According to a story from fiercepharma.com, the US Food and Drug Administration (FDA) was willing to approve the drug Tibsovo as a treatment for acute myeloid leukemia (AML) following encouraging results from a phase 1 trial. However, the European Medicines Agency (EMA) was unwilling to do the same thing. Agios, the developer of the drug, recently announced its withdrawal of its application in the EU for Tibsovo as a treatment for refractory or relapsed disease that was positive for the IDH1 mutation.

About Acute Myeloid Leukemia (AML)

Acute myeloid leukemia, also known as acute myelogenous leukemia, is a type of blood cancer which affects myeloblasts, stem cells that would normally develop into myeloid white blood cells. There are a number of risk factors for acute myeloid leukemia, including other blood disorders such as myelodysplastic syndrome, family history, certain genetic variants, chemical exposure (including chemotherapy agents), and radiation. Symptoms include an increased risk of infection, easy bruising and bleeding, fatigue, shortness of breath, fever, weight and appetite loss, anemia, and bone/joint pain. Treatment for this cancer is most often chemotherapy or stem cell transplant; there are very limited options for patients with relapsed disease. The five year survival rate for acute myeloid leukemia is only 27 percent in the US. There is a clear need for more effective treatments for this cancer. To learn more about acute myeloid leukemia, click here.

More Data Needed

The EMA said that more data would be necessary before giving a positive recommendation for the drug. Agios is currently operating two phase 3 studies that are investigating Tibsovo in previously untreated patients, and these findings, if positive, could be sufficient for eventual approval. These trials are testing the drug in combination with chemo and in combination with another drug called Vidaza. 

The earlier phase 1 data showed that the drug normalized blood counts and cleared other indicators of disease in 32.8 percent of patients, but the EMA probably made the right call, as a related drug called Idhifa (from Bristol Myers Squibb), was also rejected by the agency after it failed to improve lifespan in the phase 3 trial.

Only the results of the ongoing trials will determine the future of the drug in the EU. Agios is also looking to seek approval for Tibsovo in IDH1-mutated cholangiocarcinoma following positive findings in a phase 3 trial; the drug reduced the risk of progression by 63 percent and also improved survival.