During 2020, we also advanced approaches for lung delivery of siRNAs. Concomitant use of on-label commercially available tafamidis is not prohibited. Additional secondary and exploratory endpoints will be evaluated at 18 months. In December 2020, we completed enrollment in this study. Almost one-third of the world's population have previous or current HBV infection. These provide additional opportunities for third parties to challenge our patents. The cost of preparing and submitting an NDA is substantial. Under the PDUFA, as amended, each NDA must be accompanied by an application fee. The FDA adjusts the PDUFA user fees on an annual basis. We intend to request Fast Track designation for our product candidates, if applicable. It is unclear whether the ACA will be overturned, repealed, replaced, or further amended. We cannot predict what affect further changes to the ACA would have on our business. We do not expect the cost of complying with these laws and regulations to be material. This patient focus has continued as we have transitioned into commercialization. We also continue to advance our growing pipeline of RNAi therapeutic opportunities. There are a limited number of manufacturers that supply synthetic siRNAs. In particular, in March 2010, the ACA, was signed into law. In particular, it is unclear how data transfers to and from the UK will be regulated. Third parties may sue us for infringing their patent rights. Risks Related to CompetitionThe pharmaceutical market is intensely competitive. For example, we developed ONPATTRO for the treatment of hATTR amyloidosis.
