Answer ... A granted patent may be unenforceable if one of the following defences is successfully established:

• invalidity;
• exhaustion (first sale doctrine);
• prior commercial use;
• use in service of personal needs or for non-commercial purposes, or for the purposes of evaluation, analysis, research, teaching, testing, trial production or information collection to apply for a production licence;
• temporary importation or circulation of products, or use in a foreign means of transport in transit through Vietnam; and
• use under a compulsory licence.

Answer ... Neither inequitable conduct nor an inequitable conduct standard exists under Vietnamese law.

Answer ... No duty of candour exists under Vietnamese law.