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GP Dispensing: What happens when a patent expires

Be ready for changes in cost and availability as drugs come off patent, advises Dr Kerry O'Connor.

The life of the patent for a branded drug starts as soon as the patent is filed. The World Trade Organization norm of 20 years applies in the EU (plus up to five more years with a Supplementary Protection certificate). However, after research and development, and trials before a drug is launched on the market, the effective patent is more likely to be between seven and 12 years.

It is hardly surprising that pharmaceutical companies go to great lengths to prolong their patents, and thus preserve revenues.

Extending patents
A patent can be lengthened by introducing a new formulation for the brand, or an isomer - sometimes backed by withdrawing the original brand just prior to patent expiry - or developing a new production method. But when loss of patent protection does become inevitable, the pharmaceutical company may opt to join the rest and produce the generic themselves - hence some generics have the brand company's name on the box.

On the other hand, it is not a certainty that a generic product will be available instantly, if at all, when a patent ends. If the drug is a low-volume, high-cost, specialised drug or would not be economical to emulate, generic producers may not bother. The situation is not the same with 'blockbusters' - generic versions of Zocor (simvastatin) were available within hours of the drug coming off patent in 2003.

Pharmaceutical companies take the long view on their brand sales, and the pricing lifecycle mirrors the brand sales lifecycle. This will vary with each product, but there are a number of stages that most will go through. The introduction of the branded drug will be followed by a slow climb in its use. There may even be an increase in price after a while, but this must have government approval. There will then be a steeper climb in its use which will then plateau. Eventually, the drug's patent will expire and, once generic versions are introduced, use of the branded drug will decline.

Often as the patent expiry approaches, the company will cease to promote the product completely. And the pharmaceutical companies will see their share prices and future income becoming vulnerable as patent expiry draws nearer. This can be critical for smaller pharmaceutical companies.

If a patent expiry has just happened or is imminent, the brand may still be cheaper than a generic, but primary care organisation (PCO) advisers do not always recommend using the brand. Dispensing doctors should monitor the price, and alert the PCO adviser if the brand costs less. Remember to ask generics representatives about what is in the pipeline.

Dr O'Connor is a dispensing GP in Salisbury

Drugs to watch
Branded drugs due to come off patent

Risperidal in December 2007
Aricept in June 2008
Lescol in August 2008
Naramig in August 2008
Avandia in August 2008
Efexor in December 2008
Famvir in December 2008

Preparing for a patent expiry
The UK patent for Risperidal (risperidone), a low-volume, high-cost drug expires 7 December. The release of generic risperidone is expected this month. Dispensing GPs should keep an eye on developments and follow these guidelines:

  • Don't buy in too much stock.
  • When the generic version becomes available, continue to prescribe your existing stocks of branded drug by name - unless it is cheaper than the Drug Tariff Price, which is unlikely.
  • Switch patients to the generic, once you have checked that it is actually cheaper, giving a significant cost saving for NHS.
  • There may not be generic versions of all formulations - for Resperidal there are 12 oral formulations. Generic companies tend to stick to straightforward production, making and packaging big volume lines. Melt-in-the-mouth, modified-release versions may not be available.
  • It is not wise to prescribe a mix of branded and generic drugs.
  • When dealing with drugs like risperidone, which is initially prescribed by a psychiatrist, control of initiation of prescribing may not be in the hands of the GP.
  • Given the nature of the illness treated by risperidone, patients and their carers may need extra reassurance about any switch.
  • Currently all Resperidal formulations are in Category C. If a generic version does become available in December it may be in time for the 1 January Category M list so look for it late December on PPD or PSNC or DDA websites. Don't stock up if the price will fall.

The DDA is the only organisation that ensures the views of dispensing practices are heard by the government and key negotiating bodies. We also provide telephone advice to members and essential updated information via our website, and email alerts.

To find out more call Jeff Lee on (01751) 430835 or visit www.dispensingdoctor.org.uk

The DDA does not necessarily support or endorse the opinions or information contained on this page.

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