Old drugs, new tricks
What are off-patent drugs?In most countries a drug is ‘protected’ for 20 years under a patent. This means that from the point of the patent being granted, only the company holding that patent can produce the drug for agreed purpose. Once the patent has come to an end the drug becomes fair game. This means any company can produce it for the same purpose and the price of the drug consequently plummets. There is therefore little commercial incentive for a company to sponsor a drug to go through the licensing process, which is a requirement in order for a drug to be available on the NHS.
Off-patent Drugs Bill
Currently, there is no system in the UK to get old drugs re-licenced for new purposes without pharmaceutical sponsorship. This creates a barrier to potentially life changing treatments being made available on the NHS. But the Off-patent Drugs Bill could change that. There are a number of prospective MS drugs being investigated that fit into this repurposed, off-patent category. So it’s vital that this bill is passed to make drugs accessible as soon as the results are there to support their use for people with MS.
Examples on the horizon
Phenytoin has been used to treat epilepsy for more than 60 years. It stops sodium ions from entering nerve cells. In MS it is thought that this could protect nerves from damage. Positive results from a phase 2 trial testing the effectiveness of phenytoin as a treatment for optic neuritis have already been reported. The team behind the study measured the thickness of the retinal nerve fibre layer (the light sensitive nerves at the back of the eye) at the start and end of this trial to see if the nerves were being protected from damage. They found that people taking phenytoin had 30% less nerve damage. These results are promising and if confirmed with larger studies, could lead to the phenytoin being used as a neuroprotective treatment for optic neuritis and MS.
Fluoxetine is treatment for depression that is probably more familiar under its brand name - Prozac. More recently fluoxetine has hit the headlines as one of the three repurposed drugs being used in the MS-SMART trial which will be looking at 440 people with secondary progressive MS. Fluoxetine’s inclusion on this trial is based on some initial research which has shown a role in preventing inflammation of the nerves in MS.
Minocycline is an oral antibiotic used to treat acne or bacterial infections and it looks like it has anti-inflammatory properties that could be useful in MS. A phase 2 clinical trial involving 40 people with relapsing remitting MS tested the effects of minocycline as an add-on therapy to Copaxone. It showed that there was more than a 60 per cent reduction in new lesions in people taking the combination treatment (compared with those taking Copaxone alone). The MinoCIS, a larger, phase 3 clinical trial in Canada has recently been completed and the results are likely to be published soon.