AIDS drug prices in Africa might be a good avenue to explore. Millions in Africa are infected with HIV, and an entire generation of Africans will be lost to the disease causing political and economic instability. South Africa has threatened to ignore patent rights and produce its own drugs if companies do not negotiate the price down further. The WTO has also been petitioned to step in and remove the patents. Negatives must dominate the affirmative story by conjuring up a story of even greater death in the more distant future.
Patents are the incentive businesses have to invest lots of money in research and development.
No company would research a cure to a disease without getting back their investment capital, plus some profit to serve as reward for their job and to go into further research and development. Companies cannot expect even to obtain the funding in the first place without the promise of great profits because investors will not pour money down the rabbit hole without the patent promise. That means that the affirmative might save some people in the short term, but in the long term they destroy all incentive to search for cures to diseases not yet born. Affirmatives will need to do some deep research to win on this topic. Horizontal monopolies involve acquisition of businesses that do the same thing as you or are involved in a completely different industry.