Shares of Agios Pharmaceuticals Inc (AGIO) rose nearly 16% on Wednesday after U.S. regulators approved an expanded use of the company’s blood disorder drug.

The approval came from the U.S. Food and Drug Administration and covers a wider group of patients with thalassemia, the company said late Tuesday.

The drug, chemically known as mitapivat and sold under the brand name Aqvesme, was cleared as the first oral treatment for anemia in patients with non-transfusion-dependent and transfusion-dependent alpha- or beta-thalassemia.

Thalassemia is an inherited condition that affects the body’s ability to produce hemoglobin and healthy red blood cells. The disease often leads to chronic anemia and other complications.

Aqvesme is expected to be available late next month after the rollout of a required safety program. The label includes a boxed warning for potential liver cell injury and mandates liver function testing every four weeks during the first 24 weeks of treatment.

The drug’s label also advises against use in patients with cirrhosis. At least two analysts said the warning language and monitoring requirements matched prior expectations.

Chief Financial Officer Cecilia Jones said on a Wednesday analyst call that the yearly price of the drug would be about $425,000 per patient.

Cantor analyst Eric Schmidt said the pricing represents a modest premium to Pyrukynd’s wholesale acquisition cost of about $335,000 per year. He added that parity pricing had been expected.

Mitapivat is already marketed under the brand name Pyrukynd and was approved by the FDA in 2022 to treat low red blood cell counts in adults with pyruvate kinase deficiency.

Truist analyst Gregory Renza said the expanded approval adds an estimated $320 million in peak revenue potential on top of the existing mitapivat business.

Agios estimates there are about 6,000 adult thalassemia patients in the United States. The company expects roughly 4,000 of those patients to be eligible for treatment at launch.

The FDA decision was based on a late-stage study showing patients treated with the drug achieved a statistically significant increase in hemoglobin response compared with placebo.