How Do Ultomiris and Soliris Compare for PNH Treatment?
Ultomiris (ravulizumab) and Soliris (eculizumab) both treat paroxysmal nocturnal hemoglobinuria (PNH) by inhibiting the C5 complement protein to reduce hemolysis. Ultomiris is not universally "better," but it offers longer dosing intervals—every 8 weeks after loading doses versus every 2 weeks for Soliris—improving patient convenience and quality of life scores in trials.[1][2] Efficacy is comparable: both achieve similar transfusion avoidance (around 75-80% of patients) and hemoglobin stabilization.[3]
What Do Head-to-Head Trial Results Show?
The 302/304 Phase 3 trials directly compared them in 441 PNH patients switching from Soliris. Ultomiris met non-inferiority endpoints for lactate dehydrogenase (LDH) control and transfusion avoidance, with no new safety signals. Fewer infusions (7 vs. 26 over 26 weeks) reduced treatment burden.[1][4] Soliris patients switching to Ultomiris reported better fatigue scores on FACIT-Fatigue scale.[2]
Key Differences in Dosing and Administration
| Feature | Ultomiris | Soliris |
|---------|-----------|---------|
| Maintenance Dose Frequency | Every 8 weeks (after 2 loading doses) | Every 2 weeks |
| Infusion Time | 2-4 hours (weight-based) | 1-2 hours initially, up to 4 hours |
| Half-Life | 50 days | 12 days |
| Approved Indications | PNH, aHUS, gMG, NMOSD | PNH, aHUS, gMG |
Ultomiris's extended half-life stems from engineered high-affinity C5 binding and recycling via FcRn.[5] This suits patients prioritizing fewer clinic visits.
Which Has More Side Effects or Risks?
Safety profiles align closely—both carry boxed warnings for meningococcal infection (vaccination required) and infusion reactions. Ultomiris showed marginally lower upper respiratory infection rates (25% vs. 32%), but similar serious adverse event rates (7-8%).[1] Long-term data (up to 5 years for Ultomiris) confirm sustained control without increased immunogenicity.[6] No head-to-head mortality difference.
Cost and Access Considerations
Ultomiris costs more upfront but may lower annual expenses due to fewer infusions (e.g., ~$500K-$600K/year for both, varying by weight/insurance).[7] Patient assistance programs exist from Alexion (now AstraZeneca). Biosimilars for Soliris are emerging in Europe, potentially pressuring prices; U.S. Soliris patent expires 2025-2028 depending on formulations.[8]
When Might One Be Preferred Over the Other?