The uncertain future of pre-natal diagnostic method patents

Prashant Reddy Thikkavarapu

The field of medical diagnostics has travelled a long distance over the last century. Starting with Roentgen’s discovery of clinical X-rays in the November of 1885 to the revolutionary Human Genome project which was completed in 2003, healthcare has witnessed nothing short of a revolution in the manner in which medical illnesses have been diagnosed and treated. A key beneficiary of these advances has been pregnant mothers, who now have a range of inventive diagnostics tools designed to test their foetuses with minimal risk to either the mother or the unborn child.

Like most other technologies, investment into researching new pre-natal diagnostic tools, depends on the degree of protection these tools will receive under patent law. Investors need to be assured protection for their investment. The decision of the Supreme Court in Mayo v. Prometheus (2012) which has made it difficult to patent diagnostic method patents has slowly begun to take its toll, especially with regard to pre-natal diagnostics.

In Mayo the Supreme Court had to walk a fine line between S. 101 & S. 102. While 101 deals with patentable subject matter, 102 lays down the criteria for determining the patentability of a subject matter found to qualify as patentable subject matter under S.101. Traditionally, the U.S. Supreme Court has given S. 101 a very broad interpretation and has gone far enough to say that anything under the Sun is patentable save for the laws of nature. This limited exception makes it particularly difficult to claim patents for diagnostic methods since most discoveries in this field are basically discoveries of laws of nature. More often than not this analysis straddles both S. 101 & S. 102, especially when Courts are trying to determine whether the claimed invention is adding anything to the laws of nature.

In a recent opinion, dated November 20th 2012, the CAFC applied the Mayo precedent, for the very first time, to invalidate US Patent No. 6,573,103 in the case of PerkinElmer Inc. v. Intema Ltd. The patent in question claimed screening methods which would help diagnose the risk of fetal Down’s syndrome by contrasting particular markers from the first and second trimesters of pregnancy along with the differences in ultra-sound scans.

Yet another series of lawsuits regarding pre-natal diagnostics tools to diagnose Down’s syndrome, involves Sequenom’s patent no. 6,258,540. This patent diagnoses the existence of Down’s syndrome by analysing foetal DNA in the mother’s blood. Heralded as a path-breaking diagnostic tool, there is considerable pending litigation over this patent involving several parties. At least one such lawsuit filed by Ariosa Diagnostics Inc. against Sequenom, seeks to invalidate the ‘540 patent on the basis of the Mayo precedent.

Patent law is not the only area of uncertainty when it comes to diagnostic method patents. The code of ethics prescribed by the American Medical Association (AMA) continues to prohibit physicians from patenting medical procedures and methods. The AMA has previously climbed down from its prohibition against its members patenting medicines, surgical instruments and it remains to be seen whether it will climb down from its opposition to patenting of medical procedures.

Irrespective of the opposition to the Supreme Court’s decision in Mayo and the position of the AMA, policymakers have to eventually start dealing with the issue of incentivizing innovation in the medical diagnostics field in a post- Mayo world, else we risk investors either pulling out of the field or more tragically, postponing the public disclosure of path-breaking discoveries until they can figure out a way to translate such discoveries into patentable subject matter.

Prashant Reddy Thikkavarapu is an LLM student at Stanford Law School and one of our four student fellows this year at the Center for Law and the Biosciences