A patient advocacy group urged BIO to expel Catalyst Pharmaceuticals for charging $375,000 for a once-free drug.

In a letter to BIO, Patients for Affordable Drugs founder David Mitchell asked the trade group to drop Catalyst because of the $375,000 list price for Firdapse, its treatment for a rare neuromuscular disorder, noting that before its FDA approval last year, patients with the condition could receive the drug for free under the FDA’s compassionate use program.

“There is no possible moral justification for this move by your member,” Mitchell wrote, echoing criticisms from Sen. Bernie Sanders (I-Vt.), who earlier asked the company for a justification of the price hike.