Issue 189 | April 26, 2004
Chiron Corp. v. Genentech, Inc.


  • Patent Claim Construction: Claims must be construed before determining whether the scope of enablement provided by the written description is commensurate with the scope of the claims.
  • 35 USC Section 112, 1st paragraph, Written Description Requirement: Where the district court broadly construed the claims of the patent in suit (as requested by the patent owner) to embrace chimeric antibodies, and chimeric antibodies first appeared as a successful technology in the literature four months after the filing date of the priority application needed to antedate prior art, the patent in suit failed to comply with the written description requirement, as of the priority date.
  • 35 USC Section 112, 1st paragraph, Enablement Requirement: Chimeric antibodies were not enabled by the priority applications in this case because chimeric antibodies were unpredictable at the time the priority applications were filed, so undue experimentation would have been required to make and use the chimeric antibodies claimed by the patent in suit
  • Jury Instructions – Standard For New Trial – The patent owner failed to show error in jury instructions sufficient to clearly mislead the jury and thus necessitate a new trial because the complaining party could not meet the two requirements for a new trial on this ground: fatal flaws in the jury instructions and a request for alternative instructions which would have corrected the flaws.


The Federal Circuit affirmed the judgment below, consistent with a jury verdict in favor of Genentech, that all claims of the ‘561 patent are invalid under 35 U.S.C. Section 102. The asserted claims were not entitled to the priority of antecedent applications filed in 1984, 1985, and 1986 because Chiron did not adequately disclose or support the subject matter of its ’561 patent in these antecedent applications. Accordingly, intervening prior art anticipated the claims.

The ’561 patent claims a monoclonal antibody that binds to human c erbB 2 antigen. Human c erbB 2 antigen (also named HER2) is an antigen associated with breast cancer cells.

The inventors filed their first application in 1984, and successive continuation-in-part applications in 1985, 1986, and 1995. The 1995 application issued as the ‘561 patent.

The 1984 application disclosed one monoclonal antibody that binds to HER2. While the application disclosed the deposit of the hybridoma that produced the monoclonal antibody, the application did not identify the structure, function, or molecular weight of the antigen. This 1984 application did not mention any humanized antibodies.

The 1985 application disclosed six additional monoclonal antibodies that bind to HER2. The application did not describe the identity, structure, or function of the antigen. The application did not specifically disclose chimeric or humanized antibodies.

The 1986 application did not identify the antigen by name, and also made no specific mention of chimeric or humanized antibodies.

Chiron sued Genentech over sales of Herceptin, a humanized antibody useful for the long-term treatment of breast cancer. Because Herceptin is a humanized antibody, it minimizes any HAMA response in patients.

The district court broadly construed the claims of the ’561 patent to embrace chimeric (partly human, partly non-human) and humanized antibodies in addition to mouse antibodies that bind to HER2. Accordingly, the district court granted Chiron’s motion for partial summary judgment of infringement. Also before trial, the parties stipulated that the ’561 patent would be invalid under Section 102 based on intervening prior art if the patent were not entitled to claim priority to the filing date of any one of the 1984, 1985, and 1986 applications. Thus, the thirteen-day jury trial adjudicated only whether any of the priority applications satisfy the written description and enablement requirements of 35 U.S.C. Section 112, first paragraph.

The jury determined that none of the priority applications satisfy both the written description and the enablement requirement for the subject matter in the ’561 patent’s claims.

The Federal Circuit observed that the ’561 patent may only claim priority to an earlier application if the earlier application fulfills the requirements of Section 112, first paragraph. That paragraph requires that the application contain a written description and an enabling disclosure of the invention.

The applications in this case satisfy the enablement requirement only if one skilled in the art, after reading their disclosures, could practice the full scope of the invention claimed in the ’561 patent without undue experimentation. That is not to say that the specification itself must necessarily describe how to make and use every possible variant of the claimed invention, for the artisan’s knowledge of the prior art and routine experimentation can often fill gaps, interpolate between embodiments, and perhaps even extrapolate beyond the disclosed embodiments, depending upon the predictability of the art. But the enabling disclosure of the specification must be commensurate in scope with the claim under consideration.

