Research About Prosecution History Estoppel In Drug Patent Infringement Judge

Prosecution History Estoppel originated from promissory estoppel rule of contract law in common law which makes up for the disadvantage of the theory of consideration.Based on the fairness it carries on, the promissory estoppel rule was widely applied. With the continuous development of society, science and technology, the patent system has improved gradually. The promissory estoppel rule has gradually expanded because of its nature of fair, and developed in the soil of patent law. Prosecution History Estoppel is the limitation of doctrine of equivalents and its value for the patent system can’t be ignored because the abuse of the doctrine of equivalents will result in too large scope of patent protection.Prosecution History Estoppel has been more matured after a series of cases such as "Hughes Aircraft case", "Warner-Jenkinson case", "Festo case" in USA. Patent Law of the PRC does not make specific provision for estoppel. It is only provided in the judicial interpretation. In recent years, although the principle of estoppel is widely used in Chinese judicial practice, many problems still exist, especially the exclusion scope for the doctrine of equivalents is complete bar or flexible bar. For the flexible bar, in spite of the scope of the patent is limited by the amendment or argument the court may still not preclude the doctrine of equivalents because of the cause or purpose of the amendment or argument. For the complete bar, as long as the modification was made for the claims, the doctrine of equivalents cannot be applicable any more. So the flexible bar allows the patentees wider protection scope than complete bar. In another word, the intensity of protection for the patent is much lower under the complete bar.The choice of the complete bar or flexible bar balances the interest between the patentees and the public. In fact, patent system which can improve the development of the medical industry is the most effective measure to protect the achievements of pharmaceutical innovation. Undoubtedly, drugs are essential to people’s health and public interest and the pharmaceutical patent protection strength is also an important influencing factor for the access to the drugs. If the intensity of drug patent protection is too low, it may cause the “tragedy of the Commons”, on the contrary, it will lead to the “anti-tragedy of the Commons”. They are both detrimental to the pharmaceutical industry development.When it comes to the choice of the complete bar or flexible bar in pharmaceutical patent infringement trial, the court failed to reach a unified conclusion. This article mainly analyzes the problem that which choice in pharmaceutical patent infringement trial is most profitable for the public’s health and the improvement of pharmaceutical industry. The intensity of pharmaceutical patent protection is mostly determined by the development stage of pharmaceutical industry. At present, our pharmaceutical industry in China is still at the low-level stage, so only low intensity protection of pharmaceutical patent can help with the expansion of access to drugs and prevent duplication of research. To achieve a low intensity protection of pharmaceutical patent, we should choose complete bar in drug patent infringement judges.