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Alnylam Study to Track TTR Mutation Prevalence, Improve Characterization of Cardiac Amyloidosis


NEW YORK (GenomeWeb) – Alnylam Pharmaceuticals has initiated the DISCOVERY trial aimed at examining the prevalence of transthyretin (TTR) mutations in patients who may have cardiac amyloidosis, a disorder caused by a buildup of the amyloid protein in the heart.

Alnylam is developing an investigational drug, called ALN-TTRsc, for the treatment of TTR cardiac amyloidosis, including familial amyloidotic cardiomyoptahy (FAC) and senile systemic amyloidosis (SSA). FAC is caused by TTR mutations. SSA, in contrast, is not inherited and occurs due to amyloid deposition in the hearts of those with wild-type TTR.

"With the initiation of DISCOVERY, we aim to identify and facilitate the diagnosis of FAC by screening patients suspected of having cardiac amyloidosis for the presence of TTR mutations," Pritesh Gandhi, VP of medical affairs at Alnylam, said in a statement. Clinical data to date suggests that ALN-TTRsc can knockdown up to 94 percent of circulating TTR.

In the prospective study, Alnylam is planning to enroll up to 1,000 patients that researchers suspect have cardiac amyloidosis. Researchers intend to establish the frequency of TTR mutations and gain a better understanding of how the disease manifests in those with mutations. Through the trial, Alnylam is hoping to identify patients eligible to enroll in clinical trials for ALN-TTRsc.

Amyloidosis caused by TTR mutations occur when these mutations lead to misfolded proteins, which in turn lead to the amyloid deposits in tissues. FAC is a form of TTR-mediated amyloidosis impacting 40,000 people around the world. However, Alnylam believes the condition is under diagnosed and hopes to raise awareness with the DISCOVERY study.

Alnylam is studying the safety, tolerability, clinical activity, and pharmacodynamics of ALN-TTRsc in a Phase II trial involving 25 TTR cardiac amyloidosis patients with FAC or SSA. The company expects to announce preliminary results at a medical conference in November. Alnylam is also initiating in coming weeks an open-label extension study for the drug to further assess its tolerability and clinical activity with long-term dosing, as well as a Phase III trial by year end.

ALN-TTRsc employs an siRNA that targets wild-type and all mutant forms of TTR and employs a proprietary GalNAc conjugate delivery technology. In an update during its second quarter earnings conference call, Alnylam CEO John Maraganore noted that the company has been planning the Phase III trial in discussions with US and European regulators.