JUrISdIctIOn repOrt: cHInA
prb’S decISIOn On tHe VIAGrA pAtent
Jiancheng Jiang
Peksung Intellectual Property Ltd.
On May 31, 2009, the Patent Re-examination Board (PRB) made its
“cHIneSe prActIce IS QUIte StrIct On
Decision No. 13420 on the validity of the Viagra patent, in which the PRB
tHe dIScLOSUre OF teSt dAtA AS A VItAL
decided to maintain the validity of the patent.
pArt cOntrIbUtInG tO tHe SUFFIcIent
This decision—the first decision in the second round of litigation in the
dIScLOSUre OF cHemIcAL InVentIOnS.
Viagra patent case—was made nearly a year after the oral hearing held on July
9-10, 2008, during which claim support and inventive step were examined.
tHe OppOnentS HeLd tHe pOSItIOn tHAt,
SInce tHe SOLe cLAIm OF tHe pAtent WAS
According to Chinese patent law, if either party is not satisfied with
the decision of the PRB, it may, within three months from receipt of
tHe medIcAL USe In erectILe dISFUnctIOn
notification of the decision, institute legal proceedings in the Beijing
(ed) treAtment OF A SpecIFIc cHemIcAL
No. 1 Intermediate People’s Court.
cOmpOUnd, I.e. SILdenAFIL, WHIcH IS tHe
The Viagra patent case is regarded as one of the most high-profile IP ActIVe InGredIent OF tHe WeLL-KnOWn ed
litigation cases in China. The first round of litigation started in 2001,
drUG VIAGrA, tHe GenerIcALLY dIScLOSed
when 13 Chinese generic companies and individuals tried to invalidate
the Viagra patent with only one claim directed at a compound called
dAtA Are nOt reLAted tO tHe cLAImed
sildenafil. The grounds submitted in their invalidation requests included cHemIcAL cOmpOUnd.’’
inventive step, claim support, sufficiency and clarity. The PRB heard the
case at a two-day oral hearing on September 3-4, 2002, during which it
investigated each and every ground for the invalidation action.
The parties’ debate was focused on sufficiency of disclosure and inventive
finding, the PRB’s decision was overturned. According to Chinese practice,
step, among other issues. Concerning sufficiency, the debate centred on
the courts are not empowered to directly rule on the validity of patents.
the fact that the patent only disclosed the test data of a so-called ‘especially
Hence, the Viagra patent was remanded to the PRB for further examination
preferred compound’ (as a selective PDEV inhibitor), without an express
of validity based on grounds that were not addressed in Decision
indication of the specific identity of the tested compound.
No. 6228 and the subsequent court proceedings, i.e. inventive step and
claim support. This is when the second round of litigation started.
Chinese practice is quite strict on the disclosure of test data as a vital
part contributing to the sufficient disclosure of chemical inventions.
In Decision No. 13420 recently made by the PRB, it was held that it
The opponents held the position that, since the sole claim of the patent
was logical to deem that the so-called especially preferred compound,
was the medical use in erectile disfunction (ED) treatment of a specific
which was said to be the compound tested in the patent, is nothing but
chemical compound, i.e. sildenafil, which is the active ingredient of
the claimed compound. The PRB then found that the patent claim was
the well-known ED drug Viagra, the generically disclosed data are not
properly supported by the specification. The patent was also held to be
related to the claimed chemical compound. Pfizer argued that sildenafil
inventive over the prior art references cited by the opponents. These
is indeed one of the especially preferred compounds, as was stated in the
references disclosed the first medical use (as an agent against angina) of
specification, such that the disclosed test data did serve to support the
the chemical genera to which sildenafil belongs and the potential medical
claimed medical use.
use of another PDEV inhibitor for ED.
Subsequently, on July 5, 2004, the PRB in its Decision No. 6228 decided
that the Viagra patent was invalid on the ground of insufficiency, with
the arguments from the opponents’ side being found persuasive. Pfizer
Jiancheng Jiang is an attorney at Peksung Intellectual Property Ltd. He
appealed PRB’s Decision no. 6228 and won in both the first instance and
can be contacted at: jjiancheng@peksung.com
second instance courts. In both courts, the judges held that there was a
correlation between the test data disclosed in the patent and the claimed Jiancheng Jiang has been representing Pfizer in the Viagra patent case,
chemical compound such that sufficient disclosure was met. Based on this together with another attorney.
58 World Intellectual property review September/October 2009 www.worldipreview.com
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