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4-Patents: Bt patent wars yield new casualties

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Information Systems For Biotechnology 
National Biological Impact Assessment Program

March 1999

News For The Agricultural And Environmental Biotechnology Community 



Bacillus thuringiensis (Bt) continues to breed controversy. Outside the United States, January was a turbulent time for transgenic plants engineered to express Bt toxins. Monsanto literally drew fire in India for its tests of transgenic cotton when annoyed farmers torched test plots. In Ireland, protesters reportedly sabotaged fields of genetically engineered potatoes, while French farmers staged a raid on a cache of genetically modified seeds. On a more positive note, the House of Lords European Communities Committee gave a green light for large-scale trials of genetically engineered crops, providing that proper regulatory safeguards were in place. Despite this announcement, there is still some resistance to the farming of herbicide tolerant and insect resistant crops in the United Kingdom.

Meanwhile, the U.S. saw a number of skirmishes in the Bt patent wars in 1998. Surprisingly, three courts decided that patents assigned to Mycogen Corporation, Monsanto Company, and Novartis Seeds, Inc. are invalid.

Courting Disaster
The first of these disarming decisions occurred in February 1998, when a jury in a Delaware U.S. District Court decided that two Bt patents assigned to Mycogen Plant Science, Inc. are not valid. The suit began in October 1996 when Mycogen claimed that Monsanto, Delta & Pine Land Co., and DeKalb Genetics Corp. infringed Mycogenís patents by marketing genetically engineered cotton, potatoes, and corn. The Mycogen patents claim methods for making synthetic Bt genes and using them to develop insect resistant plants and seeds. According to Mycogen's president, the patent claims at issue are merely a subset of broader claims contained in another patent that covers the process of making bacterial genes more plant-like. His statement might have referred to U.S. Patent No. 5,380,831, which is discussed below.

A June trial concerned Monsantoís patent infringement claims against the former Agrigenetics (now Mycogen) and the former Ciba-Geigy Seeds (now Novartis Seeds). The patent in dispute, U.S. Patent No. 5,550,365, names David A. Fischhoff and Frederick J. Perlak as inventors. The patent contains claims to methods of modifying Bt toxin genes to achieve higher levels of expression in transgenic plants. The jury of a U.S. District Court in Delaware decided that, although Agrigenetics and Ciba-Geigy Seeds had infringed Monsanto's method for making the synthetic Bt genes, the infringement was excused, which effectively neutralized the patent.

Finally, in November, a Delaware federal jury decided that a Novartis Seeds patent was invalid and not infringed by Monsanto and DeKalb Genetics, Inc. This lawsuit concerned U.S. Patent No. 5,595,733, which names Gleta Carswell, Christian Harms, Yin-Fu Chang and Mary-Dell Chilton as inventors. Novartis had charged that its patent covered all insect-resistant corn produced with Bt technology. This sweeping assertion is understandable in light of the broad language of the first and sole independent claim: "a method of controlling insect larvae comprising: (a) feeding the larvae an insecticidal amount of transgenic Zea mays cells containing an isolated or synthetic DNA which encodes a polypeptide having the insect toxicity properties of a Bacillus thuringiensis crystal protein, wherein the cells have been grown or cultured in a manner to permit expression of the toxin in the cells."

A contract dispute concerning Bt toxin technology was also the subject of a trial last year. In March, a San Diego Superior Court jury awarded $174.9 million in damages to Mycogen in a breach of contract suit against Monsanto. This case began in 1989 when Monsanto granted options to license technology, including Bt insect-resistance technology, to Lubrizol Genetics, which was subsequently acquired by Mycogen. When Mycogen tried to exercise the options in 1993, Monsanto refused and Mycogen sued. A year later, a San Diego Superior Court judge granted Monsantoís motion for summary judgment, which effectively upheld Monsantoís refusal. Mycogen obtained a reversal of the ruling on appeal, and filed the damage suit that led to the $174.9 million award for lost profits due to the lack of access to Monsantoís technology. Monsanto filed motions for a new trial or a modification of the jury verdict, but the Superior Court judge denied the motions last May. Placing a positive spin on thi!
s case, Monsanto noted that earlier the judge had denied Mycogenís contention that Monsanto must license to Mycogen genetically engineered germplasm containing Bt genes.

