The US Food and Drug Administration (FDA) has allowed Sanofi Genzyme and Alnylam Pharmaceuticals to proceed with clinical trials of fitusiran, an investigational product candidate.
The FDA lifted the clinical hold on all of fitusiran studies, including the Phase II open-label extension (OLE) study and the ATLAS Phase III programme.
Fitusiran is being developed as an RNAi therapeutic to target antithrombin (AT) for treating patients suffering from haemophilia A and B.
The investigational candidate is formulated to reduce levels of AT to stimulate sufficient generation of thrombin for restoring haemostasis and preventing bleeding.
Sanofi has previously collaborated with Alnylam for the development and commercialisation of fitusiran.
In September, Alnylam stopped fitusiran dosing in all ongoing trails after a patient with haemophilia A without inhibitors experienced a fatal thrombotic event during the Phase II OLE trial.
Alnylam and the FDA discussed the new clinical risk mitigation measures for fitusiran, and agreed on amended protocol-specified guidelines, additional investigator and patient education on decreased doses of replacement factor or bypassing agent for the treatment of breakthrough bleeds in the trials.
Alnylam Pharmaceuticals Fitusiran vice-president and general manager Akin Akinc said: “We are pleased with the FDA’s decision to lift the clinical hold, as fitusiran holds the potential to help improve the lives of people living with haemophilia.
“With the additional risk mitigation measures in place, we look forward to the continued late-stage development of fitusiran and expect to resume dosing around year-end.”