On June 13, 2013, the Supreme Court of the United States unanimously held in that 1) naturally-occurring DNA sequences are not patentable, even if they have been isolated from their natural environment, and 2) sequences of complimentary DNA (cDNA) are patentable

The Court’s recent decision in Ass’n for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. ____ (2013) is significant because a long-lived cloud of uncertainty on this issue is now lifted.  The Court’s decision finally provides clarity for biotechnology, healthcare, and related businesses as they plan for the future.  It also generates an opportunity, indeed, an urgency, for companies that either hold patents on cDNA or naturally-occurring DNA or whose activities would potentially infringe such patents, to reevaluate their business plans. 

What Is Patentable?

cDNA sequences are patentable subject matter.  A brief overview of some biological processes will help explain what cDNA actually is and how it differs from native DNA. 

Eukaryotic cells (e.g., human cells) use their DNA to, among other things, make proteins.  In this process, one strand of the native double-stranded DNA is “transcribed” into a complimentary RNA chain.  Parts of the RNA chain (called introns) are cut out of the RNA chain and the remaining portions (exons) are spliced together.  It is loosely comparable to the process of physical film editing.  Introns are the outtakes and exons are the final cut.  A few other modifications are done to the ends, similar to adding the film’s opening sequence and ending credits.  The final product is called mRNA.  The primary purpose of most mRNA is to be subsequently “translated” into a chain of amino acids (called a protein).  However, innovators, such as the inventors of the patent at issue in Myriad, have developed other uses for mRNA.

mRNA can be converted to a form that is more stable and useful in a laboratory (e.g., for diagnostic testing, as in Myriad) through a process known as reverse transcription.  Reverse transcription builds a DNA chain that is complimentary to the mRNA, hence the name cDNA.  Consequently, cDNA differs from native DNA from which it was derived because cDNA is missing the portions corresponding to the introns that were removed during the production of the mRNA.  Other than the fact that cDNA is missing something, there is nothing structural that necessarily differs between cDNA and native DNA. Thus, cDNA is defined not by its particular structure but rather the source from which it originates. 

According to the Supreme Court, “cDNA is patent eligible because it is not naturally occurring.” 

The Court’s ruling specifically did not reach 1) method patents involving DNA sequences, 2) specific applications of DNA sequences, and 3) otherwise natural DNA sequences that have been modified such that they are no longer found in nature.  For now, it appears that each of these is still patentable subject matter.

What Is Not Patentable?

DNA sequences that occur in nature are not patentable.  Myriad and various amici attempted to convince the Court that isolated DNA should be patentable.  Focusing on the way the DNA was used to detect the BRCA1 and BRCA2 genes, the Court reasoned that “Myriad’s [isolated DNA] claims are simply not expressed in terms of chemical composition, nor do they rely in any way on the chemical changes that result from the isolation of a particular section of DNA.”  In other words, the Court found unmeritorious Myriad’s contention that the process of isolation was an inventive act because of the changes the isolation imparted upon the DNA.  Rather, the Court held, Myriad’s “claim is concerned primarily with the information contained in the genetic sequence,” which is the same whether the DNA is in a native or isolated form.

While the Court did not address prokaryotic (e.g., bacterial) genes, an additional implication of this decision is that no naturally-occurring prokaryotic genes are patentable.  Since prokaryotic genes do not have introns and exons, there is no way to define cDNA for a prokaryotic gene that would be analogous to the eukaryotic cDNA that has now been carved out as patentable subject matter. 

What Does This Mean?

The Court has drawn a line between cDNA and naturally-occurring DNA.  Since the latter is unpatentable, there are many issued patents that contain claims that could be invalidated if challenged.  Companies that were previously forced to work around such patent claims should analyze whether they can now operate with more freedom.  Companies that own and have relied on such patents as assets should reconsider the value of those assets and consider revising their strategy going forward to direct business-driving innovation toward patent-eligible subject matter, such as cDNA, methods, applications, and modifications to naturally-occurring DNA.