Searching Patents for Medicines

25 May 2011

Introduction

If you are on an expensive brand name drug, the chances are that the basic ingredients and / or their processes of making are patented. And if you are required to regularly take such life-saving drugs; again chances are that you have already learnt the difference between the patented drugs and their generic versions which are many times more affordable. Well, if you're taking an expensive brand-name drug and just do not know if a generic copy of it is available, you can check up with your doctor who would probably know. If not, however, you can look it up online at sites such as www.destinationrx.com. You can easily find an available generic version of the drug in which you are interested or of another patented drug in the same class that works equally well.

What is the difference between 'patented' and 'generic' drug? A patented drug is usually the original drug discovered and developed by research-oriented pharmaceutical company. Such a new drug is invariably marketed after patent protection has been sought. Patent protection ensures for the company a virtual monopoly for about 20 years (to help recover its investment on developing the drug). Patent protection, however, is not a necessary condition to put the drug into the market but more of a commercial prudence. It is, however, necessary to get necessary clearance for marketing from the Government by providing required safety and clinical data. In US, the Department of Food & Drug Administration (FDA) is the concerned Government agency to which the drug manufacturers submit a 'New Drug Application (NDA)'. Once the FDA is convinced about the drug's safety, the company is allowed to market its product under a desired 'brand name' till the drug's patent is valid.

Generic drugs are essentially equivalent to patented drugs that have gone off-patent or where there is no patent protection available to the original drug. They have the same active ingredients, dose, dosage forms etc. and are bioequivalent. Thus, drugs that were once on patent can have generic versions no sooner the original ceases to be under patent protection. The generic drugs work much the same way as original and have similar therapeutic properties but are relatively quite cheap since generic producers do not have large enough initial investments and usually work under market competition.

The Big News

The big news is that the biggest generic switch from the patented drugs is just about to come as an unprecedented wave very soon. A number of prescription-drugs that were patented in 1990s by pharma majors are about to go off patent. Generic producers all over the world are just getting ready to take the plunge not just in countries like India but in many developed countries as well. It is reported that Japanese companies are getting ready to enter the generics market in a big way. Indian pharma companies are also hoping to suitably benefit by joining hands with their Japanese counterparts in this game under the new trade agreement taking shape currently between the two countries. A recent survey report from Reuters also predicts a wave of mergers and acquisition in the pharma sector among the top global pharma producers in the wake of developing situation around the exploding generics market.

The best-selling prescription medicine, Lipitor of Pfizer which is used for lowering the cholesterol level, will soon lose the patent protection clearing the way for host of generic producers to produce quite legally inexpensive copies. The proportion of generic drugs versus patented drugs in your daily dose has, in fact, been steadily climbing up for several years now. But in the next couple of years it is predicted to jump several notches up. Lipitor is not the only big-selling brand that will go generic soon; there are many others such as Plavix, a blood thinner, and Actos, for diabetes etc.

Medicines in Patent Databases

Searching patents and related information on medicines is not only of interest to scientists, patent consultants and examiners but also to health authorities in many developing countries who are required to procure sizable quantities of various medicines for their in-country public health programmes. They are invariably compelled to search for cheaper but equally potent versions of the known drugs, due to limited budgetary resources, from all around the world without the risk of patent infringement. This is easier said than done, mainly because the commonly known drugs are rarely described by 'brand names' in the patent literature. Moreover, as is often the case, one single medicine may be protected under several different patents. Identifying and matching patents available in various free databases even with known generic names of branded drugs is generally non-obvious and one has to learn the art of getting around this problem. This knowledge and access to up-to-date patent information can also help countries to exercise the flexibilities available under TRIPS on compulsory licensing and / or promote their local generics industry.

A drug generally has three categories of names:

  1. Chemical name: It is the IUPAC name of the drug that describes the substance chemically. Example: Acetyl salicylic acid.


  2. International non-proprietary name (INN) / generic names: It is the name accepted and approved by the World Health Organization. It has been preferred for the main title of a new drug substance over other names. Example: Aspirin is generic name for Acetyl salicylic acid.


  3. Proprietary name / brand name: It is the name assigned by the manufacturer as a 'brand name' of the drug for marketing purposes, which could as well be a registered or unregistered 'Trademark' of the drug. Thus a generic drug with a single universally valid specific INN approved by WHO may have multiple proprietary names representing different formulations from one producer or similar and equivalent products from different producers.

To illustrate the above point, it may be pointed out that the popular drug sold under the brand name 'Dispirin' has its generic name as 'Aspirin' and a chemical name under the IUPAC system as 'Acetyl Salicylic Acid'. Since most medicines are generally based on new chemical entities (except the biological), they tend to be described in various databases with their chemical names and also with generic names when available and would perhaps never be mentioned with their brand names. Hence the trick lies in finding out first the equivalent generic and chemical names of the expensive prescription-drugs that are under patent protection.

