The Hindu Business Line : Selection patent and its discontents

The inherent danger of granting selection patents lies in the fact that it is extremely difficult to get into the mind of the inventor and find out whether he actually knew when he made his initial disclosure that the invention was capable of having surprising advantages which could be claimed later as a separate patent.

Feroz Ali K.

The Madras High Court decision upholding the validity of Section 3(d) of the Patents Act 1970 will be remembered for its immediate impact on the patent application for Novartis’ cancer drug Glivec and for how the decision would eventually affect the availability of cheaper versions of patented drugs.

The decision struck down a challenge to Section 3(d) mainly on the ground that the said provision is arbitrary, illogical, vague and offends Article 14 of the Constitution.

With the appeal from the Controller’s decision now pending before the Intellectual Properly Appellate Board (IPAB), which has also run into troubled waters for entirely different reasons, the focus will now turn to how the patent office, IPAB and the courts will apply Section 3(d) in deciding patent applications. In the furore caused by the Madras High Court decision, the larger issues addressed by Section 3(d) and its impact on patenting pharmaceutical substances appear to have escaped our collective attention.

The mischief of interregnum

Section 3(d) was introduced to combat a problem that is particular to countries whose laws are in a state of transition pursuant to the obligations under the TRIPS Agreement.

Any country which undergoes a regime change, such as the transition from granting process patents for pharmaceuticals to granting product patents for the same, as has been the case of India, will need provisions such as Section 3(d) to prevent the mischief of interregnum.

As the patent office began to receive applications in its mail box soon after 1995, it was quite certain the pre-1995 molecules would be ‘tweaked’ and presented as a new molecule for the grant of a fresh patent under the new law. This phenomenon of making superficial changes to known inventions and presenting the same as a new invention is popularly known as ‘ever-greening’.

It is so called as it enables an inventor to extend the protection for an invention, time and again before the patent office, by showing minor improvements to the existing invention.

Ingredients of Section 3(d)

Section 3(d) prevents ever-greening of patents and enables inventors to obtain patents for incremental innovation, such as patents for a new form of a known substance if it can be shown that there is an enhancement of known efficacy.

Section 3(d) comprises three parts and one explanation. The section states that the following are not inventions within the meaning of the Patents Act:

The mere discovery of a new form of a known substance which does not result in the enhancement of the known efficacy of that substance [First Part]; or

The mere discovery of any new property or new use for a known substance [Second Part]; or

The mere discovery of the mere use of a known process, machine or apparatus unless such known process results in a new product or employs at least one new reactant [Third Part].

The explanation to Section 3(d) reads: “For the purposes of this clause, salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of known substance shall be considered to be the same substance, unless they differ significantly in properties with regard to efficacy.”

The Madras High Court decision was only concerned with the first part of Section 3(d) and its explanation. Novartis had submitted before the court that its case did not pertain to the second and third parts of Section 3(d).

A Pandora’s box is opened

The Novartis case illustrates the danger of receiving product patent applications while the country laws are in a state of transition. There existed a possibility that the applications preferred after 1995 would contain minor modifications of patents granted elsewhere in the world for molecules discovered before 1995.

It is a fundamental principle in patent law that what comes into the public domain shall not be offered patent protection.

This principle is reiterated in article 70.3 of the TRIPS Agreement which states that there shall be no obligation on India to restore protection to subject matter which on the date of application of the TRIPS Agreement (for India) has fallen into the public domain.

To get over this problem of an earlier invention (original invention) disclosing a latter invention (incremental innovation over the original invention), pharmaceutical companies rely on a form of patenting popularly known as selection patents.

The impact of Section 3(d) was fully revealed when Novartis made a submission before the Madras High Court (in its appeal against the Controller’s order which was later transferred to the IPAB) that the patent application for its cancer drug Gleivec was a selection patent.

Selection patents

It is widely acknowledged that selection patents represent a problematic area for patent law. Selection patents are employed for protecting particular compounds which are claimed to be individually new but fall within an earlier disclosure of a broader group of compounds for which protection is already claimed.

In other words, selection patents are patents for inventions based on a selection of particular compounds for a larger group which is previously disclosed in broad terms.

Though Novartis preferred an Indian application for a crystalline form of imatinib mesylate (Glivec) in 1998, imatinib as a free base molecule was invented by Novartis in 1992 and patented in the US in 1993. The 1 993 US patent of imatinib disclosed the salt imatinib mesylate. To circumvent the problem of earlier disclosure, Novartis claimed its 1998 Indian patent for a crystalline form of imatinib mesylate as a selection patent.

The latter patent was, in the terms of Section 3(d) of the Patents Act 1970, nothing but a new form of a known substance. Selection patents are more commonly employed in the field of chemical and pharmaceutical inventions. When a chemist discovers that a particular combination of molecules may produce a particular effect, he may extrapolate his initial discovery to assert that the same effect may be found in its variants as well. This kind of initial disclosure is known as a generic disclosure.

A selection patent is claimed when later discoveries show that some of the compounds which form a part of the generic disclosure have particular and surprising advantages over what was originally discovered. However, the law requires such surprising advantages to be non-obvious to a person skilled in the art.

Curiously, the problem imposed by selection patents goes beyond determining whether the earlier disclosure anticipated the latter invention (whether the selection patent lacked novelty) and whether the surprising advantage claimed was obvious (whether the selection patent lacked inventive step). Selection patents also encompass a mental element.

(The author is a Chennai-based advocate and the author of the recent book ‘The Law of Patents — With a Special Focus on Pharmaceuticals in India’.)

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