HEMGENIX (etranacogene dezaparvovec-drlb)
Product at a Glance
- Proper Name: etranacogene dezaparvovec-drlb
- Modality: AAV Gene Therapy
- Vector Serotype: Recombinant Adeno-associated virus serotype 5 (AAV5)
- Transgene Cassette: A liver-directed AAV5 vector containing a codon-optimized DNA sequence encoding the Padua (R338L) gain-of-function variant of human Factor IX (hFIX-Padua), under control of the liver-specific promoter LP1.
- Target Indication: Treatment of adults with Hemophilia B (congenital Factor IX deficiency) who (1) currently use Factor IX prophylaxis therapy, or (2) have current or historical life-threatening hemorrhage, or (3) have repeated, serious spontaneous bleeding episodes.
Applicant
Specification Screenshot
Typical CMC Analytical Strategy: AAV Product
The following table outlines a typical analytical control strategy for this modality. It is intended as a general educational reference and does not necessarily represent the specific strategy for this product.
| Quality Attribute | Purpose / Rationale | Primary Method(s) | Orthogonal Method(s) | Acceptance Criteria |
|---|---|---|---|---|
| Appearance | Confirms basic product characteristics and absence of visible contaminants. | Visual Inspection (Manual) Automated Visual Inspection (AVI) | Turbidimetry / Nephelometry (for clarity/opalescence) | Clear to slightly opalescent, essentially free of visible particulates |
| pH (potential of hydrogen) | Maintain product stability and is within a physiologically tolerated range. | Potentiometric pH measurement | Meets product/formulation-specific spec (commonly near neutral, e.g., ~7–8, but defined by formulation). | |
| Osmolality | Ensures patient comfort and safety (isotonicity) upon injection. | Osmometry | Meets product/formulation-specific spec (typically near isotonic; sponsor-justified) (240 to 400 mOsm/kg) | |
| Capsid Serotype Identity | Confirms the correct viral vector is being used, which dictates tissue tropism and immunogenicity. | ELISA | Peptide Mapping by Liquid Chromatography-Mass Spectrometry (LC-MS) | ELISA: Confirms binding to serotype-specific antibody. LC-MS: Confirms sequence of serotype-defining variable regions in capsid proteins. |
| Vector Genome Identity | Confirm intended transgene cassette. | Sanger Sequencing | Next-Generation Sequencing (NGS) Restriction Enzyme Mapping | Sequence matches reference; variant frequencies within predefined thresholds. Restriction map matches expected pattern. |
| Capsid Protein Ratio (VP1/VP2/VP3) | Ensures proper capsid assembly and is critical for infectivity. | Capsid Proteins Characterization by Mass Spectrometry Reverse Phase HPLC (RP-HPLC) | Within predefined ranges vs. reference standard. | |
| Vector Genome Titer (Concentration/Strength) | Quantifies the active drug substance to ensure accurate patient dosing. | Digital PCR (dPCR/ddPCR) | Reportable Value Vg/mL (within approved range) | |
| Capsid Titer | Measures the total amount of Capsids to enable calculation of the full/empty ratio. | ELISA Ratio calculation from dPCR (genome titer) and ELISA (total capsid titer) | Nanoparticle Tracking Analysis (NTA) Charge Detection Mass Spectrometry (CDMS) Analytical Ultracentrifugation (AUC) | Reportable value (cp/mL) meets approved range/spec. |
| Potency | MoA-relevant biological function. | Cell-Based Potency Assays | Relative potency meets validated range vs. reference (commonly 80–125% during validation; sponsor-justified for release). | |
| Capsid Empty/Full Ratio | A key purity and potency attribute, as only full capsids are therapeutically active. | Anion-Exchange High-Performance Liquid Chromatography (AEX-HPLC) Ratio calculation from dPCR (genome titer) and ELISA (total capsid titer) | Analytical Ultracentrifugation (AUC) Mass Photometry (MP) | The specification is product-specific and justified by clinical and manufacturing data. It is typically set as a minimum percentage of full capsids (e.g., NLT 25%) or a maximum percentage of empty capsids (e.g., NMT 75%). |
| Capsid Aggregation | To ensure safety by minimizing immunogenicity risk and to maintain potency. | Size-Exclusion Chromatography with Multi-Angle Light Scattering (SEC-MALS) | Analytical Ultracentrifugation (AUC) Dynamic Light Scattering (DLS) AF4-MALS | SEC/AUC: Meets specification for % Aggregates (e.g., ≤ 5%). DLS: Z-average is within target range, low PDI, and no large aggregate peaks detected. |
