A last-chance drug that can lead to an "unprecedented" reduction in lung cancer tumours is now available on the NHS.
Tagrisso (osimertinib) was granted a licence only in February and has been hailed as a "breakthrough" drug by manufacturer AstraZeneca.
The once-a-day tablet is suitable for patients with non-small-cell lung cancer who have a specific mutation that means they have stopped responding to earlier treatments.
Experts predict around 300 patients in England and Wales will be eligible for Tagrisso every year.
The National Institute for Health and Care Excellence (Nice) has issued final draft guidance that says Tagrisso should be made available through the Cancer Drugs Fund (CDF), after a financial agreement was reached with AstraZeneca.
The drug will be available immediately as a second-line treatment for people with advanced non-small-cell lung cancer that has a specific mutation, known as EGFR T790M-positive.
Professor Carole Longson, director of the health technology evaluation centre at Nice, said the drug was being made available while clinical trials continue to assess its full effectiveness. It is the first drug to be approved under the updated CDF.
She said: "People with this particular type of lung cancer usually have distressing symptoms and their disease can progress very quickly.
"Osimertinib is clinically effective in the short term. However, we do not have the full picture yet and we need more information on its long-term benefits to find out if it is truly cost effective.
"For the first time, we are able to give patients access to a promising new cancer treatment whilst more evidence is gathered on its effectiveness. This is the system working as it should."
Pooled data from phase 2 clinical studies involving 411 people who had failed on prior treatment found the patients typically lived for 11 months without their disease getting worse.
Some 66% of patients experienced a reduction in the size of their tumours, while six out of 397 patients experienced a complete response - meaning experts could find no evidence of disease.
Overall, almost twice as many patients responded to the treatment compared with another chemotherapy, and the drug stalled progression of the cancer by an extra four months.
Dr Alastair Greystoke, senior lecturer in medical oncology at Newcastle upon Tyne Hospitals NHS Foundation Trust and clinical investigator for the drug, said: "This is a turning point in the treatment of EGFR T790M mutation-positive non-small-cell lung cancer, and very welcome news for a group of patients with limited options.
"Two-thirds of patients have a good reduction in the size of their tumours with an accompanying improvement in their symptoms, which is unprecedented for patients at this stage of their disease."
Lisa Anson, country president for AstraZeneca UK and Ireland, said: "We are very proud that NHS patients in England now have access to osimertinib. This is a breakthrough medicine with one of the fastest development programmes in pharmaceutical history.
"Now it is the first medicine to enter the newly reformed Cancer Drugs Fund, which is specifically designed to ensure earlier access to breakthrough cancer treatments."
The cost of the drug agreement with AstraZeneca is being kept confidential, Nice said. Without the agreement, it costs £4,722.30 per pack of 30 80mg tablets.
Paula Chadwick, chief executive of the Roy Castle Lung Cancer Foundation, said: "Osimertinib represents a new option for hundreds of patients who have this specific form of lung cancer.
"This new type of targeted therapy is an exciting development in the treatment of lung cancer. For many of our patients and their families this is a breakthrough moment - a recognition that these new medicines can truly benefit people with an advanced form of the disease.
"We welcome the announcement - it is good news for patients with the appropriate type of lung cancer. We hope this paves the way for further positive decisions for lung cancer patients across the UK."