The FDA is requiring further testing of Sunesis Pharmaceutical’s anti-cancer drug, vosaroxin. Tests have been conducted since 2010 as the drug’s testing has proved to allow a higher cancer survival rate. Yet, a failed test in late October revealed that the company’s drug will need more scrutiny if they want to unveil vosaroxin to the consumer base, as State Column reports. 

The drug is comprised of a chemical structure that has yet to be used in cancer research. SunesisPharmaceuticals acquired the copyright to the drug in 2003, although the bulk of their testing was conducted in 2013 when they offered trials. Its effects are currently being examined on a type of leukemia involving blood and bone marrow defined as myeloid leukemia, or AML.

Although still under the FDA’s watchful eye, the drug has been approved and issued by the European Medicines Agency. A Reuters analysis believes that the FDA and EMA approach the drugs they approve or deny with different standards.

“The EMA has a history of taking in the whole picture while the FDA historically sticks to statistics,” said Adnan Butt, an analyst from RBC Capital Markets, an investment bank with ties to the Bank of Canada.

The drug is on point to be prescribed in Europe in 2016 but additional testing by the FDA can inhibit the drug’s delivery by at least a couple years. The elapsed time has affected the company’s shares to fall 60%, and how it will influence the company has yet to be seen.