Here's a good short article from Canada on this, and on the ways in which the present system in the drug business can really screw things up - Editorial: Don't put bottom line above cure :

...It's a lose-lose scenario common in many other countries, reinforced by a policy that some companies engage in called "evergreening." With this system, they make small changes to drug formulas or dosage methods, effectively allowing them to renew expiring patents in perpetuity. But these companies argue that it's necessary to keep prices high outside of Africa in order to fund the reduced prices offered to some African countries that are hardest hit by the pandemic.

These are the harsh economic realities of AIDS/HIV medication and research. That is, for corporations to sustain production and development, a certain amount of profit must be made. We're seeing this unfold in India, where the country's leading pharmaceutical companies have begun abiding by global patent agreements and are poised to start producing drugs for the American market. The industry, potentially worth US $3 billion per year, could provide a huge injection into India's economy, while at the same time removing the world's primary source for low-cost generic drugs.

This is why it's integral that prosperous governments increase funding to make treatments readily available to all regardless of their status. We must also relax patent laws while in turn assuring that research isn't susceptible to the fluctuating budgets of big pharmaceutical companies...