The formulation was developed to ensure the stability of the viral vector during frozen storage and to be suitable for subretinal administration. Key development aspects include:
- Rationale for Concentrate/Diluent format: A frozen concentrate provides optimal long-term stability for the AAV vector. The 1:10 dilution at the time of use allows for the administration of a precise, low volume (0.3 mL) suitable for the subretinal space, which would be difficult to handle and store if provided as a ready-to-use solution.
- Rationale for Excipients: Poloxamer 188, a non-ionic surfactant, is included at a low concentration (0.001%) to prevent loss of viral particles due to adsorption to container and syringe surfaces. The buffered saline system maintains a physiological pH and osmolality.
- In-Use Compatibility: Studies have demonstrated that LUXTURNA, once diluted, is compatible with the commercially available polypropylene syringes and subretinal injection cannulas recommended for administration.