Agios' Mitapivat Shows Mixed Results in Sickle Cell Disease Phase 3 Trial
核心洞察
Agios Pharmaceuticals' mitapivat (Pyrukynd) met one of two primary endpoints in the Phase 3 Rise Up trial, significantly improving hemoglobin levels in 41% of sickle cell disease (搜索) patients compared to 3% on placebo.
The drug failed to achieve statistical significance in reducing annualized sickle cell pain crises, with treated patients experiencing 2.6 crises per year versus 3.1 in the placebo group.
Despite mixed results, Agios plans to meet with FDA in early 2026 to discuss a supplemental new drug application for sickle cell disease (搜索) indication.
Agios Pharmaceuticals reported mixed results from its Phase 3 Rise Up trial testing mitapivat (Pyrukynd) in sickle cell disease (搜索), with the oral pyruvate kinase (搜索) activator meeting one of two primary endpoints while missing the key goal of reducing painful crises. The company's stock price plummeted nearly 50% following the announcement, though Agios plans to pursue regulatory approval discussions with the FDA.
Trial Results Show Hemoglobin Improvement
In the 52-week Rise Up trial, mitapivat demonstrated significant efficacy in improving hemoglobin levels among 207 enrolled patients with sickle cell disease (搜索). The drug achieved a hemoglobin response in 41% of treated patients, defined as at least a 1 gram per deciliter increase in the oxygen-carrying protein, compared to only 3% in the placebo arm. According to Agios, responders experienced a mean hemoglobin increase of approximately 1.6 grams per deciliter.
"The data from Rise Up demonstrate that treatment with mitapivat significantly improved hemoglobin concentration and reduced hemolysis," said trial investigator Biree Andemariam, a medical professor at University of Connecticut Health, in a statement provided by Agios.
Pain Crisis Reduction Falls Short
Despite the hemoglobin improvements, mitapivat failed to achieve statistical significance on its other primary endpoint: reducing the annualized rate of sickle cell pain crises. Patients receiving mitapivat experienced approximately 2.6 pain crises per year compared to 3.1 crises in the placebo group, a difference that did not reach statistical significance.
However, Agios highlighted that patients who achieved the hemoglobin response threshold also experienced clinically meaningful benefits, including reduced rates of sickle cell pain crises and hospital visits, as well as improvements in fatigue levels.
Regulatory Path Forward
Despite the mixed results, Agios intends to discuss a supplemental new drug application with U.S. regulators. The company plans to meet with the FDA in early 2026 to explore the potential for approval based on the hemoglobin response data and the benefits observed in responder patients.
The regulatory discussion comes as Agios awaits an FDA decision on mitapivat's approval for beta thalassemia (搜索), with a Prescription Drug User Fee Act (PDUFA) date of December 7. The agency previously delayed its decision in September to assess a protocol designed to address liver safety concerns observed in beta thalassemia testing.
Safety Considerations
Regarding safety, Agios reported that "liver abnormalities" observed in study volunteers "were not suggestive of drug-induced hepatocellular injury." This addresses ongoing FDA concerns about potential liver cell damage or inflammation that prompted the agency's extended review of the beta thalassemia (搜索) application.
Market Context and Opportunity
The sickle cell disease (搜索) treatment landscape has experienced significant upheaval in recent years. Traditional therapy hydroxyurea was joined by Novartis' Adakveo and Pfizer's Oxbryta in 2019, followed by genetic medicines from Vertex Pharmaceuticals and Bluebird Bio. However, European regulators revoked Adakveo's marketing authorization, and Pfizer withdrew Oxbryta in 2024 after spending more than $5 billion to acquire it.
Uptake for genetic medicines has been slow, with Vertex reporting only 165 people had undergone first cell collections for its treatment Casgevy as of September 30. Before going private, Bluebird recorded just $11 million in 2024 sales for a treatment priced at $3.1 million.
These market setbacks have created opportunities for newer treatments like mitapivat. Currently approved as Pyrukynd for a rare form of anemia, the drug generated approximately $22 million in sales over the first nine months of the year. Mitapivat works by stimulating pyruvate kinase (搜索), an enzyme that aids red blood cell survival, making it potentially useful in diseases like sickle cell disease (搜索) and beta thalassemia (搜索).