"Health insurers are pushing to link the cost of specialty medicines to how well they work to improve a patient's condition, a bid to contain prescription drug prices after decades in which pharmaceutical companies could charge whatever the market would bear. The shift is coming as insurers absorb mounting bills for drugs with eye-popping prices and brace for a slew of new therapies for diseases such as hepatitis C, cystic fibrosis, breast cancer, lung cancer, and leukemia. Those emerging treatments could cost US government-paid health programs such as Medicare nearly $50 billion over the next decade[.]"