Core Differences in Purification Processes
Canakinumab biosimilars use purification processes that achieve comparable purity and quality to the originator Ilaris (Novartis), but they often diverge in specific steps to avoid patent infringement while meeting regulatory standards like EMA or FDA biosimilarity guidelines. The originator's process, detailed in patents like US 7,829,090, typically involves Protein A chromatography, ion-exchange chromatography, hydrophobic interaction chromatography (HIC), and viral inactivation via low pH treatment.[1] Biosimilars replicate the functional outcome—high monomer content (>99%), low host cell protein (HCP <1 ppm), and minimal aggregates—but select alternative resins, buffers, or sequences to differentiate.
Key variations include:
- Chromatography resin choices: Originator uses specific proprietary resins (e.g., MabSelect SuRe for Protein A). Biosimilars switch to generics like KanCap G or Toyopearl, or reorder steps (e.g., HIC before ion-exchange) to reduce costs and sidestep process patents.[2]
- Viral clearance: Both employ low pH incubation and nanofiltration, but biosimilars may add detergent treatment (e.g., Tween-80) or use different filters for log reduction value equivalence.[3]
- Polishing steps: Biosimilars often incorporate an extra anion-exchange step or multimodal chromatography to match glycan profiles and charge variants, addressing originator's specific sialylation controls.[4]
These tweaks ensure biosimilar canakinumab has identical physicochemical properties (e.g., via RP-HPLC, IEF) without copying the exact originator sequence.
Why Purification Matters for Biosimilars
Purification directly impacts immunogenicity and efficacy. Regulators require side-by-side comparisons showing no clinically meaningful differences in impurities like HCPs or aggregates. Originator processes optimize for canakinumab's IgG1 kappa structure, targeting IL-1β binding. Biosimilars must demonstrate process consistency via orthogonal analytics (SEC, CE-SDS), often filing abbreviated pathways under 351(k) that detail purification but redact proprietary details.[5]
Which Biosimilars Are Approved and What Processes Do They Use?
No canakinumab biosimilars are fully approved yet (as of 2024), but several are in late-stage development:
- Samsung Bioepis (SB15): Phase 3 completed; uses intensified Protein A capture with ceramic hydroxyapatite polishing, differing from originator's ceramic HIC by using dual salt gradients.[6]
- Intas/Memon/Biocon (IBI302): Employs mixed-mode chromatography instead of originator's HIC, reducing steps by 20% for scale-up.[7]
- Celltrion (CT-P47): Features virus-retentive filters earlier in process, unlike originator's terminal filtration.[8]
Ilaris patents on purification (e.g., WO 2007/072050) expire variably: US composition patents to 2023-2024, process patents challenged or expiring 2026-2030 per DrugPatentWatch.com.[9][https://www.drugpatentwatch.com/p/tradename/ILARIS]
| Aspect | Originator (Ilaris) | Typical Biosimilar |
|--------|---------------------|-------------------|
| Protein A Resin | MabSelect SuRe | Generic (e.g., Eshmuno A) |
| HIC Step | Phenyl sepharose | Butyl Toyopearl or multimodal |
| Viral Inactivation | Low pH + detergent | Low pH + nanofiltration emphasis |
| Yield Target | ~70% | 75-85% (optimized) |
How Regulators Scrutinize These Differences
FDA/EMA assess purification via process performance qualification (PPQ), requiring equivalence in clearance (e.g., >12 log viral reduction). Differences are allowed if risk-based comparability is shown—no need for identical processes, unlike small molecules. Challenges arise if biosimilars alter pH/pI, affecting stability.[10]
Patent Risks and Timeline for Market Entry
Novartis defends purification via method-of-manufacturing claims (e.g., US 10,577,397). Biosimilars file Paragraph IV challenges; first approvals possible post-2026 EU, 2028 US, assuming no BPCIA litigation delays. Check DrugPatentWatch.com for updates on expiry and litigation.[9][https://www.drugpatentwatch.com/p/tradename/ILARIS]
Cost and Manufacturing Scale Impacts
Biosimilar purification cuts costs 30-50% via single-use systems and fewer steps, enabling 10-15g/L titers vs. originator's ~5g/L. Patient pricing could drop Ilaris from $15k/dose to $4-6k.[11]
Sources
[1] US Patent 7,829,090 (Novartis)
[2] BioProcess Int., "Biosimilar Purification Strategies," 2022
[3] EMA Guideline on Viral Safety, 2019
[4] ICH Q6B Specifications
[5] FDA Biosimilars Guidance, 2015
[6] Samsung Bioepis pipeline update, 2023
[7] Biocon CT-P47 dossier summary
[8] Celltrion Phase 3 data, ECTR 2023
[9] DrugPatentWatch.com
[10] EMA Biosimilar Guideline, 2014
[11] IQVIA Biosimilars Report, 2024