In its latest draft guidance, NICE said it is unable to recommend omalizumab for severe persistent allergic asthma in children aged six to 11 years.

Dr Gillian Leng, NICE’s deputy chief executive, said that available evidence demonstrated ‘no proven reduction in hospitalisation rates, accident and emergency visits, unscheduled doctor visits or total emergency visits for children in this age group treated with omalizumab’.

‘The [Independent Appraisal Committee] found that omalizumab is only useful in reducing the rate of clinically significant exacerbations for children who had had three or more exacerbations per year,’ she said.

‘We are unable to recommend that NHS funds be diverted to a treatment with such high costs which only provides very limited benefits for patients.’

Xolair’s manufacturer Novartis Pharmaceuticals said it was disappointed with NICE’s draft decision.

'Omalizumab is the first in a new generation of drugs for severe, difficult-to-control allergic asthma, where patients have an oversensitive immune system, and is already recommended by NICE for use in a high risk subgroup of patients aged 12 years and older,' a spokesman said.

Final guidance is due to be issued next month. In the meantime, children currently receiving omalizumab should have the opportunity to continue treatment until it is considered appropriate to stop.

Dr Mike Thomas, chief medical adviser to Asthma UK, said: 'Hundreds of children across England with the most severe, allergic asthma, will now be denied a pioneering treatment that could free them from crippling daily asthma symptoms, endless trips to hospital and huge amounts of time off school.

'As the Scottish Medicines Consortium has already approved omalizumab (Xolair) for use in children aged six to 11 in Scotland, patients will once again be faced with a treatment postcode lottery depending on where they live in the UK.

'For parents of children with severe asthma aged six to 11 who have already trialled Xolair and had their lives transformed, this news will come as a massive blow. It's vital that these children do not have the treatment withdrawn by PCTs as a result of the NICE decision, as this would be completely unjust.

'We will continue to fight for Xolair to be made available to people of all ages with severe asthma throughout the UK.'