Medical forces join to defend use of drug

PUBLISHED : Monday, 26 April, 2010, 12:00am
UPDATED : Monday, 26 April, 2010, 12:00am

Eye specialists and hospital pharmacists have joined to defend the proposed subsidised use of a cancer drug in treating an eye disease, in response to criticism that patients would be being used as guinea pigs.

Their action has been triggered by debate on proposed use of the drug Avastin - registered for use in treating colon cancer - on patients with acute macular degeneration (AMD), a condition that can result in blindness.

The government recently set aside HK$12 million for the Hospital Authority for future funding of the use of Avastin in treating AMD. But the Practising Pharmacists Association and eye patients' group Retina Hong Kong strongly criticised the move last month, saying the authority would be putting patients at risk by trying to save money.

A course of the drug Lucentis, licensed for use in treating AMD, costs HK$24,000, while a course of Avastin costs HK$10,000.

The authority, which says a cheaper treatment option would result in a cure for more patients, does not fund use of either drug on eye patients at present. It plans to conduct a clinical trial of Avastin for AMD and will release details next month.

'We have to think about the overall interests of society. If a clinical trial is successful, buying more drugs with a lower price can treat more patients,' a medical professional familiar with the trial said.

AMD is caused by deterioration of the central portion of the retina, the macula. The drugs are injected into the eye to repair the damage.

The College of Ophthalmologists and the Medical Association will hold a joint press conference on Wednesday to hit back at the criticism. 'Avastin and Lucentis are equally effective in the treatment of acute macular degeneration; the only difference is the price,' college and association vice-president, Dr Chow Pak-chin said.

'If we scare people off from the use of Avastin, those who cannot afford the much more expensive Lucentis can only lose their eye sight... We have the responsibility to come out to correct the misconception.'

Private eye doctors started using Avastin to treat AMD in Hong Kong about three years ago. Such use is called 'off label', as the type of use is not specified in the drug's licence.

Chow said off-label use of Avastin for AMD was common in many developed countries and its success was well established. Without effective treatment, patients with severe AMD would go blind in two years.

The Society of Hospital Pharmacists said it was acceptable for the Hospital Authority to conduct the clinical trial. Its vice-president, William Chui Chun-ming, said the group did not agree with off-label use of Avastin in public hospitals, but it believed a clinical trial could further establish the effectiveness of the drug in treating the eye disease.

Chui said off-label application of drugs should be the last resort when approved therapies failed.

'While doctors can use their discretion for off-label use of a drug, they need approval from an ethics committee before a clinical trial,' Chui said. 'The requirements of clinical trials are more stringent, that's why we support this.'

He said Avastin was being tested on thousands of eye patients in Britain, the United States and some European countries.

'If the Hospital Authority's clinical trial comes up with a good result, it can push the drug maker to apply for a licensed application because an effective drug with lower cost can benefit more patients,' Chui said.

Chow and Chui said about 20 per cent of drugs on the market were being used off label.