TRENTON, N.J. (AP) — Warranties and money-back guarantees, long used to entice buyers of products like hand tools and kitchen gadgets, are now being used to sell something more crucial: pricey new-generation drugs for diseases like rheumatoid arthritis and cancer.

Deals being negotiated between drugmakers and the insurers who buy medicines now sometimes include extra rebates — or even full refunds — if drugs don't help patients as expected.

It's part of an effort driven by insurers and government health programs to align the cost of care with the quality of care, and slow the relentless growth...