Understanding the synthesis of analogues and SARs

Me-Too Medicines

The successful progress in treating several diseases has led to the development of a pharmaceutical industry with an estimated market of around £1 trillion (that is £1,000,000,000,000; to help give a sense of what this number equates to, 1 trillion seconds is 30,000 years!). Marketing pharmaceuticals has become a major business and consequently, it has adopted the rules common to other commercial fields.

The huge market for medicines has lead to a competition among pharmaceutical firms – as soon as a prototype drug becomes available several other similarly active compounds immediately follow, called ‘me-too’ medicines or drugs. Me-too (or ‘copy-cat’) medicines have an identical mechanism of action to the original prototype, and there are only minor differences in the way the medicines work and are processed by the body.

This increasing marketing of me-too drugs has been questioned, so pharmaceutical firms are justifying the development of not-so-innovative medicines. Arguments include: me-too drugs offer an improvement on the effectiveness (efficacy) of the prototype; they show a different profile of adverse effects; they are effective against bacteria resistant to the prototype; they improve compliance in long-term treatment; they are less expensive than the prototype.

But, are me-too medicines justified? Do they diminish the incentives for innovation in pioneering medicines without adding therapeutic value? Or, is increased choice between medicines valuable, keeping prices down, particularly for patients for whom the pioneer medicine is ineffective or entails undesirable side effects?

Drug development – from medicinal chemistry to process chemistry

We have seen that small changes in the structure of a penicillin can have a significant impact on its biological properties i.e. whether groups are electron-donating or withdrawing (we call these electronic effects) or whether the groups are small or large in size (we call these steric effects). In a pharmaceutical company, this work will be undertaken by a medicinal chemist who aims to identify the essential features of a compound that are required for the desired biological activity. Once the structure of the drug is optimised the project passes on to process chemists who make the compound in suitable quantity and quality to allow large scale animal testing and then human clinical trials. So, chemistry plays the most critical role in the drug development process, bolstering the growth of the pharmaceutical industry. (Our MChem students at York have the opportunity to explore sustainable practices in process chemistry, through a miniproject developed with AstraZeneca.)

Film makers and fiction writers have been attracted to the subject of drug discovery – remember Sean Connery in Medicine Man, Harrison Ford in Extraordinary Measures, Will Smith in I am Legend, Anne Hathaway in Love and Other Drugs and/or Robert De Niro in Awakenings? What are you favourite science-based movies, television shows or fiction books?