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Complement factor B inhibitor Pregnancy: Available data from clinical trials in pregnant women are insufficient to identify a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes. Use in pregnant women or women planning to become pregnant may be considered following an assessment of the risks and benefits; there are also risks to mother and fetus from untreated PNH, IgAN or C3G in pregnancy. In animal reproduction studies, oral administration to pregnant rats and rabbits during organogenesis at 4 to 6 times the human exposure at the maximum recommended dose of 200 mg twice daily did not induce embryo or fetal toxicity (US label section 8.1).

Iptacopan

Brand names: Fabhalta

Iptacopan is an oral complement factor B inhibitor used in the treatment of paroxysmal nocturnal haemoglobinuria.

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: 200 mg
Route: Oral — swallow capsules whole; do not open, break or chew. May be taken with or without regard to food.
Frequency: Twice daily
US label section 2.2: the recommended dosage is 200 mg orally twice daily without regard to food. MISSED DOSE: take one dose as soon as possible (even if soon before the next scheduled dose) and then resume the regular dosing schedule. VACCINATION AND PROPHYLAXIS (section 2.1): vaccinate against encapsulated bacteria, including Streptococcus pneumoniae and Neisseria meningitidis (serogroups A, C, W, Y and B), according to current recommendations at least 2 weeks before initiation; if urgent therapy is indicated in a patient not up to date with these vaccines, provide antibacterial drug prophylaxis and vaccinate as soon as possible. In the US, prescribers must enrol in the FABHALTA REMS programme. SWITCHING IN PNH (section 2.3): for patients switching from eculizumab, initiate no later than 1 week after the last eculizumab dose; for patients switching from ravulizumab, initiate no later than 6 weeks after the last ravulizumab dose — this is to reduce the potential risk of haemolysis with abrupt discontinuation of other PNH therapies. There is no available information on the timeframe for initiation after other PNH therapies. PAEDIATRIC: safety and effectiveness in paediatric patients with PNH, IgAN or C3G have not been established — verify against a children's formulary. SOURCE: no UK SPC was fetched in this bundle — this draft is distilled from the US prescribing information and must be verified against the UK SPC.

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

  • Serious hypersensitivity to iptacopan or any of the excipients
  • Initiation in patients with unresolved serious infection caused by encapsulated bacteria, including Streptococcus pneumoniae, Neisseria meningitidis or Haemophilus influenzae type b

Side effects

  • Headache (PNH, incidence at least 10%)
  • Nasopharyngitis (PNH and C3G)
  • Diarrhoea and nausea (PNH)
  • Abdominal pain (PNH, and the most common reaction in IgAN at least 5% along with dizziness)
  • Bacterial and viral infections — serious infections caused by encapsulated bacteria are a labelled warning
  • Rash (PNH); hyperlipidaemia is also a labelled warning

Interactions

  • CYP2C8 inducers (e.g. rifampin) — may decrease iptacopan exposure and result in loss of or reduced efficacy; monitor the clinical response and discontinue the CYP2C8 inducer if loss of efficacy is evident
  • Strong CYP2C8 inhibitors (e.g. gemfibrozil) — may increase iptacopan exposure and the risk of adverse reactions; co-administration is not recommended

Clinical monograph

How it works

It selectively inhibits factor B in the alternative complement pathway, reducing both intravascular and extravascular haemolysis of complement-sensitised red cells.

Prescribing in practice

  • Because complement inhibition raises the risk of serious infection by encapsulated organisms, meningococcal vaccination is required before starting and antibiotic prophylaxis may be needed.
  • Vaccination against pneumococcal and Haemophilus influenzae type b infection is also advised in line with national guidance.
  • Counsel patients to seek urgent care for symptoms suggesting meningococcal infection given the risk of rapid deterioration.

Monitoring

Monitor haemoglobin and markers of haemolysis to assess response, and remain vigilant for signs of serious infection throughout treatment.

Counselling the patient

  • Carry your patient safety card and seek urgent medical help for fever, severe headache or neck stiffness.
  • Ensure your meningococcal and other recommended vaccinations are up to date.
  • Do not stop treatment suddenly without discussing it with your team.

Evidence & guidelines

Iptacopan is recommended within its licensed use for paroxysmal nocturnal haemoglobinuria, supported by the APPLY-PNH and APPOINT-PNH trials.

Reference: NICE TA976; 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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