Alnylam Pharma spotlights more upbeat human data for gene-silencing drugs

Alnylam Pharmaceuticals ($ALNY) showed once again that one of its RNA-interference therapies could knock down desired disease genes in an early-stage study. The top-line results from a Phase I study show that its therapy ALN-TTRsc reduced levels of Transthyretin (TTR)-mediated amyloidosis protein by more than 80%, setting the stage for a mid-stage study planned for late this year in patients with a genetic heart disease called familial amyloidotic cardiomyopathy (FAC).

The data bode well for Alnylam in building its case for delivering its gene-silencing drugs to their intended targets in humans, in this case with its most advanced candidate that uses its GalNAc-siRNA platform for subcutaneous injections. Sanofi's ($SNY) Genzyme controls rights to the Alnylam's ALN-TTRsc and ALN-TTR02 programs in Japan as well as the Asia-Pacific region.

Alnylam CEO John Maraganore has rolled out the Phase I data on ALN-TTRsc ahead of the company's R&D day this morning in New York City, which provides the company a stage to tout a number of milestones in a hard-fought campaign to advance RNAi drugs into human studies. The human data have helped propel Alnylam's stock 192% over the past 12 months, well north of the 40% increase in the Nasdaq Biotechnology Index during the same period.

The topline data on ALN-TTRsc come from an ongoing Phase I study in the U.K. involving 40 healthy volunteers, with full results expected during the annual Heart Failure Society of America meeting in September in Orlando, FL. It closely follows Alnylam's ALN-TTR02, its most advanced therapy for TTR-mediated amyloidosis (ATTR), which is being developed for patients with familial amyloidotic polyneuropathy (FAP).

ATTR is triggered by mutant TTR genes that lead to dangerous buildups of amyloid proteins in the peripheral nerves and heart. About 40,000 patients worldwide have the FAC cardiomyopathy, for which there are no approved treatments and the mean survival is 2.5 years, according to Alynlam. The FAP polyneuropathy affects 10,000 patients worldwide, the company said, with life expectancies of 5 to 15 years. Pfizer ($PFE) grabbed an approval for the first FAP drug, tafamidis, in Europe, but the FDA shot down the company's case for the drug in denying U.S. approval.

Both diseases associated with ATTR are considered rare, orphan conditions, which biotech and pharma companies of all sizes have rushed to treat because of the major medical needs and market advantages such as high pricing for therapies against rare conditions. So it's no surprise to see Genzyme, the world's top provider of treatments for rare genetic diseases, latching onto Alymlam's ATTR program for Asian markets.

- here's the release