As part of the first phase of a broader trade pact signed by Chinese and U.S. officials in January, China has agreed to enact a system to prevent infringement of drug patents, a move that may boost protections for branded drugs in the vast Chinese marketplace. Under the new system, patent holders will be notified and given time to take legal action against producers seeking approval in China for copycat drugs. Pharmaceutical companies would also be able to seek extensions of patents to compensate for "unreasonable" delays by the patent office or while waiting for Chinese health regulators to approve a drug for sale.