Experimental Beta Thalassemia Drug Concludes Successful Phase 2 Trial

According to a publication from Blood Journal, an experimental beta thalassemia drug called luspatercept yielded positive results at the end of a phase 2 clinical study. Many patients enjoyed an increase in hemoglobin levels, a major improvement for someone with beta thalassemia, a condition nearly universally characterized by anemia.

About Beta Thalassemia

Beta thalassemia is a condition that inhibits the body’s production of hemoglobin, the ferrous protein in red blood cells that carries oxygen to muscles and organs.

The condition is caused by mutation to the gene HBB. This gene is responsible for coding the production of beta-globin proteins. Beta-globins are necessary for the production of functioning hemoglobin. It comes in two forms, thalassemia major and thalassemia intermedia. As you may have guessed, thalassemia major is the more serious form of the disease.

Both forms, however, are characterized by anemia (low red cell count) and poor oxygen supply throughout the body. They are differentiated only by the severity of their symptoms. Estimates of affected individuals range drastically, from one in 10,000 people in the European Union to one in 100,000 throughout the world. Such drastic differences are difficult to account for, but often can at least partially be attributed to inadequate access to healthcare in many parts of the world, meaning that many patients remain undiagnosed.

About the Luspatercept Study

The nonrandomized, non-controlled study involved 64 adult patients with beta thalassemia. Some of the patients were dependent on regular blood transfusions as part of their therapy regimen. The study found that patients who were not dependent on blood transfusions showed significant improvement in hemoglobin levels when administered a dose of luspatercept.

The findings will likely encourage a phase 3 clinical trial for Acceleron Pharma’s experimental drug. Pending further confirmation of efficacy, especially in a controlled study, the FDA may consider approving luspatercept for beta thalassemia. Though the news is encouraging, it’s important to temper expectations until all is said and done. The lack of a control group in the phase 2 study may have failed to account for natural fluctuations in hemoglobin levels, however unlikely that may seem. The FDA expects thorough investigation before granting any drug market approval, and despite the promising results published by Acceleron, luspatercept will be no exception.


Why do you think the choice was made to make the phase 2 study non-controlled? Does small-scale participation limit the type of study physicians can run? Share your thoughts with Patient Worthy!

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