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4-Patents: Questionable RNA antisense patent boosts Isis stocks



----------------------------- GENET-news -----------------------------

TITLE:  Questionable RNA antisense patent boosts Isis stocks
SOURCE: PATNEWS, USA, by Gregory Aharonian
        patent-news@europe.std.com
DATE:   March 3, 2000

-------------------- archive: http://www.gene.ch/ --------------------


A biotech patent lawyer sent me the following news item, with his 
commentary questioning the validity of a biotech patent that will be 
played with in the stock market.

                              =====

Greg,

BioWorld Today reported that Isis Pharmaceuticals Inc. saw its shares 
jump nearly 16 percent Tuesday after disclosing it had received a 
U.S. patent for a key enzyme related to antisense technology.

This apparently relates to US Patent No. 6,001,653, titled Human Type 
2 RNAse H, a patent on purified Human RNase H1, a cellular enzyme 
that degrades RNA and DNA duplexes. Isis claims the patent covers 
most antisense drugs currently in development as well as the use of 
antisense technology to identify gene function and validate drug 
targets.

Stanley Crooke, CEO for Isis: "The patent is very broadly enabling 
and solidifies our dominance in antisense, and we will aggressively 
pursue the opportunities it presents us."

According to BioWorld, the patent covers the DNA sequence for Human 
RNase H1 as well as vectors and cells containing this DNA sequence 
and probes to hybridize to the gene or mRNA. The patent includes 
claims covering methods of making any antisense drug or inhibitor 
using or relying on the RNase mechanism and specific chemical classes 
of antisense drugs that work by this mechanism.

                              =====

[I'll spare you the self-serving puffery from the pump-and-dump 
Streeters.]

I think we have the makings of another PTO fubar story here. The 
claims that are probably most important to the antisense community 
(if there really is such a place) are 11 and 12:

11. A method of making an antisense oligonucleotide which is cleaved 
by the human Type 2 RNase H polypeptide (SEQ ID NO: 1) comprising 
synthesizing an oligonucleotide which is targeted to a selected RNA 
wherein the antisense oligonucleotide, when hybridized to the 
selected RNA target to from a duplex, will bind the human Type 2 
RNase H polypeptide and thereby cleave the duplex.

12. A method of screening oligonucleotides to identify effective 
antisense oligonucleotides for inhibition of expression of a selected 
target protein comprising: (a) contacting the human Type 2 RNase H 
polypeptide (SEQ ID NO: 1) with an RNA encoding the selected target 
protein and an oligonucleotide complementary to at least a portion of 
the RNA under conditions in which an oligonucleotide-RNA duplex is 
formed; (b) detecting cleavage of the RNAof the oligonucleotide-RNA 
duplex wherein cleavage is indicative of antisense efficacy.

In my opinion, these claims could be read to cover the use/
development of any antisense compound, since Type 2 RNAse is present 
in all cells. BUT THIS RNAse AND ITS MECHANISM OF ACTION WERE ALREADY 
KNOWN TO THE PUBLIC AS ADMITTED BY ISIS AT COLUMN 3, lines 25. Isis 
only provided a cDNA clone!! See, Column 3, lines 40-42.

So, how can Isis claim the use in wild-type cells when they only 
provided cDNA of a known substance?? HEL-LO PTO!!

Stay tuned. I'll bet big pharma is polishing its brass knuckles as we 
speak.

Greg Aharonian
Internet Patent News Service

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