Because a patent specification must enable the full scope of a claimed invention, an enablement inquiry typically begins with construction of the claims. The district court’s claim construction read the claims of the ’561 patent to embrace not only mouse antibodies but also chimeric and humanized antibodies that bind to HER2.

The Federal Circuit focused primarily on chimeric antibodies. Because the priority applications in this case do not enable or provide proper support for chimeric antibodies, the Federal Circuit found no need to examine humanized antibodies.

The trial record shows that chimeric antibodies first appeared as a successful technology in the literature in May 1984, four months after the February filing date of the first application. Because chimeric antibody technology did not even exist at the time of the 1984 filing, the Chiron scientists did not possess and disclose this technology in the February 1984 filing. Thus, the ’561 patent cannot claim priority based on the 1984 application because it fails to comply with the written description requirement.

The written description requirement prevents applicants from using the amendment process to update their disclosures (claims or specifications) during their pendency before the patent office. Otherwise applicants could add new matter to their disclosures and date them back to their original filing date, thus defeating an accurate accounting of the priority of invention.

For the 1985 and 1986 applications, chimeric antibodies were not future technology, but were nascent technology. Chimeric antibodies were not enabled by these priority applications if undue experimentation would be required to make and use the chimeric antibodies claimed by the ’561 patent. Undue experimentation is not a single, simple factual determination, but rather is a conclusion reached by weighing many factual considerations. These factual considerations include (1) the quantity of experimentation necessary, (2) the amount of direction or guidance presented, (3) the presence or absence of working examples, (4) the nature of the invention, (5) the state of the prior art, (6) the relative skill of those in the art, (7) the predictability or unpredictability of the art, and (8) the breadth of the claims.

Evidence presented to the jury showed that creation of genetically engineered antibodies, such as chimeric antibodies, required significant experimentation in 1985 and 1986 because those antibodies were unpredictable at that early stage of development. The 1985 and 1986 applications provide no disclosure of either how to make and use chimeric antibodies or working examples of chimeric antibodies within the scope of the ’561 patent’s claims. Chiron’s disclosure fell short of providing a specific and useful teaching of all antibodies within the scope of the claim.

Chiron assigned error to four separate jury instruction rulings. The Federal Circuit reviews jury instructions in their entirety and only orders a new trial when errors in the instructions as a whole clearly misled the jury. Chiron needed to show both fatal flaws in the jury instructions and a request for alternative instructions that could have corrected the flaws.

First, Chiron argued that the district court erred by instructing the jury on Genentech’s burden of proof without also adding an instruction on the presumption of the ’561 patent’s validity. The Federal Circuit disagreed because the presumption of validity and heightened burden of proving invalidity are in reality different expressions of the same thing: a single hurdle to be cleared.

Second, Chiron complained about an instruction stating that an application satisfies the written description requirement if a person of ordinary skill in the art at the time the application was filed would recognize from the application that the inventor actually invented the full scope of the invention as finally claimed in the patent. The Federal Circuit rejected Chiron’s challenge, even though this instruction did not echo the precise language of the Federal Circuit’s cases, as this instruction is not incorrect.

Chiron complained that the district court erred in rejecting its proposed instruction that, to meet the enablement requirement, an application need not enable every way of making the claimed invention. The Federal Circuit rejected the notion that the district court erred by declining to include this instruction. The district court provided a succinct and correct summary of the law of enablement that Chiron did not challenge. A trial court need not further instruct the jury on what enablement does not require.

Judge Bryson concurred in a separate opinion. He agreed that enablement must be judged in light of the state of the art at the time of the application. He disagreed with the majority’s holding, in effect, that claims that are enabled by the original application may be construed broadly enough to encompass technology that was not developed until later and was not enabled by the original application. He would construe claims, where possible, as they would have been understood by one of skill in the art at the time of the invention, excluding the as-yet-undeveloped technology that the applicant did not enable.

In this case, however, the patentee did not seek to preserve the validity of its claims by construing them in accordance with the state of the technology at the time of the invention. Instead, Chiron argued that the 1984 application provides support for claims covering technology that was not in existence at that time. Judge Bryson would hold in view of this argument that the claims are not entitled to priority as of 1984, not only because of a failure to satisfy the written description requirement, but also because the 1984 application does not enable claims of the asserted scope.

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