| Capsid Charge Heterogeneity | Monitors PTMs and ensures a consistent charge profile, which impacts tropism and stability. | Capillary Isoelectric Focusing (cIEF) | Anion-Exchange High-Performance Liquid Chromatography (AEX-HPLC) Peptide Mapping by Liquid Chromatography-Mass Spectrometry (LC-MS) | Charge profile comparable to reference within preset criteria (main/variant peaks, apparent pI). |
| Vector Genome Integrity | Ensures the packaged DNA is full-length and able to express a functional therapeutic protein. | Next-Generation Sequencing (NGS) | Alkaline Agarose Gel Electrophoresis (AAGE) | Meets specification for % Full-Length Intact Genomes |
| Capsid Post-Translational Modifications (PTMs) | To monitor and control chemical modifications on the capsid surface that can impact the product's identity, stability, potency, and safety (immunogenicity). | Peptide Mapping by Liquid Chromatography-Mass Spectrometry (LC-MS) | Capillary Isoelectric Focusing (cIEF) Anion-Exchange High-Performance Liquid Chromatography (AEX-HPLC) | A specification might be set for a specific, critical deamidation event, such as "≤ 5% Deamidation at Asn-123. |
| Capsid Thermal Stability | To confirm the capsid is properly folded and physically stable, ensuring it can protect the genome. It is a key indicator of manufacturing consistency. | Differential Scanning Fluorimetry (DSF) | Differential Scanning Calorimetry (DSC) | Tm (and/or unfolding profile) comparable to reference within preset criteria. |
| Residual Host Cell Proteins (HCPs) | To ensure safety by minimizing the risk of an immune response | Host Cell Protein (HCP) ELISA | Host Cell Proteins Characterization by Mass Spectrometry | Meets product-specific limit justified by safety/risk. Example: Not More Than (NMT) 10 ng/mg. |
| Residual Host Cell DNA (hcDNA) | To ensure safety by minimizing the risk of oncogenicity or an immune response | qPCR for Residual DNA Analysis Digital PCR (dPCR/ddPCR) | Meets guideline-aligned, product-specific limits (amount per dose and, where applicable, DNA size control). ≤ 10 ng/dose (per WHO guidelines) | |
| Residual Plasmid DNA | To ensure safety by minimizing risks from plasmid backbone sequences | qPCR for Residual DNA Analysis | Digital PCR (dPCR/ddPCR) | Meets product-specific limit (e.g., ≤ 10 ng/dose), justified by process capability and safety assessment. |
| Residual Benzonase | To ensure safety by removing a process enzyme that could be immunogenic. | Benzonase ELISA | Mass Spectrometry for Process-Related Impurity Characterization | Meets product-specific limit, often ≤ 10 ng/mg (ppm) |
| Replication Competent AAV (rcAAV) | A critical safety test to ensure no replication-capable virus is administered to the patient. | Replication Competent AAV (rcAAV) Assay | Negative / No rcAAV Detected | |
| Endotoxin | A critical safety test to prevent fever and septic shock in patients | Bacterial Endotoxin Tests (BET) | Does not exceed calculated limit per USP (K/M; route/dose-based). | |
| Bioburden: Pre-Sterilization Microbial Control (IPC) | A critical in-process control (IPC) to ensure the microbial load is acceptably low before the final sterilizing filtration, providing a high degree of sterility assurance for the final product. | Membrane Filtration | Rapid Microbiological Methods (RMMs) | Meets process-defined IPC limits with action/alert levels (many processes target very low counts prior to sterile filtration); In-process limit met (e.g., ≤ 10 CFU/100 mL) |
| Sterility | A critical safety test to ensure the final product is free of microbial contamination. | Sterility Tests | No Growth | |
| Sub-Visible Particles (SVP) | To ensure safety by controlling particles that can increase the risk of immunogenicity. | Light Obscuration (LO) | Flow Imaging Microscopy (FIM) | Meets USP limits for small-volume injections (e.g., NMT 6000 ≥10 µm; NMT 600 ≥25 µm per container). |
| Extractable Volume | To ensure the patient can receive the full, labeled dose from the container. | Extractable Volume Test | Not less than labeled volume. |
Other Resources
FDA Documents
November 22, 2022 Summary Basis for Regulatory Action - HEMGENIX
EMA Documents
https://www.ema.europa.eu/en/medicines/human/EPAR/hemgenix