Arrowhead and Takeda reveal mixed new fazirsiran data

Today, US biotech Arrowhead Pharmaceuticals (Nasdaq: ARWR) announced positive top-line data from a Phase II placebo-controlled study evaluating an investigational RNAi therapeutic, fazirsiran (TAK-999/ARO-AAT), for the treatment of alpha-1 antitrypsin (AATD) liver disease. These were described as “positive,” but investor reaction was negative, with the firm’s share price falling 20% to $30.92.

The drug is being developed with Japan’s Takeda Pharmaceuticals (TYO: 4502), under a 2020 collaboration that provided Arrowhead with $300 million upfront and eligibility for $740 million more in milestone payments.

AATD is a rare genetic disorder estimated to affect 1 in 3,000-5,000 people in the USA. While a third of patients develop liver disease, the only current treatment option is transplantation.