Evaluation of mAb transmission through Supor™ Prime membrane filters

Supor™ Prime filter membranes deliver 100% transmission of mAb drug products through the membrane filter with relatively low biologic drug-product loss

We evaluated the performance of Supor™ Prime sterilizing grade membrane filters to determine the level of mAb transmission through the filter membrane and the degree of product loss. This study shows that Supor™ Prime membrane filter provides 100% transmission of trastuzumab and rituximab biologic drugs and that loss of drug product is minimal.

Introduction

Drug formulations in the market are changing with the share of subcutaneous administration over intravenous infusion increasing. Subcutaneous administration is seen to be the preferred approach both by patients and healthcare providers.

For subcutaneous injections, smaller volumes are required, and biological drugs must be prepared at higher concentrations. This is the case for mAbs used to treat various cancer and autoimmune diseases. Therefore, high-concentration mAbs are becoming more prevalent in the market. As the drug concentration increases towards the end of product manufacture, obtaining as much product as possible during final filtration stages becomes imperative.

We have developed Cytiva Supor™ Prime sterilizing grade membrane filters specifically to offer high mAb transmission performance and to minimize any impact of the drug critical quality attributes (CQAs).

This application note presents data on product transmission through the membrane for a Supor™ Prime membrane filter compared to other sterilizing grade filter membranes with two drug products, trastuzumab, and rituximab.

Method for transmission testing

Transmission testing was conducted using a low concentration mAb solution to obtain increased definition in results, therefore identifying subtle transmission differences between membrane filters tested. Transmission analysis was performed across Cytiva sterile membrane filter products, as well as other sterile filter products available in the market, see Table 1.

Table 1. Membrane filters used for the mAb transmission study

Testing was performed using two drug products, diluted to 0.25g/L concentration in phosphate-buffered saline solution (PBS). The filtering capacity across each membrane sample was executed at a flow rate of 2 mL/min and nine sample fractions were collected during each filtration trial to be analyzed via protein A affinity chromatography using HPLC to assess mAb transmission.

All studies described in this article were performed at Cytiva, Portsmouth in 2016, 2017, and 2020. All data is held at Cytiva, Portsmouth.

Product transmission during sterile filtration

We averaged transmission data between replicate samples for each membrane filter tested as part of the trastuzumab and rituximab study. Figures 1 and 2 below illustrate the average transmission values obtained via UV₂₈₀ analysis on the HPLC for each of the fraction samples taken across both drug products

Fig 1. (A) Average membrane filter transmission using trastuzumab. (B) Significant differences were seen in aliquots 1 to 3 for trastuzamab transmission on Ultipor N66 (control), Supor™ Prime, and Millipore SHC membranes. Data shows mean values ± S.D, n = 3. P-value data was obtained using the t-test model with two samples assuming unequal variances and is summarized in Table 2.

Fig 2. (A) Average membrane filter transmission using rituximab. (B) Transmission assessment for rituximab for Ultipor N66, Supor™ Prime, and Millipore SHC membranes. Data shows mean values ± S.D, n = 3. P-value data was obtained using the t-test model with two samples assuming unequal variances and is summarized in Table 2.

The following was observed across both studies:

• The Ultipor N66 grade NR membrane filter was used as a positive control for both drug product filtration studies and low transmission was observed. However, this was expected.
• Cytiva membrane filters, including Supor™ Prime, provided 100% transmission across all sample fractions taken.
• We observed lower transmission in the first sample fractions taken for both drug products with the Millipore Express SHC membrane filter meaning adsorption in the early filtration stages. As loading increased, this became negligible.

To compare Supor™ Prime with other filters that showed potential adsorption in Figures 1 and 2, we used a t-test assuming unequal variances. The results of this comparison are shown in Table 2 below.

Table 2. Statistical comparison of aliquots 1 to 3 for Millipore SHC vs Supor™ Prime membrane filter, n = 3. Data was obtained using the t-test model with two samples assuming unequal variances

In Table 2, we see key statistical differences between the feed and filtrate sample using the Millipore Express SHC filter with aliquot 1 and 2 with trastuzumab but only aliquot 1 with rituximab. Using the t-test model with two samples assuming unequal variances, we determined a statistically significant difference between Supor™ Prime and Millipore Express SHC membranes during these early phase filtration steps with these drug products. The first two aliquots with trastuzumab show p < 0.05 with this t-test model, while for rituximab, we observe p < 0.05 in aliquot 1 only. In addition, there is significant statistical strength to indicate that there is adsorption of mAb on the Millipore Express SHC membrane in the early stages of testing, as opposed to the Supor™ Prime membrane, which shows no or minimal adsorption with either drug. 

Conclusion

• Across both drug products, we observe that the Millipore SHC membrane shows higher adsorption for the early sample aliquots taken during the filtration studies. The first and second aliquots with trastuzumab show statistically that there was a loss of mAb observed in the tests, while aliquot 1 for rituximab showed similar results regarding loss of mAb through adsorption.

• Overall, this transmission study shows that the Supor™ Prime filter provides 100% transmission utilizing two different mAb products.

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