(CNN) -- Sen. Bernie Sanders sent a blistering letter to a pharmaceutical company on Monday, demanding answers about its decision to charge $375,000 for a formerly low-cost drug and calling it corporate greed at its worst.
"Catalyst&apos;s decision to set the annual list price at $375,000 is not only a blatant fleecing of American taxpayers, but is also an immoral exploitation of patients who need this medication," the independent senator from Vermont wrote. "Simply put, it is corporate greed.
"I am profoundly concerned that Catalyst&apos;s actions will cause patients to suffer or die."
Sanders sent the letter to Patrick McEnany, president and CEO of Calayst Pharmaceuticals, about the pricing of its drug Firdapse, which is used to treat a rare neuromuscular disease called Lambert-Eaton myasthenic syndrome, also known as LEMS. The disease weakens and fatigues the body&apos;s muscles and affects about 1 in 100,000 people in the United States.
"How many patients will suffer or die due to Catalyst&apos;s decision to set the list price at $375,000?" Sanders asked.
However, Sanders&apos; letter also notes that the company has said many Firdapse patients will pay about $10 out of pocket each month, and he asked for more detail about that claim.
The company said in a statement Monday, "Catalyst&apos;s top priority is improving patient care in the LEMS community and potentially elsewhere within the neuromuscular community. We will respond to Senator Sanders&apos; letter in a timely manner and provide information about Firdapse and the programs that we have in place to raise awareness of LEMS, facilitate accurate and timely diagnosis, and broaden affordable patient access to an FDA-approved treatment."