Why is Hong Kong's medicine so cheap?

Medicine authorities should try to cut taxes and median costs to reduce the price of medicine, says an article on Beijing Youth Daily. Excerpts below:

Many residents of the Chinese mainland go to Hong Kong to purchase medicine because it's cheaper there. For example, Herceptin, which is a kind of medicine to treat breast cancer, isn't included in the medicine catalogue of medical insurance on the mainland, and has to be paid for by the patients and their families. Herceptin costs about 25,000 yuan ($4,080) on the mainland, and around 15,000 yuan in Hong Kong.

Such a huge price difference attracts more and more mainland tourists to purchase not only milk power but also medicine in Hong Kong.

Medicine manufacturers said the main reason for the price gap is because Hong Kong's medicine is not taxed.

Medicine prices should not only be set by the market because it's related to people's health, It's the authorities' responsibility to reduce taxation and the median costs of medicine.