Pratima Chowdary, the principal investigator for the FLT180a programme, presented the latest data from the first cohort of two patients who were treated with the lowest study dose (4.5x1011vg/kg). A single infusion at this low dose was well tolerated by patients with severe Haemophilia B with no infusion related reactions. FIX activity remains stable and consistent post steady state at 40 +-5.5 over 66 weeks and 74 weeks post-administration, respectively, with no evidence of transaminitis. Both patients remained free of spontaneous bleeding episodes and did not require any Factor IX supplementation. The Freeline programme uses the company’s proprietary AAVS3 capsid and a gain of function variant of human factor IX (FIX). The therapy is being evaluated in collaboration with UCL in a Phase 1/2 trial known by Freeline as B-AMAZE, with the goal of normalising FIX activity in patients with moderate and severe Haemophilia B.

Principal investigator Pratima Chowdary said:

“The data is encouraging, showing durability of clinical results for FLT-180a. We are currently progressing the study to identify a dose level that leads to normalisation of FIX activity levels with minimal or no toxicity.”

Poster & presentation for The Joint 10th BIC and the 3rd Inhibitor International Conferences were as follows:

Presenter: Pratima Chowdary

Session: OC Hemophilia

Abstract title: B-AMAZE, a Phase 1/2 trial of a novel investigational adeno associated virus (AAV) gene therapy (FLT180a) in subjects with severe or moderately severe haemophilia B (HB)

Date: 07.09.19

Location: Plenary hall "Sala del Maggior Consiglio”

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Further information:

JW Communications

Julia Wilson

+44 (0) 7818 430877

juliawilsonuk@gmail.com

About Freeline

Freeline is a privately-held clinical-stage biotechnology company focused on AAV based gene therapy targeting the liver. Our vision is to create better lives for people suffering from chronic systemic diseases using the potential of gene therapy as a one-time curative treatment. Freeline is headquartered in the UK and has operations in Germany and the US.