Breast cancer drug tyverb has now been made available for private prescription in UK. The National Institute for Health and Clinical Excellence (Nice) will assess it later in the year before deciding if patients can get it on the NHS.
This follows in the wake of the drug's receiving European licence, British media reports say.
Tyverb, also called lapatinib, can prolong the lives of women suffering a type of advanced breast cancer by stopping the disease from growing.
Around a quarter of women with breast cancer are diagnosed with the HER2-positive form of the disease. Jane Emily Tomlinson
, prominent amateur English athlete, was denied access to the drug, generating a huge debate last year.
Tomlinson, an iconic figure, raised Ģ1.75 million for charity by completing a series of athletic challenges, despite suffering from terminal cancer.
She had treatment for breast cancer in 1991, aged 26, but the disease returned in 2000 throughout her body. During the next six years, Tomlinson completed the London Marathon three times, the London Triathlon twice, the New York Marathon once and cycled across Europe, the United States and Africa. Jane Tomlinson died in 2007, aged 43.
Under the expanded access programme, tyverb was made available before licensing to eligible women in areas where the primary care trusts signed up for it.
But Mrs Tomlinson had to travel from their home in Leeds to Nottingham to receive the drug because the Leeds Teaching Hospitals NHS Trust did not join the programme.
Her condition had seriously deteriorated during the three-month delay.
Her husband Mike said last October his wife had found it "distressing" that she could not get easy access to lapatinib before her death in September.
The most common side effects of lapatinib are diarrhoea and nausea, although some liver problems have been reported which were investigated by the European Medicines Agency before licensing.
A GSK spokesman said its own safety review resulted in data showing a 'rare' incidence of 0.4 per cent of liver problems in users, which were picked up by routine monitoring and resolved after patients stopped taking the drug.
Simon Jose, general manager of GSK UK, said 'The launch of lapatinib as an oral combination with capecitabine gives patients the benefit of having their treatment at home and a new treatment option.'
Pamela Goldberg, chief executive of Breast Cancer Campaign, said the announcement means around 2,000 women a year in the UK may benefit.
"It is encouraging news that Tyverb has received a conditional licence indication for metastatic breast cancer," she said.
"However, it is important to emphasise that it is not a new wonder drug suitable for all breast cancer patients.
"Around 2,000 women in the UK with HER2 positive metastatic breast cancer who have previously followed a specific drug regime could benefit from this treatment.
"The signs are promising and we hope that Tyverb will be developed further as a treatment in the earlier stages of breast cancer."
Dr Alexis Willett, policy manager at Breakthrough Breast Cancer, said: "The launch of lapatinib will give hope to those diagnosed with the more aggressive HER2-positive form of the disease when it no longer responds to Herceptin."