It seems lots of pain was inflicted on many people because of the patent system. Usually drugs are upheld as the prime example of why patent systems are necessary. This seems more than questionable, given this example. Combined with the fact that companies have no conscience, it would be nice to have better ways to do expensive research than a) in companies and b) for patents.
Medically reasonable alternatives have been on the market since 1950 (hydrocodone for example). Patents didn't drive the use of Oxycontin. The article is even about the supposed justification of choosing Oxycontin, the 12 hour dosing, not being sufficient or even harmful.
So yes, it was partially the fault of the patent system.