Dosing Continues in Hemophilia B Gene Therapy Trial

Updated date from the B-LIEVE study is expected in the second half of 2022 and first half of 2023.

Freeline Therapeutics has initiated dosing in the second cohort of their phase 1/2 B-LIEVE study (NCT05164471) of FLT180a (verbrinacogene setparvovec) for the potential treatment of hemophilia B.1

"The ultimate promise of gene therapy is a functional cure," Pamela Foulds, MD, chief medical officer, Freeline, said in a statement.1 "The initial data from the first B-LIEVE cohort enhance our confidence that a low, one-time dose of FLT180a with a short, prophylactic immune management regimen has the potential to provide a functional cure to people with hemophilia B by delivering predictable and sustained FIX normalization together with a good safety profile. The data also provide confidence in the dosing for our pivotal Phase 3 trial, which we anticipate beginning in 2023 as planned.”

Patients in the second cohort will be dosed with the same 7.7e11 vg/kg of FLT180a and prophylactic immune management regimen as the first cohort based on the data from that cohort and advice from an Independent Data Monitoring Committee. The first cohort finished dosing in April and topline data will be presented at the International Society on Thrombosis and Haemostasis Congress in London on July 9-13, 2022.

The B-LIEVE study is confirming the 7.7e11 vg/kg dose initially selected based off data in the phase 1/2 B-AMAZE dose-finding trial (NCT03369444). Patients from the B-AMAZE trial continue to be assessed in a long-term follow-up study.

READ MORE: Final Analysis of Phase 3 HOPE-B Trial: Durability of Etranacogene Dezaparvovec and QoL Improvements

The B-LIEVE study is primarily assessing safety via incidence and severity of adverse events (AEs) and also factor IX (FIX) levels for dose confirmation purposes. Secondary outcome measures include annual bleeding rate, FIX concentrate consumption, FIX prophylaxis, quality of life, spontaneous bleeding, antibodies, and liver findings. The first patient was dosed in the study in March 2022.2

FLT180a is designed to restore sustained FIX activity in people with hemophilia B by delivering the Padua variant of FIX with an AAV3 capsid. Updated data from B-LIEVE will be presented in the second half of 2022 and the first half of 2023, and Freeline plans to initiate phase 3 start-up activities in the first half of 2023.

"Our goal is to provide transformative and durable one-time treatments to people with severe chronic diseases. We are working with urgency to advance our therapeutic candidates and are focused on finding the most effective way of bringing them to patients," Michael Parini, chief executive officer, Freeline, added to the statement.1 "FLT180a is on track to deliver proof of concept that our gene therapies have the potential to achieve our goal. We continue to believe that executing in the clinic together with financial discipline and operational excellence will demonstrate Freeline's value for patients, potential partners and investors alike."

REFERENCES
1. Freeline initiates dosing of second cohort in B-LIEVE dose confirmation trial of FLT180a in hemophilia B. News release. Freeline Therapeutics. June 14, 2022. https://firstwordpharma.com/story/5594465
2. Freeline Announces First Patient Dosed in the Phase 1/2 B-LIEVE Dose-Confirmation Trial in Hemophilia B. News release. Freeline Therapeutics. March 9, 2022. https://www.freeline.life/investors/newsroom/freeline-announces-first-patient-dosed-in-the-phase-12-b-lieve-dose-confirmation-trial-in-hemophilia-b/