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HIV-1 capsid inhibitor (long-acting) Pregnancy: UK SPC §4.6, verbatim: 'There are no or limited amount of data from the use of lenacapavir in pregnant women. Animal studies do not indicate direct or indirect harmful effects with respect to pregnancy, foetal development, parturition or postnatal development (see section 5.3). As a precautionary measure, it is preferable to avoid the use of Sunlenca during pregnancy unless the clinical condition of the women requires treatment with Sunlenca.' Breast-feeding: 'In order to avoid transmission of HIV to the infant it is recommended that women living with HIV do not breast-feed their infants. It is unknown whether lenacapavir is excreted in human milk.' Fertility: 'There are no data on the effects of lenacapavir on human male or female fertility. Animal studies indicate no effects on lenacapavir on male or female fertility (see section 5.3).'

Lenacapavir

Brand names: Sunlenca

Lenacapavir is a first-in-class HIV-1 capsid inhibitor, given as a long-acting subcutaneous injection (with oral lead-in), used in combination for multidrug-resistant HIV-1 infection.

Adult dose

Dose: Initiation phase only — 600 mg orally on Day 1, 600 mg orally on Day 2, 300 mg orally on Day 8, then 927 mg by subcutaneous injection on Day 15
Route: Oral on Days 1, 2 and 8 (300 mg film-coated tablets; Day 1 and Day 2 are '2 x 300 mg tablets' each, Day 8 is '1 x 300 mg tablet'), then subcutaneous injection on Day 15 — 927 mg given as '2 x 1.5 mL injections', footnoted 'Two injections, each at a separate site in the abdomen'. §4.2 method of administration: 'Sunlenca tablets should be taken orally with or without food… The film-coated tablet should not be chewed, crushed, or split, because the effects on lenacapavir absorption have not been studied.'
Frequency: A fixed, non-repeating initiation schedule on Days 1, 2, 8 and 15 — not a daily maintenance dose. Continuation dosing after the Day 15 injection is NOT covered by the fetched tablet SPC (see notes).
SCOPE — INITIATION ONLY. This is the page's primary indication (HIV-1 treatment) and covers both of the page's routes (oral loading and subcutaneous injection), but only the initiation phase. §4.2 verbatim: 'Initiation of treatment with lenacapavir requires Sunlenca film-coated tablets to be taken as oral loading prior to administration of Sunlenca injection… On treatment Day 1 and Day 2, the recommended dose of Sunlenca is 600 mg per day taken orally. On treatment Day 8, the recommended dose is 300 mg taken orally. Then, on treatment Day 15, the recommended dose is 927 mg administered by subcutaneous injection.' The every-6-month continuation injection is NOT in this bundle's UK source — the tablet SPC stops at Day 15, and the only 'every 6-months (26 weeks)' wording anywhere in the bundle belongs to the US YEZTUGO label, which is pre-exposure prophylaxis in HIV-negative individuals and must not be transferred to a treatment page. Re-source the continuation dose from the Sunlenca solution-for-injection SPC before publishing it. ⚠️ DO NOT 'CORRECT' THE SCHEDULE ABOVE AGAINST THE US LABEL: YEZTUGO's initiation is a different schedule altogether (927 mg subcutaneously PLUS 600 mg orally both on Day 1, then 600 mg orally on Day 2 — no Day 8 and no Day 15), and it is also the only source of the interim oral regimen '300 mg orally once every 7 days'. Those are prophylaxis figures for a different product. PRESCRIBER / ADHERENCE (§4.2): 'Therapy should be prescribed by a physician experienced in the management of HIV infection… the healthcare professional should carefully select patients who agree to the required injection schedule and counsel patients about the importance of adherence to scheduled dosing visits… In addition, the healthcare professional should counsel patients about the importance of adherence to an optimised background regimen (OBR) to further reduce the risk of viral rebound and potential development of resistance.' MISSED ORAL DOSE (§4.2): if the Day 2 (600 mg) dose is missed by less than 6 days, take 600 mg as soon as possible and 300 mg on Day 8; if by 6 days or more, take 600 mg as soon as possible and 300 mg on Day 15. If the Day 8 (300 mg) dose is missed by less than 6 days, take 300 mg as soon as possible; if by 6 days or more, take 300 mg on Day 15. 'Regardless of when the Day 2 or Day 8 oral dose is being taken, subcutaneous injection should be administered on Day 15 as described in Table 1.' VOMITING (§4.2): 'If the patient vomits within 3 hours of taking an oral dose of Sunlenca, another oral dose should be taken. If the patient vomits more than 3 hours after taking an oral dose… there is no need to take another oral dose of Sunlenca, and the scheduled dosing regimen should continue.' No maximum dose is stated anywhere in the fetched sections, so maxDose is left empty. Elderly (§4.2): 'No dose adjustment of Sunlenca is required in elderly patients (see section 5.2).'

Paediatric dose

Route: Not applicable
Frequency: Not applicable
NO PAEDIATRIC DOSE. UK SPC §4.2, Paediatric population, verbatim: 'The safety and efficacy of Sunlenca in children under the age of 18 years old has not been established. No data are available.' dosePerKg is null and no weight-based calculation should be offered. The US YEZTUGO label in the same bundle does describe adolescents weighing at least 35 kg (§8.4), but that is HIV-1 pre-exposure prophylaxis in HIV-negative adolescents — a different indication from this page — and must not be transferred here. If a child or adolescent needs antiretroviral therapy, verify against a children's formulary and specialist HIV advice.

