Drug companies producing some treatments for epilepsy will have less scope to compete in the UK following new guidelines launched by the national medicines regulator.
The Medicines and Healthcare products Regulatory Agency (MHRA) has ruled that some anti-epileptic drugs should not be substituted, in a highly unusual exception to conventional international rulings.
The general practice in the UK and many other countries is to seek to maximise competition and reduce prices by encouraging doctors to prescribe drugs by their generic name rather than the brand of the original producer. Additional incentives allow pharmacies to “substitute” branded drugs for cheaper alternatives.
But a growing body of research has suggested that patients with a few medical conditions including epilepsy can prove extremely sensitive even to tiny changes in the formulation or concentration of their treatment.
An MHRA spokesman said: “The lack of robust evidence of harm does not exclude the possibility that significant harm may sometimes occur.”
It comes at a time of debate over “biosimilars”, or generic versions of complex large biological-based molecules, which have modest differences but which regulators in the European Union have already started to approve and are under consideration by their US counterparts.
EU authorities have argued that generic competition and substitution is possible between rival producers of biological medicines once products come off patent, but that they should be identified by brand names in the event of any safety concerns from individual producers. They have also required higher testing standards than for “small” chemically-based generic drugs.
The MHRA last week issued guidance that for four anti-epileptic drugs – phenytoin, carbamazepine, phenobarbital and primidone – patients should normally be maintained on a specific manufacturer’s product.
The National Health Service paid approximately £25m for prescriptions of the four drugs last year, all of which are generic. Amanda Cleaver from the Epilepsy Society said: “Consistency of supply is a really important issue for people with epilepsy.”
The regulator said a second category could be switched based on clinical judgment, while a third category – including levetiracetam, lacosamide and tiagabine – could be substituted.
Simon Wigglesworth, deputy chief executive at Epilepsy Action, called for tougher controls on switching of the latter category. He said: “We are surprised and disappointed that this decision has been taken without wider consultation. We have major concerns about the introduction of category three of this guidance. We would ask that the MHRA suspend this category, pending wider consultation on the evidence that its introduction is based on.”
Teva, the world’s largest generic drugs manufacturer, said it did not expect any significant financial impact from the ruling, because it produced a wide range of different anti-epileptic treatments.
It said it was glad that the guidelines did not discriminate against generic versions – which might equally be the drug initially prescribed by doctors – but rather ruled against the substitution of drugs.