Alnylam Pharmaceuticals this week released data from a natural history study designed to measure blood levels of the wild-type and mutant versions of the gene transthyretin in both transthyretin-mediated amyloidosis patients and mutation carriers.
Alnylam is currently conducting a phase I study of an RNAi-based treatment for TTR amyloidosis, a hereditary, systemic disease caused by a mutation in the transthyretin gene (GSN 7/8/2010).
“Although it is known that serum TTR concentrations in [TTR amyloidosis] patients and gene carriers are below the normal range, little is known about temporal changes in TTR levels in either patients or carriers,” the company said. “Accordingly, Alnylam conducted a natural history study to measure serial TTR levels over a four week period in ATTR patients and gene carriers, and to determine the intra- and inter-patient variability in serum TTR.”
The study enrolled 26 patients and carriers of seven different amyloidogenic TTR mutations.
Data from this study showed that TTR levels were stable over time in patients and carriers. “The average serum TTR concentration was approximately 200 micrograms/mL with 10 to 20 percent intra-subject variability over the 28-day observation period,” Alnylam noted. “Results showed that inter-subject TTR variability was approximately 25 percent.”
Alnylam expects to report phase I data on its drug, ALN-TTR, in the third quarter.