Sanofi Genzyme Reports Results From Phase 2 Open-Label Extension Study

(RTTNews) - Sanofi Genzyme, the specialty care global business unit of Sanofi (SNYNF), and Alnylam Pharmaceuticals, Inc announced new positive results from the ongoing phase 2 open-label extension (OLE) study with fitusiran in patients with hemophilia A and B, with or without inhibitors (N=33).

Fitusiran is an investigational RNAi therapeutic targeting antithrombin (AT) for the treatment of patients with hemophilia A and B, that is designed to lower levels of AT with the goal of promoting sufficient thrombin generation upon activation of the clotting cascade to restore hemostasis and prevent bleeding.

The companies also announced that phase 1 clinical trial results demonstrating an encouraging preliminary safety and tolerability profile and initial evidence that monthly subcutaneously administered fitusiran lowered AT levels and increased thrombin generation in patients with hemophilia A and B without inhibitors were published online today.

The updated clinical results in the fitusiran phase 2 OLE study showed that the safety and tolerability profile of fitusiran remains encouraging, with no thromboembolic events, including during co-administration of replacement factor or bypassing agents. The majority of adverse events (AEs) were mild or moderate in severity, with the most common AEs consisting of transient, mild injection site reactions (ISRs).

In addition, once-monthly subcutaneous (SC) administration of fitusiran achieved lowering of AT, increases in thrombin generation, and, in a post-hoc exploratory analysis, reductions in the median estimated annualized bleeding rate (ABR) in patients with and without inhibitors. Based on these results, the companies announced last week the initiation of the ATLAS phase 3 program for fitusiran in patients with hemophilia A and B with or without inhibitors.