Premier and Vizient are group purchasing organizations which handle all the supply for a ton of hospitals - 800k or so hospital beds between the two out of about a million total in the US. They started out as hospital purchasing groups which were created by hospitals who banded together to get better deals so they usually monopolize purchasing for an entire hospital. Now they’ve grown so big they’ve got monopolistic pricing power as consumers (I don’t know the right economic term) since there are so few organizations buying for all the hospitals.

When buying syringes, bandages, and most of the things hospitals need, that’s not a big deal but the way many oncology drugs are administered these organizations end up handling all of the negotiations instead of pharmacies and insurance companies. Patients and even their healthcare providers have basically zero say in the purchasing because it’s all rolled in.

Since the US is the most profitable market in an already low margin business, the generic manufacturers can’t justify the production lines for cancer drugs without at least one of these clients so they‘re driven to extreme price wars. In good times, they eek out a profit, but in bad times when variable costs go up, they’re no longer viable.