A guide to patent searching in medicines brought out recently by WHO provides a clever solution to this complex problem of identifying and matching patents in databases with branded drugs of interest. Since, USA continues to be the most important market for all new drugs that usually would be among the first few countries where an innovator company of a new drug would obtain both marketing permission and the patent protection. As already mentioned above, in US, FDA is the agency which grants the use and marketing of a new patented drug, a reference to its 'Orange Book' has been suggested as the first step. Like 'Orange Book' of US, the 'Patent Register' of 'Health Canada' is another important and similar source for such information in next door Canada.

All new drugs that are approved for marketing in the United States have to be necessarily listed in the 'Orange Book'. The companies seeking to market new drugs are required to provide information regarding relevant patents and their expiry dates along with the new drug applications (NDAs). If some patents are not granted till the time of submission of NDA, they could be submitted within 30 days of the issuance of the patents.

In Canada, however, submission of patent information is optional for the originator company to submit along with filing of New Drug Submission (NDS) or Supplement to New Drug Submission (SNDS). Most often, however, companies use their discretion to have their patent listings in Patent Register of Health Canada which they are required to submit within 30 days of patent issuance.

Both FDA's 'Orange Book' and Patent-Register of Health Canada are incidentally online and one can search required information freely. Both these resource, therefore, are extremely useful as starting points, even though these databases are far from comprehensive for searching a complete inventory on any medicine. Both these allow searching through various fields, most importantly through 'active ingredient', formulation, composition and provide relevant patent data. The Patent-Register of Health Canada also provides information on 'biological' products used as medicines.

The FDA's 'Organge Book' and the 'Patent-Register of Health Canada' can be accessed from here by clicking on the relevant links. One can easily find the relevant patent numbers for an 'active ingredient' of interest in either of the databases, provided it is listed there-in. Along with relevant patent information, one can also find the patent-expiry data. Heath Canada's Patent-Register gives an option to choose the generic name of the active ingredient from a drop down menu and also provides an option to search by 'brand name' as well as 'patent number', if known.

If the above exercise does not result into achieving the objective or is only partially successful, one would be required to search patents in the usual manner through key-word search or through 'inventor', 'assignee' and 'international patent classification' etc. After one has identified relevant patents through any of the above means, one may be required to download full-text pdf files of the patents. Following are the prime sources to locate these patents through 'number search' and download the full-text patents.

    United States Patent and Trademark Office (USPTO)

    Canadian Intellectual Property Office (CIPO)

    European Patent Office (EPO), [email protected]

Another useful source for downloading full-text pdf files of known patents besides extensive search from US, WIPO and European databases is 'FreePatentsOnline.com'. It's active link and search window is provided at the end of this article.


Expanding / Narrowing the Scope of Search

It must be realized that patent searching is essentially an iterative process that must be continually repeated to include newer patents in the inventory. While it is important to look for all new patents coming into the fray, many of which can be easily located through the known 'generic names' without much difficulty, it goes without saying that the task remains incomplete and virtually meaningless unless the key initial patents are identified on which the originator company based its production and marketing. In this respect, the teaching of the above WHO guide assumes great significance.

As an example, the guide helps locate the initial patents for 'abacavir', an HIV drug. The very first patent in this series is US5034394 (23 July 1991) of Burroughs Welcome under the title of 'Therapeutics Nucleosides' which is a key patent with a few others. The generic name 'abacavir' for a group of nucleosides under the IUPAC system was not known when the product was launched. One of its formulations is sold under the brand name 'ziagen' in the US ascribing the generic name 'abacavir' in the parantheses. The drug for its therapeutic use as well as its chemical composition is now fairly well known by its generic name 'abacavir', so that one can easily find thousands of patents which mention 'abacavir' as a reference in their description. But there is no way, one can find the above key patent by searching on 'abacavir'.

Stretching the above argument a little bit, one can also find some US patents with the term 'abacavir' in their abstracts but the earliest of these patents is US6514979 (04 Feb. 2003) of University of Maryland investigating synergistic combinations with 'abacavir'. A few other patents are as late as the year 2009. It must be noted that these patents refer to new research on the same molecule and identify it by the 'generic name' almost after more than 15 years, the drug was introduced. The thousands of other patents which cite 'abacavir' have all come much later and refer to it for various reasons.

Further Reading

    How to conduct patent searches for medicines: a step-by-step guide : WHO - 2010

    FreePatentsOnline.com

    Advanced Patent Search