Battle Royal at PTO
Both the February and June trials raised the issue of the identity of the first party to express a Bt toxin gene in plants or to modify a Bt toxin gene for increased expression in plants. During the past year, Monsanto representatives have alluded to an ongoing interference procedure at the U.S. Patent and Trademark Office (PTO) that would determine the first inventor of the "basic Bt technology."

 An interference proceeding is required when two or more patent applications, filed by different inventors, claim substantially the same patentable invention. Since the patent rights of one party would interfere with the patent rights of another party, the PTO must determine who is the first inventor of a patentable invention and entitled to the patent. An interference may involve either two or more applications or one or more applications, and one or more patents. In an interference, the patentable invention is defined by a "count," which is similar to a patent claim. Each interference party must submit evidence proving when the invention, described by the count, was made.

Although the details of an ongoing interference are not open to the public, an issue arose in a Bt toxin interference, which was appealed to the Court of Appeals for the Federal Circuit. The published decision on this one issue sheds some light on the nature of the Bt toxin interference (1). In a nutshell, interference No. 103,781 began in November 1996 when the PTO declared a three-party interference between the following two patent applications and issued patent: 1) U.S. Serial No. 07/827,906, entitled "Improved Expression of Genes in Plants," filed by Kenneth A. Barton and Michael Miller, and assigned to Agracetus; 2) U.S. Serial No. 08/434,105, entitled "Synthetic Plant Genes and Method for Preparation," filed by David A. Fischhoff and Frederick J. Perlak, and assigned to Monsanto; and 3) U.S. Patent No. 5,380,831, entitled "Synthetic Insecticidal Crystal Protein Gene," filed by Michael J. Adang, Thomas A. Rocheleau, Donald J. Merlo, and Elizabeth E. Murray and assigned to!

The PTO devised a single count in the interference, which relates to a method for enhancing the expression of modified Bt toxin genes in plant host cells. That count read "A method of designing a synthetic Bacillus thuringiensis gene to be more highly expressed in plants, comprising the steps of: a) analyzing the coding sequence of a gene derived from a Bacillus thuringiensis which encodes an insecticidal protein toxin, and modifying a portion of said coding sequence to yield a modified sequence which contains a greater number of codons preferred by the intended plant host than did said coding sequence, or b) analyzing the coding sequence of a gene derived from a Bacillus thuringiensis which encodes an insecticidal protein toxin, and modifying a portion of said coding sequence to yield a modified sequence which contains a greater number of codons preferred by the intended plant host than did said coding sequence and fewer plant polyadenylation signals than said coding sequence!

Possible Heir to the Throne
Shortly after the declaration of the interference, Monsanto bought the plant biotechnology assets and related intellectual property of Agracetus. Monsanto wanted to continue the interference with both patent applications because it was not possible, at least at that time, for Monsanto to choose the best application for establishing priority of inventorship. This was because discovery had not yet been completed, and it was not clear what the final language of the count would be, or what evidence Mycogen would marshal to establish the date of invention. That is, Monsanto's dilemma was that the final count might be supported by one of its applications and not the other. Not surprisingly, Mycogen argued that Monsanto had sufficient information to pick one of the two commonly owned applications. The PTO agreed with Mycogen, but the Federal Circuit reversed the decision, explaining that the "three party" interference should continue until the PTO determines the final count and disco!
very is complete. The victor of this interference contest should have a dominating patent in its arsenal.

Even before the dust of the Bt patent wars has settled, a new contender has entered the fray. Researchers at the University of Wisconsin-Madison have announced the discovery of insecticidal toxins produced by Photorhabdus luminescens (2). Although a U.S. patent has not been issued on these new bioinsecticides, the UW group does have several international patent publications. An international patent publication from Bio Integrated Technology S.R.I (Italy) also concerns P. luminescens toxins and their use as insecticides. Is this the beginning of insect toxin wars: the next generation?

1. Barton v. Adang, 49 USPQ2d 1128 (Fed. Cir. 1998). A copy of this decision (No. 97-1491) is also available from the Federal Circuit web site (

2. See Bowen D et al. 1998. Insecticidal toxins from the bacterium Photorhabdus luminescens. Science 280:2129-2132; and Bowen DJ and Ensign JC. 1998. Purification and characterization of a high-molecular-weight insecticidal protein complex produced by the entomopathogenic bacterium Photorhabdus luminescens. Applied and Environmental Microbiology 64:3029-3035.

Phillip B. C. Jones, Ph.D., J.D.
Seattle, Washington

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