The results of the phase 1 study open-label trial showed the therapy was safe, raising the possibility of a more effective and more appealing treatment for the progressive and fatal disease, in which amyloid builds up in the body's organs and tissues, where it can cause loss of sensation, heart problems, or other symptoms. Life expectancy after diagnosis is about seven to 12 years. Current treatment involves long-term therapy to stabilize the protein and slow the formation of amyloid or inhibit TTR protein production by degrading its mRNA, thereby slowing the formation of amyloid.

The new therapy, called NTLA-2001, was given once to six patients at 0.1 mg/kg to half and 0.3 mg/kg to the other half. After 28 days, the concentration of TTR protein in the serum was reduced by 52 percent in those receiving the lower dose and by 87 percent in those receiving the higher dose.