Dose adjustments

Renal

UK SPC §4.2, verbatim: 'No dose adjustment of Sunlenca is required in patients with mild, moderate, or severe renal impairment (creatinine clearance [CrCl] ≥ 15 mL/min). Sunlenca has not been studied in patients with end stage renal disease (CrCl < 15 mL/min or on renal replacement therapy) (see section 5.2), therefore Sunlenca should be used with caution in these patients.'

Hepatic

UK SPC §4.2, verbatim: 'No dose adjustment of Sunlenca is required in patients with mild or moderate hepatic impairment (Child-Pugh Class A or B). Sunlenca has not been studied in patients with severe hepatic impairment (Child-Pugh Class C) (see section 5.2), therefore Sunlenca should be used with caution in these patients.'

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients listed in section 6.1 (UK SPC §4.3)
  • Co-administration with strong inducers of CYP3A, P-gp, and UGT1A1 (UK SPC §4.3), such as: antimycobacterials — rifampicin; anticonvulsants — carbamazepine, phenytoin; herbal products — St. John's wort (Hypericum perforatum). §4.5: these 'may significantly decrease plasma concentrations of lenacapavir resulting in loss of therapeutic effect and development of resistance'
  • Not a contraindication but 'not recommended' (§4.4/§4.5): co-administration with medicinal products that are moderate inducers of CYP3A and P-gp, e.g. efavirenz
  • Not a contraindication but 'not recommended' (§4.4/§4.5): co-administration with medicinal products that are strong inhibitors of CYP3A, P-gp and UGT1A1 together (i.e. all 3 pathways), such as atazanavir/cobicistat
  • For contrast, §4.5 states that strong CYP3A4 inhibitors alone (e.g. voriconazole) or strong inhibitors of CYP3A4 and P-gp together (e.g. cobicistat) 'do not result in a clinically meaningful increase in lenacapavir exposures'
  • SCOPE: the fetched §4.5 ends in an explicit source-fetch truncation marker, so this interaction list is not complete — verify against the full SPC

Side effects

  • Nausea — common (≥1/100 to <1/10). §4.8 summary, verbatim: 'The most common adverse reaction in heavily treatment experienced adult participants with HIV was nausea (6%).' Frequency based on all participants (Cohorts 1 and 2) in CAPELLA
  • Immune reconstitution inflammatory syndrome — frequency 'not known'. §4.4/§4.8: in patients with severe immune deficiency at initiation of combination antiretroviral therapy, an inflammatory reaction to asymptomatic or residual opportunistic pathogens may arise; examples given are cytomegalovirus retinitis, generalised and/or focal mycobacterial infections, and Pneumocystis jirovecii pneumonia
  • Autoimmune disorders (such as Graves' disease and autoimmune hepatitis) reported in the setting of immune reactivation — 'the reported time to onset is more variable and these events can occur many months after initiation of treatment'
  • SCOPE NOTE — the §4.8 table above is from the TABLET SPC and lists only nausea and immune reconstitution inflammatory syndrome. Injection-site reactions are absent because the solution-for-injection SPC was not fetched in this bundle; do not read this list as complete for the subcutaneous product

Monitoring

  • §4.2: 'Therapy should be prescribed by a physician experienced in the management of HIV infection.'
  • §4.2: counsel and confirm adherence to the scheduled injection visits, and to the optimised background regimen (OBR), to reduce the risk of viral rebound and development of resistance from missed doses
  • §4.4: 'patients should remain under close clinical observation by physicians experienced in the treatment of patients with HIV associated diseases' — Sunlenca does not cure HIV infection and patients may still develop opportunistic infections and other complications
  • §4.4: 'Any inflammatory symptoms should be evaluated and treatment instituted when necessary' — immune reconstitution reactions typically appear within the first few weeks or months of combination antiretroviral therapy
  • No laboratory monitoring schedule (e.g. viral load or CD4 intervals) is specified in any fetched section of this SPC.

Clinical monograph

How it works

It binds the HIV-1 capsid protein and interferes with multiple steps of the viral lifecycle, including capsid-mediated nuclear uptake, virus assembly and release, and capsid core formation.

Prescribing in practice

  • Because subcutaneous lenacapavir forms a long-acting depot that persists for many months, it must be combined with a fully active regimen and residual drug levels considered if stopped, to avoid resistance.
  • Injection-site reactions, including nodules and swelling, are common with the subcutaneous depot.
  • It is a moderate CYP3A inhibitor and interacts with strong CYP3A and P-glycoprotein inducers, which should be avoided.

Monitoring

Monitor HIV viral load and treatment response, and review injection sites and concomitant medicines for interactions.

Counselling the patient

  • Keep all scheduled injection appointments, as missed doses can let the virus become resistant.
  • A firm lump or swelling where the injection is given is common and usually settles.
  • The medicine stays in your body for many months, so tell any clinician you have received it.

Evidence & guidelines

Efficacy in heavily treatment-experienced patients with multidrug-resistant HIV-1 was shown in the CAPELLA trial.

Reference: NICE TA942; BHIVA; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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