Real-World Stability Confirmed for Biosimilar Ximluci in Prefilled Syringes

The growing adoption of biosimilars for complex retinal diseases is heavily dependent on confirmation of the drug’s stability under realistic clinical handling conditions. A recent study, published in Advanced Therapies,¹ provided critical data supporting the extended physicochemical and biological stability of XSB-001 (Ximluci; STADA Arzneimittel AG), a biosimilar referencing Lucentis (reference ranibizumab), which has been available in Europe since 2023.²

A recent study confirms the stability of XSB-001 biosimilar for retinal diseases, ensuring quality during clinical handling and enhancing patient care efficiency. | Image credit: 61766578 - stock.adobe.com

Ranibizumab, an anti–vascular endothelial growth factor (VEGF)–A fragment, is a cornerstone treatment for serious retinal conditions, including neovascular age-related macular degeneration (nAMD) and diabetic macular edema. While XSB-001 previously demonstrated equivalent efficacy and safety to the reference product in clinical trials, the question of its stability following preparation for injection remained a key consideration for health care providers and payers.

Ophthalmic practices often draw up injectable medications into syringes days or weeks in advance for efficiency and logistical planning. This “in-use” preparation exposes the drug to variables like container materials, temperature fluctuations, and light. As such, researchers decided to conduct this study, which evaluated XSB-001 under real-world handling conditions for 30 days. They specifically sought to confirm that prefilled syringes stored long-term and subsequently exposed briefly to ambient temperature and light (simulating transportation and preparation time) would maintain their required quality specifications.

Key Data Points Confirming Extended Quality

The stability study examined XSB-001 stored in its original vials at 5±3°C and subsequently prepared into 2 different types of commonly used syringes. Samples were maintained for 30 days, with a critical subset then exposed to 48 hours of room temperature, humidity, and ambient room lighting to replicate actual clinical use prior to injection.

Across all test conditions and both syringe types, the biosimilar maintained all required physicochemical and biological criteria.

Purity and Structural Integrity:

• Monomer Content: Size exclusion–high-performance liquid chromatography (SE-HPLC) analysis confirmed high monomer purity, averaging 99.6%. This surpassed the required threshold of 99.0% or greater.
• Impurity Control: Low molecular weight species were consistently observed to be below the detection limit (<0.35%), satisfying the requirement of 1.0% or less.
• Main Peak Purity: Reverse-phase high-performance liquid chromatography (RP-HPLC) analysis showed consistent main peak purity of 97.3%, exceeding the 97.0% or higher criterion.
• Biological Activity: The study confirmed that the biological activity of XSB-001 remained fully intact across all conditions. The potency, which was tested using a VEGF$_{165}$ reporter gene assay, fell within the acceptable range of 85% to 120%. Furthermore, subvisible particulate analysis indicated particle counts were well within acceptable limits, a critical safety measure for intravitreal injections.

The collective findings demonstrated that XSB-001 maintained its quality and biological activity under extended storage for up to 30 days in prepared syringes. This stability is pivotal for optimizing patient flow and ensuring the most efficient use of health care resources by minimizing drug waste associated with just-in-time preparation.

The authors concluded that this confirmed stability makes XSB-001 "a reliable option for planned hospital use and compounding manufacturing and intravitreal administration without compromising efficacy."

However, as with any laboratory study, certain limitations should be noted. Although the study rigorously monitored light and temperature exposure during the 48-hour ambient period, these factors can vary widely in real-world clinical settings, such as during transport between clinics. Furthermore, the study was not designed to evaluate clinical outcomes; it solely focused on the molecular integrity of the drug substance.

Ultimately, these data reinforce the utility of XSB-001 in managed care settings by demonstrating that the biosimilar's complex molecular structure withstands the practical demands of compounding and extended preadministration storage.

References

1. Björnestedt R, Waters S, Paišytė A, et al. Evaluation of XSB-001 (ranibizumab biosimilar) physicochemical and biological stability in prepared syringes for intravitreal injection. Adv Ther. 2025;42(9):4597-4610. doi:10.1007/s12325-025-03319-z
2. Ximluci, a Lucentis biosimilar, launches in Europe. The Center for Biosimilars^®. April 4, 2023. Accessed October 9, 2025. https://www.centerforbiosimilars.com/view/ximluci-a-lucentis-biosimilar-launches-in-europe