FDA Gives Eltrombopag Breakthrough Therapy Designation for SAA

The US Food and Drug Administration (FDA) has given Breakthrough Therapy designation to a first-line therapy for severe aplastic anemia (SAA).

Novartis’ eltrombopag (Promacta), a bone marrow stimulant, was granted the designation as a combination therapy with standard immunosuppressive treatments for patients with SAA. The drug was previously approved by the FDA to treat adults and children with chronic immune thrombocytopenia (ITP), who are refractory to other treatments.

The FDA’s designation indicates eltrombopag as a treatment for a serious or life-threatening disease that demonstrates clinically substantial improvement over existing therapies.

SAA is a rare blood disorder that occurs when patients’ bone marrow does not produce enough red blood cells, white blood cells, and platelets. It can cause fatigue, trouble breathing, recurring infections, and abnormal bruising or bleeding in patients. Patients are currently limited in effective therapies — about one-third of patients do not respond to current therapies, or relapse.

Eltrombopag’s safety and efficacy as an addition to standard immunosuppressive therapy for SAA was tested in phase 1 and 2 clinical trials, sponsored by the National Heart, Lung and Blood Institute (NHLBI), a part of the National Institutes of Health (NIH).

In the trial, over half (52%) of patients with treatment-naïve SAA achieved complete response at 6 months when treated with eltrombopag at baseline and along with standard horse antithymocyte globulin (h-ATG) and cyclosporine (CsA) therapies. Overall response rate in patients was 85%.

The investigative therapy is designed to mimic the thrombopoietin protein, helping the body produce more platelets and improve poor cell counts. It is approved in more than 45 countries for treating patients with SAA, more than 100 countries for adult patients with chronic ITP, and more than 50 countries for the treatment of thrombocytopenia in patients with chronic hepatitis C.

Samit Hirawat, MD, head of Novartis Oncology Global Drug Development, said the company intends to continue working closely with the FDA to the make the treatment available to patients with SAA “as soon as possible.”

"Promacta is a promising medicine that, if approved for first-line use in severe aplastic anemia, may redefine the standard of care for patients with this rare and serious bone marrow condition," Hirawat said.

Novartis anticipates regulatory filings for first-line indications in both the US and European Union to come later in 2018.