), then continue maintenance dosing 1, 2
- Clinically reassess patient, including consideration of resistance testing 2
Critical Administration Details
- Subcutaneous only—NOT intradermal (risk of serious injection site reactions) 2
- Administer by healthcare provider only 2
- Injection angle: 90 degrees 1
- Two separate 1.5-mL injections spaced at least 4 inches apart 1, 2
- Can be taken with or without food (oral doses) 2
Drug Interactions
- Strong or moderate CYP3A inducers require supplemental dosing 1
- Lenacapavir increases concentrations of certain medications for up to 9 months after last injection—monitor for side effects and adjust doses accordingly 1
- Consult FDA prescribing information for complete drug interaction details 1
Common Pitfalls
Injection site reactions are the most frequent adverse event (nodules in 27%, swelling 23%, pain 19%) 1. These are typically mild-to-moderate and decrease over time. Nodules can be several centimeters and persist for months to over a year 1. Incorrect technique (angle <90°) significantly increases reaction risk 1. Ice packs and topical/oral analgesics before and after injection may help 1. Discontinuation due to injection site reactions is rare (≤1.2%) 3, 4.
Eligibility Requirements (for PrEP indication)
- Weight ≥77 lbs (≥35 kg) 1
- Negative blood-based HIV antigen/antibody test within 7 days before first dose 1
- No signs/symptoms of acute HIV infection 1
- No significant drug interactions or contraindications 1
Follow-Up
Every 6 months (or more frequently as needed): HIV testing, STI screening, HBV assessment if switching from tenofovir-based PrEP 1