Do drug patents can stifle innovation in poor nations?

From SciDev.Net:

"Most drug discoveries are made by public institutions. Private pharmaceutical companies, however, generally take over the development and commercialisation of the drugs, filing numerous patents in the process. In recent years, cumulative innovation — the development of products based on earlier discoveries — has meant that more and more patents are being registered.

This "privatisation of science" has been accelerated by shortcomings in the patent system, says Carlos María Correa, director of the Centre of Interdisciplinary Studies of Industrial and Economic Law at the University of Buenos Aires. Writing in the Bulletin of the World Health Organisation, Correa says large drug companies have exploited the patent system using strategies he calls 'blanketing', 'fencing', 'surrounding' and 'flooding'. All of these involve the registration of large numbers of patents.

By using patents "offensively" to block potential competitors, drug companies can inhibit innovation, says Correa. He says this is especially worrying in developing countries where competition laws are weak or poorly enforced. Developing nations need to design and implement patent laws that prevent strategic patenting and which promote competition and access to medicines, Correa concludes."