In a recent press release, Alnylam Pharmaceuticals announced that the company had achieved “alignment” with the U.S. Food and Drug Administration (FDA) on safety measures and risk mitigation strategies with an eye towards resuming clinical trials of the investigational therapy fitusiran. Alnylam is developing the therapy to treat patients with hemophilia A and B, both with and without inhibitors.

Clinical trials involving fitusiran were suspended in September 2017 after the confirmed death of a hemophilia A patient who had been receiving the therapy as part of a Phase 2 open label extension study. The National Hemophilia Foundation reported on this development on September 7th.  In light of a recent “Type A” meeting with the FDA, which generated amended protocols and trial materials, the agency will now consider whether to remove the hold and allow trials to continue. Type A meetings are employed by the FDA after a clinical hold is put in place, so that both applicants and the regulatory agency may discuss a path forward.

Fitusiran is a subcutaneous therapy (administered under the skin) that employs small interfering RNA (siRNA) technology to target antithrombin (AT), 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. Fitusiran works by silencing the gene responsible for AT, which inhibits the protein’s anticoagulant function. This then compensates for the imbalance caused by deficiencies in other clotting proteins, such as factor VIII (hemophilia A) or factor IX (hemophilia B).

“We are pleased with the outcome of our meeting with the FDA regarding next steps for the fitusiran clinical program and remain committed to reinitiating the Phase 2 OLE and the Phase 3 ATLAS program around year-end,” said Akin Akinc, PhD, Vice President and General Manager, Fitusiran. “Further, we look forward to continuing our partnership with physicians and nurses to support education efforts on fitusiran safety, which we believe are a critical step when introducing a new therapeutic modality with the potential to address important unmet needs in hemophilia.”

Source: Alnylam press release dated November 9, 2017