Alnylam’s RNAi Therapeutic Onpattro Shows Sustained Treatment in hATTR Study

Clinical Trial Data

New data from an open-label extension study of Alnylam's Onpattro shows long-term efficacy and sustained treatment benefit for polyneuropathy of hereditary ATTR (hATTR) amyloidosis. The long-term data shows the drugs ability to reverse or halt neuropathy progression, the company said.

Over the weekend, Cambridge, Mass.-based Alnylam presented the data from the Global Open Label Extension study at the 2019 Peripheral Nerve Society (PNS) Annual Meeting in Italy, as well as a new analysis from the APOLLO Phase III study of patisiran.

Onpattro was approved by the U.S. Food and Drug Administration in August for hereditary transthyretin-mediated (hATTR) amyloidosis in adults, the first RNA interference (RNAi) therapeutic to ever be approved in the U.S. hATTR amyloidosis is a rare disease that affects about 50,000 people worldwide. In addition to polyneuropathy, or a degeneration of peripheral nerves, the disease can lead to significant disabilities that include loss of ambulation that can lead to the inability to walk and a decline in cardiac function.

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At the conference, Alnylam presented one-year interim results that showed serum transthyretin (TTR) levels were reduced by approximately 80 percent after six months in patients in the placebo arm of APOLLO who started treatment with patisiran. About one-third of the patients in that trial had previously taken tafamidis, which is Pfizer’s branded drug sold as Vundaqel and Vyndamax. Tafamidis was approved in May for the treatment of the cardiomyopathy of wild-type or hereditary transthyretin-mediated amyloidosis. Thirty-four percent of those patients discontinued treatment with tafamidis due to disease progression; the majority of other patients discontinued tafamidis to participate in the APOLLO study for unspecified reasons, Alnylam said.

Alnylam noted that in the APOLLO trial, patients who had been on placebo and saw a “rapid trajectory of disease progression” was halted once they began treatment with patisiran. Those patients did not return to the drug they were taking prior to administration of patisiran, which Alnylam said highlighted the important role of treatment with patisiran.

Additionally, patients who were treated for 30 to 36 months demonstrated sustained improvement in neuropathy impairment and quality of life measures versus baseline, Alnylam said. Those levels were “durably maintained” over time, the company said.

Eric Green, the general manager of the TTR program at Alnylam, said the four-year data of patisiran shows that hATTR amyloidosis patients with polyneuropathy continue to experience durable improvement. Treatment with Onpattro allows the patients to maintain reversal of neuropathy impairment and continues to demonstrate a strong safety profile, Green said.

“Additional analyses from APOLLO showed that patients previously treated with tafamidis experienced improvements in both neuropathy impairment and quality of life with patisiran,” Green said in a brief statement.

Alnylam also reported the results of an indirect treatment comparison of patisiran and inotersen, which is Ionis Pharmaceuticals and Akcea Therapeutics branded drug Tegsedi. While there was no head-to-head study of the two drugs, Alnylam said the indirect treatment comparison revealed favorable treatment effects of patisiran relative to inotersen across all endpoints evaluated. Tegsedi was approved in October for polyneuropathy of hereditary transthyretin-mediated amyloidosis in adults.

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