Eli Lilly became the second drugmaker this week to sue the U.S. government for rejecting their proposed changes to a program that requires selling discounted drugs to certain medical facilities.

Eli Lilly (NYSE:LLY) has filed a lawsuit over a U.S. health agency's alleged attempts to block its model for offering rebates for drugs supplied under the government's 340B Program, days after its rival Johnson & Johnson (NYSE:JNJ) filed a similar lawsuit.

Lilly follows fellow drugmaker Johnson & Johnson, who sued the Health and Human Services Department on Tuesday, accusing the agency of blocking its plan to sell its psoriasis treatment Stelara and blood thinner Xarelto to some hospitals at full price before applying drug rebates.

The lawsuit is the second by a large drugmaker in recent days challenging how it provides required discounts to certain hospitals.