Freeline to present data on its AAV gene therapy platform and programmes at the 23rd annual American Society of Gene & Cell Therapy 2020

Freeline, a biotechnology company focused on developing curative gene therapies for chronic systemic diseases, today announces it will present four abstracts at the 23rd annual American Society of Gene & Cell Therapy (ASGCT) meeting on 12-15 May, 2020. Due to the ongoing COVID-19 pandemic, the organisers, in consultation with relevant authorities, have announced that this year’s ASGCT meeting will be held virtually.


Freeline will be presenting data from its Adeno-Associated Virus (AAV)-based gene therapy programmes and platform. The titles, abstracts and timing details of our four abstracts are as follows:

  1. Title: Utilising apheresis to remove neutralising AAV antibodies in patients previously excluded from gene therapy

Author: Jonathan Foley

Session Date/Time: Thursday May 14, 2020 - 5:30 PM - 6:30 PM

It is well established that in the global human population, due to previous infections of wild type AAV, antibodies develop which could be neutralising antibodies (NAbs) to a subsequent AAV-based gene therapy. It has been shown that there are varying degrees of neutralising antibodies (Nabs) and the AAV seroprevalence varies geographically, with age, and with serotype. In order to give the best possible treatment benefit to as many patients as possible with Freeline’s potentially transformative therapies, the company has been evaluating methods that reduce AAVS3 NAb titres in patients. Freeline will present data demonstrating that plasmapheresis can reduce anti-AAVS3 NAb to levels which would allow for clinical trial inclusion. The company will announce its plans to further evaluate this approach in a clinical trial as part of Freeline’s FLT180a programme in Haemophila B. Freeline’s data will show that plasmapheresis, a routine method for removing antibodies from blood circulation, can be used to deplete AAVS3 NAb in patients to levels that could meet our predetermined trial eligibility criteria.            

  1. Title: Development of a scalable serum free single-use (SU) suspension platform for the manufacturing of high potency and quality AAV batches

Author: Ahmed Youssef          

Session Date/Time: Thursday May 14, 2020 - 5:30 PM - 6:30 PM

For commercial-scale manufacturing of AAV, Freeline has developed an iCELLis-based manufacturing platform. Combined with its proprietary plasmid system, this platform provides AAV vectors with high potency and quality, ensuring high efficacy and patient safety at yields which are comparable to that of a well-developed 200L suspension bioreactor. High efficacy and safety of our gene therapy products is core to Freeline´s mission to create better lives. Freeline will provide data for a scalable suspension cell manufacturing platform which has the potential to meet our high vector potency and quality standard, and will prepare Freeline for the development of gene therapies in indications with large patient numbers or requiring higher doses than our programs currently in development.

  1. Title: Investigation of potential pseudo wtAAV species providing replication competence

Author: Felicia Thoennissen

Session Date/Time: Tuesday May 12, 2020 - 5:30 PM - 6:30 PM

Freeline will provide data of an in-depth analysis of main replicating AAV species generated during AAV vector packaging, and show differences between vector preparations derived from our more classical and superior unique split packaging plasmid system. Additionally, the company will present data on how the analytical tools established in this process provide insight into molecular events, resulting in the composition and formation of replicating forms other than rAAV vector sequences such as rcAAV. This is a highly valuable quality indicator for vector batches and the plasmid packaging system used. This work addresses concerns around rcAAV and its safety implications and represents an improvement on the industry standard.

  1. Title: Benchmarking of FLT210, a potent next generation AAV-hFVIII vector candidate with superior quantity and quality characteristics, against a known FVIII-SQ comparator

Author: Andreas Schulze

Session Date/Time: Wednesday May 13, 2020 - 5:30 PM - 6:30 PM

Freeline’s previously announced FLT210 programme in Haemophilia A, as with all other Freeline disclosed programmes, leverages the company’s platform technology, including its proprietary AAV capsid known as AAVS3. Freeline’s goal with the Haemophilia A program is to improve on existing gene therapies in development for this condition by creating a novel, proprietary Factor VIII construct that fits within the natural capacity of an AAV capsid. Freeline will show data for highly potent candidates with construct sizes less than 4.97kbp, one being less than 4.75kbp in length, thereby focusing on improved quality characteristics.

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