When drugs and chemotherapy failed to stop her lung cancer from spreading, Madam Teng thought she had run out of options.

But earlier this month, the administrative assistant, who is in her 50s and did not want her full name to be used, started taking an experimental drug called AZD9291 that is not available on the market and has not been approved in any country.

Dr Daniel Chan, from the private Singapore Oncology Consultants group, had recommended the drug based on an analysis of her tumours and clinical trials in the United States.

He also obtained approval from the Health Sciences Authority (HSA) to import it for her under a "named-patient basis".

Physicians here can apply to the HSA to import unregistered medicines for specific patients, and the HSA's statistics show that more people have been turning to this route for help.

The HSA told The Straits Times that the number of applications has increased by about 10 per cent on average in each of the past five years.

It did not provide absolute figures, and noted that the rise includes repeat applications from some patients.

It added, however, that "this increase can be largely attributed to new therapies used to treat patients with diseases like cancer and serious infectious diseases".

Several doctors said that patients are now more likely to do research on their diseases online.

This could lead them to discover drugs approved in other countries, but not in Singapore, that could help them.

The HSA warned, however, that "the benefits versus the potential risks of such medicines must be weighed carefully by the doctor for the patient".

Doctors said that the drugs could be free under expanded access programmes where pharmaceutical companies make drugs available, under certain circumstances, to patients who cannot take part in clinical trials.

Madam Teng, for example, is getting the AZD9291 drug for free. But her doctor, Dr Chan, said that other drugs brought in under the named-patient basis could cost up to about $10,000 a month.

He said: "Some patients will not qualify for drugs or treatment available here due to age or pre-existing conditions, and they risk falling through the system's cracks. The 'named-patient basis' drugs could help these people."