Biotech firm Isis Pharmaceuticals (NASDAQ:IONS) announced in a press release recently  that it has begun a phase 2/3 clinical trial of its ISIS-TTR antisense drug for treating the rare genetic disease transthyretin (TTR) amyloidosis. The initiation of the trial also qualifies Isis for a $7.5 million milestone payment from its partner on the drug's development, GlaxoSmithKline (NYSE:GSK).

TTR amyloidosis affects only around 50,000 individuals worldwide, according to Isis's statement. The disease causes progressive peripheral nerve and heart tissue dysfunction, with few treatments currently available for patients.

The FDA has already given orphan drug status and fast-track review designation for ISIS-TTR's treatment of familial amyloid neuropathy. The results from Isis's study will go toward supporting a regulatory application to market ISIS-TTR for treating this disease. Isis's international study will involve up to 200 patients for fifteen months, analyzing the effect of ISIS-TTR in patient neurological dysfunction and quality of life.

Isis's chief operating officer B. Lynne Parshall commented on the launch of the trial in the release, saying, "The encouraging data from our Phase 1 study, in which our drug was well tolerated and produced significant reductions in TTR protein, supported the advancement of ISIS-TTR(RX) directly into this registration-directed Phase 2/3."

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