NEW YORK (Reuters) – Pfizer Inc filed a lawsuit on Friday seeking to require the federal government to let it help Medicare beneficiaries afford two drugs to treat a rare and sometimes fatal heart condition, and which cost $225,000 a year.

The drugmaker said the U.S. Department of Health and Human Services’ Office of Inspector General is blocking it from offering financial aid to patients unable to afford copayments for its Vyndaqel and Vyndamax drugs, because it views such aid as an illegal kickback.

A spokesman for the inspector general declined to comment.

Pfizer’s drugs treat transthyretin amyloid cardiomyopathy, which causes the heart to stiffen and impedes its ability to pump blood. The condition can cause progressive heart failure and death if left untreated.

Though the U.S. Food and Drug Administration in May 2019 approved both drugs, which are also known as tafamidis and which Pfizer has called a potential blockbuster, the New York-based drugmaker has drawn criticism for their costs.

A study in February from the American Heart Association said tafamidis was the most expensive cardiovascular drug launched in the United States, and its long-term cost-effectiveness was “uncertain.” (https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.119.045093)

Drug companies cannot subsidize copayments for patients enrolled in Medicare, though they may donate to independent nonprofits that offer copay assistance.

In Friday’s complaint filed in Manhattan federal court, Pfizer said its intention is not to “corrupt” doctors into prescribing its drugs more often, but rather to ensure that patients receive needed treatment.

It said the government’s restrictions violate its constitutional rights to due process and free speech.

Pfizer agreed in May 2018 to pay $23.85 million to resolve U.S. civil charges it used a purportedly independent charity to cover copayments for patients taking three other drugs. It did not admit liability.

The case is Pfizer v U.S. Department of Health and Human Services et al, U.S. District Court, Southern District of New York, No. 20-04920.

(Reporting by Jonathan Stempel in New York; Editing by Matthew Lewis)