The step of identifying an initial lead drug candidate is the cornerstone of the drug development process and is also usually the point at which actions are taken to protect the associated intellectual property (IP). However, is this the best time to be filing patent applications? What other factors need to be taken into account when an IP strategy is being developed?
The drug development process is a long and complex journey that typically begins with basic research and culminates – if successful – in a new drug that is effective in the treatment (or prevention) of a disease.
In this article, we will focus on the initial stages of the drug development process – the identification of a target, and the subsequent lead identification and medicinal chemistry program – with a view to drawing out some aspects of patent protection that may be useful to consider at this stage.
BC (Before the Chemists)
Prior to screening libraries of compounds and/or conducting in silico studies to identify suitable chemical (or biological) leads, the mechanism of action of the disease of interest is studied and reviewed. The aim of this step is to elucidate the target for the treatment (e.g. a receptor).
If the identified target is new (i.e. it has not been previously discovered that receptor X can be targeted to treat/prevent disease Y), it can be tempting to file a patent application to protect this discovery.
At this stage it is worthwhile considering the scope of protection that you will be able to obtain. For the typical “inhibitor of receptor X for the treatment of Y” claims, you will need to include examples of many different inhibitors to obtain a claim that is not restricted to particular inhibitors of receptor X. In addition, for any identified inhibitors, you will most likely be restricted to the specific compounds tested, unless you have prepared and tested a number of analogues of those compounds.
Other relevant considerations at this stage of the drug development process include whether:
It is important to recognize, however, that this is the stage at which many researchers are keen to find a commercial partner to provide the funding and expertise necessary to help in the identification of a drug candidate. One option may be to prepare a provisional application, which is never progressed, but which serves as a starting point for initiating confidential discussions with a potential commercial partner. This approach has a number of advantages for both parties, including: bringing focus to the discussions (both parties know what is on offer); identifying clearly who owns the initial IP (and what that initial IP is); and making the foundation of the collaboration clear.
AD (At compound Discovery)
Once a target has been identified, the next stage typically involves conducting in silico studies and/or screening compound libraries to find initial lead candidates. One or more suitable lead candidates are then selected, based on factors such as whether they satisfy the “rule of five”, have appropriate selectivity for the intended target, are relatively simple to synthesise, offer diverse routes for multiple chemical modifications, and, ideally, already have information on pharmacokinetic properties, showing that they are within a reasonable range of bioavailability and half-life.1
Following lead selection, a medicinal chemistry program is initiated to find a compound that can fulfil a number of criteria, particularly the following: satisfies basic needs of future manufacturing and storage, produces the desired pharmacologic effects on the target and in animal models of the disease (with a route of administration and frequency of dosing commensurate with practical use in humans), and does not produce any obvious signs of toxicity that would preclude its use in humans.2
While the identification of one or more lead candidates is generally considered to be an optimal time to pursue IP protection, the following may be useful to keep in mind at this critical stage of portfolio development:
With regard to the last point, splitting the compounds into separate applications may be useful where you foresee that different compounds (or different groups of compounds) may have slightly different uses, or where they solve slightly different problems, in a way that means that different commercial partners may be interested in the different compounds. It may also be a case of ensuring that your earlier applications do not affect the validity of your later-filed applications – having narrowly-defined disclosures can be very beneficial in this regard. Another advantage of having separate applications is that each application can be the subject of a separate extension of term, which may afford you a longer term of patent protection for the different groups of compounds, than if all of the compounds were bundled into the one application.
We hope this article has provided you with some useful insights into how best to protect your IP at this critical stage of drug development. It is tempting at an early stage in the drug development process to attempt to capture all of your IP in a patent, or a number of patents. However, a more measured approach can avoid “shooting yourself in the foot” in respect of protecting future developments, and is by far the better commercial strategy.
1 Hefti, F.F. (2008) BMC Neurosci, vol 9 (Supp 3), S7