Anti-CD19 Monoclonal Antibody (B-Cell Depleting) Pregnancy: US label §8.1: no adequate data on the developmental risk in pregnant women. Inebilizumab is a humanised IgG1 monoclonal antibody and immunoglobulins are known to cross the placental barrier; transient peripheral B-cell depletion and lymphocytopenia have been reported in infants born to mothers exposed to other B-cell-depleting antibodies during pregnancy, and infant B-cell levels after maternal exposure to inebilizumab have not been studied. A pregnancy exposure registry exists. §5.4: may cause fetal harm based on animal data — advise females of reproductive potential of the potential risk to a fetus and to use an effective method of contraception during treatment and for 6 months after stopping. (US labelling — verify against the UK SPC §4.6.)

Inebilizumab (Anti-CD19 — IgG4-Related Disease)

Brand names: Uplizna

Inebilizumab is a humanised anti-CD19 monoclonal antibody given by intravenous infusion. It is used to deplete B cells in CD19-positive disease, with established use in neuromyelitis optica spectrum disorder and emerging use in other antibody-mediated conditions.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: IgG4-related disease (also NMOSD and gMG): initial dose 300 mg by intravenous infusion, followed 2 weeks later by a second 300 mg intravenous infusion; then subsequent doses (starting 6 months from the FIRST infusion) of a single 300 mg intravenous infusion every 6 months

Route: Intravenous infusion only — must be diluted in 250 mL of 0.9% sodium chloride injection and given via an infusion pump through a line containing a sterile, low-protein-binding 0.2 or 0.22 micron in-line filter. Do not shake the vial; do not use other diluents.

Frequency: Day 1 and week 2 (loading), then every 6 months starting 6 months from the first infusion

NO UK SPC (eMC) WAS RETRIEVED IN THIS BUNDLE — the regimen above is taken from the US FDA prescribing information for UPLIZNA (Horizon Therapeutics USA, Inc.; label date 2025-12-11; https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ec8e46bc-7edf-405d-8c8e-2b2f7042fcb5). VERBATIM (§2.3, NMOSD, IgG4-RD and gMG): 'Initial dose: 300 mg intravenous infusion followed 2 weeks later by a second 300 mg intravenous infusion. Subsequent doses (starting 6 months from the first infusion): single 300 mg intravenous infusion every 6 months.' The same dosage applies to all three labelled indications. INFUSION RATE (§2.3, Table 2, when diluted in a 250 mL bag): 0–30 minutes 42 mL/hour; 31–60 minutes 125 mL/hour; 61 minutes to completion 333 mL/hour — titrated to completion over approximately 90 minutes. Monitor the patient closely for infusion reactions during the infusion and for at least one hour after completion. PREMEDICATION BEFORE EVERY INFUSION (§2.2, Table 1): intravenous corticosteroid — methylprednisolone 80 mg to 125 mg, 30 minutes before; oral antihistamine — diphenhydramine 25 mg to 50 mg, 30 to 60 minutes before; oral antipyretic — acetaminophen (paracetamol) 500 mg to 650 mg, 30 to 60 minutes before. ASSESSMENTS BEFORE THE FIRST DOSE (§2.1): hepatitis B virus screening (contraindicated in active HBV); quantitative serum immunoglobulins; evaluation for active tuberculosis and testing for latent infection; administer all live or live-attenuated immunisations at least 4 weeks before initiation. BEFORE EVERY INFUSION (§2.2): determine whether there is an active infection and delay the infusion until it resolves. PREPARATION: withdraw 10 mL from each of the 3 vials (100 mg/10 mL each) and transfer a total of 30 mL into the 250 mL bag; mix by gentle inversion; administer immediately or store for a maximum of 24 hours at 2°C to 8°C or 4 hours at room temperature. PAEDIATRIC (§8.4): 'Safety and effectiveness in pediatric patients have not been established' — no paediatric dose is stated, so paedDose is null; verify any under-18 use against a children's formulary. ELDERLY (§8.5): in IgG4-RD, 29% (32/112) of patients were 65 years or older with no overall age-related differences in safety or efficacy; no separate dose is stated. NO RENAL DOSING SECTION WAS RETRIEVED IN THIS BUNDLE. Some sections of the fetched US label were truncated at the source-fetch limit — clinician to confirm against the full label and the UK SPC before publication.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

A history of a life-threatening infusion reaction to inebilizumab
Active hepatitis B infection
Active or untreated latent tuberculosis

Side effects

IgG4-related disease — urinary tract infections and lymphopenia (most common, ≥ 10% and greater than placebo)
NMOSD — urinary tract infection and arthralgia; generalised myasthenia gravis — headache and infusion-related reactions
Infusion reactions, including anaphylaxis — premedicate before every infusion; permanently discontinue if a life-threatening or disabling infusion reaction occurs
Serious, including life-threatening and fatal, infections — delay administration in patients with an active infection until it resolves
Reduction in immunoglobulins — monitor immunoglobulin levels at the beginning of, during and after discontinuation of treatment until B-cell repletion

Interactions

Immunosuppressive or immune-modulating therapies, including systemic corticosteroids — concomitant use may increase the risk of infection; consider the risk of additive immune system effects when co-administering
Live-attenuated or live vaccines — not recommended during treatment and after discontinuation until B-cell repletion; give live or live-attenuated vaccines at least 4 weeks before initiation

Clinical monograph

How it works

It binds CD19 on B cells and antibody-secreting plasmablasts, causing antibody-dependent cellular cytotoxicity and depletion of a broad range of the B-cell lineage.

Prescribing in practice

Screen for hepatitis B and active or latent infection before treatment, as B-cell depletion increases the risk of serious and reactivated infection.
Premedication with a corticosteroid, antihistamine and antipyretic is used to reduce infusion-related reactions.
Update vaccinations before starting where possible and avoid live vaccines during B-cell depletion.

Monitoring

Monitor immunoglobulin levels, full blood count and for signs of infection during and after the depletion period.

Counselling the patient

Report fever, persistent cough or any new infection promptly.
Tell any clinician you have received a B-cell depleting medicine, as effects persist for months.
Infusion reactions are most likely with the first dose; staff will monitor you closely.

Evidence & guidelines

Efficacy in neuromyelitis optica spectrum disorder was shown in the N-MOmentum trial.

Reference: Stone et al. NEJM 2023 (MITIGATE trial); FDA Approval Uplizna 2024; ACR IgG4-RD Guidelines 2021; MHRA SPC (NMOSD indication); 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways