## Facts

- Dr. Stephen E. Wright filed a patent application claiming processes for producing live, non-pathogenic vaccines against pathogenic RNA viruses, the vaccines produced, and methods of using them.
- The specification provided a general description but only one detailed working example involving a recombinant vaccine conferring immunity in chickens to Prague Avian Sarcoma Virus (PrASV) using recombination with RAV-O in chicken embryo cells.
- The examiner allowed claims limited to the specific disclosed PrASV/chicken/RAV system but rejected broader claims that were not confined to a particular virus, host, or system.
- The examiner rejected claims 1–23, 25–42, and 45–48 for lack of enablement under 35 U.S.C. § 112, first paragraph; the Board of Patent Appeals and Interferences affirmed and denied reconsideration.
- Wright submitted affidavits and relied in part on later scientific developments to argue enablement, but the Board found the showing insufficient as of the 1983 filing date.

## Issues

1. Whether the application enabled a person of ordinary skill, as of the filing date, to make and use the full scope of the broad RNA-virus vaccine and process claims without undue experimentation under 35 U.S.C. § 112, first paragraph.
2. Whether the PTO had a sufficient basis to find nonenablement and shift to the applicant the burden to rebut that finding.

## Decision

- The Federal Circuit affirmed the Board’s rejection for nonenablement under 35 U.S.C. § 112, first paragraph.
- The court held the PTO had a reasonable basis for concluding that a single, narrow working example did not enable broad claims covering vaccines and methods applicable to pathogenic RNA viruses generally.
- The court agreed that, given the unpredictability and genetic diversity of RNA viruses, practicing the full claim scope would require undue experimentation.
- The court rejected reliance on later developments and affidavits that did not establish enablement as of the filing date.

## Legal Principles

- Enablement requires that the specification teach a person of ordinary skill, as of the filing date, to make and use the full scope of the claimed invention without undue experimentation.
- When claim breadth substantially exceeds the disclosed working embodiments and the art is unpredictable, more representative examples or detailed, reliable guidance may be required to support broad genus-level claims.
- In PTO proceedings, once the Office provides a reasonable basis for nonenablement, the burden shifts to the applicant to rebut with persuasive evidence tied to the filing-date state of the art.
- Post-filing advances cannot supply missing enablement; the inquiry is anchored to what the application taught and what skilled artisans could do at the time of filing.

## Conclusion

The Federal Circuit upheld the PTO’s nonenablement rejection because Wright’s application disclosed only a single, specific RNA-virus vaccine example and did not provide filing-date teaching sufficient to support broad claims to live vaccines and production methods for pathogenic RNA viruses generally without undue experimentation.


In re Wright, 999 F.2d 1557 (Fed. Cir. 1993)