Alnylam Pharmaceuticals recently has initiated a Phase 1 open-label extension (OLE) study for ALN-AT3, its investigational therapy for patients with hemophilia and rare bleeding disorders. ALN-AT3 is a subcutaneous therapy (administered under the skin) that employs small interfering RNA (siRNA) technology to target antithrombin (AT). AT is a liver-generated clotting protein that plays a key role in the regulation of blood clots.

siRNA molecules are segments of RNA (ribonucleic acid) that block or “silence” the activity of certain genes through RNA interference, a natural biological process common in plants and mammals. With ALN-AT3, silencing the gene responsible for AT inhibits the protein’s anticoagulant function, thereby compensating for the imbalance caused by deficiencies in other clotting proteins such as factor VIII (hemophilia A) or IX (hemophilia B).

“This Phase 1 OLE study brings us one step closer to our goal of providing a safe, subcutaneously administered, long-acting option for hemostasis management to people with hemophilia and other rare bleeding disorders. The initiation of this study marks our continued progress with ALN-AT3, and we are pleased to provide hemophilia patients in our Phase 1 trial the opportunity to receive this investigational medicine on an ongoing basis,” said Akshay Vaishnaw, MD, PhD, Executive Vice President of R&D and Chief Medical Officer at Alnylam. “We believe the ALN-AT3 data presented to date have been very promising, demonstrating potent, dose-dependent, and durable knockdown of AT with the potential to re-balance hemostasis in people with severe hemophilia through normalization of thrombin generation.”

The Phase 1 OLE study will evaluate the long-term safety and efficacy of ALN-AT3 and provide subjects with the opportunity for continued dosing. Alnylam plans to report clinical data from the  study at least yearly, beginning in 2016.

Learn more about this study at clinicaltrials.gov.

Source: Alnylam press release dated October 8, 2015